Tooling for worm gears

[losikid]

Anyone know where i could get the cutter to turn me out some chromoly worms...its for the losi hd gears, i think .75 module

[squirt]

you need a gear hob machine to do worm gears properly . if you had access to a cnc with a 4th axis on it you could tilt the 4th on the proper angle and run the gear hob on the side of the blank in the the 4th axis while it is spinning at the right timing. can be done but you need some coin for the cutter and lots of programming time. and a couple of practice pieces. just the cutter would be around $250 or more.

squirt

[losikid]

No i need the worm pinion, not spool...so it is a simple lathe threading operation...but i need to know what type of thread it is or what tool to use. and also threads per inch, etc to know what feeds and speeds to set the cnc. Which i can probably figure out

[Erik D_lux]

We had to have our cutters custom ground. The thread angle does not match anything off the shelf. Also, buy a couple. You might go through quite a few depending on the material youre using.

[losikid]

Originally Posted by Erik D_lux

We had to have our cutters custom ground. The thread angle does not match anything off the shelf. Also, buy a couple. You might go through quite a few depending on the material youre using.

Well its the hd worms so it may be different, i'm going to put them up on the optical comparator tomorrow and see if i can gather any more info on them...like the angle, and shape of the thread. I have ground my own threading tools before, but that was just a simple 60* angle

I don't plan on running many, 5-10 sets at tops, just enough to finish up the stock, I'll keep 1-2 sets for myself, i'll send you a set like we were talking before, and who knows with the rest, give them away or sell them, re-coop my costs.

It be non hardened 4340 (chromoly correct?), then hardened after machined out. Atleast thats what i'm thinking.

[losikid]

For those wanting to know the angle is ~42* and the flat spot on the bottom is ~.02 wide...this was with a quick glance on the optical comparitor, i may be a smidge off. I'll get them dead on when i';m grinding out a tool for them, unless i can find a carbide, it will be hss tool

[HndsWthtShdws]

Originally Posted by squirt

you need a gear hob machine to do worm gears properly . if you had access to a cnc with a 4th axis on it you could tilt the 4th on the proper angle and run the gear hob on the side of the blank in the the 4th axis while it is spinning at the right timing. can be done but you need some coin for the cutter and lots of programming time. and a couple of practice pieces. just the cutter would be around $250 or more.

squirt

Or you can mount a round gear blank on your lathe toolpost and push the blank into a worm gear with cutting edges ground into it. You would need access to a simple lathe of pretty much any size. Can be done but you barely need any tools and only a couple hours pissing around in the shop. Keep It Simple Stupid.

Sure he is using a bought hob, but for four parts you can use a steel worm and a dremel/angle grinder to create cutting edges:
http://www.youtube.com/watch?v=wiYDdffAJLQ

Cutting the worm itself is just like cutting a thread, but you can make the thread any shape you want, all it takes is a $0.40 tool blank and 5 minutes at the bench grinder:
http://www.youtube.com/watch?v=0q_q53wsyHU

[losikid]

Originally Posted by HndsWthtShdws

Cutting the worm itself is just like cutting a thread, but you can make the thread any shape you want, all it takes is a $0.40 tool blank and 5 minutes at the bench grinder:
http://www.youtube.com/watch?v=0q_q53wsyHU

Yep, but i'll be cutting chromoly, so a hss tool blank isn't ideal, it probably need to be shapended/ regrounded after 1 worm, possibly halfway inbetween, BUT i think i'm going to try and take a 60* carbide cutter, grind it down to the 42* and try it, i'll have a couple feet of stock so its worth a try