:) A question for the home hobbiest. What is the best, easiest, most accurate method or methods, for setting the z-axis to zero. I've read about using feeler gauges, setting it by eye (does not apply to my 54 years young eye balls), or using new fangle electronic gizmoes (there is a new thread on this today, go figure!!!), or maybe tissue paper during a full moon!!! Cost is always a factor but I'm wondering just what everyone is doing!!!
All inputs are appreciated, especially those who have been creative. It always amazes me how some jobs get done!
Bill from South Carolina
:banana:

Bill,
I've started cutting strips of paper, and using that as a feeler guage under the cutter. It's repeatable for me, and I think I :cheers: :cheers: had seen it in the Tormach manual from their web site. They may have used cigarette paper. I just cut up strips and measure the thickness.

Works for me,
Ron:cheers:

what about tool setters?

Go cocks!

I use paper on top of the work or with a gauge block. Fast and easy.

Steve

I third the paper trick. Right on top of the work. When the paper just starts to grab under the tool, I set Z to 0.004. That's close enough for me.

Brian

Thanks Guys. I'll have to try the paper trick this weekend. Sounds accurate enough and most definately, my price range!
Bill

The paper trick, often referred to as using cigarette papers (they're thin, uniform in thickness, and were in everyone's pocket at one point), is the most common way to do touch-offs (the official name for this action).

If you need more precision, there are electronic devices (as mentioned) and there are also rigs that use a dial indicator. The latter can be built if you have a spare indicator (there is a nice bit about how to do this on the Industrial Hobbies web site), or you can buy a handy little gadget to do it that is built into a cube exactly 2" high. You move down until the need moves, read of the value, and the offset is exactly 2.<value>". You can set the little cube atop your workpiece or the machine table depending on what sort of offset you're trying to determine.

eBay seller 800watt offers these little cubes on eBay for circa $30. Just do a search on "presetter" under the Business and Industrial category and you'll see a variety of such things. Auction #140026272002 is one such. Just put that auction number in the eBay search to see it.

A related approach is to preset the tooling in the holders at a known height, use the tool offset table in your CNC software, and just tell the program the known height. You can either measure the heights with a height gage, or buy a tooling system from an outfit like Tormach that offers a system designed to keep them all at the same height.

So there's really two issues. One is finding "Work Zero" and one is accounting for different tool lengths. You're CNC software will let you attack these separately (nice if you have multiple tools that want to run quickly for production) or treat it all as one event.

Best,

BW

How about building a zero setter using a l.e.d. and disc battery. You could make a 3 layer aluminum block using delrin or a similar materilal to isolate the electrical poles. Once completed, measure it to establish the known height value or adjust it to a desired value. I think it would take less than 2 hrs. and cost less than $4.00 in parts. Plans for a practical device may be a good post topic, any suggestions.

I place a mark on the top of the job with a permanent marker pen and then VERY carefully bring Z into contact with the spinning cutter until I see the cutter scratch the ink....... Very close! Havent had a problem yet. Same procedure for X and Y.

Hi Bob, this is not correct. You still need a height gauge to provide the tool offsets. The point of the Tormach system is that the tool tip always remounts in the same z-axis position, eliminating the need to "touch off"
again.

Regards
Phil

You can either measure the heights with a height gage, or buy a tooling system from an outfit like Tormach that offers a system designed to keep them all at the same height.

BW

Hi Bob, this is not correct. You still need a height gauge to provide the tool offsets. The point of the Tormach system is that the tool tip always remounts in the same z-axis position, eliminating the need to "touch off"
again.

Regards
Phil

Tormach ships a height gage and small surface plate together with their toolholders. If you have mill holders, a height gage, and a surface plate, what is to keep you from setting them yourself to a fixed height? Yes, you lose their quickchange aspect, but at least all the tools are at the same height, or perhaps one of a very small set of heights easily remembered or labeled on the tool rack.

In fact, you can buy commercial systems that do exactly this called tool pre-setters that are intended for use in the tool crib. When you go check out a tool, it's in the holder and you get a slip of paper telling you what height and tool table entry to select.

So given your own height gage, and a bit of ingenuity, you can duplicate the fixed tool height function of the Tormach system by presetting your tools to a known height with your gage.

Best,

BW

Hi again Bob, We may be passing one another in the doorway here.

If you have a tool holder with an MT or R8 taper what height will you measure, from the tool tip to where? The Tormach system fits spindle shoulder to tool holder shoulder so you measure from tool tip to the tool holder shoulder. It's not a fixed height it's a known height. This gives repeatable height location to a very high degree when used with tool offsets.

Regards
Phil

Tormach ships a height gage and small surface plate together with their toolholders. If you have mill holders, a height gage, and a surface plate, what is to keep you from setting them yourself to a fixed height? Yes, you lose their quickchange aspect, but at least all the tools are at the same height, or perhaps one of a very small set of heights easily remembered or labeled on the tool rack.

In fact, you can buy commercial systems that do exactly this called tool pre-setters that are intended for use in the tool crib. When you go check out a tool, it's in the holder and you get a slip of paper telling you what height and tool table entry to select.

So given your own height gage, and a bit of ingenuity, you can duplicate the fixed tool height function of the Tormach system by presetting your tools to a known height with your gage.

Best,

BW

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

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


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

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

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

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

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

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