Does anybody have experience using the tool setter or touch probe with a spindle that has ceramic bearings? Do they mess with the conductivity through the tool or do they work fine?
They kill conductivity. I had to switch back to attaching the magnet.
Agreed. My spindle with ceramic bearings requires using the magnet.
Ah, thanks, I suspected that might be the case.
How much does it bug you?
I’d buy a spindle with regular bearings. For hobby use the spindle will last a long time.
Kenric
I’m considering ceramic because I expect to be cutting a fair amount of metal and other non wood. Also if there’s any noise advantage i dont mind squeezing every possible db out… But mainly its because although this will be my first hobby CNC, I’m coming off about 5 years running a lower end industrial 4x8 with a fairly serious spindle on it, and I’m a little worried that I’m more likely to get over aggressive with it than too timid :).
I like the G Pennys with the “bullet head”, they look cool 
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Hey Bunkstaff,
what prolongs the life of ball bearings in spindles the most is a spindle with sealing air. This reliably prevents anything from getting into the bearings and can delay bearing wear for years. You should also make sure that you have angular contact bearings in the spindle.
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True. A spindle of a quality level that would justify/include sealing air is likely gonna be beyond my means. But the bullet head g-penny looks to have a much less permeable business end, and it claims angular ceramic bearings(series 7 if that’s a real thing). It’s cheap enough that I won’t be in tears when I trash it, and if I don’t, then the extra 100 or so seems reasonable for some extended life.
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I went with the ceramic bearings as I think they can operate at much higher temperatures, I have the Air Cooled G Penny and the internal fan blows from the top down and I believe the bearings are sealed from the outside environment to some degree. My spindle even when running hard for several hours gets no hotter than 105 F using an infrared gun on the outside.
With regard to the tool setter, ceramic bearings have no effect on the functioning as it is a mechanical switch.
Pat
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Thanks for the info Pat. Yes I also expect I may have some very long cuts, that is indeed another reason I’m looking at ceramic.
Wouldn’t the tool setter solve this problem? Never used one before.
Turn out ceramic bearings dont affect the conductivity through the spindle that the touch off block requires, so its not an issue. But to answer your question, the toolsetter works fine because its basically just a regular button closing a circuit internally. The touch-off block functions as a chunk of metal that closes a circuit when the tool tip touches it. If you were using just a toolsetter button without a touch-off block, it would just mean that you would have to set your z=0 manually, and the toolsetter would preserve that 0 setting between tool changes. Totally doable, but the touch-off block is handy. And anyway it’s not an issue, ceramic bearings don’t affect the touch-off block at all.
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Thank you. Basically need to use the touch block to zero even when using the tool setter or somehow manually zero first by some method. I suppose that makes sense.
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Exactly. Zeroing isn’t hard, just a little tedious. You just move the tip of a tool (that has already been measured) to the exact position of your desired 0 and reset the controller to 0 there. Often thats the surface of your material, but not necessarily, depending on how you setup your program. You can use a piece of paper slipped between the surface and the tool and move the tool down in tiny increments until the paper pinches, and thats usually close enough. I had to do it this way in a professional context for maybe a year while our touch off kept failing. Annoying, but it does give a deeper connection with the process I suppose.
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Ceramic bearings do not conduct electricity and in fact ceramic is a very good insulator. Can’t imagine how touch probing could work with them unless you use a jumper wire to the tool.
Pat