638 forum posts
I've been restoring a small benchtop mill from the 1940's, there is quite a lot of backlash in the x and y, I'm going to fit new leadscrews and nuts.
The current screw is 5/8, so a trapezoidal 16mm will be a suitable replacement.
I can only find one supplier for a T16 leadscrew and nuts, and it's a 4mm lead, ideally I'd prefer a 3mm lead, does anyone know any suppliers?
The one I found is called 'accu' and they only seem to have a 4mm lead.
Any help much appreciated thanks.
|Thor 🇳🇴||08/07/2020 06:10:27|
1411 forum posts
T16 with a 3mm pitch might not be easy to find, usually 3mm pitch go to T14. I found one in the US, this supplier lists T16 with 3mm pitch, may be expensive to get delivered to Europe though.
|not done it yet||08/07/2020 08:09:30|
|6321 forum posts|
Bornemann comes up on my ‘puter as a bespoke supplier. Would not be cheap, but likely no worse than importing from the US?
HPC Gears says ‘specials can be manufactured to order’.
|John C||08/07/2020 09:17:56|
|267 forum posts|
|Mike Woods 1||08/07/2020 09:27:06|
|40 forum posts|
I wonder if any of the Warco, Chester, Sieg, Amadeal or Axminster lathes or milling machines use this T16 x 3mm format. If so, the perhaps you could buy a spare part from one of the suppliers and modify to suit? Both my lathe and mill are in storage at the moment, otherwise I would measure them, but I am sure that the lathe is T16 x 3mm x 500mm. Mine is a Chester 920, so has a keyway over its entire length for a feed worm gear, other lathes which use half nuts for both feed and threading would not have that. Also, what is used on the remanufactured Myfords? Maybe others with ready access to their machines could offer some advice. Just a thought.
Edited By Mike Woods 1 on 08/07/2020 09:30:22
|John Haine||08/07/2020 09:27:50|
|4170 forum posts|
Was the original 1/8" pitch? 3 mm is an awkward number for dials. 2.5 mm would surely be better?
Why 16 mm? You can get 3 mm in smaller size.
|john fletcher 1||08/07/2020 09:29:21|
|724 forum posts|
If you do a search for lead screws , I think you might find some thing like Humber Engineering or Hull Engineering, both ring a bell but can't be sure. Some time ago some here ,spoke of an engineering company in the Hull area who stock lead screws and he was a satisfied customer. John
|Chris Evans 6||08/07/2020 09:32:47|
1959 forum posts
Not sure of your pitch but I have bought from Automotion Components in the past.
|William Chitham||08/07/2020 09:59:52|
|125 forum posts|
For some reason 2.5mm pitch screws are vanishingly rare which is a shame since that is what I need for a Boxford crosslide.
|229 forum posts|
There is a firm in Hull called Kingdton Engineering who make leadscrews
|Niels Abildgaard||08/07/2020 11:40:23|
|406 forum posts|
These people also has nuts (Mutter) and trapez 16 * 3.
|old mart||08/07/2020 13:09:32|
|3345 forum posts|
If you are replacing both leadscrews, check to see if they are right and lefthanded. If they are and you want to save money by buying one length of leadscrew, you will have to decide which axis will turn in the opposite direction to before choosing. I fitted a 3mm pitch leadscrew to the Smart & Brown model A at the museum to replace the worn out 8tpi one, and made a dial with 118 divisions on it instead of the original 125. This was because the rest of the lathe was imperial. With both leadscrews on your mill metric, you might just as well go with 120 divisoins, for 0.025mm steps.
If you end up with 4mm pitch screws, then dials with 160 divisions would give the 0.025mm steps.
Edited By old mart on 08/07/2020 13:15:16
638 forum posts
Thanks for all the suggestions, I will take a look at all of them when I have 5 minutes.
The screw on there is a 5/8" 10tpi that I believe is 1/8" lead, replacing it with a 4mm lead isn't the end of the world, it just allowed for slightly smaller divisions with a 3mm.
The company I originally found that does a Tr16 x 4mm works out about £50 - £60 which is pretty reasonable.
I'll have a look at some of the suggestions and see what the prices are and leave a note here for anyone else who might have a similar problem.
Thanks to all
|Michael Gilligan||09/07/2020 07:27:53|
18923 forum posts
Sorry, Pete ... I don’t understand that statement ^^^
21435 forum posts
Indeed, 10tpi will be 0.100" lead which allows for the handwheel to have a handy 100 divisions.
Personally I would avoid half mm pitches or uneven ones and go for 2 or 4mm pitch as it makes it easier to count the number of turns. 2mm should do on a small benchtop machine and allows a handwheel to have quite small divisions and is a lot closer to your existing 2.54mm pitch than 4mm. Not such an issue if fitting a DRO.
4mm pitch would also need a bit more effort to turn, lack feel and be a bit harder to set to an exact position as you will have less rotation for a given amount of movement.
Edited By JasonB on 09/07/2020 07:49:08
|Andy Carlson||09/07/2020 08:28:42|
|393 forum posts|
Imperial ACME screws can be had, certainly from HPC Gears in Chesterfield and Kingston Engineering in Hull so the first question is whether you actually want to change it to a metric pitch.
Also check whether each screw is right or left handed before investigating prices and availability.
|old mart||09/07/2020 18:46:50|
|3345 forum posts|
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.
|colin vercoe||09/07/2020 20:11:09|
|59 forum posts|
Halifax Rack and Screw company, if they are still in operation.
638 forum posts
Sorry, I'd had long day when I wrote that, I'm not surprised you didn't understand it, I don't.
It's a 5/8" leadscrew, 10 turns of the dial moves the table 1" which would make the lead closer to 2.5mm?
638 forum posts
You're right, after some consideration, 2mm lead would be much better.
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.