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Leadscrew suppliers

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Pete.10/07/2020 01:18:42
222 forum posts
36 photos
Posted by old mart on 09/07/2020 18:46:50:

Having minimum backlash is a huge advantage, and while the mill is in bits, it would be worth seeing if there is room to incorporate backlash adjustment. Also, if fitting DRO's is a likelyhood, then the actual pitch wont matter as you will never be looking at mechanical scales.

I won't be fitting a DRO, I don't want to alter the machine too much, but as I work in metric, putting a metric leadscrew in would be a good compromise.

I will likely incorporate something to adjust backlash, I plan on using it for small jobs as I do have a bigger mill, but adjustment on the backlash would make it nicer to use.,

JasonB10/07/2020 08:06:57
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Posted by Mike Woods 1 on 08/07/2020 09:27:06:

I wonder if any of the Warco, Chester, Sieg, Amadeal or Axminster lathes or milling machines use this T16 x 3mm format.

TR16 x 2 on some of the Sieg mills, what length of thread do you need?

Michael Gilligan10/07/2020 08:16:40
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15886 forum posts
693 photos
Posted by Pete. on 10/07/2020 01:04:13:
Posted by Michael Gilligan on 09/07/2020 07:27:53:
[…]

Sorry, I'd had long day when I wrote that, I'm not surprised you didn't understand it, I don't.

[…]

.

It happens to us all, Pete yes

... go for the 2mm pitch.

MichaelG.

Kiwi Bloke10/07/2020 10:50:41
443 forum posts
1 photos

Another supplier... Halifax Rack and Screw.

Edited By Kiwi Bloke on 10/07/2020 10:50:59

Len Morris 213/07/2020 09:40:14
17 forum posts

A while ago I bought an Ex MOD Adcock & Shipley plain hand horizontal milling machine. Its a nice size for the small workshop with a 24x7 table. It was very cheap as nobody wanted the plain hand operation where the table was simply moved by a lever. I altered it for a 10 tpi lead screw with ball handles and 100 division dials.

Looking for a lead screw I found them far too expensive expensive. In the end I just used a length 3/4 Whit threaded bar. Cheap as chips and very easy to make the nut. I think we get too hung up about square threads. I hasn't worn after many years and will cost practically nothing if it ever does need replacing.

Works a treat and worth considering for a machine that only sees amateur use.

Edited By Len Morris 2 on 13/07/2020 09:41:43

old mart13/07/2020 13:03:09
1829 forum posts
148 photos

That 3/4" W which is 10tpi sounds like a good idea, and if you are not sure of the accuracy, then it would not be hard to do some tests with different measured movements against the dial readings. The OP could use a suitable metric equivalent, although getting hold of trapezoidal stock is much easier in the UK.

Len Morris 213/07/2020 17:25:59
17 forum posts

Agree about the accuracy of commercial thread bar. It's not going to match true lead screw standards. However, the dials get me within 5 thou and if I need better (depending on the job) it's easy enough to put a DTI on it for the final cut.

I also use my miller for turning large diameters jobs up to 20 inches. Over arm removed, 8 inch 4 jaw mounted on spindle nose, tool post mounted on table and knee height used to give center height. Disks, drums and alloy wheels no problem. With a DTI I can get within 1/10 of a thou if needed. Obviously no tail stock but suppose you can't have everything!

Ian P13/07/2020 20:17:27
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2407 forum posts
101 photos

My take would be that on a manual mill (ideally with DRO) if you use bog standard threaded rod the pitch accuracy can be 'improved' by having a much longer nut that engages over a high number of threads. I was told (yonks ago) that this averages out pitch changes and helps reduce backlash.

Ian P

Len Morris 213/07/2020 21:21:25
17 forum posts

Good comment Ian. My nut is some 40 mm long. There wasn't room to put anything longer under the table. Once made it was bored out 10 though, split on one side and adjusted onto the threaded rod by 3 cap screws to get rid of backlash. Works fine but again, it is commercial threaded bar and I wouldn't pretend it's as accurate as a proper ground lead screw. Wish I could afford a DRO !

Michael Gilligan13/07/2020 21:37:31
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15886 forum posts
693 photos
Posted by Len Morris 2 on 13/07/2020 21:21:25:

Good comment Ian. […]

.

Agreed yes

The only caveat being that both the long nut and the screw will wear comparatively rapidly, if they are busy averaging-out all those variations.

... Still a good bargain-price solution though !

MichaelG.

Ian P13/07/2020 21:59:56
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2407 forum posts
101 photos
Posted by Len Morris 2 on 13/07/2020 21:21:25:

Good comment Ian. My nut is some 40 mm long. There wasn't room to put anything longer under the table. Once made it was bored out 10 though, split on one side and adjusted onto the threaded rod by 3 cap screws to get rid of backlash. Works fine but again, it is commercial threaded bar and I wouldn't pretend it's as accurate as a proper ground lead screw. Wish I could afford a DRO !

I would say that igaging or igaging type of DRO's are pretty affordable and the accuracy is adequate (same technology as digital calipers) so ideal for budget home engineering where you are making parts to fit each other rather than to volume production interchangeability. Backlash and feedscrew errors become almost unimportant

Ian P

Ian P13/07/2020 22:33:24
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2407 forum posts
101 photos
Posted by Michael Gilligan on 13/07/2020 21:37:31:
Posted by Len Morris 2 on 13/07/2020 21:21:25:

Good comment Ian. […]

.

Agreed yes

The only caveat being that both the long nut and the screw will wear comparatively rapidly, if they are busy averaging-out all those variations.

... Still a good bargain-price solution though !

MichaelG.

I've just been trying to think about the wear aspect..

Small nut, wears more than the leadscrew. Make the nut longer and its lasts longer (more metal to wear away) but presumably wears the leadscrew by taking the highs of the threads that are out of pitch relative to the average pitch. Once the screw high spots are worn away, the lead of the screw becomes a more consistent pitch.

No idea if this is what really happens but I have a vague memory of Joseph Whitworth using long nuts on early metrology equipment.

Ian P

Michael Gilligan14/07/2020 10:16:36
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15886 forum posts
693 photos
Posted by Ian P on 13/07/2020 22:33:24:

Posted by Michael Gilligan on 13/07/2020 21:37:31
[…]

The only caveat being that both the long nut and the screw will wear comparatively rapidly, if they are busy averaging-out all those variations
[…]

I've just been trying to think about the wear aspect..

[…]

.

Good thinking, Ian

... In reality the distribution and severity of the wear will [I believe] be largely determined by the nature of the errors in the ersatz leadscrew. : Pitch variations, lumps & bumps, eccentricity, etc.

MichaelG.

.

P.S. ___ Yes : Sir Joseph Whitworth used long nuts on his metrology equipment, but he also used very good leadscrews.

.

f6c3d910-a8a0-4f6b-ab39-82cf3a771e04.jpeg

Edited By Michael Gilligan on 14/07/2020 10:31:55

Len Morris 214/07/2020 11:27:23
17 forum posts

Can't understand all the concern about wear. Lubrication and an adjustable nut takes care of all that and incidentally never had to adjust the nut since it was installed. I probably use my miller at best for say an hour week. It's for a home workshop, not industrial use!

I find backlash on a miller to be very important, DRO or otherwise. On some jobs it can be very difficult to avoid a clime operation without a complete reset. Backlash under those conditions is not pleasant at all.

duncan webster14/07/2020 11:30:03
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2651 forum posts
36 photos

For light climb milling I manually push the table in the direction of travel with power feed on so that the leadscrew is just controlling the speed, not actually driving. I don't do this with big cuts!

Ian P14/07/2020 11:43:44
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2407 forum posts
101 photos

My comments about wear were triggered by Michael G's mention that a long nut setup would have 'comparatively rapid' wear.

What I said earlier about backlash was mainly referring to positional error, slide friction or sticktion has always been (on my machines) enough to overcome the climb cutting forces. Maybe I have my gibs set to tight?

Ian P

Michael Gilligan14/07/2020 13:50:56
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15886 forum posts
693 photos
Posted by Len Morris 2 on 14/07/2020 11:27:23:

Can't understand all the concern about wear. […]

.

dont know ___ What concern ?

I, for one, was just engaged in conversation

MichaelG.

Len Morris 216/07/2020 15:16:50
17 forum posts

Michael,

Fully accepted. No intention to be contentious.

Len

Michael Gilligan16/07/2020 16:17:50
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15886 forum posts
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yes

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