I just purchased a Tormach tooling system to use with my Sieg. I got everything I want with one little problem. I have a high quality keyless drill chuck with a JT3 mount. The problem is that Tormach doesnt sell a JT3 adaptor for use with their system. I believe I could make one since I purchased a great deal of tooling to go with my new lathe but I dont know the taper angle or how to figure it out. According to the wikipedia the small end is .7461 inches in diameter and the large end is .8110. The overall length is 1.2188. I know with this info you should be able to algebraically figure the angle out but I don't remember how. Has anybody else run into this problem and solved it. I am ordering a JT6 mount and was also considering turning a boot to fit over the JT6 mount and to mate to the JT3 mount. Any feeback is welcome, especially for the boot idea since it doesnt seem that good of an idea to begin with.

I also noticed the lack of a J3 TTS adapter. My Jacobs 14N ball bearing drill chuck uses the J3 taper also. Tormach needs to include the J3 adapter in their TTS tooling line.

Don Clement

Knowing the angle is not much use to you anyway. How would you set the compound angle to 2 decimal places. Try this this link.

http://home.iprimus.com.au/stevor/drill_arbour.htm

The guy has had more luck at turning tapers with this technique than I have. It might be something to do with the rigidity of his lathe.

Phil

I just purchased a Tormach tooling system to use with my Sieg. I got everything I want with one little problem. I have a high quality keyless drill chuck with a JT3 mount. The problem is that Tormach doesnt sell a JT3 adaptor for use with their system. I believe I could make one since I purchased a great deal of tooling to go with my new lathe but I dont know the taper angle or how to figure it out. According to the wikipedia the small end is .7461 inches in diameter and the large end is .8110. The overall length is 1.2188. I know with this info you should be able to algebraically figure the angle out but I don't remember how. Has anybody else run into this problem and solved it. I am ordering a JT6 mount and was also considering turning a boot to fit over the JT6 mount and to mate to the JT3 mount. Any feeback is welcome, especially for the boot idea since it doesnt seem that good of an idea to begin with.

Tormach offers a machinable blank part 30475: TTS Machinable Blank: Hardended and ground TTS geometry on the spindle end, but the working end is 39 mm x 60 mm cylinder of unhardened steel.

I'm thinking you could mount the blank in the spindle and a lathe tool in the vise and program in the taper. To get a ground finish mount a piece of steel with a straight edge set at the taper angle in the vice. With the spindle running bring the steel close enough to the taper so that a piece of aluminum oxide cloth will be lightly trapped between the steel and the TTS blank and pull the abrasive through. A squirt of WD 40 helps to keep the particles from clogging the abrasive too quickly.

Setting the steel at the right taper isn't all that difficult. Just press it up against the turned blank and snug up the vise. Back the table off a .001 or two and shine a light in the gap and tap on the steel if it needs adjustment.

To check the taper fit smear a little lipstick or Prussian Blue on the female taper and see if there is an even transfer onto the male part after twisting them lightly together.

Odo

Interesting approach for the taper. This is of course a method of machining all kinds of tool-holders etc. Concentricity is effectively guaranteed. It would be kinda difficult to get it wrong.

Phil

Tormach offers a machinable blank part 30475: TTS Machinable Blank: Hardended and ground TTS geometry on the spindle end, but the working end is 39 mm x 60 mm cylinder of unhardened steel.

I'm thinking you could mount the blank in the spindle and a lathe tool in the vise and program in the taper. To get a ground finish mount a piece of steel with a straight edge set at the taper angle in the vice. With the spindle running bring the steel close enough to the taper so that a piece of aluminum oxide cloth will be lightly trapped between the steel and the TTS blank and pull the abrasive through. A squirt of WD 40 helps to keep the particles from clogging the abrasive too quickly.

Setting the steel at the right taper isn't all that difficult. Just press it up against the turned blank and snug up the vise. Back the table off a .001 or two and shine a light in the gap and tap on the steel if it needs adjustment.

To check the taper fit smear a little lipstick or Prussian Blue on the female taper and see if there is an even transfer onto the male part after twisting them lightly together.

Odo

So if I understand u correctly u are suggesting using a cnc mill to do this. Or a lathe? If a mill, why. I'm a bit new to this so please bear with me but how do you program it in. I do understand the part about the cloth and ground finish and the prussian blue bit and that cloth bit is something i never would have thought of to get the ground finish.