Gear Blanks
Turned and hardened gear blanks with the bore and faces finished, ready for cutting or grinding.
Blanks supplied to a gear cutter, or to us for cutting, with the bore, faces and chamfers finished before hardening. Everything that has to stay accurate after heat treat is done first.
3–5 weeks
25 pieces
ISO 9001:2015
Technical Specifications
| Parameter | Value | Unit |
|---|---|---|
| Bore tolerance | H7 | - |
| Face runout | 0.02 | mm TIR |
| Diameter range | Ø30–Ø800 | mm |
| Hardening | Case or through | on request |
| Bore-after-HT | Ground, H7 | standard |
| Stress relief | Before finish turning | standard |
Available Materials
- Steel 8620
- Steel 4140
- Steel 20MnCr5
- Stainless 17-4 PH
- Steel 1045
Typical Applications
- Gears before hobbing
- Sprocket blanks
- Timing gear blanks
- Idler blanks
- Crown wheel blanks
Surface Finishes
- Turned
- Ground faces and bore
- Hardened, then ground bore
- Black oxide
- Phosphate coated
Industries Served
- Automotive & EV
- Industrial Equipment
- Agricultural Machinery
- Tooling & Mould Making
- Rail
What drives the price of this part
Derived from the callouts on this page. Where a driver is not on the drawing, it is not on this list.
- Tolerance
- Bore tolerance at H7 is the tightest callout this family carries. Tightening a callout is a process decision, not a machining decision: below the standard ±0.005 mm the work moves to grinding or jig boring, and the price moves with it.
- Part size
- Diameter range at Ø30–Ø800 mm decides which machine the part lands on and how many setups it needs. Size is the driver buyers most often leave out of a first enquiry, and it is the one that changes the quote fastest.
- Material
- The first material listed, Carbon Steel 8620 (case hardening), rates 7/10 on our machinability scale at 149–200 HB (as-supplied) · 58–62 HRC case after carburising. On this shop's scale a harder alloy means slower passes and more tool changes, and that is cycle time the quote has to carry.
- Order size
- Minimum order is 25 pieces, where setup and tooling are amortised across the batch and per-part cost settles around cycle time and material. Below that quantity the same part costs more per piece, not less.
See how cycle time is calculated in the machining time calculator and what else moves a price in the cost driver reference.
How these parts are inspected
Matched to the callouts above and the instruments actually on the floor.
- Coordinate measuring machine (Zeiss CONTURA G2, two machines, GR&R 8.4% on the critical feature)
- Dimensional report against the drawing, with a 100% check on critical features rather than a sample
- Certificate of conformance and the mill certificate with every shipment
- Bore gauges and an optical comparator for hole position and edge form
The full equipment list, with counts, is on the capability page; the inspection sequence is on quality and inspection.
Questions buyers ask
- Why grind the bore after hardening?
- Because hardening moves it by 20–40 µm, which is more than an H7 fit allows. Boring before heat treat and hoping is how a gear ends up tight on its shaft.
Related part families
Precision Spur Gears
AGMA 8–12 spur gears, hobbed and profile ground, from 12 mm to 800 mm pitch diameter.
Gear Housings
Machined gearbox housings with bored bearing seats, held to centre-distance ±0.02 mm.
Splined Shafts
Involute and straight-sided splines cut or rolled on shafts, checked at the pitch diameter.