Gear Teeth Calculation Formula

Chain Length Calculator; Input: Output: Chain Pitch (inches) Drive Sprocket Teeth : Driven Sprocket Teeth : Center Distance (inches) Links : Length (inches) Reduction. The strength calculation computes the factors SF (fatigue fracture) and SH (pitting) along with tooth forces on the worm and worm gear, as well as the efficiency of the gear. Standard Drill Sizes. V = displacement in in³/rev w = gear width in inches d = gear tip diameter in inches L = dimension across both gears when meshed in inches. Center Distance. If all 3 gears are the same size then there is no gear ratio change. ) rpm = arbor rpm tp = tooth pitch (inch) Bandmill Saws - Gullet Capacity. 3, (again, just for example), then you would round down to the nearest tooth count of 18. Step 2 - Select Speedometer Drive Gear Teeth Options: 6 Tooth; T5 transmissions may be converted to 6 tooth gear to correct speedometer more accurately. fz=Vf÷(z×n)=500÷(10×500)=0. Gear wreck will happen because of its tooth fatigue and tooth surface wear, so strength design from both side is necessary. The normal set of change gears includes the following gears: 20, 20, 35, 40, 40, 45, 50, 55, 57, 60, 65, 80, and 80 teeth. 2006 Pearson Education, Inc. But the gears in horology (watches and clocks) use another tooth form. 825 Distance apex to crossing point (mm) [tz] 0. ofan entire helicopter transmission, the highest response Z71 can "calculation coordinates of fo~r the the tooth gear-tooth surface three-dimensional coordinates, and finite hence, elementthe be that from the spiral bevel gear mesh. Further work 32 7. Gear-inches are useful because you’re given a numerical value for your specific setup compared to all others. Gear Parameter Calculator. The normal rating for gears is based on 12 hours/day. 8 = 200 steps / turn. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. Study on Interference and Undercutting of Double Involute Gears: INTRODUCTION The smaller number of teeth can achieve a more reliable gear transmission when the center distance is fixed.But small number of teeth will produce the problem of undercutting.Undercutting is an important problem in designing and manufacturing gears with small numbers of teeth.Conditions of undercutting for. and lower the resolution will be. The teeth or splines of the gear are progressively cut into the material (a flat, cylindrical piece of metal) by a series of cuts made by a cutting tool called a hob. Feed Rate: inches per minute RPM: Number of Teeth (or. Backlash Allowance for Helical Gears. Gear makers play lots of games with tooth addenda and dedenda for various reasons, so the major and minor diameters of the gear can vary a lot from the simple formula. 8° (200 per revolution) 0. Key issues to be kept in mind while designing a gear profile are of high positional accuracy, affordable precision, consistent performance and zero backlash. Standard System of gear tooth profile: American gear manufacture Association(AGMA) and American National standard Institute(ANSI) for standardized following for form of gear teeth profile depending upon the pressure angle. Primitive Diameter = Module * Teeth No. 40 R50 DO R30 1. com Involute Gear Pin Measurements. Detailed gear design terminology can be found in [3]. *FREE* shipping on qualifying offers. Gear loads acting on straight tooth bevel gears and spiral bevel gears on cross shafts are shown in Figs. The chordal tooth thickness measurement method uses a tooth caliper that is referenced from the gear’s tip diameter. Pitting Resistance Geometry Factor, I. ofan entire helicopter transmission, the highest response Z71 can "calculation coordinates of fo~r the the tooth gear-tooth surface three-dimensional coordinates, and finite hence, elementthe be that from the spiral bevel gear mesh. Then, divide the number of teeth on the driven gear by the number of teeth on the drive gear to get the gear ratio. Determine number of teeth on both gears: N = PD × DP Where: N = Number of teeth PD = Pitch Diameter of gear DP = Diametral Pitch of gear NOTE: Velocities of both gears will always be the same. Now applying the same principle on your second combination we get: 12*(12/30)*(8/x)=1. The image to the left shows a schematic of a Reverted Gear-Train. The second approach calculates the local slope of the force-deflection curve about a nominal deflection. The calculation of a hypoid gear drive is very math-intensive but this online calculator shields you from all those complex formulas. 3, (again, just for example), then you would round down to the nearest tooth count of 18. A “Gear ratio” is the relationship between the number of teeth on two or more gears that are meshed. How to Calculate Gear Pitch. For example, a 3. And involute is used in calculations associated with involute gearing. Strength of gear materials: AGMA uses its own data for strengths. Gears; Gear Racks. FEA-Integration; Slewing rings; Ball screws; eAssistant; Online-Calculations. Pitch Circle: Internal diameter: Number of Teeth Z: Module: Diam. The verification of the force calculation module was conducted using experiments carried out by [4]. 3) Efficiency calculations are difficult. Edit: at least, you are limited if you want to use off-the-shelf gears with standard modules. Pitch = Module * pi. 5/5 to 128/256 and pressure angles of 30°, 37. To calculate what the hunting tooth frequency is, you must first determine the common factors of each gear (CF). 4862 Dedendum angle (°) [thef=delta-delf] 0. Another way of introducing backlash is by increasing the center distances between the gears. ; Problems related to vibration: Whenever the base pitch of the meshing gear and pinion are different from the. The balance of forces that exist around the roller are shown in Figure 2. Tom Kunicki has a calculator with specific features useful for fixed-gear and singlespeed riders: "Rabbit, A Singlespeed and Fixed-gear Calculator" John Allen has pages giving exact, fractional ratios calculated from gear tooth counts: "Drive ratios of bicycle hub gears" What's New; Sheldon Brown on Facebook; Site Feedback & Questions. α, the coefficients and are determined, then from equations (2) are determined the radii of the lantern circles. Bevel gear set bearing loads When calculating the bevel gear set bearing loads use the pitch diameter calcula Involute tooth form formula derivation DOCUMENT PDF: DOWNLOAD Tooth wear nomenclature DOCUMENT PDF: DOWNLOAD. I plugged numbers into gearspec from this link and by process of of elimination determined I had a 105T 20 degree pa, 1. Circular pitch p: The width of a tooth and a space, measured on the pitch circle. Here we'll design a spur gear with equations, where ALL you've got to do is change 2 variables, then ta da your gear has updated ! Note: The Unit system we'll use is cm. Their calculation formulas are as follows:. Select the diametral pitch with units of teeth per distance, and then select the number of teeth for each gear, and the other parameters are computed. Displacement (D) – The displacement of a rotary gear pump is the volume displaced during one complete. Calculate gear measure over pins for involute spur gears. Formulas for gear calculation – external gears Contents: Relationship between the involute elements Determination of base tooth thickness from a known thickness and vice-versa. Q – gear pump performance capacity. of the mating gear teeth. Chordal Tooth Height. Change gear calculator. If the A and C gear is the same size there is no ratio change, the B gear is an idler gear and has no effect on the ratio. CA constant = 1. The ratio from gear set to gear set is calculated separately then multiplied together. This paper adopts Ishikawa method which is commonly used in the calculation of tooth deformation. This is of particular. The Gear Ratio Calculator will determine the ratio of a gear set, based on the number of teeth on the ring gear and teeth on the pinion gear. Your Calculation. Miter gears are a special class of bevel gears where the shafts intersect at 90° and the gear ratio is 1:1. tp = tooth pitch (inch) gd = gullet depth gaf = gullet area factor (. RPM-6th Gear Help on: Top speed for 49 sprocket combinations; Adjust RPM & Gear Help on: Change RPM and Gear in sprocket combinations matrix; Resulting RPM. 88" 7 Tooth @2. Note: Simple formulas using +-*/() may be entered if desired, not just straight plain numbers. In gear designing is very important to analyze the magnitude and the direction of the forces acting. The following terms are related to spur gears: Addendum: The height of the tooth above the pitch circle. Indicate which gear ratios would be useful for heavy loads, going over rough terrain, or going fast. For example, a 3. For above mentioned gear comparison between analytical value and value obtain by the ANSYS Workbench 14. Involute function. calculate the geometric parameters of the gear, draw an accurate image of the gear with a detail of the teeth, adjust the tooth thickness by use of correction (optimization of toothing), calculate the tooth root bending stress with the Lewis method, return a DXF file containing the 2D profile of the gear to be used with 2D and 3D CAD software. Reference: Erik Oberg, et. 1416 × rpm) ÷ tp) tb = tooth bite (inch) fpm = feed speed (fpm) bwd = wheel diameter (in. 17 Enclosed Gear Unit Requirements 2. • Drive Gear Teeth = 7 • Axle Ratio = 3. In the formula: the values of coefficient i, i, i, i, I and i; fi denotes the ratio of the radius of the root circle to the radius of the shaft bore of the gear; f denotes half of the span angle of a tooth on the root circle. 12 by your Jeeps tire diameter (Example:. Select the diametral pitch with units of teeth per distance, and then select the number of teeth for each gear, and the other parameters are computed. Between the motor and the pump we fit the gear reducer. Reference circle and reference diameter (d). Their calculation formulas are as follows:. Center Distance The distance between the axes of two gears in mesh. Gear Ratios # Teeth Driver Gear # Teeth Follower Gear Gear Ratio Best Use. ) Tire Height - Please use Inches when measuring. Gear calculator solving for velocity or speed MPH given tire radius, revolutions per minute RPM, and gear ratio. Question: Calculate The Angular Velocities And Torques For Gears B, C, And D In The Compound Gear Train. If the 15-tooth gear is the driving gear and the 30-teeth gear is the driven gear, their velocity ratio is 2. Tb= Thickness of belt, measured from tooth valley to the flat side of the belt. • Gear grinding is adaptable to custom tooth shapes. Per Mile = 815 (225/60 VR15) step 3. ASME/ANSI B29. Please Note: These part numbers are for the standard style pinion gear. The lower the chain revolutions, the more frequently each chain link engages the same sprocket tooth, so greater and more uneven the wear. This is a simpler version of gear terminology and teeth calculation formulas 1. Simply divide the number of teeth on the output gear by that of the input gear. Hanover Massachusetts 02339 Tel. A 2000 rpm gear with 24 teeth is driving a gear with 84 teeth. Ring Teeth. A good way to calculate this is to multiply. Rush Gears is open and manufacturing parts in response to the Covid-19 pandemic. Simply divide the number of teeth on the output gear by that of the input gear. 3183 of Tooth at Pitch Line GEAR DIMENSION CALCULATION TIPS* L I N N G E A R C O M P A N Y To Get Knowing Rule To Get Knowing Rule * These formulas are for general informational use only. Gear Ratios # Teeth Driver Gear # Teeth Follower Gear Gear Ratio Best Use. The thickness is measured at the reference circle as detailed in Figure 1. Calculate the molar flow rates and compositions of the reflux stream and the vapor feed to the condenser. Pitch circles of two gears are tangent. Think of it in shoe sizes. References 33. ; Poor design, as a result of manufacturing errors, which causes an inadequate load ratio between 2 or more pairs of gear teeth. Choose your rear axle gear ratio: Speedometer Gear Selection Select your transmission drive gear tooth count: 6 Teeth 7 Teeth 8 Teeth 9 Teeth 10 Teeth 11 Teeth 12 Teeth 13 Teeth 14 Teeth 15 Teeth 16 Teeth 17 Teeth 18 Teeth 19 Teeth 20 Teeth 21 Teeth 22 Teeth. Straight cut and spiral bevel gears offer relatively high efficiency due to the rolling contact between gear teeth. This chapter will explore the theory of gear tooth action and the design of these ubiquitous devices for motion control. – The driver_microstep parameter is here 16 (16 micro steps) – The Belt_pitch would be 2mm – The pulley_number_of_teeth would be 16 teeth. Though the teeth are not straight-sided (but usually of special form to achieve a constant drive ratio, mainly involute but less commonly cycloidal), the edge of each tooth is straight and aligned parallel to the axis of rotation of gear. • If teeth are too large, the gear designer must: provide undercutting –leave space at base of teeth very weak teeth increase number of teeth smaller teeth are weaker increase pitch circle radius bigger, faster, noisier gears increase pressure angle more friction make gear teeth stubbier non-standard gears 11. Standard Drill Sizes. Gear Ratio = 200/25 = 8:1. ) Tire Height - Please use Inches when measuring. A gears geometry is defined by DP, pressure angle, number of teeth and some feature to define the tooth’s theoretical thickness at the pitch diameter. The gears are sitting in a “meshed” state, meaning that the teeth of the gears are engaged with each other and that they are ready to transmit power. The diametral pitch of a gear describes how densely its teeth are set around it. Use the top row of drop downs to select the number of teeth on each of your rear sprockets, and the left hand selectors to enter the number of teeth on each of your. Example to calculate the centre distance of two 64 dp spur gears. Key issues to be kept in mind while designing a gear profile are of high positional accuracy, affordable precision, consistent performance and zero backlash. 88" 7 Tooth @2. Pitch Circle spur gear 1: Pitch Circle spur gear 2: Centre Distance: A simple formula for calculating internal gears. Each spur gear has a theoretical pitch circle defined by PD = N/DP where the pitch diameter equals the number of teeth divided by diametral pitch. But the gears in horology (watches and clocks) use another tooth form. 52 for round back tooth) Bandmill Saws - Tooth Bite tb = (fpm × 12) ÷ ((bwd × 3. It is sufficient to consider the relative sizes (or numbers of teeth) of the input and output gears. 000001 gram). This is a specialised set calculators that uses the gear systems (Diametral Pitch or Module) and the number of teeth to calculate the Outside Diameter, Centre Distance and Ratio of Spur gears and. Two housings, each made from either aluminum or plastic, are available for driven gears with 34 or more teeth. On the other hand, if the motor rotates at 300 RPM, the input gear has 24 teeth and the output gear has 8 teeth (this is gearing up), the rotational speed of the wheel will be: OutputRPM=300 rev min × 24 8 =900 rev min If there are one or more additional (idler) gears between the input and output gears, they can be disregarded in determining the final speed. may be determined as the volume of fluid pumped per revolution at zero differential. 6 teeth per centimeter. This ring is called an annulus, from the Latin for "little ring. Though the teeth are not straight-sided (but usually of special form to achieve a constant drive ratio, mainly involute but less commonly cycloidal), the edge of each tooth is straight and aligned parallel to the axis of rotation of gear. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. References 33. The shape of gear teeth has become. This causes the gears to produce radial reaction loads on the shaft, but not axial loads. 1 Gear design 5. ph: 07 3255 5195 fax: 07 3255 5586 brisbane queensland australia. 1 Dedendum strength Lewis formula (1) is generally employed for flexural stress on dedendum. The figure below shows the involute belonging to the base circle with the radius \(r_b\). For example, if a gear has 32 teeth and a diameter of 8 inches (20 cm), the diametral pitch is four teeth per inch or 1. Flex spline thickness, device outer diameter and number of divisions for tooth profile calculation set-up can be specified. Key issues to be kept in mind while designing a gear profile are of high positional accuracy, affordable precision, consistent performance and zero backlash. The worm acts as a single toothed gear so the ratio is; number of teeth on wormwheel. 5 for unpreloaded bearings on the output shaft e. Spur gears/straight-cut gears are the simplest type of gear. The average number of teeth in contact as the gears rotate together is the contact ratio (CR), which is calculated from the following equation, CR= q r2 ap r 2 bp + q r ag r2 bg csin. 0268; CT constant = 1. According to teeth position: Gears are classified as straight, inclined and curved. This paper adopts Ishikawa method which is commonly used in the calculation of tooth deformation. They consist of a cylinder or disk with teeth projecting radially. The circular pitch, therefore, equals the pitch circumference divided by the number of teeth. Two housings, each made from either aluminum or plastic, are available for driven gears with 34 or more teeth. Gear Generator is a tool for creating involute spur gears and download them in SVG format. In order to characterize gears and above all to ensure that the teeth of two gears can mesh properly, one of the most important parameters is the so-called module \(m\). The rack's profile is a cutting edge whose straight sides and fillets machine respectively the active flanks and the roots of the gear's teeth. Formulas for gear calculation - external gears Contents: Relationship between the involute elements Determination of base tooth thickness from a known thickness and vice-versa. You should be able to find your gear ratio listed on the axle tag, however, if that has gone missing, you can simply count the number of teeth on each gear and divide the number of ring gear teeth by the number of pinion gear teeth. The gear blank is basically a gear without any teeth. Simply enter the number of teeth on your ring gear and pinion gear and click the "Solve" button. If you hear the word "profile" of a gear, you should relate it to the arc that goes from the bottom of the tooth to the top of it, basically up to the tip or outside diameter of the gear. ISO13399; Property (Symbol) Useful links (Machiningcloud) General Standard / Other Materials. Figure 7-3 Involute curve. 10: rotation velocity. Twice the chordal tooth height plus the chordal tooth reference circle should equal the outside diameter of the gear. The highest gear on road racing bikes is usually around 108-110 inches. This paper adopts Ishikawa method which is commonly used in the calculation of tooth deformation. •Circular Pitch is the distance along the pitch circle from a point on one gear tooth to the same point on an adjacent gear tooth as shown on the sketch at the bottom of Figure 3. FEA-Integration; Slewing rings; Ball screws; eAssistant; Online-Calculations. In this blog, we are going to define spur gear terminology and provide formulas for determining the values of these terms. Gear Ratios # Teeth Driver Gear # Teeth Follower Gear Gear Ratio Best Use. Ball Mill Finish Calculator. The velocity ratio of the gears does not depend on the exact spacing of the axes, but is fixed by the number of teeth, or what is the same thing, by the pitch diameters. Note that due to the nature of the way the gears mesh, they will turn in opposite directions. NPTEL provides E-learning through online Web and Video courses various streams. To determine the correct gear ratio of the speedometer for your car, use the following formula to calculate the number of teeth on the driven gear (round to the nearest available gear):. b) A pair of gears having 40 and 20 teeth respectively, are rotating in mesh with the speed of the smaller being 2000 r. F = effort force (N, lb f) W = load force or weight (N, lb f) r = gear wheel inside diameter (m, in). To determine, first calculate the Horsepower Table Rating (HP Table) from the following formula: HP Table = Design HP (Step 3) Multiple Strand Factor (Table 2) Horsepower Table Ratings are given for each chain size on pages 6-19. Chordal Tooth Reference Circle. The formula for simple gears, as shown above is calculated as (# Teeth in Driven Gear / # Teeth in Driving Gear). There are some general dependencies: Module x sum of number of both teeth = Double center distance. 14 ½ ⁰ full depth involute system 3. For a 30 tooth, 60 second escape wheel a 60:1 ratio is needed to count 60 minutes for one hour. The simple way to calculate the proper speedometer driven gear is by setting up a ratio. Great job! Gear ratios are chosen to convert the time counted by the escape wheel into minutes and hours. Variables such as traction, wind resistance, and tire growth have a considerable effect on your vehicle's actual top speed Use this gear ratio calculator to select the best ring & pinion and gear ratio combinations to serve your needs. Reference circle and reference diameter (d). The gear ratio is therefore 2:1 (pronounced "two to one"). Input Parameters Gear type - according to the position of root and head cone Gear ratio and tooth numbers Pressure angle (the angle of tool profile) α t Helix angle β m Axis angle Σ Tangential module on outer cone met (for metric calculation) Tangential Diametral Pitch on outer cone Pet (for English units) Note: Module and Diametral Pitch are reciprocal values. Chain is Missing or Lost. The gear pitch x number of teeth is same as the printing drum circumference. Gear ratios vary between manufacturers, between the engine models of each manufacturer and between High Thrust and regular gear ratios. Assume that the gear teeth are of 20-degree. Calculator for the right gear ratio on the speedometer. Let’s keep the below parameters as input. Backlash due to tooth thickness changes is typically measured along the pitch circle and is defined by the formula shown here. Calculate the number if teeth required in the ring gear for the ratio 5:1. For sprockets, the formula is the same, but replace the diameter with # teeth. Torque Supporter = 1. 1 Dedendum strength Lewis formula (1) is generally employed for flexural stress on dedendum. Tire diameter will also have an effect on a vehicle's final. The rack's profile is a cutting edge whose straight sides and fillets machine respectively the active flanks and the roots of the gear's teeth. Due to the side thrust generated from the helical cut gear the high load would cause the planetary gear set to have a short life because of a premature failure of the thrust washer. The number of teeth on both starters is the same. Gear size calculator $ Gears & Sprockets Plastic Model Gears; Steel Model Gears; Industrial Grade Gears; Gear Racks; Sprockets & Chain;. Take chain pitch and multiply x two. Their calculation formulas are as follows:. The gear ratio is therefore 2:1 (pronounced "two to one"). Ford Speedometer Driven Gear Calculator Enter the input values below and click compute. Herein, to calculate gear loads for straight bevel gears, the helix angle β = 0. Final drive gear ratio: Transmission drive gear ratio*:. This will also allow you to produce a. Two gears will mesh together correctly if and only they have same circular pitch. The gears are sitting in a “meshed” state, meaning that the teeth of the gears are engaged with each other and that they are ready to transmit power. interest to the gear designer is the case where the curved surfaces are of cylindrical shape because they closely resemble gear tooth surfaces. Electric scooter motor and gear ratio guide with gear ratio calculator. Chordal Tooth Height. Standard End Mill Sizes. Number of gear teeth: n, (n A = number of teeth in gear A, …. Formula for Chain Speed Calculation. First let me go through the gear formulas for the involute spur gear. 1 Spur Gear Design Calculator a When gears are preshave cut on a gear shaper the dedendum will usually need to be increased to 1. Number of Teeth: Ouside Diameter: Number of Teeth Z: Module: Outside Diameter: Centre Distance: Pitch Circle spur gear 1: Pitch Circle spur gear 2: Centre Distance: A simple formula for calculating internal gears. Then model the gear accordingly. Now that the number of teeth on the gears or pulleys have been counted and written down, we can plug the numbers into an easy formula to get the gear ratio of the car’s transmission. you have determined the chordal addendum and chordal. 14 ½ ⁰ full depth involute system 3. This is usually done when you have a small number of teeth in the pinion and a large number of teeth in the gear. C = PCD(g) + PCD(p) 2. ) rpm = arbor rpm tp = tooth pitch (inch) Bandmill Saws - Gullet Capacity. A gear train contains 2 spur gears. All you need to know to start the calculation is the pitch of your boat's propeller. The following terms are related to spur gears: Addendum: The height of the tooth above the pitch circle. It is prevalent when the number of teeth of the external gear is small. Pitch Circle: Number of Teeth Z: Module: Diam. DRVE= Number of teeth on drive gear. The teeth of the spur gears are parallel to the shaft axis. Gear Ratios # Teeth Driver Gear # Teeth Follower Gear Gear Ratio Best Use. In this figure, the diameter of the gear on the left is twice that of the gear on the right. Buick, Oldsmobile & Pontiac transmissions use a 2. 15 Gear-Tooth Tolerances 2. per Mile / 1001 Tire Rev. There is a formula for BA threads only, because they are almost unique in being a mathematically derived series. 805 (mm) [txi] 129. Gear makers play lots of games with tooth addenda and dedenda for various reasons, so the major and minor diameters of the gear can vary a lot from the simple formula. Sometimes it is impossible to calculate the indexing because the plates do not provide a number of holes that are divisible by the number of teeth or divisions. This free online calculation for helical gear geometry calculates the most important geometry Parameters according ISO 21771. Fill the equation cell with this formula (teethThick*360 deg)/( (22/7)*pitchCirc_dia) it’s just a formula to converse the teeth thickness to an equal angle (I’m sorry I can’t say this properly in English)… Remember to type deg after 360, it doesn’t matter if you don’t type the other unit. American Gear, Inc. cos(phi*Math. It assumes 90 degree angle between the gears. The following is a calculation for the Reference Diameter of a helical gear with transverse module mt = 2, Number of teeth z = 30, Helix angle β = 15° (R) Reference Diameter d = z mt = 30 × 2 = 60 The following is a calculation for the Reference Diameter of a helical gear with normal module mn = 2, Number of teeth z = 30, Helix angle β = 15. 1 are based upon given module m and number of teeth (z 1 and z 2). If you divide the number of ring teeth by the number of pinion teeth, you get the ratio: 4. Assume that the gear teeth are of 20-degree. If you want to learn how to use the gear ratio to calculate the gears' speeds, keep reading the article!. Calculate the volume of a 0. A method for the sag-tension calculation in electrical overhead lines I. C = PCD(g) + PCD(p) 2. The number of teeth, module, helix and pressure angle parameters are used to automatically calculate. Example: A gear reducer with 1000 in/lbs of input torque, an input. 4 Root Fillet Radii of Curvature 3. You have me confused. To calculate what the hunting tooth frequency is, you must first determine the common factors of each gear (CF). This setup uses three 50/10 double gears after the 10 tooth gear that comes from the motor. So a gear 1. I have these realtionship with worm gear Box. Replaces both plastic transmission gears with metal; Fits mini lathes and 3MT mini mills; Small Gear: 12 Teeth / 20 Teeth, 12 mm Bore, 4 mm Keyway; Large Gear: 21 Teeth / 29 Teeth, 30 mm Bore, 5 mm Keyway. Effects of Gear Mesh Stiffness on the Dynamics of Helical Gears To demonstrate the effect of gear mesh stiffness on gear dynamics, let’s use a pair of helical gears as an example. All gears with matching teeth need the same module. Old school 3×9 or more and more popular 2×10 or perhaps the newest addition by SRAM XX1 1×11, or any other options? What combination is best for hilly courses, technical courses or flat ones?. What power is required to pedal at different speeds in different gears with and without a headwind. Then model the gear accordingly. thickness constants, you can calculate the corrected. Center Distance The distance between the axes of two gears in mesh. The rendering of the gears can take a long time particularly if the quality parameters ('number of rotation steps' and 'number of segments per 360 degree' are increased. The formula to calculate tire revolutions per mile is: Tire Revs Per Mile = 20,168 ÷ tire diameter (inches) Using the tire example above: 20,168 ÷ 27 = 747 revs per mile. 8°/step stepper motor will need 360 / 1. C = PCD(g) + PCD(p) 2. Output Speed = Input Speed / Ratio of Gear Reduction. To convert to feet divide by 12. Perform calculations using known ratio and known timing belt length Depending on the variables chosen for calculation the online calculator will display all possible configurations available. Identify different types of gears. 2 for preloaded bearings on the output shaft e. That ‘rack’ engagement is chooses because there is an equation of relative shift of. Two of the most important parameters, often confused with each other, are the pitch diameter (or thread pitch diameter), typically denoted as (d) and the module (or modulus. Calculate the number if teeth required in the ring gear for the ratio 5:1. Profile shift is supported for all gear configurations as well (I hope I got it right). per Mile / 1001 Tire Rev. com 2 Sprocket Tooth Design Formulas Refer to Fig. 4285 Cutting depth is. Default speed Help on: Calculate RPM per gear at 50 Mph or Km/h in 3 setups. The input speed is 2500rpm / 0. Let’s keep the below parameters as input. Hobbing is a machining process for gear cutting, cutting splines, and cutting sprockets on a hobbing machine, which is a special type of milling machine. Chain Length Calculator; Input: Output: Chain Pitch (inches) Drive Sprocket Teeth : Driven Sprocket Teeth : Center Distance (inches) Links : Length (inches) Reduction. Involute interference can be avoided by the conditions cited below: where α a2 is the pressure angle seen at a tip of the internal gear tooth. The entire spectrum of a Pinion transmission can be shifted to fast or slow with the secondary ratio to the rear wheel. pitch with gears from 12 teeth to 127 teeth. 1, Part II, July Gear Technology). In comparison to other gear sets which are typically limited to a gear ratio of up to 10:1, worm and wheel gear-sets can achieve gear ratios of up to 360:1. Two of the most important parameters, often confused with each other, are the pitch diameter (or thread pitch diameter), typically denoted as (d) and the module (or modulus. Below, the 9:78 and 13:90 gear train produces a 60:1 ratio. The majority of calculations for spur gears can be applied to helical gears too. This causes the gears to produce radial reaction loads on the shaft, but not axial loads. When you buy gears you normally specify the number of teeth and the number of teeth per inch (or centimeter). If you enter 13T and 22T the centre distance will be incorrect. In a first step, calculation can be negotiated. Example: A gear reducer with 1000 in/lbs of input torque, an input. The Pulley 2 RPM shows you that your blade will spin at 7000RPM. Though it’s hard to know just how much of a change will make the right difference for you, it’s possible to get a good feel for it by comparing your. worm gear, a threaded shaft engages the teeth on a gear. How to Calculate Gear Ratio. 1416 × rpm) ÷ tp) tb = tooth bite (inch) fpm = feed speed (fpm) bwd = wheel diameter (in. In this type of vehicle, heavy 1-ton p/u and larger, the planetary gears have spur cut teeth. Motor step angle 1. The calculations involved are trivial compared to those for cams or linkages. AGMA does not have a standard for calculating bending fatigue capacity for internal gears but our Excel-lent can calculate bending fatigue capacity of internal gears as well. These standards can include the effect of rim. The addendum of a standard proportion tooth equals 1. This formula gives a convenient two- or three-digit number. GEARS Educational Systems 105 Webster St. Machinery's Handbook. desired safety. function genGearToothData(m, Z, phi) { // ***** external gear specifications var addendum = m, // distance from pitch circle to tip circle dedendum = 1. The development of the. Root Diameter (RD) The diameter of a circle coinciding with the bottom of the tooth spaces. 100" OD with 20 teeth = 20 +2 =22 / 1. A gear is a mechanical device that transmits rotary motion by changing the magnitude and line of action of the effort force. 9) = 1710 Nm. This will also allow you to produce a. CP = x MOD. The results are also given as decimals. C = PCD(g) + PCD(p) 2. Situations that cause gears to fail. Insufficient resistance to bending or contact force, which causes teeth to fail. Number of teeth of pinion (n. In other words, the Gear ratio is the ratio between the number of teeth on two gears that are meshed together, or two sprockets connected with a common roller chain, or the circumferences of two pulleys connected with a drive belt. I put the 29" in the formula for the tire's diameter and 4. The generating plane intersects with the blades at the height of the calculation point. When the larger gear makes one full revolution, the smaller gear has to spin faster to keep up. Situations that cause gears to fail. Contact stress; Calculation of fits according ISO 286; Deep Groove Ball Bearing; Geometry of helical gears; Calculation of multi-layer interference fits; Tooth root stresses; GearEngineer; TBK 2014; Gear Production Suite; CM2 FEM. Enter the number of teeth for each of the two spur gears. Involute interference can be avoided by the conditions cited below: where α a2 is the pressure angle seen at a tip of the internal gear tooth. gear teeth is directed. Helical teeth enter the workpiece at a single point with impact progressively increasing across the width of the cut. The shape of gear teeth has become. 10: rotation velocity. But the gears in horology (watches and clocks) use another tooth form. Effects of Gear Mesh Stiffness on the Dynamics of Helical Gears To demonstrate the effect of gear mesh stiffness on gear dynamics, let’s use a pair of helical gears as an example. CA constant = 1. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. A toothed gear must have an integral number of teeth. Standard End Mill Sizes. The velocity ratio of the gears does not depend on the exact spacing of the axes, but is fixed by the number of teeth, or what is the same thing, by the pitch diameters. Output Speed = Input Speed / Ratio of Gear Reduction. Sometimes it is impossible to calculate the indexing because the plates do not provide a number of holes that are divisible by the number of teeth or divisions. KHK stock miter gears are available in two types, spiral and straight tooth, with high precision grade for demanding torques and speeds, and commercial grade for economical applications. The ring gear; Each of these three components can be the input, the output or can be held stationary. Most peripheral milling cutters are made with helical teeth. Therefore if noise reduction techniques Lire to he imiplemiented effectively. The number of teeth, module, helix and pressure angle parameters are used to automatically calculate. The diametral pitch of a gear describes how densely its teeth are set around it. circular pitch (P): the distance from one face of a tooth to the corresponding face of an adjacent tooth on the same gear, measured. Use the calculator below to figure out various gear specifications given two of the following; tooth count, diameter, and/or pitch. Multiply above number by number of teeth on sprocket of saw. Results and conclusions 24 6. 6, for example, then you would round up to the nearest tooth count of 19. NPA the angle that a tangent line on the tooth at the pitch diameter forms with a line that joins the center tooth. For the Tire field, enter your tire diameter in inches. This tool is only a reference, and you should always refer to the manufacturers specifications before installation. The larger the tooth, the bigger the gear diameter has to be for the same number of teeth. Divide 75 teeth by 25 teeth to find the velocity ratio. METRIC TIRE TO DIAMETER (INCHES) CALCULATION. Diametral Pitch (DP) A ratio equal to the number of teeth on a gear per inch of diameter. The shape of gear teeth has become. This is a specialised set calculators that uses the gear systems (Diametral Pitch or Module) and the number of teeth to calculate the Outside Diameter, Centre Distance and Ratio of Spur gears and. Teeth number (z). For example if the input gear has 9 teeth then its factors are 1×9 and 3×3. worm gear, a threaded shaft engages the teeth on a gear. However, the pitch surface is a hyperboloid and the axes of the gear system do not intersect. Typically, here we calculate the thickness referred to the module of the gear and we give it as a percentage of the module. Ordinarily the ratio is found by dividing the number of teeth on the larger gear by the number of teeth on the smaller gear or pinion. This is pretty straightforward, it is the number of teeth of the gear. The gears are sitting in a “meshed” state, meaning that the teeth of the gears are engaged with each other and that they are ready to transmit power. vice is needed, a gear train or one of its cousins, the belt or chain drive mechanism, will usually be used. The normal set of change gears includes the following gears: 20, 20, 35, 40, 40, 45, 50, 55, 57, 60, 65, 80, and 80 teeth. In addition it let you compose full gear layouts with connetcted gears to design multiple gears system with control of the input/output ratio and rotation speed. wear-life factor. Gear teeth if existing shaft data is present Integrate the KISSsoft Add-in (menu options in CAD) Add-in functions (calls) Calling KISSsoft from the Add-in Adding manufacturing data Opening the calculation file for the created gear Simplified gear view 3D interface to Autodesk Inventor Gear teeth if existing shaft data is present. 30 Rear End. [6][7] The following table, Table 1, is presenting the formulas that are used to calculate the blank and tooth dimensions of spriral bevel gears according to ANSI/AGMA/ISO standards [3],[4],[7]. Number of Teeth: Ouside Diameter: Number of Teeth Z: Module: Outside Diameter: Centre Distance: Pitch Circle spur gear 1: Pitch Circle spur gear 2: Centre Distance: A simple formula for calculating internal gears. Select the diametral pitch with units of teeth per distance, and then select the number of teeth for each gear, and the other parameters are computed. Profile shift is supported for all gear configurations as well (I hope I got it right). The teeth on a helical gear cut at an angle to the face of the gear. Gears with unequal numbers of teeth alter the speed between the input and out put gears. All calculated values in Table 4. This equates to 4,800 RPM when used with the 108-106. Make a chart of different gears and gear ratios. In the formula: the values of coefficient i, i, i, i, I and i; fi denotes the ratio of the radius of the root circle to the radius of the shaft bore of the gear; f denotes half of the span angle of a tooth on the root circle. You should be able to find your gear ratio listed on the axle tag, however, if that has gone missing, you can simply count the number of teeth on each gear and divide the number of ring gear teeth by the number of pinion gear teeth. L = chain pitch (link length) (12. pressure angle [deg] S v. Feed Rate: inches per minute RPM: Number of Teeth (or. Circular pitch p: The width of a tooth and a space, measured on the pitch circle. Let’s keep the below parameters as input. This calculation is based on the following formula: Speedometer Gear Teeth = (Drive Teeth * Rear End Ratio * Tire Revolutions per Mile) / 1,000. Choose 7x Mini Lathe for most 7x10, 7x12, 7x14, and 7x16 mini lathes. Below, the 9:78 and 13:90 gear train produces a 60:1 ratio. 9 the results of the climb hobbing case is presented. sim and simdesign/gear20. ; Problems related to vibration: Whenever the base pitch of the meshing gear and pinion are different from the. 5° (48 per revolution) Driver microstepping 1 - full step 1/2 - half step 1/4 - quater step 1/8 - uStep (mostly Gen6) 1/16 - uStep (mostly Pololu) 1/16- uStep (Smoothieboard) 1/32- uStep (Crazy Smoothieboard). The average number of teeth in contact as the gears rotate together is the contact ratio (CR), which is calculated from the following equation, CR= q r2 ap r 2 bp + q r ag r2 bg csin. Another way of introducing backlash is by increasing the center distances between the gears. With this in mind, a sun gear is a central gear around which one or planet gears move in a circle while themselves rotating. Circular Tooth Thickness The width of a tooth measured along the arc at the pitch. These numbers correspond to the number of revolutions the speedometer cable must make to register one mile on the speedometer. Motor step angle 1. Gears can be animated with various speed to demonstrate working mechanism. Spur gears transmit power through shafts that are parallel. and determined by calculations or estimations. Effects of Gear Mesh Stiffness on the Dynamics of Helical Gears To demonstrate the effect of gear mesh stiffness on gear dynamics, let’s use a pair of helical gears as an example. It is a dimension measured along a line or curve. This ratio γ = 1. Reference: Erik Oberg, et. Note: Simple formulas using +-*/() may be entered if desired, not just straight plain numbers. What power is required to pedal at different speeds in different gears with and without a headwind. Enter the equation as shown below. This tool is only a reference, and you should always refer to the manufacturers specifications before installation. Containing formulas and examples of both helical gear mathematics and the design of helical gear teeth, this volume examines tooth forms produced by standard cutters with their application to differential and planetary drives. It is a very easy number to calculate: (the diameter of the drive wheel) x (the size of the front sprocket) / (the size of the rear sprocket). 30 Rear End. In addition to power calculations, geometry aspects of peripheral milling cutters also are important, namely helix and rake/clearance angles. Links in chain. If you divide the number of ring teeth by the number of pinion teeth, you get the ratio: 4. belt conveyor speed calculation How to calculate belt conveyor speed with motor rpm and ger, we know motor rpm, gearbox ratio, gear spoket no of teeth, , belt conveyor speed calculation formula How to calculate the velocity of the conveyor belts - Quora A simple conveyor belt system consists of. This is a simpler version of gear terminology and teeth calculation formulas 1. You will need the following formulas: Driven Gear Teeth = Drive Gear Teeth x Gear Ratio x Tire Rev. Now applying the same principle on your second combination we get: 12*(12/30)*(8/x)=1. See full list on khkgears. ) (33 teeth / 10). Pressure Angle (∞): If you can draw a common normal line to the meshing teeth surfaces at the contact point between the meshed teeth and a tangent plane common to the pitch circles of both the gear then angle between the common normal line and the tangent plane is called pressure angle. There are two ways you can compute this gear train’s ratio. This chapter will explore the theory of gear tooth action and the design of these ubiquitous devices for motion control. Understand why teeth profiles are needed. The distance between a point of a tooth to the same point of the adjacent tooth, measured along circumference of the pitch circle is known as circular pitch. It is the dynamic impact loading a tooth encounters as it picks up its share of the load as it enters the zone of tooth action at the mesh. ASME/ANSI B29. But undercutting weakens the tooth strength severely and there may be the situation where a smaller number of teeth in a gear is to be adopted. 1 Gear design 5. Iupital has good strength, durability, wear resistance, and chemical resistance, so can be used to each gear. A 2000 rpm gear with 24 teeth is driving a gear with 84 teeth. In this tutorial, we w. TYPE OF GEARS Here is a brief list of the common. The AGMA rating formulas also recognize a tooth loading effect which is velocity dependent, but is largely independent of the system transmitted load. The simple way to calculate the proper speedometer driven gear is by setting up a ratio. Change gear calculator. The number you get will be chain speed in inches per minute. Diametral Pitch (DP) A ratio equal to the number of teeth on a gear per inch of diameter. The formula under these circumstances is similar--just break the system down into a series of chain drives and multiply the gear ratios together: drive ratio 1 X drive ratio 2 X wheel diameter where: drive ratio 1 = # of teeth on driving sprocket on chain 1 / # of teeth on driven sprocket on chain 1 and. Standard System of gear tooth profile: American gear manufacture Association(AGMA) and American National standard Institute(ANSI) for standardized following for form of gear teeth profile depending upon the pressure angle. Let us say the first gear has 7 teeth, the idler gear has 20 teeth, and the driven gear has 30 teeth. Q – gear pump performance capacity. Number of teeth of pinion (n. It the larger wheel 2 turns once, wheel 1 turns 1. 5 for unpreloaded bearings on the output shaft e. For sprockets, the formula is the same, but replace the diameter with # teeth. Here we'll design a spur gear with equations, where ALL you've got to do is change 2 variables, then ta da your gear has updated ! Note: The Unit system we'll use is cm. Input Parameters Gear type - according to the position of root and head cone Gear ratio and tooth numbers Pressure angle (the angle of tool profile) α t Helix angle β m Axis angle Σ Tangential module on outer cone met (for metric calculation) Tangential Diametral Pitch on outer cone Pet (for English units) Note: Module and Diametral Pitch are reciprocal values. The tip diameter (da) and root diameter (df) correspond to the top and 3. Gears Center – is the center of the pitch circle. The AGMA formulas account for the usual accuracies of. Show All Your Work. Gears B And C Are Connected. com Involute Gear Pin Measurements. These two measures are equivalent: the number of teeth and teeth per inch give the circumference, which in turn determines the radius. Included in the standards are rating formulas for gear tooth bending to prevent crack initiation (AGMA 1990). The same formula holds true for other gear sets as well. The input speed is 2500rpm / 0. For example, if the ratio is 2 or "2 to 1", this means that the smaller gear or pinion makes two revolutions to one revolution of the larger mating gear. The gear ratio formula for two meshing gears is simple and intuitive, while the gear ratio formula for the planetary mechanism is not. There is good basic information on Gear - Wikipedia, the free encyclopedia. belt conveyor speed calculation How to calculate belt conveyor speed with motor rpm and ger, we know motor rpm, gearbox ratio, gear spoket no of teeth, , belt conveyor speed calculation formula How to calculate the velocity of the conveyor belts - Quora A simple conveyor belt system consists of. They're more efficient than spiral miter gears because they create less friction. •Addendum of a tooth is its radial height above the pitch circle. 03 × w × (2d − L) × L − d 2 Where. Formulas and CalCulation examples Formulas Calculation example definitions: Calculation of revolutions of main spindle in [min-1]:* Calculation of feed per tooth in [mm/tooth]: Calculation of feed per min. This causes the gears to produce radial reaction loads on the shaft, but not axial loads. single tooth are equivalent to a resultant force applied at the pitch circle (about halfway up the tooth), at the large end of the tooth. More than ever people ask nowadays: "What gears to choose for my bicycle?". and α w is working pressure angle: Equation (5-3) is true only if the outside diameter of the internal gear is bigger than the. Formulas to evaluate the permissible strength for the volumetric and superficial fatigue of steel with application on cylindrical involute gears with external teeth gears are given on AGMA Standard 2105-D04 as follows. FEA-Integration; Slewing rings; Ball screws; eAssistant; Online-Calculations. Circular Pitch The distance between adjacent teeth measured along the arc at the pitch circle diameter. desired safety. 500" and a roller diameter of. Gear B has 200. Pitting Resistance Geometry Factor, I. The available gears are given as a comma separated list of integer values (For example, if your gears have 11, 12 and 15 teeth, enter "11, 12, 15" in the textbox below). 6 Temperature in gear contacts 19 3. Their calculation formulas are as follows:. 5/5 to 128/256 and pressure angles of 30°, 37. This setup uses three 50/10 double gears after the 10 tooth gear that comes from the motor. com: Fairywill Teeth Whitening Kit with Led Light for Sensitive Teeth,Teeth Whitening Kit, 35% Carbamide Peroxide 3ml(3) Gel with 5X Blue Light Accelerated, 2 Form Fitting Teeth Trays And A Case: Beauty. Spur Gears - Terms, Definitions, and Calculations. 01 Pitch diameter of the sun gear is 24. Using the 16 tooth size as gear A and the 60 tooth size as gear B gives us a ratio of 3. HiTorque Mini Lathe (with 21 Tooth Change Gear). Spur gears transmit power through shafts that are parallel. To convert to feet divide by 12. HUB DIAMETER is outside diameter of a gear, sprocket or coupling hub. 7 Modeling wear of gears in 3 dimensions 21 4. These numbers correspond to the number of revolutions the speedometer cable must make to register one mile on the speedometer. This calculation is used to match oversize tires with new ring and pinion gears to obtain the desired engine RPM at highway speed. Hanover Massachusetts 02339 Tel. The tooth profile as shown in Figure 1(b) represents a commonly used gear tooth, and is an involute of a circle. I have no idea how the magic number of 0. Diametric Pitch. To determine, first calculate the Horsepower Table Rating (HP Table) from the following formula: HP Table = Design HP (Step 3) Multiple Strand Factor (Table 2) Horsepower Table Ratings are given for each chain size on pages 6-19. Replaces both plastic transmission gears with metal; Fits mini lathes and 3MT mini mills; Small Gear: 12 Teeth / 20 Teeth, 12 mm Bore, 4 mm Keyway; Large Gear: 21 Teeth / 29 Teeth, 30 mm Bore, 5 mm Keyway. You will model it just as you would a standard gear, but make the tooth thicker by the amount you calculate. These values are then used in conjunction with the rating procedures described in AGMA 2001-B88, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth, for evaluating various spur and helical gear designs produced using a generating process. This type of gear comes with two kinds of tooth profiles in accordance with the datum surface. From it, at specified value of. It is prevalent when the number of teeth of the external gear is small. For spur gears, the formulas to calculate the chordal tooth thickness are detailed in Table 1. Show All Your Work. Their calculation formulas are as follows:. The geometry of bevel gears is shown in Figure (2). The formula to find the gear inches for your bike is simple. Input Parameters Teeth type - common or spiral Gear ratio and tooth numbers Pressure angle (the angle of tool profile) α Module m (With ANSI - English units, enter tooth pitch p = π m) Unit addendum ha * Unit clearance c * Unit dedendum fillet r f * Face widths b 1 , b 2 Unit worm gear correction x Worm size can be specified using the: worm diameter factor q helix direction γ pitch diameter. Get Into Gears. The average number of teeth in contact as the gears rotate together is the contact ratio (CR), which is calculated from the following equation, CR= q r2 ap r 2 bp + q r ag r2 bg csin. With this in mind, a sun gear is a central gear around which one or planet gears move in a circle while themselves rotating. In order to calculate the gear ratio of the two meshed gears we need to know either: the number of teeth of both input and output gears. Sometimes it is impossible to calculate the indexing because the plates do not provide a number of holes that are divisible by the number of teeth or divisions. Manufacturers' literature typically gives the drive ratios of internally-geared hubs only as decimal numbers or percentages. I put the 29" in the formula for the tire's diameter and 4. The available gears are given as a comma separated list of integer values (For example, if your gears have 11, 12 and 15 teeth, enter "11, 12, 15" in the textbox below). One of a pair of gears used to connect two shafts whose axes intersect, and the pitch surfaces are cones. Calculate the rpm of the output shaft. of the gear tooth. 3” Outside Diameter (O. ATLANTA HT, HP and E servo-worm gear unit, BG bevel-gear unit = 1. Now going back to sketch env. The tooth profile as shown in Figure 1(b) represents a commonly used gear tooth, and is an involute of a circle. NPTEL provides E-learning through online Web and Video courses various streams. The average number of teeth in contact as the gears rotate together is the contact ratio (CR), which is calculated from the following equation, CR= q r2 ap r 2 bp + q r ag r2 bg csin. 625, #60 =. The most common methods of gear design and analysis are based on standards published by the American Gear Manufacturers Association. 7142 Pitch diameter is 5. Based on the above calculation, discuss the relationship. 046 Torque Nm = Torque lbs Ins. Gear Ratio = 60:1 (Rotary velocity is also reduced by 60:1). The addendum of a standard proportion tooth equals 1. 17 Enclosed Gear Unit Requirements 2. This calculation is based on the following formula: Speedometer Gear Teeth = (Drive Teeth * Rear End Ratio * Tire Revolutions per Mile) / 1,000. Always remember- 99% of gears in world are involute tooth form- designed for smooth motion and efficient torque transfer. Spur gears are the most common type of gears. Two of the most important parameters, often confused with each other, are the pitch diameter (or thread pitch diameter), typically denoted as (d) and the module (or modulus. 1 : EXAMPLE: If the wormwheel has 60 teeth: 60. This is especially helpful when trying to identify a gearset that needs replacement with the same ratio ring and pinion. 2 for preloaded bearings on the output shaft e. For compound gears, one calculates this same gear ratio for each pair of gears (however many pairs are being used in a given application), and then multiply them together, achieving the same answer as shown in the example above:. Hanover Massachusetts 02339 Tel. Gear Output Speed. Normal diametral pitch. Fillet Coefficient is a constant that is divided by the diametral pitch to determine the radius of the hob tip that creates the gear tooth root. However, the rendering of the graphics is currently killing the performance. 4) Driver and driven equipment must be in line to avoid additional gearing. Decoding Chevrolet VIN, trim tags, cowl tags, engine, engine block casting numbers, cylinder head casting numbers, intake manifold casting numbers, transmission, interior codes, and paint codes. sim and simdesign/gear20. Situations that cause gears to fail. Chain is Missing or Lost. 7142 Pitch diameter is 5. If the gear has an odd number of teeth, you can approximate it by trying to rock the measuring device back and forth to the adjacent teeth. Axle ratio or rear end gear ratio is calculated by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. The dimensions of a sprocket can be calculated as follows, where P is the pitch of the chain, and N is the number of teeth on the sprocket; Pitch Diameter = P ÷ sin (180° ÷ N) Outside Diameter = P.