Description
Details
GEARBOX is supplied with:
- Gearbox with a 90-tooth HTD 5M pulley and a helical pinion
- HTD 550-5M timing belt
- 18-tooth HTD 5M motor pulley with a ø14 mm mounting bore
GEARBOX 5:1 Motor-to-Pinion Reduction (NEMA34 Mounting Example)
Compact gear reducer designed for CNC router applications. It features a 5:1 motor-to-pinion reduction ratio, meaning that the motor rotates five times for one complete revolution of the pinion. The gearbox supports direct mounting of a NEMA34 stepper motor and provides stable torque transmission and improved motion control for both hobby-grade and professional CNC systems.
Rack Gears
The rack gears are available in two versions: a light-gray plain-steel version and a black-oxide version with additional corrosion protection. Both versions are made from quenched and tempered steel.
The light-gray version is the most popular because it integrates visually with most machine designs. Rack gears should be lubricated during operation to reduce wear and help protect the surface against corrosion.
The racks are supplied only in complete 960 mm lengths; cut-to-length service is not available. The rack bars are precision-milled and externally ground. Normal module: 1.5. Pressure angle: 20°. Helix angle: 19°31’42”.
Opposite Tooth Gauge
The Opposite Tooth Gauge is a short alignment rack used when assembling helical rack sections. Its teeth are cut in the opposite helix direction, allowing it to engage both adjoining rack sections during installation. This helps maintain accurate tooth continuity across the joint and reduces assembly time.
Helical vs Spur Gears
- Due to its progressive contact, process performance is smoother and produces less noise. Dynamical loads are also reduced.
- This type of gears can work at higher speeds than spur gears.
- The contact ratio is also higher.
- The transmitted load is spread along an angled line making bending loads smaller.
- Tooth wear is reduced and they can transmit more power than spur gears with teeth of the same size.
| SPUR GEAR | HELICAL GEAR |
|---|---|
 |  |
| In case of spur gear, teeth are parallel to the axis of the gear. | In case of helical gear, teeth are inclined with the gear axis in the form of a helix. This angle of inclination is known as helix angle (15° – 25°). |
| In spur gear drive, contact between teeth of two meshing gears occurs suddenly. | In helical gear drive, contact between teeth of meshing gears occurs gradually. |
| Here the contact between two meshing teeth is always a line of same length. | Here contact starts with a point, gradually becomes a line and leaves as a point. |
| Sudden engagement of teeth results in impact loading. So teeth are subjected to impact loading. | Due to gradual teeth engagement, load on the tooth builds up gradually. So teeth are subjected to gradual loading. |
| Impact loading caused by sudden tooth engagement results in greater vibration and noise. | Gradual tooth engagement provides smoother and quieter operation. |
| Spur gears generally have a lower contact ratio under comparable conditions. | Helical gears generally have a higher contact ratio, so the load is shared by more teeth under comparable conditions. |
| Service life depends on load, speed, lubrication, alignment, material, and manufacturing quality. | Under comparable conditions, the higher contact ratio of helical gears can reduce tooth loading and may extend service life. |
| Mating spur gears must have the same module and pressure angle. | Mating helical gears must have the same normal module, pressure angle, and helix-angle magnitude, with opposite helix hands for parallel shafts. |
| Spur gears are suitable for low to moderate speed applications. | Helical gears can be utilized at high speed also. |
| Spur gear drive produces only radial force. As the teeth are parallel to axis, the thrust force is zero. | Due to presence of helix angle, helical gear drive produces radial as well as thrust force. So the bearing must be capable of sustaining such thrust force. |
| Spur gears are a simple and efficient choice where noise and vibration are less critical. | Helical gears are preferred where smoother engagement, lower noise, and higher contact ratio are important. |
Dimensions
HTD 5M big pulley (90 teeth)
HTD 5M small pulley for stepper motor / mounting hole ø14mm (18 teeth)
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| DOWNLOAD 3D MODEL | 3D Model / IGES / Rhino 3D / STEP / Parasolid |
Helical Tooth Rack and Pinion
| Normal Module | Pressure Angle | Tooth Angle | Helical Gear number of teeth | Rack / Pinion Helix Hand | Pitch per tooth* | L | A0 | B | I | D | D1 | L1 | A | C1 | C2 | E | A1 | SKU | |||||
| 1.5 | 20° | 19°31’42” | 23 | Right-hand rack / left-hand pinion | 5.000 mm | 960 | 20 | 20 | 120 | 60 | 30 | 900 | 8 | 6.8 | 11 | 8.8 | 18.4 | 1145002 | |||||
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| Pictures, dimensions , table data and technical drawings of this product are made with reasonable care and liability is excluded for the accuracy and correctness of this data. | |||||||||||||||||||||||
*Nominal pitch calculation: For a helical rack with normal module 1.5 and a helix angle of 19°31’42”, the transverse pitch along the rack axis is approximately 5.000 mm per tooth. A 23-tooth pinion therefore produces a nominal linear movement of 23 × 5.000 = 115.000 mm per complete pinion revolution. Manufacturing tolerances, belt compliance, backlash, assembly alignment, and controller settings can affect actual travel, so the finished machine should be calibrated by measuring movement over the longest practical distance.
Example: calculating stepper-motor pulses per millimeter of axis movement
The motor-to-pinion reduction ratio is 5:1. The 90-tooth HTD 5M pulley is driven by the 18-tooth motor pulley: 90 / 18 = 5. Therefore, the motor rotates five times for one complete revolution of the pinion.
The nominal linear movement of the 23-tooth helical pinion is 115.000 mm per complete pinion revolution.
Formula:
(Controller pulses per motor revolution × reduction ratio) / pinion movement per revolution = steps per mm
- (200 × 5) / 115.000 = 8.695652 steps/mm — 200 pulses per motor revolution, full-step mode
- (400 × 5) / 115.000 = 17.391304 steps/mm — 400 pulses per motor revolution, half-step mode
- (800 × 5) / 115.000 = 34.782609 steps/mm — 800 pulses per motor revolution, 1/4 microstepping
Important: Microstepping increases command resolution but does not by itself guarantee equivalent mechanical positioning accuracy. Final calibration should be performed on the assembled machine.
| Microstep Division | Pulses per Motor Revolution | Steps per mm |
| 1 (full step) | 200 | 8.69565217 |
| 2 | 400 | 17.39130435 |
| 4 | 800 | 34.78260870 |
| 5 | 1000 | 43.47826087 |
| 8 | 1600 | 69.56521739 |
| 10 | 2000 | 86.95652174 |
| 16 | 3200 | 139.13043478 |
| 20 | 4000 | 173.91304348 |
| 25 | 5000 | 217.39130435 |
| 32 | 6400 | 278.26086957 |
| 40 | 8000 | 347.82608696 |
| 50 | 10000 | 434.78260870 |
| 64 | 12800 | 556.52173913 |
| 100 | 20000 | 869.56521739 |
| 128 | 25600 | 1113.04347826 |
| 200 | 40000 | 1739.13043478 |
| 256 | 51200 | 2226.08695652 |
The table above shows the nominal steps-per-mm values for common stepper-driver microstep settings, based on a 200-step motor, a 5:1 motor-to-pinion reduction ratio, and 115.000 mm of pinion travel per revolution.
Mach3 interface example: for 400 pulses per motor revolution, enter 17.3913 steps per mm. The value visible in the older screenshot should not be used.
Pinion Gearbox