Author Topic: Cross slide replacement nut  (Read 904 times)

Offline appletree

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Cross slide replacement nut
« on: March 23, 2018, 07:44:06 AM »
After a bit of advice, I have a stunning Raglan 5 inch lathe, however the cross travel nut is disproportionally worn and requires replacement so :-
I have been advised that Raglan made the nuts from brass as opposed to bronze to minimise wear on the screw, recommendations Please?

I cannot measure the screw did easily without disassembly, which I do not want to do just now.

Appears to be about 5/8 od square thread, 8tpi LH

1 What material?
2 Screwcut?
3 Make a tap from silver steel an heat treat?
4 Make new screw and nut in 10tpi (dials easier to use)?

Comments,experiance other ideas please Phil

Offline John Rudd

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Re: Cross slide replacement nut
« Reply #1 on: March 23, 2018, 01:24:40 PM »
1) go for brass....easier to work with
2)ermmm dunno really..
3) could do..
4) that would be my choice, making life a lot easier all round, but keep the orig parts in case you decide to sell on the lathe...lh taps/dies can be bought from RDG without being too expensive..
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Offline NormanV

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Re: Cross slide replacement nut
« Reply #2 on: March 23, 2018, 01:46:08 PM »
You could try here:
http://www.latheparts.co.uk/

Offline appletree

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Re: Cross slide replacement nut
« Reply #3 on: March 23, 2018, 01:46:50 PM »
Yea if I went for 10 tpiit would solve a few issues, I think RDG taps are acme but with a fresh start that would not be a problem.
If screw cutting I would have to machine towards the tail stock (blind) as my chuck is screwed on a not ideal for reverse rotation.

Keep the experience coming guys (thanks John).

Phil

Offline appletree

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Re: Cross slide replacement nut
« Reply #4 on: March 23, 2018, 02:06:19 PM »
Hi Norman that was my original idea, have had a couple of things of John before and they have been very good. I ordered the said nut and a long tee slotted cross slide nearly 18 months ago and waiting.


Phil

Offline philf

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Re: Cross slide replacement nut
« Reply #5 on: March 23, 2018, 02:33:50 PM »
Phil,

Delrin nuts can be moulded to fit the screw perfectly. I have seen the process on the web.

A friend of mine made a lathe around 50 years ago with a Delrin nut and when he got rid of the lathe many years later there was little sign of any backlash. He then bought a Hardinge capstan lathe and proceeded to make a carriage with cross and top slides.  He bought a metre of fairly cheap rolled trapezoidal screw. He used a few inches of the spare screw to make a tap to machine the threads.

Phil.

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Offline chipenter

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Re: Cross slide replacement nut
« Reply #6 on: March 23, 2018, 03:05:38 PM »
The  club I belong to has a Raglan Little John mk 1 that has spare cross slide lead screws and nutts with a shop made tap , I could mesure thees when I go there Wednesday iff that is any help .
Jeff

Offline Pete.

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Re: Cross slide replacement nut
« Reply #7 on: March 23, 2018, 03:15:26 PM »
Phil,

Delrin nuts can be moulded to fit the screw perfectly. I have seen the process on the web.


I've made a couple. Takes a couple of tries to get it right and you need to be patient  when heating the screw but it does work and well.

Offline appletree

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Re: Cross slide replacement nut
« Reply #8 on: March 23, 2018, 04:24:50 PM »
The  club I belong to has a Raglan Little John mk 1 that has spare cross slide lead screws and nutts with a shop made tap , I could mesure thees when I go there Wednesday iff that is any help .

Hi Chipenter
Thanks for the offer, but sadly the mk1 and mk2 are 1/2 od and 10 tpi, I know I had to gift my MK2 to my son to get permission for the 5 inch to come through the door! I could have fought and paid the price later, but the vacated space was the space I needed lol

Phil

Offline nrml

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Re: Cross slide replacement nut
« Reply #9 on: March 23, 2018, 04:29:23 PM »
Make an 'Evanut'. From all accounts, it should be a lot easier to make and should outperform metal nuts of any description. http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-leadscrew-nuts-the-easy-way

Offline NormanV

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Re: Cross slide replacement nut
« Reply #10 on: March 23, 2018, 04:54:44 PM »
I have considered "Evanuts" for my Raglan Mk 1 and my Loughborough lathe but there does not appear to be much space in the "tunnel" that they would have to pass through. I mostly use the Loughborough lathe and was able to transfer the nut from the Raglan, which leaves me with a problem with my Raglan. I had hoped that Latheparts would have been the answer.

Offline AdeV

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Re: Cross slide replacement nut
« Reply #11 on: March 23, 2018, 07:24:14 PM »
Am I missing something about that "Evanut" thread?

Like, there's zero information on actually making one, as if the post has been mostly removed?
Cheers!
Ade.
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Offline Pete.

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Re: Cross slide replacement nut
« Reply #12 on: March 24, 2018, 02:14:11 AM »
It has because Evan the author had some kind of hissy fit. Never mind though because. it's copied on another forum:

http://www.denfordata.com/bb/viewtopic.php?f=50&t=3727

Offline chipenter

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Re: Cross slide replacement nut
« Reply #13 on: March 24, 2018, 02:33:32 AM »
Tony at Lathes.co.uk is asking 95 for a cross slide nutt , 125 for the screw .
Jeff

Offline appletree

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Re: Cross slide replacement nut
« Reply #14 on: March 24, 2018, 04:54:22 AM »
Thanks for all the various replies, I have considered the event or at least something similar, some people think metal chips will get embedded and turn the nut into an abrasive.
Tony's nuts are expensive at 95 (somebody told me John ward made the Raglan bits for Tony, though I don't know that personaly), hence after all the above considerations, I posted the questions at the start of the thread (no pup intended).


Phil

Offline Pete.

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Re: Cross slide replacement nut
« Reply #15 on: March 24, 2018, 02:11:09 PM »
Thanks for all the various replies, I have considered the event or at least something similar, some people think metal chips will get embedded and turn the nut into an abrasive.
Tony's nuts are expensive at 95 (somebody told me John ward made the Raglan bits for Tony, though I don't know that personaly), hence after all the above considerations, I posted the questions at the start of the thread (no pup intended).


Phil

The plastic nut will no more get embedded than a brass, bronze or cast iron nut. Anyone who has used a delrin nut will know that the wear rate is very low and they (can) have little to no back-lash for a long time before you start to notice it creeping in.

Offline AdeV

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Re: Cross slide replacement nut
« Reply #16 on: March 24, 2018, 03:22:58 PM »
It has because Evan the author had some kind of hissy fit. Never mind though because. it's copied on another forum:

http://www.denfordata.com/bb/viewtopic.php?f=50&t=3727

Thanks Pete, appreciate that link! Doesn't look too difficult... now, have I got any Acetal....  :scratch:
Cheers!
Ade.
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Offline appletree

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Re: Cross slide replacement nut
« Reply #17 on: March 24, 2018, 03:42:51 PM »
Not definite yet but tending towards a new screw but in 10tpi and moulded drelin nut, both easyish to do, nothing lost, plus more usable 100 thou per turn, all original parts retained for posterity, any errors will affect all components so result should be low/zero backlash, might even go metric!

Phil