Thread: 40 taper tooling confusion

I've just entered the world of 40 taper tooling with an old TOS mill and I'm trying to work out whether I should standardise on a particular type or set the mill up to easily swap between types with different drawbars etc.

Its ISO40 natively, so has the parallel section above the taper and M16 thread. The drawbar is retained somehow - haven't investigated how as yet.

Ideally it would be nicer to just have all ISO40, but the likes of BT40 seems to be more common in industry here down under, so more likely I can pick those up used for a reasonable price.

I've got all the original ISO40 horizontal arbors, but for the vertical spindle I've only got a small mix. Couple of original ISO40 shell mill ones, a new ISO40 collet holder and collets (something uncommon - not ER) and a couple of others - one has the parallel bit above the taper but not M16 (possibly NT40), and one with just the taper so the ISO drawbar won't reach it.

Any sage advice from those of you who have already been down this road?

Steve

If the price and availability is right use both just make a draw bar to suit.

I run a TOS FA3 mill and use ISO40/BT40/NT40 tooling. I simply use the appropriate threaded rod as a drawbar. I did make up a collar that I use to centre the drawbar.

I think I may have a picture of them somewhere. I'll see if I can find it.

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Originally Posted by Vernonv

I run a TOS FA3 mill and use both ISO40 and BT40 tooling. I simply use the appropriate threaded rod as a drawbar. I did make up a collar that I use to centre the drawbar.

I think I may have a picture of them somewhere. I'll see if I can find it.

The FA3 looks like a nice machine - much more manual and less electrics than mine. Looking at the electrical box on mine I'm wondering if I need to adopt your tagline..
A picture would be great if you can find one.
Was your original drawbar retained or did it just pull straight out of the head?

Edit: thanks - you beat me to it with the photo.

Steve

Originally Posted by OxxAndBert

Was your original drawbar retained or did it just pull straight out of the head?

There was no drawbar with it when I bought it - the guy I bought it off never actually used the machine.
As you can see the drawbar is not retained.

If you get BT40 tooling you can make a parallel section to screw in the top to replicate ISO40. That way you don't need a longer draw bar for running BT40. use low strength loctite to stop it unscrewing.

Originally Posted by OxxAndBert

Couple of original ISO40 shell mill ones, a new ISO40 collet holder and collets (something uncommon - not ER) and a couple of others - one has the parallel bit above the taper but not M16 (possibly NT40)

Probably 5/8-11 TPI.

I have all variants including SK40. It's a PITA. I just use allthread to make up drawbars as needed. Plus adaptors for the various threads. After a while you have enough bits to cover the options.

40 taper is good - plenty of surface area and decent drive dogs for power transmission, readily available and not too massive like 50 taper. The real sweet spot IMO.

PDW

Originally Posted by snapatap

If you get BT40 tooling you can make a parallel section to screw in the top to replicate ISO40. That way you don't need a longer draw bar for running BT40. use low strength loctite to stop it unscrewing.

I'd briefly thought along those lines but it looked like there wasn't going to be enough length to make it work. Awesome that it does.
Means I probably just need to make a 5/8-11 threaded drawbar for the imperial threads and I'll have most bases covered.

Steve

Originally Posted by OxxAndBert

I'd briefly thought along those lines but it looked like there wasn't going to be enough length to make it work. Awesome that it does.
Means I probably just need to make a 5/8-11 threaded drawbar for the imperial threads and I'll have most bases covered.

Steve

I have M16 to 5/8-11 and vice versa adaptors to screw into oddball holders. I found you can do quite a bit of butchery err adaptor manufacture using coupling nuts, FWIW. Just weld a short stud in one end. Loctite stud lock would probably work too but a TIG welded joint isn't going to fail.

One of my mills has a captive drawbar for M16 ISO 40 tool holders so I had to make a bunch of adaptors to use the short form holders. Once you have a bunch the pain fades a bit, though these days I try to only buy metric stuff.

PDW

Good idea with the coupling nuts - thanks.

Steve