Posted by Bill S on May 08, 2005 at 10:44:03:
In Reply to: a big helix gear posted by owenlee on May 06, 2005 at 21:38:48:
Here is my thought about a setup that works and then begins to break cutters:
There is likely some looseness or play somewhere, probably in the workholding spindle. It sounds like the cutter may be climb cutting (just a guess), so any work spindle backlash can contribute to breaking the cutter.
With power off, mount a large diameter gear and put a dial indicator out at a radius so you can apply torque back and forth to the spindle and measure backlash. If you see any displacement in the dial when you relax the torque, then the machine's worm drive probably needs adjustment. Either the drive worm's endplay is excessive or the worm/gear mesh needs to have backlash adjusted out.
Also check any looseness in the table/ways and in the cutter for cutter endplay or cutter drive.
Climb cutting requires a pretty tight machine.
My bet is on the work spindle drive.
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