Adam, I too tend to be overwhelmed by Mach’s tool-length/offset/fixture features. There is also a simple way.

Touch off on the top surface and set the Z-DRO to zero as you describe. Now jog over to the mill table (or any other reference surface that can be used as a repeatable datum) and touch off. Write down this value.

Now when you install the ball cutter (or otherwise loose your Z reference), touch off on the spot that was used as a datum above. Set the Z-DRO to the recorded value and you are good to go.

Hope this helps,
Al

Zero at the bottom was just a suggested solution that I think Himy made for you. That IS a solution, but it is not a rule. There are lots of ways to skin a cat, and you have not invented a new problem. We all have the same issue to deal with. You seem to have become impaled on the 're-zeroing issue, so my suggestion is to simply walk around that obstacle and not re-zero at all.

I'll just give you a quick example of the best way to solve your problem and you'll need to do your homework from there. You need to study the tool offset feature of Mach and get yourself a couple of end mill holders for whatever spindle taper you have.

Example: you have one endmill holder with your roughing endmill. You have another end mill holder with your ball end finishing mill. You LEAVE these items together so that you change the holder/endmill together as if it were one solid piece.

Now, since the holder/endmill combination has a fixed length, you simply need to tell Mach what the difference is and it will AUTOMATICALLY compensate for you when you change tools and you do NOT have to re-zero.  For simplicity, lets say the holder/roughing mill is zero, but when you switch to the holder/finishing mill and place the end on the same surface, the DRO now reads positive .25". No problemo, just tell Mach that your finishing mill is .25" longer than your roughing mill and when you change the tool, you tell Mach "changing to tool number 2 now" and Mach will automatically adjust for the longer tool.

That's all I have time for right now, but Mach has these features that are designed for exactly the situation you have, and it is invisible to the CAM program.   

Al- it took a few minutes to visualize what you discribed, but now I can se and understand it. Thanks. That will work.

Simpson - I´ve been playing with the different tool offsets. It works, but I don`t have the tool holder.
Im building a larger router and I use the Kress spindle. I dont think there is a tool holder for Kress, but I could weld some kind of stop on all my tools and messure the lenght from there.

I know I didn`t invented a new problem. I just thought there is some kind of a smart macro doing all the job.
I like the way you explain it for a newbee like me  "You LEAVE these items together so that you change the holder/endmill together as if it were one solid piece".  

But thanks for all your help. I know how it works now.

Adam

Im building a larger router and I use the Kress spindle. I dont think there is a tool holder for Kress, but I could weld some kind of stop on all my tools and messure the lenght from there.

If there is no quick change available for your spindle (or if is stupid expensive), and your tools don't bottom in the collets (or however you hold them) you can still get a repeatable reference length by just putting a collar on each tool so that it installs in he same place each time you use it.

That will have the same effect as an end mill holder realtive to your tool change proceedure. You measure the tool once and tell Mach how long it is and then when you change tools, you just tell Mach which tool you are going to use and it looks up the length of that tool and 're-zeros' for you  . . . is one way to view it.

The tool tables and fixtures can be a big elephant to eat for a newbee, but take it a bite at a time and you'll get it. It's worth the effort and you will wonder how you every got along without it, once you figure out how convienient it is and how much time it saves.

Quote from: kak on June 08, 2009, 05:53:27 PM

Im building a larger router and I use the Kress spindle. I dont think there is a tool holder for Kress, but I could weld some kind of stop on all my tools and messure the lenght from there.

If there is no quick change available for your spindle (or if is stupid expensive), and your tools don't bottom in the collets (or however you hold them) you can still get a repeatable reference length by just putting a collar on each tool so that it installs in he same place each time you use it.

That will have the same effect as an end mill holder realtive to your tool change proceedure. You measure the tool once and tell Mach how long it is and then when you change tools, you just tell Mach which tool you are going to use and it looks up the length of that tool and 're-zeros' for you  . . . is one way to view it.

The tool tables and fixtures can be a big elephant to eat for a newbee, but take it a bite at a time and you'll get it. It's worth the effort and you will wonder how you every got along without it, once you figure out how convienient it is and how much time it saves.

Of course, a tool with a collar for a depth stop, inserted into a collet, will only be accurate to a couple thou, as how far the tool pulls up into the collet will depend on how tight you pull the drawbar.

Regards,
Ray L.

If he had a drawbar, he'd be able to use holders.

It seems he is using a router head or something similar, so it would likely be a collet of some type.

Hello everybody, this is my first post.

I have the RayLs Mach3 Macros and screensets and everything is working perfect but I need one more thing and I don't know how to do it.

If I use "Auto tool zero", everything is ok because I have a DRO for adjust the "Plate Thickness", but if I wanna use the other things, like "Edge finder", "Vise X" or "Center Finder", I don't have a DRO for the "Plate Thickness".

How can I add a DRO for that?

I'm begginer so I don't know how to do. I need some help.

Thanks in advance.