Key way steel

[jem]

What type of steel is keyway steel please. On my digger (backhoe , backackter call it what you will) the wheel drive shaft is 26 mm dia, and I had previously attached the wheel hub to it shaft using 3 8mm bolts going just into the shaft. which caused the ends of the bolts to shear. so now I want to fix the two together using perhaps 3 keyways at 120 degrees to each other round the shaft. The shaft and hub are both mild steel. So what size key, and how deep should it go into the shaft. I realise that this is a tricky question, as I dont know the force involved, except it shears 3 8mm bolts. but it is only for driving the machine on fairly flat ground, the machine weighs me, plus a 3 cylinder diesel engine, and all the hydraulics, so the weight of a very small car. it does travel very slowly.

any help would be most appreciated please

best wishes

Jem

[Nigel Bennett]

Key steel is usually a medium carbon steel - it used to be En6 but En8 (080M40 IIRC) would be an equivalent.

[uuu]

Here's a table of key sizes: Key sizes

Suggested size here is 8mm wide and 7mm high.

Wilf

[jem]

Thank you very much for your most helpful replies.

best wishes

Jem