OK Zaxis Zeroing Technique - Benchtops/Mini/Bridgeports!

[BobWarfield]

I agree, you need a repeatable or known height, and that was a better choice of words than my "fixed", though in my mind I was thinking more of having all the heights the same or a few choices.

To answer your question, my ER32 collet chuck has such a feature so that the back of it is a flat shoulder that meets the nose of the spindle in the same place every time when inserted into the R8 collet. In that case, I would measure from that shoulder to the tip of tool.

The tool holders I have at present, some do, and some don't. However, they're dead simple to turn on a lathe, so making some with shoulders would be straightforward, at which point the same method would work. To simplify the operation on a lathe, I would turn them with shafts to fit an R8 collet rather than replicating the R8 taper as off-the-shelf mill holders do. Again, measure from that shoulder to the tip of the mill.

I must say that I have heard reports that mill holders with set screw are inferior in accuracy to the ER collets, however. If one is going to do some turning to make holders, it may make sense to take the time to do little ER chucks the way Tormach has. I'd have to run some tests to see what I think about it, but the complaint is that a mill holder never centers the mill as well as a collet due to the action of the set screw and necessary clearance in the bore.

Another point for Tormach is don't they have a way of clamping that shoulder to the spindle nose for greater rigidity with large cutters? Seems like I recalled that.

Best,

BW

[philbur]

Hi again Bob, Now it looks like we are going through the door in the same direction.

The disadvantage of the arbitrarily machined shoulder is that the taper has a tendency to pull further into the spindle the harder you tighten the draw bolt. With the Tormach (and your ER collet holder) design the shoulder is hard up against the spindle shoulder so the "draw" of the taper is irrelevant. I guess this would potentially be more of a problem with MT tapers than R8. I have not checked this issue but accepted it as read.

The method for using larger cutters with the Tormach system is to include a stiff rubber/plastic washer between the holder and the collet, to prevent the holder from "walking" out of the collet. The washer however reduces the z-axis mounting repeatability. Soin my opinion it's a bit of fudge. I have not as yet used this washer.

Regards
Phil

Originally Posted by BobWarfield I agree, you need a repeatable or known height, and that was a better choice of words than my "fixed", though in my mind I was thinking more of having all the heights the same or a few choices. To answer your question, my ER32 collet chuck has such a feature so that the back of it is a flat shoulder that meets the nose of the spindle in the same place every time when inserted into the R8 collet. In that case, I would measure from that shoulder to the tip of tool. The tool holders I have at present, some do, and some don't. However, they're dead simple to turn on a lathe, so making some with shoulders would be straightforward, at which point the same method would work. To simplify the operation on a lathe, I would turn them with shafts to fit an R8 collet rather than replicating the R8 taper as off-the-shelf mill holders do. Again, measure from that shoulder to the tip of the mill. I must say that I have heard reports that mill holders with set screw are inferior in accuracy to the ER collets, however. If one is going to do some turning to make holders, it may make sense to take the time to do little ER chucks the way Tormach has. I'd have to run some tests to see what I think about it, but the complaint is that a mill holder never centers the mill as well as a collet due to the action of the set screw and necessary clearance in the bore. Another point for Tormach is don't they have a way of clamping that shoulder to the spindle nose for greater rigidity with large cutters? Seems like I recalled that. Best, BW

[bill south]

Thanks Guys;
Has anyone had experience with the Tormach system? I was following Swede with his new setup before he went off the air and never "tested" the system or at least reviewed it as was his usual routine.
I've considered purchasing an entry level setup but the cost still has me stalled.
Thoughts???
Bill

[philbur]

I have been using the Tormach CNC system for several months now.

It provides the quickest manual tool change you can achieve. The only thing that would reduce the time would be the addition of a powered drawbar. It's not just the speed of the change it's the fact that the machine controller already knows where the tool tip is with out having to "touch off" each time. It really comes into its own for short production runs of say 20, 30 or 40 + parts. But even with one offs, if you have a range of tools already setup and entered in the tool table, then tool changes are simple and quick. It's extremely well made and accurate and repatability on tool positions is excellent.

Do you need it for the price, only you can say. The principle of operation is simple so if you are long on time and short on cash make your own. An endmill holder is about as simple as it gets.

Regards
Phil

Originally Posted by bill south Thanks Guys; Has anyone had experience with the Tormach system? I was following Swede with his new setup before he went off the air and never "tested" the system or at least reviewed it as was his usual routine. I've considered purchasing an entry level setup but the cost still has me stalled. Thoughts??? Bill

[BobWarfield]

Originally Posted by bill south Has anyone had experience with the Tormach system? I was following Swede with his new setup before he went off the air and never "tested" the system or at least reviewed it as was his usual routine. I've considered purchasing an entry level setup but the cost still has me stalled. Thoughts??? Bill

If you plan to CNC, you need some way to deal with tool offsets. I can't imagine having to touch off manually after every tool change, but I guess its all a question of how you value your time.

Towards that end, if it was me, I would be weighing whether I liked the Tormach approach better, or a touchsetting system where the tool touches down on a button and the offset is automatically calculated. I think you could probably buy the Aussie powered drawbar that Thomas has adapted to the IH Mill as well as setup a touchsetter for about what the Tormach costs, discounting your time, and there could be a fair amount of that involved.

You could also turn the equivalent of the Tormach on a lathe if you have the time and are equipped well enough.

OTOH, the Tormach is ready to go out of the box.

FWIW, I did do a bunch of research and gather some notes on Automatic Toolsetters for Mach 3. You can find that information here:

http://www.thewarfields.com/MTCNCTipsTechniques.htm

I regret that I was unable to uncover a finished "bulletproof" solution, but I did find enough clues to satisfy myself it could be done relatively easily.

Best,

BW

[MacCNC]

Nice toolsetting web page Bob!

I have been using the touch-off with paper trick but I think after reading your page I will try to make a simple plate switch and try some of those macros.

Mac