Bitsetter probing failure in the cool

After running without problems yesterday I had a moment of panic this morning when bitsetter probing failure prevented machine initialization. After some experimentation, it turns out that the bitsetter plate was not returning to the top position after the first rapid -z travel of the tool pushed it down. A bit of gentle pressure with a finger under the plate was enough to get the machine running OK.

It turns out that the difference was that the shop temperature was 60F this morning; cool, but not really cold. I normally try to keep the shop around 68F for dimensional accuracy reasons. Once the shop heated up the bitsetter operated normally again. I do not know what the internal construction of the unit is, but it seems to be a bit temperature sensitive.

This is not a big deal, but I thought I would post about it in case anyone else encounters the problem and looks on the forum. I guess it just does not get cool in sunny California. :wink:

I had the same issue in the Utah winter. I removed, opened, and cleaned the BitSetter. I then used a PTFE spray for lubrication. No issues since. I’m guessing the lube they used freezes and the dry PTFE doesn’t. :slight_smile:


Mine’s hung up 3-4 times already. I take it all apart, blow out the dust, and tried a little WD-40, then tapped on it like a telegraph ticker. Still it eventually freezes up again.

Anyone know how to get the plunger apart for proper cleaning & inspection. Wondering if I polish the shaft or bearing surfaces it will help??

It’s likely because the WD40 is freezing. You may have to use something like PTFE that doesn’t.


It is threaded together. One of mine actually unscrewed itself just from use/vibration. One day it just quit working or was constantly activated. Was a bit tricky to get the bottom of the plunger back together inside the housing, but afterwards it worked fine again.

I don’t think any kind of lubricant is advisable within the bitsetter as it would tend to gum up the plunger/housing surfaces with a mix of fine dust particles.



WD40 goes on like a lubricant but dries to be a sticky mess. It was originally used to displace water on distributors on older cars. As @SLCJedi suggested the PTFE Spray would be better and after the propellant dries it does not collect dust like dried up WD40 would. WD40 is a good penetrate but a lousy lubricant long term.


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