Line boring one piece vtwin kohler block

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FTlatheworks

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I have a one piece vertical engine block with cast iron sleeves. I have a pm1236 lathe. I need to bore the sleeves out at least .020in. I was hoping I could make a jig for the carriage and power feed it towards the chuck. It’s a v twin, so I would have to make sure to set it up at the right angle. The other problem, it’s not technically line boring, since the tool I would make will only be held in the chuck and maybe a steady rest for added rigidity.

Is this possible to do? You may ask, why don’t you just send it to a machine shop? The answer is, I can’t afford all 65 of my hobbies. Also, I want to see what I can get away with on a cheap high hp build. Please let me know what y’all think.
 
It probably depends how much the block weighs and if you can align it at center height on the bores.

Stu
 
From my experiences with kohler v-twin engines I would have to say I don’t think your lathe would have the swing to bore a cylinder. Have you checked?? Also you would need to bore about three to four inches length. Which I would suspect would be pretty flimsy. Idk the standard way would be setting up in a mill or dedicated boring machine. I think your best bet would be a mill and a stout boring head.
 
The answer is NO you can't bore cylinders satisfactorily on a lathe that small. Maybe on a much bigger lathe. A lathe carriage is
not ideal for holding workpieces. It's made for holding cutting tools. The carriage is only stable with downforce applied.
The block will move around too much and ruin the bore, I'm sure of it.
Plus you'll spend hours trying to align it correctly- impossible meat
Need a milling machine with power downfeed
 
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Alignment is difficult, even with a carriage made with T-slots for add ons.
 
That easily could be done on our L&S or our old 1917 south bend.

The older machines had t slots on the carriage just for this TYPE of work.

Can yours, maybe.

Line boring required a bed long enough to move the work PAST the cube that is mounted in a mandrel between head and tailstock.

The alignment needs to be perfect.

Work held on carriage perfect.

This is a quick and cheap job for a engine shop, they do These in their sleep.

You will not save any money, your setup time will be long and one chance to destroy your block.

Also of note, how thick is the special lining?

We changed rings in a Command 20 that had so many hours the rings were almost gone, but no Ridge or bvious wear in the cylinders, look at getting correct size pistons Orr correct shop.

Sent from my SM-G781V using Tapatalk
 
Just curious could you use a boring head for a mill chucked in lathe rather then line boring or making some kind of tool.
 
FTlatheworks said:
I have a one piece vertical engine block with cast iron sleeves. I have a pm1236 lathe. I need to bore the sleeves out at least .020in. I was hoping I could make a jig for the carriage and power feed it towards the chuck. It’s a v twin, so I would have to make sure to set it up at the right angle. The other problem, it’s not technically line boring, since the tool I would make will only be held in the chuck and maybe a steady rest for added rigidity.

Is this possible to do? You may ask, why don’t you just send it to a machine shop? The answer is, I can’t afford all 65 of my hobbies. Also, I want to see what I can get away with on a cheap high hp build. Please let me know what y’all think.
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I have a large mill with power down feed so I would bore a cylinder on that, but you can accomplish what you are attempting to do, just check the clearance over your carriage with your part. I think you can use the 2 bolts intended to hold your follow rest for a carrige fixture hold down and I would personally hold the boring bar between centers..... In the attached video Quin does a simlar operation on a much smaller machine.

 
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Cylinder boring is a specialized operation because you need to stay perpendicular to the crankshaft. I've built many, many small engines (racing karts), believe me this is a job to outsource with a shop that has the right equipment.

You could make the equipment yourself, but probably not practical for one-off use.

Here's the type of tool used for this job.

KWIK WAY BORING BARS AND STANDS

allstates.com

Most automotive machine shops should be able to handle this job, I'd recommend calling around to shops in your area to find one with experience here.

John
 
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