On Mar 2, 12:05*pm, Ecnerwal
wrote:
I'm seeking thoughts, insight, tips or tricks relating to portable line
boring. I have a backhoe, and when it was built, LBJ was president.

None of the usual suspects (MSC/Enco/McMaster) even admit to the
process. Several specialty suppliers have setups which seem godawful
overpriced ($1500 or so and up) for what they are - and don't even start
me on bore welders (5K+ and it still needs a MIG welder to run it - but
I can get by with boring and sleeving, I think). One guy offers a book
and plans and DVDs, also godawful overpriced ($1.5K). None to be found
on sleazebay at present.

I'm leaning towards kludging something together in the $500 (less if I
can) and sweat realm, which may not have auto feed (if it's manual feed
and the manual feed is fine enough to work, that should be OK, and
cheaper).

The basic structure of these things is a bar/shaft of whatever length,
and bearing sets that are tack-welded (or tackwelded and screwed) to the
machine. You line the bar up with either the hole (easy with cones) or
the centerline of where the hole is supposed to be if it's badly worn
(they mostly are) and chuck a lathe bit into one of several square holes
in the bar. There's some sort of power to rotate the bar, and some sort
of feed which will at least go a bit further than the spacing of the
holes in the bar. You fire it up and bore as far as you can, or though
one flange if it's something like bucket pivots, then set the bit in a
new hole and bore more, or in the other/next flange. Good for things
where the machine to be worked on is difficult to bring into the machine
shop.

--
Cats, coffee, chocolate...vices to live by

Guy Lautard had a description/rough diagram of such a setup in one of
the Machinist's Bedside Readers, the one he described was used for
blower housing reboring. I've also seen similar rigs shown for
reboring steam locomotive cylinders in situ, basically a keyed
rotating bar with two end plates and a drive pulley, the cutter holder
slid on the keyed bar and was advanced using a screw with a star wheel
on one end. The trick was to get the two end plates lined up in the
center of the hole to be bored, then fastened into place so they
didn't shift under cutting load. I've seen similar rigs in Model
Engineer magazine in the past for boring stuff that was too big to
swing in the lathe. So not a new idea. Just something that's not
really a commercial product these days.

Stan