machining stealth diff halves

[jwscab]

I've tossed this around a few times and done it once before but never took great pictures

with the difficulty of finding 2.25 diff halves, I've turned down GT/B4 (2.6) diff halves, so I tried it again. It's a got a little pucker factor because you turn hard material so a lot can go wrong.

I have really nice collets and tightened up all the gibs and places on the lathe to keep it tight the best i can, as the one I have is rather lightweight.

the trick is to have brazed carbide tooling and a high head speed. I cranked up the pulleys to the highest setting. Couldn't tell you what carbide it is, some old one from a box of hand me down tools from a machinist cousin.

anyway, its pretty crazy, as the swarf comes off the tool red hot(cools quickly), basically you turn the metal to the point it gets so hot it softens and will machine.

all things considered, if you can get a pair of machined outdrives from the guy on ebay for $50.00, or the hard to find side by itself cheaper, it's definitely a better deal, but if you have some tools at your disposal, it's worth a try. You need to trim the OD, and the inner shoulder to seat the ring. its not identical to the stock parts due to the way the have the added lip on the OD, but everything works. I use a dab of CA on the rings to fully seat them.

original part on left, machined 2.6 diff half on right.

[Phin]

Nice.

Would it be easier to start with B3 (2.4:1) out drives? Custom Works even makes them in aluminum. https://www.customworksrc.com/cgi-bin/commerce.cgi?preadd=action&key=4381

[NomadRacer]

Machining hardened steel is a serious job. I've tried it with a small degree of success, ruining a few cutting bits along the way. I'd rather buy the ones on ebay from Dynotech that where on there a few days ago (got a set!) or get some nice aluminum ones from Brian, aka mk-Zero.