Matched involute geometry
Both gears share the selected metric module, pressure angle, root-clearance convention and circumferential backlash.
Editable spur gear generator
Generate a matched spur-gear pair and test the mesh before the final mechanism
Set the module, tooth counts, face width and independent bores for two external involute gears. EazyMake derives their ratio, pitch diameters and nominal centre distance, then creates marked backlash trials from the same shared geometry.
A transparent prototype workflow for matched external gears: shared geometry stays visible, backlash is named, and digital checks remain separate from load or wear evidence.
What this generator can make
Start with a bounded workflow, then edit the dimensions and supported features without hiding the fit assumptions.
Independent tooth counts
Change Gear A and Gear B tooth counts to explore ratio and envelope while retaining compatible shared tooth geometry.
Independent shaft bores
Size each circular bore for the real shaft, then treat bore fit as a separate calibration question from tooth backlash.
Marked backlash pairs
Export tighter, selected and looser equal-size trial pairs so tooth engagement can be compared before the full gears.
What to measure before generating
The generator can keep dimensions consistent, but the real installation and mating parts remain the source of truth.
Required ratio
Define the input and output shafts, direction change and tooth-count relationship needed by the prototype.
Shaft centres
Measure or design the axis spacing; the nominal centre distance is half the sum of the two pitch diameters.
Shaft diameters
Measure both shafts independently and decide whether each printed bore should slide, locate or be finished after printing.
Radial and axial envelope
Check outside diameters, face width, hubs or supports and clearance to neighbouring parts through the complete motion.
A measurement-to-mesh workflow
Each step keeps the editable parameters, calibration artifact and final printable parts connected.
Define the motion pair
Choose the driver, driven gear and ratio, remembering that two external gears reverse direction.
Choose shared tooth geometry
Set one module and supported pressure angle for the pair, then select tooth counts that avoid the generator's undercut limit.
Fit the installation
Compare the derived pitch diameters, outside diameters and centre distance with the real shaft and housing layout.
Separate backlash from bore fit
Print the marked meshing trials, and run an additional bore experiment when shaft fit is also important.
Prototype the assembly
Inspect and export both gears, then test alignment, support and motion in the complete hand-driven prototype before any broader claim.
Start from an editable example
Use a template to understand a complete parameter set, then replace its dimensions with your own evidence.
Know the limits
- The generator produces nominal unshifted external involute geometry with a printable root blend, not a generated cutter trochoid.
- A smooth hand-rolled trial does not establish torque capacity, wear life, safe speed, noise, lubrication needs, guarding or shaft support.
- Backlash and bore fit are different interfaces. One successful trial value should not be copied to the other without a separate experiment.
Common questions
Practical answers about what the current generator does—and what still needs a physical test.
How does the gear generator calculate ratio?
The displayed Gear B-to-A ratio is Gear B's tooth count divided by Gear A's tooth count. Which shaft speeds up or slows down depends on which gear is the driver.
Do both spur gears need the same module?
Yes. A meshing pair must share module and pressure angle. The generator keeps those values common while allowing separate tooth counts and bores.
What does the backlash setting mean?
It is the total circumferential clearance at the pitch circle across the meshing pair. The marked trial pairs compare a tighter, selected and looser value.
Are these gears ready for a powered machine?
No. Generation, mesh inspection, export and a smooth manual trial do not establish safe powered use. Material, loads, wear, alignment, supports and guarding need a separate engineering test plan.
Learn the fit workflow
Use the guides to choose and record a calibration experiment before treating a trial value as evidence.
Build from your measurements
Open the generator, choose a bounded starting workflow and keep the relevant physical trial attached to the final project.