Repair old boring head?

ScrapMetal

ScrapMetal

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Guys, I picked this old German made boring head on the cheap. It looks like it's had a very hard life and the holes where the boring bars get mounted are egg-shaped. I'm guessing they continually used too small of bar in there and it slowly beat them to this shape.

germanbore01.JPG

germanbore02.JPG

I've been giving some thought to maybe repairing them. Should I even bother? I was thinking that I could bore it out even more and put in sleeves but I'm open to any suggestions.

Thanks,

-Ron
 
ScrapMetal said:
Guys, I picked this old German made boring head on the cheap. It looks like it's had a very hard life and the holes where the boring bars get mounted are egg-shaped. I'm guessing they continually used too small of bar in there and it slowly beat them to this shape.

germanbore01.JPG



I've been giving some thought to maybe repairing them. Should I even bother? I was thinking that I could bore it out even more and put in sleeves but I'm open to any suggestions.

Thanks,

-Ron
Click to expand...

I can't offer you the benefit of much experience, but it looks in the first pic as though there's a definite joint line between the holder and the cross-slide. If so, maybe you could separate the two and make a new holder, which might actually be less work than sleeving the old one?

M
 
I'm not so sure it needs fixing. If the hole had been pressed out of shape, some material would have 'flowed' out of the end of the hole. The ends are still perfectly flat and don't appear to have been dressed with a file. Looking at the intersecting curves, it looks like intentional diameters. It may have been designed to hold two specific shaft diameters. The end hole is identical to the side hole. Most machinists would use one hole more than the other, so they wouldn't be the same, unless they are still the original size.
 
I do think the small dia. bar will fit in the extra rounded hole nice and the bigger dia. bar will fit nice in the bigger dia., try it out the way it is and the set screw will hold it I do think.
Paul
 
Ron,
I think if you sleeved it the sleeve material would be of insufficient wall thickness to resist being chopped out even faster.
But like Hawkeye says, the appearance of the holes seems to "similar"

Cheers Phil
 
What they said, and ignore mine. Theirs makes sense. :eek:

M
 
You ALL made sense! I'll take a closer look at it. I just wasn't thinking about it being shaped that way on purpose. I guess it would work though... It would be nice to have some documentation on it so maybe I'll have to dig in to this strange "internet" thing and see if there is any out there. Talk about a long shot! :headscratch:

As always, thanks much guys. You've given me another way to approach this.

-Ron
 
Tony Wells said:
It's made that way, Ron.
Click to expand...

+1

My old Flynn has the same shape holes--think about it--any round shank within reason will have 3 areas of contact: set screw, and two areas of line contact which will widen out to pick up sufficient area to carry the set screw load as the screw is tightened. This is like a v-block and superior to to 2 areas of contact resulting from an "undersize" bar being gripped by a set set screw in a round hole.

Regards

Bob
 
Thanks for confirming that guys. Now I can look for a set or two of boring bars to go with it. Anyone have recommendations on boring bars? - This will be for the horizontal mill on my Wells-Index. (I guess I need some for the Wohlhaupter boring head as well. See - Tool Gloat!)

-Ron
 
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