View Full Version : Broken Bit

01-27-2007, 10:22 PM
I completed a carving and then it was going to cut the board to size, so it told me to put in the 1/8 cutting bit. I put that in and I pulled on it to make sure it was in there good, and then it gave it test spin. The bit fell out. I waited for it to complete its depth measurement cause I figured it would detect that there was no bit and it would stop and tell me to insert the bit, which it did. I figured after that it would re-do its depth test, but it didn't. It went through a little plastic piece and made a hole in the center bar for the slider plate and broke about 1/8 inch off the bit before I could get it stopped.

Why did it not detect there was no bit in the collet and why did it not re-do its depth test after inserting the bit again?

01-27-2007, 10:24 PM
I had a bit fall out after the 'test spin' phase and I think it stopped on it's own, but I don't recall correctly. Maybe I just stoppped the machine. Sounds like a bug report to me....

Wood Butcher
01-28-2007, 08:05 AM

Remember the old rule, “Measure three times, cut once?”
We need to add
“Put in the bit, make sure it’s seated, and be prepared to stop the machine.”
Lubrication of the adaptor chuck and verification of operation should be done before every project, just to be safe.
My other favorites are,
“Measure with micrometer, mark with chalk, cut with axe.”
“Cut to fit, paint to hide.”
Good luck.
:D :D

01-28-2007, 10:56 AM
I believe the answer to this problem is if a bit ever falls out, before the depth is measured, and measures a missing bit, always unplug the machine or do something to reset the logic of the controller. A logic bit was probably set in the program when it went to measure the missing bit and the incorrect data was loaded into a register. The program most likely didn't know the bit depth data was out of limits because it was missing and it went on it's way fat, dumb, and happy not knowing you had stopped it and replaced the bit after the length check. This resulted in a broken bit, caused when the program thought it had a shorter bit than was actually installed or in this case, re installed after the bit length test was done. If you are in the middle of the program cut, and there is a problem changing the bit, there must be a way to reset the program to make the bit find home again, without unplugging it. This would be a question for the programmers to answer or if someone has found a procedure to do it please share it.

Reminds me of my days working for Sony when a Fanuc Robot was picking up Picture Tubes from one conveyor line with a suction cup and setting them in conveyor pallets on another. One day the pallets jammed before the Robot and it just kept dropping picture tubes on the floor where a pallet should have been. A forced on logic bit in the program was the cause of the dropped tubes, someone playing with the program. Normally it would have stopped and waited for a empty pallet but the "Pallet Ready for Tube" bit was forced set to always on in the Conveyor Omron PLC, Programmable Logic Controller. Until it was caught and stopped the Robot went on fat, dumb, and happy like your Carve Machine until the bit broke.

When it really got interesting at Sony was when the power blinked or went off with tubes hanging from suction cups all over the place in mid stride. 32, 27, 20, 19, and 17 inch CRT's, Cathode Ray Tubes, 24 hours a day 7 days a week. Now most of it is gone, progress..... Flat Panel's.