automatic feed slip? help

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Speedy

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I cannot remember in terms of adjustment how to fix this below symptom.

I have a full size engine boring bar, kwikway.
when I engage auto feed the machine will bore into the cylinder smoothly, but as it gets further down the cylinder the column will drop with a thud and leave a small ridge in the cylinder uncut.

is this a symptom of the column gib bearing being too loose?
 
You might try posting on Practical Machinist forum. More guys on there working with fullsized automotive machine tools like the Kwikway.
 
Hi,

Been many years since I owned one of those, got rid of it because I wasn't really using it.

It's possible the gibs are loose and the cutting load is slowly building up until the screw and nut push it down with a thunk. But it should show poor finish also. It is also possible the screw is loose and riding up on you until it thumps itself down. Worst case is a worn nut and screw.

You will need to track it down to know for sure.
 
thank you Dalee, and hopper.

I went with the loose gib idea and broke out the measuring tools, I had 1.5 thou of play. seemed loose to me and found the manual online. it calls for .0002 back/forth play for total of .0004. so I was very loose.
after fiddling with it for awhile I got it in spec and had to compromise being tighter in the lesser used areas. slightly worried I am slightly to tight but will go with it.

runs great now :)

I could only make one pass on my test cylinder as its to thin now, but I noticed at the end it left a portion uncut. I don't know how I could pull the bar so far out of alignment with adjusting the gib so I am hoping my prior attempts of boring with the loose gib was the culprit.
measuring all the areas that did cut, I am on the money, including the lower portion around the uncut area. will see if my local bike shop has a old cylinder and will test again to be certain.
 
Not being a wise ass here, but 1.5 thou (.0015) is a lot of play. Specs call for .0002 - .0004 ? Maybe time to stone or scrape the ways.
 
no worry, in my previous post I did state I got everything in spec and the ill symptoms are gone.

just tracking down another cylinder to confirm its boring true. and it should..... I hope.
 
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