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bully wrote:Looks like we may have to get someone to mill down the B4 outdrives to suit the 2.25 diff gear and rings then seeing as the oe 2.25 ones are very hard to find now.

won't work.

you know, instead of trying to wedge b4 parts inside a custom trans case and not be able to keep the stock mounting points on the rc10 chassis OR the motor plate anyway, wouldn't asking him to make 2.25 outdrives be the simplest thing to do? 2.25 diff gears and rings are everywhere right now. stock up.

i have machined down aluminum b3 outdrives to fit in a 2.25 for oval of course.

removing the raised lip on the outside of the b3 outdrive caused no issues?

I wouldn't think so. you lose a tiny bit of total width in the outdrives, and you might need to glue the diff rings, but I have been toying with this idea, I just have to put both parts in front of me and look at it. The only other gotcha is you might need to nip off a tiny bit off the male side of the adj. screw threads if it ends up too long. I think there is a ton of clearance there though.

the outdrives i had did not have a raised lip. they were completly flat accross the surface of the diff ring. i just machined down the the outer diameter and then the inner lip the ring fits on. while i was at it a also machined a D notch so i could run tc3 notched diff rings. they fit and work great, i have done this to 2 or 3 sets.

Any pics? Or possibility of mass production?

sorry i dont have any pics, or any handy to snap pics of. i would have to tear down a already built tranny since they are all currently in a transmission in my oval rides but next time i rebuild one i will have to take pics. as for mass production i no longer have access to a lathe like i use to. someone else would have to attempt it but first they would have to come up with aluminum b3 outdrives which arent as available as they once were.

I'd think you would be able to use any of the stealth outdrives, as long as you used carbide tools, I bet those steel parts are very hard.

thinking about it, the worst case, if the parts machine OK, you'd probably want to use a shim on one of the outdrives to add back the thickness of the lips that get machined off.

anybody got a junk b/t2, b/t3, b/t4 outdrive floating around? I could try it and see what happens.

I'm still alive, just sold the last 2 cases that were buried in my tooling/fixture box.

Trying to bootstrap my own shop right now, getting all the ducks in order, going through the motions, getting a proposal wrote up, waiting for everything to start into motion.

Part of what I need to do is prove there's a market that can sustain a business, so I guess I need your help.

If you guys can get me a semi-solid solid number of how many housings would sell if I could make them, it would put me that much closer.
I'm pushing to be incorporated and have at least one VMC in the bay by spring time, possibly have something running before that. I can dream...

I realize others have stepped in where I've failed, and I'm fine with that, progress marches on and I don't want to hinder it.

I can tell you all the "part time" shops in all segments of the RC market have had to go work for someone else. The door for a full operation shop to dominate the manufacturers market is wide open.

Sounds like there may be some interesting things in the future then.

You can put me down for a couple of casings!

Interesting that this thread popped up now. I picked up a new lh and rh side diff outdrive pair for a b4/t4 to try and machine down to fit inside a 2.25 stealth. It's doable, but like I said, it's hardened steel. I'll be able to pull it off for myself, but someone with a stronger/more rigid lathe would have to set up tooling to make a bunch of them. I was able to turn down the inside flange to fit the 2.25 diff ring easily enough, but turning down the OD is pretty hard on my lathe and tooling. So I'll have to grind it down to fit inside the stealth gear. The steel is hard enough that the collet just won't hold the outdrive during a heavy enough cut to work; since the drive and collet are both hard, it slips. You have to take a decently deep cut on the hardened steel with carbide tooling otherwise it just skates off the surface.

Hardened steel is a pain in the keister for sure...

It sounds like setup rigidity and surface speed are the main culprits in this case, but ti could be tool geometry as well.
Are you using an insert cutter, or a brazed carbide on a HSS carrier?

It may be easier to fabricate a completely new part than to modify the existing one, since those are rather thin walled to begin with, and if you crank down enough to hold them you'd likely deform them.

Case hardening can be done with a MAPP gas torch and a cavity made of fire brick if you are careful.

I've got a meeting tomorrow to work out the business plan, so the snowball ball is picking up speed.

300D50 wrote: I've got a meeting tomorrow to work out the business plan, so the snowball ball is picking up speed.

Good luck Walt with your endevour. Let us know what happens and how it works out.

Todd