Bantam metric leads crew & half nut

This topic has 8 replies, 4 voices, and was last updated 30 May 2021 at 20:54 by Dan Shilling.

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27 May 2021 at 12:28 #14270
Dan Shilling
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@danshilling
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27 May 2021 at 12:28 #547369
Dan Shilling
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@danshilling
I've bought a Colchester Bantam, it's metric but I need a metric leadscrew & half nut to complete the machine.

I can get from a Colchester lathe Specialists a new leadscrew for £375+vat but though the machine's good it would not justify that price especially as I have already paid near on £400 for it.

Imperial is findable but metric seems impossible to find a good leadscrew & half nut.

So I was wondering on the off chance if anybody had a spare metric leadscrew and half nut for a Bantam or was breaking one?

Regards,

Simon
30 May 2021 at 11:17 #547778
Dan Shilling
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@danshilling
Posted by Dan Shilling on 27/05/2021 12:28:52:

So I was wondering on the off chance if anybody had a spare metric leadscrew and half nut for a Bantam or was breaking one?

Any suggestions would be welcome.
30 May 2021 at 13:15 #547795
Dave Wootton
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@davewootton
Hi Dan

I bought lengths of Metric leadscrew from a company called Kingston engineering from hull, they also sold nut blanks, no idea of the cost as it was for work and they sorted out the grubby details of money. Was a while ago but i see they have a website. I'm sure there was a firm in Bristol that sold it as well.

Dave

There is a firm called Nobilla that breaks Colchester lathes, but their prices are not bargain basement! However I bought a used Bantam tailstock spindle from them described as good condition, but when it arrived it was as good as new , in fact I think it was unused, so I was delighted. The chap that told me of them said they are very fussy about the condition of what they sell.

Edited By Dave Wootton on 30/05/2021 13:29:03

Edited By Dave Wootton on 30/05/2021 13:34:04
30 May 2021 at 19:17 #547827
not done it yet
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@notdoneityet
Do you already have a lead screw? If so, one possibility is to replace the threaded portion with a metric trapezoidal screw thread.. Half nuts might likely depend on the machine design.

Kingston engineering would quote you for a replacement lead screw with nuts, I expect. I have seen several mentions of Kingston, on this and other fora in the past. All reports have been favourable, but I’ve never needed to avail myself of their services….
30 May 2021 at 20:27 #547831
Dan Shilling
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@danshilling
Posted by Dave Wootton on 30/05/2021 13:15:04:

There is a firm called Nobilla that breaks Colchester lathes, but their prices are not bargain basement!

yes they only have new and that's where the £ 375 and the nut £100 then vat on top! comes from. Would be fine if the machine was hardly used but as it's 45 years old a good second would be more suitable.

I'll look into the kingston option – I do have an imperail leadscrew and half nut
30 May 2021 at 20:30 #547832
Dan Shilling
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@danshilling
Posted by not done it yet on 30/05/2021 19:17:49:

Do you already have a lead screw? If so, one possibility is to replace the threaded portion with a metric trapezoidal screw thread.. Half nuts might likely depend on the machine design.

Kingston engineering would quote you for a replacement lead screw with nuts, I expect. I have seen several mentions of Kingston, on this and other fora in the past. All reports have been favourable, but I’ve never needed to avail myself of their services….

I'll look into the kingston option though I have not fully given up finding a good second hand metric leadscew and half nut – seems rare as hens teeth!
30 May 2021 at 20:35 #547833
Brian Wood
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@brianwood45127
Hello Dan,

I am surprised that no-one else has mentioned it before now , but surely there are change wheel arrangements that will give you metric threading using an imperial leadscrew. Are there no guidance set ups in a plate fastened to the change wheel cover or elsewhere on the lathe? It would save you a lot of money and the approximations are usually remarkably close.

Brian
30 May 2021 at 20:54 #547836
Dan Shilling
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@danshilling
Posted by Brian Wood on 30/05/2021 20:35:07:

Hello Dan,

I am surprised that no-one else has mentioned it before now , but surely there are change wheel arrangements that will give you metric threading using an imperial leadscrew. Are there no guidance set ups in a plate fastened to the change wheel cover or elsewhere on the lathe? It would save you a lot of money and the approximations are usually remarkably close.

Brian

With the 127t change wheel -that I don't have – you can get approximately the metric back just like you can on an imperial machine but some threads such as modular won't work not that anybody tends to make these.

It's just if I could get a metric leadscrew it would complete the machine and I could set the machine straight from the plate without fussy calculations and approximations all the time.
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