Tool Bushings
Upper, lower and thrust bushings sized from the published tool diameter of the model, in wear-resistant alloy steel.
Organised by tool diameter, not by brand
Bushings are the highest-turnover machined part in a breaker fleet, and they are the clearest illustration of why the cross-reference table is built around tool diameter. A bushing family is defined by bore, outside diameter and length; the brand is only a label placed on top of that geometry.
Running clearance is the specification that separates a good bushing from a fast-wearing one. Too tight and the tool seizes when the front head heats up, too loose and the tool hammers the bushing oval within weeks.
Specification
| FIELD | UNIT | ORISE VALUE |
|---|---|---|
| Bore range | mm | 40 to 210, covering every tool diameter in the cross reference |
| Outside diameter range | mm | 70 to 320 |
| Length range | mm | 80 to 400 |
| Bore tolerance | ISO class | H8 · H9 on large bores where the drawing allows |
| Running clearance, bore to tool | mm | 0.6 to 1.2 up to Ø100 · 1.0 to 1.8 above Ø100, quoted per bore |
| Material | — | 42CrMo · 40Cr |
| Hardness | HRC | 43 to 48 |
| Heat treatment | — | Forge blank → finish machine → carburise and quench → finish grind |
| Lubrication features | — | Grease grooves and holes as drawn |
| Interference fit into front head | mm | 0.05 to 0.15, set from the measured front head bore |
Measure the front head as well. A front head that has been running with a worn bushing is often oval itself. Supplying a new bushing to the nominal outside diameter into a worn seat will not fix the machine.
Volume item. Bushings are the natural first order for a new customer: low value per piece, high repeat rate, quick to verify. We treat first bushing orders as a qualification run and supply a dimensional report with them.
What we need from you
- Tool diameter of the machine, from the cross reference or measured
- Whether the bushing is upper, lower or a thrust ring
- Old bushing outside diameter and length, or the front head bore
- Grease groove pattern if the original had one
- Quantity per order and expected annual usage
Send the part, the drawing or the model
A photograph with a scale rule and the machine model is usually enough to begin.