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

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 12×2 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 :/

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 Les, the problem with a straight leadscrew swap would be the length problem; i need screws quite a bit longer than i think even an X3 would allow

studding was looking promising for a while but getting it in left and right hand was another set of fun and games

as for DRO's i had considered them instead of different pitch screws but as i needed longer screws i thought i would swap to make my maths simpler and maybe fit DRO's later i do worry about rotary encoders only showing screw rotation and not actual distance travelled… but it would seem that i am a worrier

Hi Ian, thanks for the info on DRO's; i need new longer screws regardless of pitch and i would like them to be as accurate as possible; i think 2mm screws are a compramise that will allow good fine control as well as not making distance moves too painful;

as for screw accuracy most places seem to quote better than 0.1mm per 300mm; i dont know if thats good or bad but it seems fairly standard regardless of the pitch; i know a DRO will be better than this but i think i might opt for CNC first