PRODUCT · Rotary Transmission
Helical Gears
Ground gears, module 1–8. Helical gear · 19°31'42" left-hand · ground · 20° pressure angle.
Last updated Reviewed by Luo Genwen, Production Plant Manager
Specifications · Selector
Helical gear online selector
All 28 standard sizes from the product catalogue PDF. Filter by module, teeth or bore — or search by model code. All dimensions in mm.
Complete size table · 28 sizes (static version for printing and full-text search)
| Model Code | Pitch p | Module m | Teeth z | Bore D1 mm | DK mm | Do mm | D mm | L mm | L1 mm | L2 mm | T mm | U mm | Backlash mm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1M-20-12 | 3.141 | 1 | 20 | 12 | 23.22 | 21.22 | 18 | 20 | 5 | 15 | 13.8 | 4 | 0.08~0.16 |
| 1M-25-12 | 3.141 | 1 | 25 | 12 | 28.53 | 26.53 | 20 | 20 | 5 | 15 | 13.8 | 4 | 0.08~0.16 |
| 1M-30-15 | 3.141 | 1 | 30 | 15 | 33.83 | 31.83 | 30 | 20 | 5 | 15 | 16.8 | 5 | 0.08~0.16 |
| 1M-35-15 | 3.141 | 1 | 35 | 15 | 39.14 | 37.14 | 35 | 20 | 5 | 15 | 17.3 | 5 | 0.08~0.16 |
| 1.5M-21-16 | 4.712 | 1.5 | 21 | 16 | 36.42 | 33.423 | 30 | 46 | 26 | 20 | 18.3 | 5 | 0.08~0.16 |
| 1.5M-30-22 | 4.712 | 1.5 | 30 | 22 | 50.75 | 47.747 | 36 | 48 | 28 | 20 | 24.8 | 6 | 0.08~0.16 |
| 1.5M-39-22 | 4.712 | 1.5 | 39 | 22 | 65.07 | 62.071 | 36 | 48 | 28 | 20 | 24.8 | 6 | 0.10~0.18 |
| 2M-21-22 | 6.283 | 2 | 21 | 22 | 48.56 | 44.563 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.10~0.20 |
| 2M-30-22 | 6.283 | 2 | 30 | 22 | 67.66 | 63.662 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.12~0.22 |
| 2M-30-32 | 6.283 | 2 | 30 | 32 | 67.66 | 63.662 | 55 | 65 | 37 | 28 | 35.3 | 10 | 0.12~0.22 |
| 2M-39-32 | 6.283 | 2 | 39 | 32 | 86.76 | 82.761 | 55 | 65 | 37 | 28 | 35.3 | 10 | 0.12~0.22 |
| 2.5M-20-22 | 7.854 | 2.5 | 20 | 22 | 58.05 | 53.052 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.10~0.20 |
| 2.5M-25-22 | 7.854 | 2.5 | 25 | 22 | 71.31 | 66.315 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.12~0.22 |
| 2.5M-25-32 | 7.854 | 2.5 | 25 | 32 | 71.31 | 66.315 | 55 | 65 | 37 | 28 | 35.3 | 10 | 0.12~0.22 |
| 3M-20-22 | 9.425 | 3 | 20 | 22 | 69.66 | 63.662 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.12~0.22 |
| 3M-20-32 | 9.425 | 3 | 20 | 32 | 69.66 | 63.662 | 55 | 65 | 37 | 28 | 35.3 | 10 | 0.12~0.22 |
| 3M-25-22 | 9.425 | 3 | 25 | 22 | 85.58 | 79.578 | 36 | 56 | 28 | 28 | 24.8 | 6 | 0.12~0.22 |
| 3M-25-32 | 9.425 | 3 | 25 | 32 | 85.58 | 79.578 | 55 | 65 | 37 | 28 | 35.3 | 10 | 0.12~0.22 |
| 4M-18-32 | 12.566 | 4 | 18 | 32 | 84.39 | 76.395 | 55 | 75 | 35 | 40 | 35.3 | 10 | 0.14~0.24 |
| 4M-21-32 | 12.566 | 4 | 21 | 32 | 97.13 | 89.127 | 55 | 75 | 35 | 40 | 35.3 | 10 | 0.14~0.24 |
| 4M-21-35 | 12.566 | 4 | 21 | 35 | 97.13 | 89.127 | 55 | 75 | 35 | 40 | 38.3 | 10 | 0.14~0.24 |
| 4M-24-32 | 12.566 | 4 | 24 | 32 | 109.86 | 101.859 | 55 | 75 | 35 | 40 | 35.3 | 10 | 0.14~0.24 |
| 4M-24-35 | 12.566 | 4 | 24 | 35 | 109.86 | 101.859 | 55 | 75 | 35 | 40 | 38.3 | 10 | 0.14~0.24 |
| 5M-18-45 | 15.708 | 5 | 18 | 45 | 105.49 | 95.493 | 68 | 85 | 35 | 50 | 48.8 | 14 | 0.14~0.24 |
| 5M-24-45 | 15.708 | 5 | 24 | 45 | 137.32 | 127.324 | 68 | 85 | 35 | 50 | 48.8 | 14 | 0.16~0.26 |
| 6M-20-55 | 18.85 | 6 | 20 | 55 | 139.32 | 127.324 | 80 | 100 | 40 | 60 | 59.3 | 16 | 0.16~0.26 |
| 6M-25-75 | 18.85 | 6 | 25 | 75 | 171.16 | 159.155 | 110 | 120 | 60 | 60 | 79.9 | 20 | 0.16~0.26 |
| 8M-18-75 | 25.133 | 8 | 18 | 75 | 168.79 | 152.789 | 110 | 140 | 60 | 80 | 79.9 | 20 | 0.18~0.28 |
Static copy of the selector data for reference and printing; use the interactive selector above to filter, sort and request a quote. All dimensions in mm; full range and tolerances per the PDF catalogue.
Click a column header to sort. Source: Wolfer helical gear catalogue. Download PDF catalogue ↗
FAQ
Common questions about this series
Helical Gears: what size range does the table cover?
The table on this page lists 28 standard sizes: module 1–8, 18–39 teeth, bores from Ø12 to Ø75 mm. Sizes outside this range are made to your drawing.
Helical Gears: what is it and when should I use it?
Ground gears, module 1–8. Helical gear · 19°31'42" left-hand · ground · 20° pressure angle. Helical gears run quieter and carry more load than spur gears of the same size because several teeth are in mesh at once; the trade-off is an axial thrust that the bearings must take. Use them for higher-speed or noise-sensitive parallel-shaft drives, and match the hand (left/right) of the mating gear.
Helical Gears: can I order a size that is not in the table, or just one piece?
Yes. Everything on this page is made to drawing, and the table is only the standard-size subset of the catalogue. Minimum order quantity is one piece — we routinely make single replacement parts for OEMs whose original supplier has discontinued the item. Send a DWG, STEP or PDF drawing (or a sample part): you get a formal quotation within 24 hours after the information is complete, and the first article ships within 30 days of drawing approval, with inspection records.
Helical Gears: what do I need to send to get a quote?
Send the drawing or these values: module (or DP), number of teeth, pressure angle, helix angle and hand (for helical), face width, bore with tolerance and keyway, hub dimensions, material and heat treatment, required accuracy class (ISO 1328 / DIN / AGMA / JIS) and quantity. A STEP file plus a 2D drawing with critical tolerances is ideal; a photo of the old part with basic measurements is enough for a first quote.