Where to purchase 3/4″ straight shank arbors?

[HollowpointParticipant @hollowpoint]

Hi guys

Does anyone know where I might be able to purchase some 3/4″ straight shank drill chuck arbors?

I want them for a tailstock turret which I purchased many years ago. I never got around to using it, but I would now like to give it a try.

The only ones I can find are from RDG tools. (B16). I have lots of different drill chucks I can use but I’m not having much luck finding matching arbors!

[bernard towersParticipant @bernardtowers37738]

I have two tailstock turrets and find that drill chucks get in the way a lot of the time. One of mine has ER16 collet chucks instead and gives you a lot more room.

[HopperParticipant @hopper]

I like Bernard’s ER collet set up. And they are cheap enough to buy these days, if you don’t want the top-of the-line micron-chaser quality ones.

But the drill chuck arbors should be easy enough to make up  in the lathe. Set the topslide angle with a dial indicator on a known arbor, or against a parallel turned bar and measure thou per inch of taper. Check fit of taper to chuck with a bit of felt pen line on the taper and adjust to suit if needed. Once you have got the angle right, make up a batch of blank arbors to keep for future use, as well as the job in hand.

No need for any fancy material or hardening. Mild steel will be plenty good enough for hobby use.

[DC31kParticipant @dc31k]

Not so easy to find in UK. Call Rotagrip and ask. Call Gloster Tooling and ask.

As above, 3/4″ straight shank ER chucks are plentiful from CTC Tools. Sell the excess Jacobs chucks you have and invest the proceeds in a modern tooling system.

Arc have 16mm ones in JT0, 1, 2 so you might be able to sleeve them.

Rotabroach items are always described as 3/4″ Weldon shank, so that could be an area to investigate but I do not know if they use JT chucks or threaded chucks as the norm.

Some available from US via Amazon:

These people have a selection, but are in US:

https://www.ebay.co.uk/itm/354300167202

Buy some 3 Morse to Jacobs adaptors (smallest size that will contain the 3/4″ shank – Chronos have 3, 6 and 33 JT very cheap. They also have JT3 on 1/2″ parallel, which could be sleeved) and remove the excess material. You can cut down a 3MT female socket so it leaves enough of the male taper of the JT adaptor projecting for you to turn it down (cheap CBN insert from China) to 3/4″ parallel. The cutting forces will be forcing the male into the female so the reduced length would not be a problem (light tailstock support will also assist).

The “batch of blank arbors” above is OK for multiple copies of the same thing. But if you have one chuck with each size taper on it, setting up for that taper might cost more time than buying an item with the taper already on it.

[JasonBModerator @jasonb]

You could by a parallel 3/4″ sleeve with MT socket, even ARC do these. Then put an MT drill arbor into that or save room and use an MT shank drill bit.

For commonly used drills then a holder much like a side lock would do. only need some 3/4″ PGMS, ream hole and cross drill  & tap for a grub screw

[bernard towersParticipant @bernardtowers37738]

As Jason says a piece of pgms wouldn’t take long to machine, worthwhile if you have a decent batch of parts to make and also a great space saver (you won’t catch your hands so easily on all those sticky out bits!)

Hopper the collet chucks where homemade.

[bernard towers]

On bernard towers Said:

…worthwhile if you have a decent batch of parts to make…

It is also worthwhile in the sense that you can tune the length of the pieces you make so that the point of each cutting tool ends up in nearly the same place.

Imagine if you had a stub drill, pilot drill and tapping drill: it is a lot less movement of the tool-advancement mechanism if the sharp edges of each all line up.

If there is a gross difference in the length of the tools, you can run out of travel on the tailstock, so lengthening the shortest item can also help here.

That is another advantage of ER collets: you can grip low down on the shank of a drill bit and high up, even partially on the flutes.

[HollowpointParticipant @hollowpoint]

Thanks for all the suggestions guys, much appreciated.

I eventually managed to find one of the arbors I needed on eBay but I will probably take all of the advice given and combine it all, I’m thinking an ER collect chuck and some home made arbors for the other slots.

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