Need to borrow a 1/2-10 LH Acme tap, single start

[Steve Steven]

Anyone have one they would loan me? I am helping a friend make a compound nut for his Clausing MkII Master lathe, I cannot find a nut suitable to make into the required shape. The shape is a cylinder bored at right angles to the cylinder axis, can't find that shape available on the internet. I have a price of $60 for one of the taps, but would like to avoid that if I can since this will be a one-time use.

Suitable recompense in the form of parts, materials or $$ can be arrainged!

Thanks for any assistance!

Steve

[Bob Fisher]

If you happen to own a South Bend lathe, become a member of the same named forum. They have one to lend to owners. If you ask me how I know, I tried but, alas I own a Logan. OR maybe, alas for the SB owners that don't have Logans. At any rate, I finally single pointed several from different materials. The most difficult part is grinding the tool. Once you have accomplished that you can make one any old time. Thanks, Bob F.

[Alistair Hosie]

I can't get into borrowing or lending tools.Perhaps with close friends and certainly family no I have no problems ,but with complete strangers no sorry.I have tried this and it always ended in grief to myself and arguments with them,as I eventually despite all promises had to end up chasing the borrowers for my tools which had always been returned filthy covered in paint,or plaster and such things.I can see a situation when a company might have a lending department for tool hire say at a reasonable cost. Alistair

[Evan]

That is an easy tool to make. If you have a piece of lead screw the same thread then nearly all the work is done. You just need to grind some flutes in it and relieve it so it can cut. If you don't have some lead screw then it still isn't difficult to turn up a stretch of acme threaded rod the same size. If all you are making is just one nut it doesn't even need to be hardened. If you use 1045 rod which is commonly available you can harden it buy heating it red and quenching it in water, then heat in oven at 500 degree for an hour.

This is one I made from some lead screw stock and the nut that I cut with it, without hardening the tap.





If you use lead screw stock to make the tap then after tapping the nut freeze and then chase it again with the tap. That will provide a thou or so of clearance.

I would make the entrance taper longer than the one I made. It has a lot of material to remove in just one pass and it takes a BFW to turn it.

[Bob Fisher]

Sorry Steve, I just noticed that you need 1/2X10 LH. Logans use 7/16x10 LH. my apologies. Evan, I was able to find 1/2 but not 7/16 acme rod in a LH thread. Otherwise I may have considered your approach That is a nice looking tap and an even better looking thread. Is that leaded steel? Just to pull your leg a bit, did you score the shank of that tap turning it with your BFW ? Do you think that a plastic lead screw nut using your heating method would work for a crosslide nut? If so, what type of plastic?Thanks, Bob.

[PixMan]

I've got a LH 5/8-10 should anyone ever need to borrow it. It came from the great dealer in the UK, RDG Tools, and was cheaper than I ever imagined. It worked perfect to tap a piece of 660 bronze used to make a cross-slide nut for a Harrison M300.

I used the tap to make the nut, then turned and threaded the screw to fit the nut snugly. Once that was fitted, I drilled & tapped the mounting cross holes, cut the nut in half, milled away the required amount to match the stripped OE nut (to afford backlash adjustment in the future) and sent the lathe owner on his way.

http://www.rdgtools.co.uk/acatalog/A...EFT_HAND_.html

[Evan]

I scored the end with the BFVGs.

The next one I made I ground the end square. An acetal nut should work just fine. In that picture is the acetal nut for the Y axis on my mill, also tapped with the same tap. After three years of heavy use I am thinking of replacing it since it now has a few thou of lash.

The steel of the leadscrew is 1040, I seem to recall. It isn't leaded.

[Bob Fisher]

Love those VG's. Sometimes nothing else will work!

[Steve Steven]

Thanks, guys. Looks like no one has one, so we will buy one.

Steve

[medwards]

I've got that tap. I might even have a compound nut for that lathe that is still in decent condition.