Thread: lead screw

Still searching

This company may be worth a try as well .........Mike

www.mooreinternational.co.uk

Hi Mike,
Can you not try to make one....just for the experience? Surely you can use the lathe as it is and get to use that magical reversing dog clutch?

Hi Ewan


The cross slide backlash on the Hendey is rather chronic, I'd hate to try and make a new lead screw on it as it is , it would be rather tricky to do as the tool might move . I maybe could use the Sheraton lathe as its much more ' tight ' in the crosslide .

I'd have to make a new nut as well, that's beyond me at this stage . Could you make a accurate 18mm diameter with 5mm pitch ACME bronze nut ?

I've noticed The Hendey has a short top slide travel for some reason, I don't know why they designed it that way its about the same travel as the Sheraton has, which is a much smaller machine

I have purchased leadscrew/nut combinations from TEA Transmissions in Queensland (Engineering trade components supplier - Special purpose engineering products - TEA Transmissions Australia).
They had a stand at the National Manufacturing Week exhibition in Sydney recently and they have a range of very interesting equipment.

John.

Buy more rod then you need and use the excess to make a tap.

Originally Posted by .RC.

Buy more rod then you need and use the excess to make a tap.

Yes I did think of the tap idea .But I think would make it from drill rod and then harden it .

The nut would be made from bronze , I could rough cut it with a HSS tool, then do the final finish with the tap .

Thanks for the link John .... I will check that out at the library

MIKE

If you don't mind me asking, what's involved in making an ACME tap?

Am I too simplistic to think of it as a piece of threaded rod (of the same thread) with flutes cut in it and then a chamfer or taper turned at the starting end? For a one off use in Bronze, would it need to be hardened?

Cheers,

Simon

That's about it. For a one off use it probably doesn't need to be hardened. The important thing (especially with phosphor bronze) is that it is sharp. From that point of view hardened will probably hold an edge better.

Michael

I would imagine the cutting edge of the flute will have to be in line with the centre axis of the acme rod, kind of like having the centre height right on your lathe. The bronzes I've worked with are 85% copper which is pretty soft in it's as cast condition but will work harden. Is it a single thread or a double thread?, the reason I ask is that on my lathe it's a left hand double start thread.

Originally Posted by morrisman

Hi Ewan

I'd have to make a new nut as well, that's beyond me at this stage . Could you make a accurate 18mm diameter with 5mm pitch ACME bronze nut ?

Once the Leblond is done i would say no worries(as long as i had the screw), but my little lathe doesn't like pitches that big. The idea of making a tap is good though. I would use a bit of silver steel for the screw and grind a tap with as many flutes as possible. I think Marks concern wouldn't be too much of a problem, so long as all the flutes are the same. I would want to finish grind them on a T&C grinder. Depending on the bronze you use it could work harden really quickly, or if you use a leaded gunmetal it will cut like butter but have a shorter life. Best to make a spare if this is the case.

Mike if you do make a tap and then "harden it" you will get some shrinkage of the diameter and also the length which will change the thread pitch slightly also.

How much I don't know ? But it would be a PITA if you go to all the effort and end up with a dodgy tap ?