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help with tool length offsets
« on: March 26, 2009, 01:45:31 PM »
Hey fellas,
I'm setting up a tool changer on my mill and have a question about TLO's.
I know mach needs a datum tool set 1st to reference the other tools but
have read posts saying the datum tool is tool 0 while others say tool 1.
If it is tool 0, how can you enter the Z height in the tool table?
I'm running ver 3.039.
Thanks Bill

Offline Graham Waterworth

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Re: help with tool length offsets
« Reply #1 on: March 26, 2009, 02:24:19 PM »
When setting up your machine there are 2 common ways to do this.

Tool 1 is your datum tool.

Your datum tool (Tool 1) is used to touch on the Z datum face of the part, the machine is zeroed at this position and all other tools are then touched on the same point and the difference in length is then entered into the offset for that tool.

The problem with this method is that if you change tool 1 for a different tool 1 then all offsets need to be reset to the new tool.


A probe or setting tool.

You use a probe (Tool 0) to touch on the Z datum face, zero out the Z axis at this point then touch each tool on the face and set every tools offset with the difference in length from the probe.

The advantage of this method is that all tools have a offset to a standard tool/probe.  If the probe is placed into a setting holder and a height gauge placed on the top and zeroed out the next tool can be put in the setter and the height recorded for that tool, this is then the offset for the machine for that tool.  This offset will not change unless the tool is moved in the holder or needs to be replaced.

« Last Edit: March 26, 2009, 02:27:16 PM by Graham Waterworth »
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Re: help with tool length offsets
« Reply #2 on: March 26, 2009, 04:24:02 PM »
so when I use g31 with my auto z probe 1st, that registers as tool 0?
If i try using g31 for say setting tool 6 later, that z height will then become the datum?
That might be where problems are arising.

Offline josh

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Re: help with tool length offsets
« Reply #3 on: April 10, 2009, 01:31:13 PM »
i dont know if you would want to try this method but it is pretty easy and fast.
first get a tool that you are never going to use that will be your set up tool.
know they sell sleeves to go over the drills with a little set screw. once you have a length set for that set up tool (say 1inch)
know all you do is get all your tools and put some sleeves on to the same height. as your set  up tool and know  all you tools are set all the time.
so all you have to do to run a new part, is set your set up tool and all the tools are set.
hope this made sence and also help out
Re: help with tool length offsets
« Reply #4 on: April 10, 2009, 04:10:46 PM »
On a knee mill setting tool length is easy. Select your longest tool and call it 1 inch.
Put it in the quill and run the quill down one inch.
Crank the table up to touch the tool. Put each remaining tool in the quill, run it down to touch and record the length.
Now when setting up a job, take any tool that you will be using, put it in the quill, run it down what ever its length is,
crank the table up to touch. All of the rest of the tools are also set now. If you put a new tool in a holder you just
use one of the other tools to set the table position and then touch off the new tool and record its length.
You don't have to change anything except the new tool.
Setting up this way, Z zero is Machine zero and the tool length offsets the tool down. That means you can't have a Z+
move without a tool length in effect that is longer than the Z+ move.