Just a Sparky
Hot Rolled
- Joined
- May 2, 2020
- Location
- Minnesota
This is just a brain teaser that's been stuck in my head off and on for a while now. I figure if I can get it down into writing here and discuss it openly rather than keeping it bottled up as a jumbled collection of half-formed ideas in my head then maybe I'll finally be able to stop thinking about it.
I'm trying to sort out the pros and cons of various different approaches of cutting the occasional one-off gear on old manual machines.
Specific to my situation are the small work envelopes available on my mill and shaper. A small Burke No. 4 with a single slot table and roughly 7" x 2" of travel + a 7" shaper. Finding suitable dividing heads for such small machines is not easy nor cheap.
This makes my 13" South Bend an attractive option in my mind for this sort of work - with a plentiful work envelope and a QCTP with height-adjustable tool holders for zeroing homemade involute form cutters. Through the use of a milling attachment plus a hydraulic motor and my 3/4HP power pack it wouldn't be terribly difficult to build a small horizontal milling spindle for it. This would open up the option of using true store-bought involute cutters in addition to cheap fabri-cobbled single point cutters. It would also minimize the amount of wear on my machine and the labor involved. E.g. 52 passes for a 52 root gear rather than 52 * N strokes per root. The only conundrum from there is figuring out how to index the spindle without turning the whole project into a Rube-Goldberg nightmare.
What are your guys' thoughts? Are compact, affordable indexing heads available to fit my single-slot mill and/or shaper that I'm not aware of? Should I look into electronic indexing with a stepper motor and some timing pulleys? Is there a better, easier way of doing things that I haven't thought of? Bearing in mind that this is all aimed at cutting a hypothetical once-in-a-while oddball gear that can't be purchased and adapted to suit. What's the best angle to approach this problem?
I'm trying to sort out the pros and cons of various different approaches of cutting the occasional one-off gear on old manual machines.
- One can index their lathe spindle somehow and grind an approximated single-point involute tool to be used in the tool post akin to a shaper. Or use a milling attachment and a spindle perpendicular to the work to perform a gear milling operation.
- Or one can use a horizontal mill in conjunction with an indexing head and either a real set of involute cutters or again, an approximated single-point tool.
- One could also use a shaper as described in the lathe solution above... with the need once again to purchase an indexing head.
Specific to my situation are the small work envelopes available on my mill and shaper. A small Burke No. 4 with a single slot table and roughly 7" x 2" of travel + a 7" shaper. Finding suitable dividing heads for such small machines is not easy nor cheap.
This makes my 13" South Bend an attractive option in my mind for this sort of work - with a plentiful work envelope and a QCTP with height-adjustable tool holders for zeroing homemade involute form cutters. Through the use of a milling attachment plus a hydraulic motor and my 3/4HP power pack it wouldn't be terribly difficult to build a small horizontal milling spindle for it. This would open up the option of using true store-bought involute cutters in addition to cheap fabri-cobbled single point cutters. It would also minimize the amount of wear on my machine and the labor involved. E.g. 52 passes for a 52 root gear rather than 52 * N strokes per root. The only conundrum from there is figuring out how to index the spindle without turning the whole project into a Rube-Goldberg nightmare.
What are your guys' thoughts? Are compact, affordable indexing heads available to fit my single-slot mill and/or shaper that I'm not aware of? Should I look into electronic indexing with a stepper motor and some timing pulleys? Is there a better, easier way of doing things that I haven't thought of? Bearing in mind that this is all aimed at cutting a hypothetical once-in-a-while oddball gear that can't be purchased and adapted to suit. What's the best angle to approach this problem?
