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Van Norman 777 boring machine

Linkss56

Plastic
Joined
Aug 14, 2021
I have a VN 777 boring bar it says it will only do 5.3" I need to do 5.5" I don't see any reason it wouldn't do it with the right tooling is there any reason I wouldn't? And what would I need? Thanks.
 
Probably won't do larger bores because the centering apparatus (cat's whiskers, I called them) don't have enough length to expand to that diameter... so you couldn't center the bar in the hole.
 
Having used a VN bar for years, Joe E. is correct. If you extend the tooling out farther than designed and do not use the catspaws, you'll get major chatter and diameter variance depending on how deep a cut and the material.
 
if its just a one off or there all the same size make a fanged sleeve ring with an id of 5" that sets about a one inch deep in to the bore and center off of that





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The catspaws not only center the bar but they reduce chatter by lightly contacting the bore as it feeds down. It'd be nice to know what the op is trying to bore.
 
here are some pic. of the centering fingers van norman , kwik way and rottler the only one that i have used is the rottler and the fingers are used at the top of the bore above the ring were the bore is true and after the bar is centered the fingers are retracted [there not sticking out after that point]


Van-Norman-777-S-Boring-Bar-5-Centering.jpgs-l400.jpgOIP.lepbulyq8EDxXy4iwUJ9AgHaFj.jpg
 
My local machine shop folded up and nobody was notified, luckily I stopped by and got half of my stuff, who knows what happened to the other half. They only bored the blocks to 5.375 instead of 5.5 so I'm only needing to take off .125 I was thinking about making a sleeve that was .250 thick and sticking it in there so the boring bar could remain centered but wasn't sure how it would slide with the cats paws.
 
What are you working on? It makes a difference. I guess it's an aftermarket Dart block or similar. If so, a high nickel block bores and hones much harder than standard cast. You need to bite the bullet and find a shop with a 4 axis that can do the job properly AND put the bores where they are supposed to be. At that bore size, you probably won't have a lot of wiggle room for head gasket alignment.
 
A recently deceased friend of mine was a Mopar Guru.

He did things with slant 6's that you wouldn't believe. He even adapted a cylinder head off a Jaguar inline 6 to the Chrysler Slant 6... things like that. I never saw the finished product, just watched as he bored the head bolt holes offset from original to match the chrysler block.

Anyhow, he had an entire automotive machine shop setup at his house.... complete with a few of those Van Norman boring bars.

He had friends who were in to scrapping cars.. back before it was the big business it is now. They gave him every slant six they found.

He took those blocks and, with the aid of a ultrasonic thickness tester, would map out the cylinder wall thickness of each new block to find candidates for boring out to maximum diameter for creating engines for his dirt track race car. He explained that they were not all the same... core shifting and all that.

He also built a machine to bore motorcycle cylinder jugs and other small engines.

Sadly, he passed away and all that stuff is languishing in there, collecting dust, as his female siblings fight over how to get the most money out of his stuff. They'd never been in his shop since I'd known him.
 
I had posted what I was working on specifically but it must not have posted, I'm working on Minneapolis Moline blocks, they are cast in pairs and are separate from the crankcase. I have bored thousands of these over the years but not this big of bore, I have fabricated a table to hold that specific block even. The blocks are cast iron, I live very rural and the nearest machine shop is hours away and they want way to much money to do it. I'll figure a way to get it done with what I've got it's nice to be working with a already bored block that is true to begin with.
 








 
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