Tormach Engineering Sneak Peak - Power Draw Bar

Matt D. explains the prototype power drawbar design.

Category:

Science & Technology

Tags:

• Tormach
• PCNC
• TTS
• Power Draw Bar
• CNC
• Milling

[JTMarlin8]

This is not a real power drawbar, just a pneumatic collet closer.

And the Tormach "TTS" is a standard R8 collet with straight shank tools. You can duplicate the whole setup for a lot less money.

The repeatability is probably decent as long as the R8 keyway remains intact. However, R8 collets + straight shank tools have more runout than tapered tool shanks like BT30s and larger.

[tormachlabs]

JT, thanks for watching. I'd like to clarify a few points for those not familiar with TTS (Tormach Tooling System).

TTS is a dual contact system. It has a 3/4" straight shank and a ground precision surface that references the spindle nose. As the collet closes, spindle nose contact comes under high pressure, so Z height is exactly repeatable.

[tormachlabs]

TTS was designed to be compatible with R8 spindles because of the wide use of the R8 taper in Bridgeport and other small mills. It was also designed to be a quick-change manual tooling system with the ability to use an off-line measurement system. These are features not available for conventional R8 tooling.

You are correct: BT30 systems will have a little less runout than TTS because of the elimination of the collet reduces the number of components in which TIR error can stackup.

[tormachlabs]

The benefit of TTS over BT30 and other systems is affordability. High precision toolholding systems have their place, but keep in mind that the machine tool is a system and there is very little advantage to using these systems unless your mill is capable of highly precise motion or operating at speeds where tool balance becomes an important consideration. For many small mills, such design is overkill.

[DAVIDDECAUSSIN]

If you triple the number of springs you will cut in half the pressure required to realse the tool. When you fully compress the spring the force required to compress doubles.

[DAVIDDECAUSSIN]

Looks great how ever you say it keeps the load off the spindle bearings. In the static load that pressure on the spindle bearings is minimal. If I may suggest from past experience that you at least triple the number of springs to reduce the amount that the springs compress. This will add a significant life to the spring life. I know because I learned the hard way. Keep up the good work. Your company has a fine product.

[saunixcomp]

This looks very appealing. This, plus TTS with a pre-set tool table, removes so much hassle yet avoids the cost of an ATC!

[hossmachine]

This is going to make many people very happy.

Shows the right way to get high clamping force for the TTS and cause no harm to the bearings.