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POTD . What did you BREAK in the shop today ?
- Thread starter mmcmdl
- Start date
- Joined
- Feb 8, 2014
- Messages
- 11,176
I broke a tap also. But this one was a little different, it was a rounding error in the math. 
A bug in my CNC program in the rigid tapping routine. The machine was supposed to start at +0.200, move in to -0.875, then retract to +0.200. Well it moved in to -0.875, then retracted to -0.344, then decided to rapid out to +0.200.....SNAP. We have rigid tapped thousands of holes and not had a problem, but this time conditions were different enough that the bug showed up. It's these types of things that make you crazy
Found that I had set a variable to Integer rather than Double as it should have been, and in all cases prior to this setup it was rounding up to the nearest integer, but in this case the dimensions were such that it rounded down. Fixed the software and then tapped 250 5/16-18 blind holes, 0.875 deep in 304 SS with no problem. Spiral flute machine tap, after 250 holes it is still sharp and cutting fine.
A bug in my CNC program in the rigid tapping routine. The machine was supposed to start at +0.200, move in to -0.875, then retract to +0.200. Well it moved in to -0.875, then retracted to -0.344, then decided to rapid out to +0.200.....SNAP. We have rigid tapped thousands of holes and not had a problem, but this time conditions were different enough that the bug showed up. It's these types of things that make you crazy Found that I had set a variable to Integer rather than Double as it should have been, and in all cases prior to this setup it was rounding up to the nearest integer, but in this case the dimensions were such that it rounded down. Fixed the software and then tapped 250 5/16-18 blind holes, 0.875 deep in 304 SS with no problem. Spiral flute machine tap, after 250 holes it is still sharp and cutting fine.