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it's an insert not brazed. Yeah, I don't have too much experience with hardened material, it's probably a little bit of all things contributing, but rigidity/tool geometry is most likely, and you are right, it's probably easier to machine them new from fresh unhardened stock, and use something that is easily hardened post-machining.

Since I last replied to this thread, I had some time at the lathe, double checking all my machine settings, for tight gibs and proper tool geometry, etc. Happy to say that I managed to hit a sweet spot for the machine, and was able to spin up both left and right halves to use in a 2.25:1 trans. The trick to it was to bring the tool into the work at an angle, rather than straight in, of course it could be my cheap (probably chinese) inserts, and tool height was extremely critical. It did appear that the parts were either not as hard as I thought, or case hardened. I'll try and snap a pic tonight.

BTW, since these only cost around 5 bucks each, if they can be modified, it would cost way less than buying raw material and spending all the machining time at the going machine shop rates.

here is a crappy cell phone pic:

i have done that on aluminum outdrives before but never on stock steel ones.

yes, it look a little bit of learning curve to get it right, but it worked.

Looks good, yep that hardened steel needs a super rigid setup and the right tool position-height-spindle speed to cut properly.

Jake

Couldn't the steel be unhardened before the machining, and then rehardened afterward? Isn't the hardening process done by heating and then fast quenching, and undone by heating and allowing to slowly cool? I could be way off, I got a little lazy during the last half of materials science 201 when they were talking ablaut triple point and crystal structure....

yes, you could, but the process isn't exactly simple, and I don't have a tempering oven. It's easier to use a carbide insert, and spend a little time working to make it cut properly. It really isn't very difficult once it's set up.

Plus, annealing and heat treating ruins the finish, so it would have to be refinished afterwards.

jwscab wrote:BTW, since these only cost around 5 bucks each, if they can be modified, it would cost way less than buying raw material and spending all the machining time at the going machine shop rates.

here is a crappy cell phone pic:

Which outdrives are these orginally for?

Are the Dynotechs all sold out?

2.40 B2/3

These outdrives are b4/t4.

Have you used them? How did they work out?

I haven't put them in a trans to run, but i did a test build and they assemble fine and work as they should. The only real 'problem' that happens is you lose that little ridge on the outside of the diff ring. Most diffs in the industry have a flat surface for the diff rings anyway, so worst case, a drop of CA on the back side to help secure the rings would probably be fine.

This was another great tech thread. I was looking forward to the end seeing lots of cars running alloy transmission cases. Shame it did not pan out in the end. I wish you luck getting the project off the ground again.

Expect an update within the next month, with a proposal for a group buy limited re-release.