(very) Early Colchester Bantam change gears

[Paul Relf-DaviesParticipant @paulrelf-davies37806]

Hi all,

I’m working towards bring an pre-war (perhaps 1932, based on the serial mumber) Colchester Bantam lathe back into service.

As part of the initial assessment I gave the machine I measuerd all the change gears and discovered they are all 14DP, with an 8-splined 13/16″ bore.

However, I bit of rooting round round the internet suggests that Bantams (post-war I assume) use 16DP gears…?

Assuming pre-war Bantam change gears are now effectively unobtainium, are there any other lathes who’s change gears might be compatible?

cheers

[DC31kParticipant @dc31k]

A few early Colchesters used 14DP gears, including ‘larger’ models than the Bantam.

Drummond lathes use 14 DP, Harrison L5 and 140 use 14DP, Chipmaster uses 14DP. I saw one reference that Raglan use 14 DP (but do not know this for sure).

Of these, Drummond gears are most easily available, but the centre detail is different.

This might be an option: buy some modern 16DP gears to get the splined centre and 3D print a 14DP gear around the outside.

https://www.thingiverse.com/thing:1808219

 

[Paul Relf-DaviesParticipant @paulrelf-davies37806]

Thanks for rour reply, DC31k

I had been thinking (assuming I couldn’t find any ‘off the shelf’ gears to work) of sacrificing one ofmy existing duplicate gears – for some reason I seem to have 4 x 35T for some reason – to get the correct splined bore and buying a generic 14dp 28 spur gear. I could then machine them both to an interference fit & press them together.

However, it hadn’t occured to me that I could 3D print some or all of the required gear…would be be strong enough? I know change gears get machined from nylon/delron, but I haven’t heard of them being printed before… I’ll give it a try.

[DC31kParticipant @dc31k]

[Paul Relf-DaviesParticipant @paulrelf-davies37806]

Thanks again, DC31k.

My current project is to add a reverse tumbler mechanism to the lathe.

To this end, the trickiest gear I need to come up with is the output gear, as it needs to be both 14DP and have the correct 8-splined bore. The other gears will just need smooth bores, so should simpler to acquire.

 

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