Machining an sbf raw forged crank

roverman · July 02, 2014, 11:41:27 AM

Anybody done this ? I have a good sized cnc lathe, but no live tooling, or tooling for crankshaft machining. I have a raw forging coming, of which I hope to machine for RV8/sbb. I plan to make 1.70" off-set fixturing, for 3.4" stroke. I'll like start at #3 main, for linear start dimension, to better accomodate the longer ford dimensions. Onward, roverman.

BlownMGB-V8 · July 02, 2014, 10:12:38 PM

You going to rough turn it and then have it ground and polished?

Jim

roverman · July 03, 2014, 01:44:06 PM

Yep, is the plan. Maybe have the rod journals rough/finish ground. They are already roughed for sbf, so "might" require welding, to make the RV8 off-sets. Onward, roverman.

roverman · July 07, 2014, 12:05:49 PM

Any skilled 4340 welders ? I've been quoted $100/journal, x (9), to submersed arc weld this crank. Not a viable option. How about argon flood tig ? What rod for 4340 ? Plan is to anneal,machine and nitide. Thanks, roverman.

roverman · July 15, 2014, 11:02:11 AM

It's here ! It's massive ! Must weigh 70+ lbs. Ford Windsor SVO,(Ford made). Capable of 4.1" stroke, a bit much for a RV8 ? More likely to be 3.4"= 302". Very small chance of finding 5L "vintage" anything class ? Onward, roverman.

roverman · July 15, 2014, 08:27:19 PM

Viola ! I've started making chips, kinda fun. Made quick/dirty V blocks, to mount crank on verticle mill. Faced snout end and center drilled, with 90 deg. spindle attachment,(very handy) ! Lathe is next. Onward, roverman.

MGBV8 · August 01, 2014, 11:50:06 AM

You need one of these, Art.

http://www.youtube.com/watch?v=81UjjSH2iFw

DiDueColpi · August 01, 2014, 01:07:09 PM

Holy crap Carl!!
What a machine.
The control that it exhibits is phenomenal.
Do you think that crank is just a demo or does it actually fit something?

Cheers
Fred

BlownMGB-V8 · August 01, 2014, 05:16:23 PM

Yes, well, just imagine the amount of programming that took. I'll guarantee you the crank is a mass production part. There's no way anyone would go to that much effort just for a demo.

Jim

MGBV8 · August 01, 2014, 05:17:16 PM

Don't know, Fred. Found it on a motorcycle forum. Pretty amazing.

MARTECH Machinery & Automation

http://www.martechcnc.com/

phongshader · December 24, 2014, 01:10:16 PM

any news or progress on the crank?

roverman · December 24, 2014, 06:37:44 PM

Alas, domicile outranks crank style. My current project is converting a modular classroom, to a residence. Seems like I never do nuthin-nice an easy. Cheers, roverman gone modular.

tbo · December 27, 2014, 08:39:29 PM

Wow. That was amazing . Wish my Dad was still around to see that.He had a machine shop with a big lathe about six feet long and a Model A three speed transmission mounted on it. When he went from first second to third gear cut metal used to fly off that thing in big long curlyques like it was going out of style!Still makes me smile just to think about it