Touch probe and large bits

When I use the touch probe with bits larger than say 1/2" I get issues with the X & Y probing. So far I have issues when using a 1" surfacing bit and 3/4" straight bit. I put the touch probe on my part and try and center the larger bits on the circle. It will probe z but then when it moves to the zero the x most of the time it wont move enough and come down on the block. So I found to cheat a bit to the right when I have a larger bit it wont hit the block on the way down and will get a good x zero. But then when it goes to zero y it usually wont move enough to the back of the machine and the bit hits on the travel move to Y. I am a bit frustrated as the machine asked what diameter bit I am using. What’s the point of asking me if your not going to incorporate that into the xyz zero. At this point I am thinking I will have to load 1/4 bit zero xyz then change to the larger bit and then zero again. Anyone else have issues with larger bits.


Are you entering the bit size before you probe this should allow the controller to adjust to the diameter of the bit size and adjust accordingly?

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I had the same problem, you just have to use a 1/4" bit for x & y, then do Z with your large bit:


@pootaholic, Yes I am entering the size of the bit. Thats why I thought it wasn’t working right. Why ask me what the diameter of the bit is if your not going to adjust the movement.

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It uses the diameter of the bit to calculate the distance it needs to move to measure the X and Y on the edges of the touch probe. But as Craig commented just use a smaller diameter bit as it just needs to know where the centre of the bit is.

Is there a plan to fix this from Onfinity? I had the same issue. I put the size of bit when asked but it is a 1.25" 3 sided surfacing bit and as you rotate the bit the radius is different so it could not get an aceturate reading anyway. I guess from reading the post here I have to use a small bit to set the XYZ then change bits and redo the Z? Correct?


Hey Wayne,

Surfacing bits and V-bits are not suitable for probing X and Y with a touch probe block.

Precisely. For probing X and Y, you could also use a bit’s shank. The only thing that matters is that you know its exact diameter (check with sliding caliper) and enter this value into the field that pops up when probing.

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