Quote:
Originally Posted by Jared
Do you have any techniques for doing this well? We had a bad experience with really small tools (1/8" end mill for hex, 1/16" drill for corner point holes) in steel. We were feeding at under 1 IPM for most of it yet we managed to still break bits. I'm guessing it's quite a bit easier to do this in aluminum.
Also, would you recommend purchasing a hex broach? We don't have one, and we've recently ended up buying a bunch of gears/pulleys/sprockets that we could likely broach ourselves.
We've 3D printed with vex pro, B&B manufacturing for gates profiles ( http://www.bbman.com/catalog/category/timing_pulley) and SDP-SI. |
We don't do it in steel, there is no reason for the pulleys to be steel imo. I do know feeding too slow can be a problem, there are formulas out there for all this that others can cover.
We rough cut the OD of the pulley with a larger cutter (1/4" and above) to .020" or so larger than the actual OD. Then we rough the teeth partially with a 3/16" or 1/8" cutter (I forget), and then finish with a light pass with the 2.5mm cutter. I don't know exact feeds, speeds, depths, etc... but on our router (which is not a very fast accelerating machine currently due to steppers) it was ~ 6 minutes for the entire pulley (including pocketing) for a 24T 5mm pitch.
I would heavily recommend broaches, at least a 1/2" one at this point. Followed by 3/8". It really opens up your COTS options as quickly adding hex bores becomes easy. I'd recommend getting the matching size reamers to make machining that much faster.