Ed Huntress wrote:
"Ecnerwal" wrote in
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In article ,
"Ed Huntress" wrote:

You're probably aware that you only have to bore that line very
rough. Portable align-honing equipment to finish the job will take
out a lot of metal these days, although you won't be able to take
out the tens of thousandths they get with fixed diamond honing
machines.

No, I was not aware of that, though most of the web-links that come
up on align honing are about engine building and concerned with
working to tenths. I do find a few things more in the line of the
work I'm doing. Mind, for most of the stuff I'm doing, if I can press in
a bushing
without deforming its inside surface too much, I don't have to get
too fussy about the bore finish.

And I freely admit (and would welcome enlightenment) that I don't
have a great understanding of honing - I've got one of those "three
swivelling stones on a spring spider" cylinder hones which I've used
to reduce some burrs in a hydraulic cylinder, but those seem to be
dependent on having a good round, straight hole to start with.

Something like this:

http://greatnecksaw.com/images/produ...arge/25041.jpg

These look somewhat different, though there's not enough detail to
see how the head works in terms of stone movement. I gather it might
be somewhat more controlled than the above type.

http://www.precitech.no/Finbearbeidi...20prtabelt.pdf

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Honing has changed a lot in the last ten years. It used to be
strictly a finishing operation. Now, thanks to the diamond abrasive
and non-compliant production-honing techniques developed by Sunnen
and others, it can be used to remove remarkable amounts of metal and
it can correct out-of-round and out-of-line conditions that were
impossible years ago. It's replaced boring in some production
applications, combining what used to be two steps into one.

That's all done with fairly hefty stationary machine tools, but the
portable honing equipment used by small-time engine rebuilders and so
on has benefitted from some of this technology. I knew the subject
fairly well six or seven years ago, when I was researching and
writing about it, but it's slipped away from me. I don't know where
we are today except that it's somewhere better than we were with the
compliant-hone tools you're talking about.

Maybe someone involved in engine work or commercial machining
applications can fill you in. If not and if you want to know, get
back to me and I'll see if there's still anyone at Sunnen I can call.

The stones are mounted on rods with a rack cut into them , the center rod
of the hone assembly is a pinion that fits into a square block that has
holes for the rack rods . There is a small planetary gearset built into the
drive/center rod to extend or retract the stones . Two stones and two wipers
constitute a set .
At least that's how my Sunnen cylinder hone is made . And yes , they will
straighten an oval/tapered hole . I've used mine more than once to bore
motorcycle cylinders to the next oversize ... also works very well to
lightly scuff a cylinder and remove the ridge at the top in preparation for
new rings .
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