- posted 11 years ago
Hi, can any denizen of the group recommend an UK supplier for Imperial
leadscrews? I'm after a replacement for my cross-slide screw (5/8" x 8tpi
Acme, left-hand thread, very worn!) that won't be too expensive nor so
inaccurate there's no point swapping it...
I appreciate that I'll need to make a new bronze nut to fit, interesting
bit of screwcutting to try there! Were I to try making an anti-backlash nut,
is the simplest way going to be making part of the nut a separate item that
screws into the main nut via a *slightly* different pitch thread joining the
two parts? i.e make an insert with the 5/8" - 8tpi L/H Acme on the inside
and a (for instance) 7/8" - 9Ttpi Whitworth (also L/H) on the outside,
locknut to suit? The main body of the leadscrew nut would have most of its
length threaded for the Acme screw, the rest for the insert (approx. 1-3/4"
of Acme, 3/4" of Whitworth so that more of the wear would occur on the
adjuster Acme thread).
This I think would mean a full clockwise turn of the "adjuster" would
withdraw it by 1/9" and move 1/8" along the leadscrew taking up 1/72" of
slack (roughly 14 thou") as it wears - I'd hope it wouldn't *need* a full
turn though! I'm aware that at a couple of points in the insert there would
be "minimal" thickness between the threads (about 50 thou") but this should
only be for a fraction of a thread turn...
Why Whitworth? I'm trying to stick with Imperial and contemporary threads
if possible!
Any pitfalls, pratfalls, practical difficulties I should be aware of?
Cheers all,
Dave H.