Source of 2mm Pitch Large Diameter Leadscrews

Hi, i am looking to replace the lead screws in my X2 Mill with reasonably priced alternatives of a different pitch, instead of the existing 1.5x15mm i would be a lot happier with those of a 2mm pitch

i have managed to find 2mm pitch screws but the largest diameter is 12mm; which i dont think is large enough given the 15mm diameter of the current set

does anyone know where i could find some screws between 13 and 16mm (the exact diameter is not as important as the pitch) i will need both left and right handed screws and nuts... i have checked Marchant Dice, Zapp, Abssas and Moore International with no joy... is this something i am going to have to make myself? i assumed that they would be available as so many lathes use large diameter small pitch lead screws for the carriage feeds

any help would be greatly appreciated and thanks in advance

TimS Have you tried Halifax Rack & Screw in Brighouse Yorkshire

Roy

Tim

It may be worth asking the hobby machine suppliers whether they stock spares for similar machines, the likes of Chester, Axminster, Amadeal & Warco. I have always found that at least two of the above are always ready to help if they can. As many of these machines seem to be from siimilar designs you may be lucky and get a straight fit that requires no machining.

Good luck

Martin

From memory (and NOT from measuring) the lead screws in the Chester Champion 20V mill are 2mm pitch and about 15mm dia. Not sure they include a left hander though. The machine includes two different bronze nuts to fit, slotted with grub screws to take up the clearance.

Cheers, Tim (a different Tim)

Edited By Tim Stevens on 21/05/2014 09:21:27

i haven't tried Halifax Rack & Screw roy but i will send them an email... the usual problem of non standard items is cost

i will also have a look at the manufacturers you mention martin to see what they can offer; i had skipped them under the presumption that to my knowledge they all came with 1.5mm screws

Perhaps here you find something you can use http://www.maedler.nl/Category/1643/1620/76/77.aspx , strangly they use the word "slope" for the pitch of the thread or is that what is normaly used in English? Niko.

Thanks Tim i might look out for them if they do left and right

and many many thanks speelwerk/niko; they do a thread that would suit perfectly... ill have to look at shipping but i had not considered being able to buy studding in left and right hand

everything i have heard in english is the use of pitch to represent what they have called slope; however i can understand what slope means so it could well be an auto translation issue... strangely i would never have even considered the use of the slope for pitch so my searches would have never shown the site you suggested... so thanks again

Tim

I have looked at the above site and can only see 2mm pitch at the required diameter in the studding/threaded bars section. This I suspect this is standard studding with the metric iso thread form. I doubt that this will make an effective lead screw for a mill nor is it likely be accurate over any length. This is the sort of thing that is used in construction and I suspect you could buy the same from B&Q or the likes. If you look at the thread form used for lead screws it is I believe trapezoidal and rolled or ground for accuracy.

Cheers

Martin

Thanks for the extra info Martin; i share your concern with accuracy but the longest threaded portion i will need is 380mm (just slightly longer than the max length my metric lathe will take) they are made to DIN 975 so i dont know the standards for that; but a quick search showed that you can get trapezoidal threaded M16 which i admit would be better

so now to see if i can find an even more specialised thread form of an already nearly impossible to find item... is the reason they aren't readily available simply because people make these parts themselves or is it the advent of CNC reducing the need for finer pitch screws?

thanks, tim

Have you thought about ball screws, you can get 2x16, these people who do CNC conversions sell them

Hi Jason, i hadn't found any ball screws with a small enough pitch to strongly consider them; i have looked at the link and the prices are so high to rule them out completely; another reason i ignored them is because i thought ball screws shouldn't be used on manual machines due to the lack of holding resistance?

12 x 2 mm seems to be pretty standard for the X1 and X2 mills. Have a word with Arceurotrade (advert on right) they stock many spares for these machines.

Russell.

Have you thought of adding a 3:4 ratio with a timing belt and pulley drive? Sounds easier to me than replacing the screws and nuts. Anyway what's wrong with 1.5 mm pitch?

Hi Russel i will scour their pages fully later; last time i checked they were out of stock of some but maybe they have got some more in

John the reason for the change was mainly due to my terrible maths abilities; 1.5mm gets a bit complex for me; i needed to extend the length of the x axis screw as it only gives me a tiny amount of travel relative to the slide length so it seemed sensible to change to a longer screw of a more sensible pitch

i had considered belt drives and pulleys but it seemed a bit complicated when screws of the right sizes are made (just not necessarily available)

i have checked with Marchant Dice and they do make a 12x2 in right hand so i may use that on the x axis; make the y axis screw myself (perhaps with a Arc Euro 2mm Nut) and opt for a coarser pitch for the z axis to replace the god awful fine feed... would be oh so nice to find all the parts in one shop but unless i can find one i am stuck with a mismash :/

Tim, these folk do all types of leadscrews and nuts, you can check out the catalogue.

**LINK**

Chris Gunn

Hi Chris; many thanks for the link; unfortunately they don't do any in 2mm pitch should i be asking the reasons why they aren't available?

perhaps i should be asking what pitch leadscrews other people use on smallish milling machines? after a 2mm pitch the most obvious (to keep the maths fairly simple) would be a 4mm but a quarter turn per mm seems quite inaccurate

am i imagining a problem with coarser screws on small work?

should i be looking at even finer screws than my 1.5mm original?

or should i start practising cutting 2mm acme/trapezoidal threads myself?

Tim

Hi Tim,
I think the leadscrews on the Seig X3 milling machine are 2 mm pitch on the metric version. I will check when I next go to my shed. You may find someone that has fitted the extra long table to an X3 selling the old leadscrews. If you were not too bothered about accuracy you could just use M14 studding/threaded rod. It could work out cheaper to put some type of digital readout on your X2 than buy new leadscrews. You may be able to find an optical rotary encoder on a motor from an old printer and build a display unit. This was the first method I used to put a DRO on my X3. Even buying Chinese type linear scales could cost less than a new leadscrew.

Les.

Hi Tim

The Warco WM14 metric mill has 2mm pitch lead screw at the larger diameter for both the x and y axis. I believe that WM16 and WM18 use 2mm screw threads so it is not uncommon by any means.

Cheers

Martin

Tim

Why not consider an alternative approach. Keep your 1.5mm pitch feedscrews (good for fine control for small work) and fit digital readouts (DROs)?

Arc Euro have the iGaging type with remote displays which are not expensive and are easy to fit.

One big advantage is that the accuracy of the leadscrew then becomes unimportant. If you were considering using lengths of threaded rod, or screwcutting your own its unlikely you would get higher accuracy than the DRO would give.

Standard iGaging DROs have a resolution of 0.01mm but even with the standard leadscrews you can use DRO to measure the major distances and then 'fine tune' the slide position using the index collars. That way cumulative screw pitch errors are less relevant.

Ian P

In right hand you can get TR16x2 at http://www.ebay.nl/itm/Trapezgewindespindel-TR16x2-rechts-DIN103-100mm-3516-/310194464383

or http://www.igus.eu/wpck/3810/DryLin_Trapezgewindespindel?C=DE&L=en

and this one also has it in left hand

http://www.metallbau-pietrzak.de/shop/index.php?cPath=488_305_491_509

Niko.

Edited By speelwerk on 23/05/2014 09:40:48