Line boring JD B block on a LeBlond Lathe

My neighbor brought me a JD B two cylinder engine block asking if I could bore it out from 5.600 to 5.750 diameter for custom pistons he's had made for a pulling tractor. My Van Norman 777S can only go to 5.3 inch diameter and my horizontal mill doesn't have enough travel to bore the 14.5 deep hole. I could make a longer bit holder for the Van Norman and some spacers to center the bar in the bore. The hole in the base of the Van Norman is only 5.6 inches in diameter so I'd end up boring out a .150 in step in the base of my boring bar. I don't think it would harm the boring bar but I hate cutting on it if there's another way.

I was thinking and reading up about line boring it on my 19" LeBlond. I have a 4 inch diameter solid bar stock I could make into a boring bar but my problem is supporting and centering the work piece in lathe. I don't have t slots in my saddle so I'd have to remove the compound and then fabricate a plate as a work table to support the block. I'm concerned that I won't get a ridged enough platform and I'll end up with a egg shaped bore or worse. There's also some looseness in the saddle I'll have to find a way to eliminate. I can make a table out of a 1.5 inch thick aluminum plate to bolt to my compound mount using it's two clamp screws. I can also make a bracket to support the work table from underneath where a steady rest normally bolts to the saddle. I guess, my question I'd appreciate your input on is the likely rigidity of the table for a single point boring of such a large hole? I don't want to screw up his block so unless I can be pretty confident in my set up, I'd better pass. I'm hoping someone has successfully accomplished something like this. Thanks.

I do a lot of rube gold berge set ups, and it is possible to do it this way but I think it would be best to pass on this one. A boring mill would be a much better. I have a 19 inch LeBlond and I think you will have chatter problems even with a 4 inch bar, it will have to be about 30 inches long.

JD Model B blocks will be hard to get if you mess up. Just my 2 cents

It would be money well-spent to find an automotive machinist who has a boring bar. Regards, Clark

I have rebuilt crank grinders for the following companies who I would bet could do or know who can do the job.
Southern Illinois Crankshaft, Inc. is a Job Shop / Contract Manufacturer located in Red Bud, Illinois, USA. and This company sells company also Engine rebuilding equipment. Call them and find out who can do the job right. Barks Equipment - Cape Girardeau, MO - New and Used Automotive Machine Shop Equipment Rich

In addition to what Richard said you can try these guys in Davenport IA. Seems like they get into a lot of nutball automotive & diesel stuff.

https://abrahamsmachine.com/index.html

Good luck
Matt

I think pretty much any decent automotive machine shop can bore that block. I have had blocks on two JD-B's and a JD-D bored and sleeved back to standard at a local shop with no problem. (As I recall, the JD-D, with two 6-3/4 bores, cost something like $700 complete with sleeves. I think just boring a JD-B block oversize wouldn't run much more than $250 total -- that is not worth trying to jury-rig something and screw it up!)

Do you start a hot rodded JD-B with a crank, or is it a push start then.

I guess I've not been to a tractor pull recently.LOL

Thanks all, I think I'd better pass on this one. I like helping my neighbors out but they won't think I'm helping of I ruin the block. I appreciate all the comments.