Straight shank tool holders?

[tk1971]

For the most part, I’ve been pretty satisfied with the sizes of end mills that I have collets for the Model 70 (1/4”, 5/16”, 3/8” & 1/2”).

I want to get a dividing head and would like to cut a gear but I’m having trouble finding straight shank tool holders. Seems like the import cutters have a 20mm/22mm bore while US cutters are 1” in the size/angle I’m looking at.

In an ideal world, my lathe is all back together and I’d just try to make one.

Anyone having the same issues? Any quick solutions?

 

[Chewy]

I am confused by what you are asking. The dividing head should be able to accept a collet or mount of some kind. It may have a Morse taper bore that you can get an adapter for or make one. Some have 4 jaw chucks mounted to the head. I use a spin indexer or rotary table. The spin indexer takes 5C collets. The rotary table, I make a stub shaft or bolt down on the face and then use dividing plates. If you are making a gear, you pretty much need some kind of shaft or protrusion to space away from the head for clearance. You may need to set up to turn between centers. It would help with a couple of pictures of what you are looking at and what you are trying to make. Almost everybody on this forum has experience in cutting gears and splines.

 

[tk1971]

The straight shaft tool holder is for the Rusnok 70 mill and would hold the cutter. The maximum shank diameter would be 1/2” and the cutter I saw while searching has a 1” bore size.

I don’t yet have the dividing head and I’ve been looking at pictures and videos of what others have done so I think I understand that part of it (mounting, etc).

If my lathe was running (still restoring it) I’d like to attempt making one myself, but I’m stuck on the mill side of this setup currently.

Thanks.

 

[Chewy]

Now that you posted the model, you are in trouble. A quick look says that machine uses Y collets and only goes up to 1/2" in size.

https://www.angelfire.com/nj2/machineparts06A/BrandsAtoZ.html

Check with Angelfire to see if they can find any others. You will have to measure and make your own collets from the looks of it. I would seroiousley look into another mill that uses R8. There are several videos and discussions on making collets, so I would start there first.

 

[tk1971]

1/2” collets is the largest for the 70. In order to use the readily available 1” or even the various metric import cutters, I’ll need an arbor with a 1/2” straight shank on one end and a tool holder in those sizes on the other end.

I bought an arbor with 1/2” on one end but 3/4” on the other, so it won’t fit any cutters I can find.

I have a feeling I’ll have make them with a lathe once I put it back together.

 

[Chewy]

Do you want to end up with something like this? It's an ER32 collet chuck. Turn the shaft and shorten to fit your existing collet. Then you can go all sizes from 1/16" to 3/4" and Metric. Bad point is you will loose a couple of inches in the Z. Just saw an ER 20 chuck with 3/8" shaft

https://www.ebay.com/itm/225036667655?hash=item34653b0b07:g:9woAAOSw~ANfcTOB&amdata=enc:AQAHAAAA8JLvS1DMky8A/IUdEZiCcbHNrr6hS4PG1T8ORJQQ9B5zbzPhEDQFiym4Wdv6nikILZLC1f0+kGA1kPTer2RUezu92S38QMAey+EOYarg7RgsizY2XuKOBIIWeJQSD8w9o+1QR/u54JWNEjQMus46DbKqiOyDDcRqjaPPYVh/NW8wWW8NKJGew7hDT1aDtJOy8dtYGuux3XI6seLSELYheUALUz936bOTCwQgGXWln/PyjUb7xeAJok/aNxi4/AU9kA6CaWyqV0QJjabIEBnPgjJ4jbGw9Z++qG4WeePzMoCdRfsVvYViRzg1sckicfhgfg==|tkp:Bk9SR_qFlZvhYA

 

[tk1971]

I'm going to try something. I'm going to get a 20mm gear cutter arbor with MT2 on the other end. When I get my lathe running, I'll turn it down to 1/2" for my Rusnok 70.

 

[tk1971]

I ended up with a 22mm ID involute gear cutter and a mt2 to 22mm arbor.

Some turning on the lathe to a 1/2” shank for the Rusnok 70 and now I can cut gears.

 

[tk1971]

I also bought an ER20 chuck with a 1/2” straight shank in order to use a 60 degree (20mm shank) dovetail cutter. Lost some Z, but the main concern is how much wobble that is visible just spinning it. There goes the precision, but it’s usable and likely fine for what I’m using it for (compound stop for my lathe).

What I’d like to do instead is to put the dovetail bit on the lathe and turn down the shank from 12mm to 3/8”.

Anyone know if metric Y collets exist?

Here’s a pic of the ER20 setup.

 

[pontiac428]

I think I've only seen 3/4" shank arbors for 1" cutters. Turning it down works, but I'm not sure 1/2" has enough holding power for a circular cutter. Probably the reason you aren't finding one. And stacking adapters is never a good formula for concentricity. Long stickout beyond the spindle is a frustrating recipe for deflection. That small spindle is going to be a challenge to work with. Maybe making a R8 or ER collet holder that fixes to the spindle using all available surfaces would be one possibility. Otherwise, someone is going to have to tell you that you are trying to do more with your mill than it was designed for.