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Collet for milling, 12 x36
- Thread starter ELHEAD
- Start date
- Joined
- Dec 25, 2011
- Messages
- 10,552
First, two no-no's. Don't use a 3-jaw chuck and don't use anything on a 3MT shank that is not drilled for a drawbar. The chuck jaws and the milling cutters are both hardened and ground and the chuck will not reliably hold the cutter. A 3MT shank adapter that is not held in by a draw bar will sooner or later come loose while cutting and at the very least ruin the workpiece. Don't ask me how I know this.
1) The cheapest will probably be 3MT collets. Use standard diameter (1/16" increment) shanks on the cutters. Disadvantage only available in 1/16" increments and only up to 1/2" or so. You will need a 3/8"-16 drawbar.
2) Next for only holding end mills and key seat cutters may be the individual 3MT shank cutter holders in all the necessary diameters. Use standard shank diameter Weldon style (has a flat for the set screw) cutters. Disadvantage fairly cheap in the tang style but very difficult to find tapped for draw bar. Don't risk using the tang style. If you find a batch of them in all sizes and fairly cheap, you could consider modifying them to drawbar. Advantage, avaliable up to at least 1". You will need a 3/8"-16 drawbar.
3) About the same typical cost will be the original Atlas supplied cutter holder. If you don't have to pay an arm and a leg for the bushings. Consists of a 3MT to 1/2" shank cutter holder and four reducing bushings. To go with it, you may need to make two more bushings which Atlas did not supply (1/8" and 3/16"). Disadvantage only available up to 1/2". You will need a 3/8"-16 drawbar.
After these , the remaining choices in ascending order of cost are:
4) European style ER collets with suitable screw-on collet chuck. Advantage wider diameter range in each collet. Disadvantage may be inferior directional stability as they are much shorter than other collets. Size range depends upon which size group you use.
5) Atlas 3AT or generic 3C collets with collet closer adapter (3MT) and handwheel drawtube Advantage good directional stability - disadvantage cost. Collets come in 1/64" increments up to 1/2" and current commercial new cost is about $20 per collet for US or German made and maybe half that for Chinese (only 3C in the latter source).
6) 3AT or 3C with lever operated collet closer. Advantage speed of part change - disadvantage cost.
7) 5C collets with front mounted collet chuck. Advantage size capacity up to 1-1/16" - disadvantage cost of both collet chuck and collets..
Unless your choice is one of the screw-on collet chucks, you will need a spindle thread protector. I have all but #4 and for milling cutters usually use #1 or #3.
Robert D.
1) The cheapest will probably be 3MT collets. Use standard diameter (1/16" increment) shanks on the cutters. Disadvantage only available in 1/16" increments and only up to 1/2" or so. You will need a 3/8"-16 drawbar.
2) Next for only holding end mills and key seat cutters may be the individual 3MT shank cutter holders in all the necessary diameters. Use standard shank diameter Weldon style (has a flat for the set screw) cutters. Disadvantage fairly cheap in the tang style but very difficult to find tapped for draw bar. Don't risk using the tang style. If you find a batch of them in all sizes and fairly cheap, you could consider modifying them to drawbar. Advantage, avaliable up to at least 1". You will need a 3/8"-16 drawbar.
3) About the same typical cost will be the original Atlas supplied cutter holder. If you don't have to pay an arm and a leg for the bushings. Consists of a 3MT to 1/2" shank cutter holder and four reducing bushings. To go with it, you may need to make two more bushings which Atlas did not supply (1/8" and 3/16"). Disadvantage only available up to 1/2". You will need a 3/8"-16 drawbar.
After these , the remaining choices in ascending order of cost are:
4) European style ER collets with suitable screw-on collet chuck. Advantage wider diameter range in each collet. Disadvantage may be inferior directional stability as they are much shorter than other collets. Size range depends upon which size group you use.
5) Atlas 3AT or generic 3C collets with collet closer adapter (3MT) and handwheel drawtube Advantage good directional stability - disadvantage cost. Collets come in 1/64" increments up to 1/2" and current commercial new cost is about $20 per collet for US or German made and maybe half that for Chinese (only 3C in the latter source).
6) 3AT or 3C with lever operated collet closer. Advantage speed of part change - disadvantage cost.
7) 5C collets with front mounted collet chuck. Advantage size capacity up to 1-1/16" - disadvantage cost of both collet chuck and collets..
Unless your choice is one of the screw-on collet chucks, you will need a spindle thread protector. I have all but #4 and for milling cutters usually use #1 or #3.
Robert D.
- Joined
- Apr 30, 2012
- Messages
- 1,138
I think a 3/8" and 1/2" collet will do 99% of the milling you will do on the lathe. You can get them cheap about anywhere and a piece of all thread for a drawbar will get you going. Take small cuts and lock any axis you're not using.