I am working on developing a collection of involute gear cutters for my shop. I just acquired a pair of new 8DP cutters for a project and they both have what I would say is an unacceptable amount of runout. I don't expect them to track perfectly, but I feel that .018" and .027" variation measured from the bores to the tips of the teeth is a bit much. I can make these work with a pair of custom offset mandrels, as I want to finish the job this weekend. What is an acceptable standard for concentricity?
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Involute Gear Cutter Runout.
- Thread starter dcash
- Start date
- Replies 4
- Views 1,217
rblalexander
Aluminum
- Joined
- Oct 28, 2015
That's pretty terrible, but in the end it doesn't matter so long as you touch off on the highest tooth. If the runout is that bad I wouldn't trust the profile grind to be anywhere near right though.
Rudd
Stainless
- Joined
- Jul 30, 2003
- Location
- savannah, jaw-ja
So how are you measuring runout? Does your number include how ever much your arbor is out?
(Just had to make a new arbor for my horizontal because the one that came with it was off. Cutting is more even now.)
(Just had to make a new arbor for my horizontal because the one that came with it was off. Cutting is more even now.)
Screwmachine
Titanium
- Joined
- Mar 8, 2001
- Location
- Switzerland
Absolutely
You should check your arbor, then shift the cutter through 45 degree turns on it and hopefully cancel out.
Then there's the face of the arbor (and cutter)... ..
My arbor has less than .002" run out. I measured the cutters themselves from the center bore to the tip of each tooth. I know I can just touch off with the highest tooth, but then the thing bangs away like a one tooth fly cutter because nine of the teeth aren't sharing the work, and the feed per rev must be slowed by a factor of ten. You can see the wobble from across the room on the worst one.
Asked the distributor to check their stock before sending replacements but only got "We don't have the equipment to do that". (You are a tool distributor but you don't even have a dial caliper?)
I'm going to set them up on an indexing head so I can measure the back of the teeth to see if the error was introduced during the form relieving process or final sharpening, as I can regrind the face of the teeth to remove the error. Checked a dozen other cutters and all had less than .002-.003 variation, even a couple Chinese ones that look like hell but work surprisingly well.
Thanks for your input.
