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| Finding a chuck key! |
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| raynerd:
Hello, sorry if this is a :loco: sort of question but it is driving me bonkers! I`ve got two chucks, one is a tiny 0MT drill chuck, one is a recently aquired lathe 3 jaw chuck and I`ve even got another chuck tonight arriving possibly without the key. I`ve googled and googled and I don`t see how to identify the correct key with the chuck! for example, the lathe chuck that I have has a 4mm pin and I`ve got a key with a 4mm pin but the leaves are no way near big enough to engage! So clearly there must be more to it than just the pin size..! I know Chronos state pin size and number of teeth but how do you identify how many teeth you need from looking at the chuck? I presume the more teeth, the bigger the key size. Any help appreciate. Please don`t tell me it is trial and error :doh: Sorry if this is an obvious one. Chris |
| andyf:
Chis, I suppose you could you work out how many teeth there should be on the key for the little drill chuck by measuring the chuck's o/d across the wide end of the teeth and halving it to get the radius R1. Then measure the distance from the centre of the chuck key hole to the bottom of the teeth on the chuck, which will be (roughly) the radius R2 of the bevel gear on the key you need. Then count the number of teeth round the chuck, and multiply it by R1/R2 and round it down to get the number of teeth there should be on the key (more or less!). It sounds like your lathe chucks may have bevel gears around them too, so the same calcutation should work for them. I don't suppose this helps: http://www.newmantools.com/jacobs/keys.htm Andy |
| caskwith:
Go to a tool shop and pick up one of the multikeys, they are usually around a quid and have 4 different size keys in one. Try these and when you have one that fits you can count the teeth. |
| raynerd:
Hi Caskwith I have tried to do this and have purchased two on a whim buy. Each time I get them home, I find the centre pin is too large despite thinking otherwise when in the shop. Andy, sounds like a plan and I`ll give it a go and see how I get on. To be honest, maybe it is easiest just trial and error after all! Chris |
| Stilldrillin:
Can't you turn down the pin dia, Chris? :scratch: Ah! First, you'd need to hold it in the chuck........ :bang: David D |
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