[TR] Triumphs Digest, Vol 5, Issue 96

Randall tr3driver at ca.rr.com
Fri Mar 18 16:14:44 MST 2011


> You can do the same thing with a drill bit - grind the cutting
> edge
> of one drill flute longer than the other and it will drill an oversize
> hole.

Yes, but that happens because a drill bit is normally working from a
"center" at the tip.  Grind one lip longer than the other, and the point is
no longer in the middle of the drill (making it farther from the point to
one flute).  Run that same drill bit through a pilot hole (so the tip of the
bit no longer engages the work) and it won't cut oversize.  Or at least not
nearly as much.  A properly sharpened drill bit does cut just a bit
oversize. 

> There is enough radial clearance in the bearings

And even if there wasn't, the drill bit would flex that much.

> drill press quill

Who said anything about a drill press?  Remember, we are doing this by hand,
using the opposite bushing as a pilot.

At any rate, it wouldn't hurt anything if the hole were a few .001"
oversize.  Just put a dab of Loctite on the bushing before you tap it into
place.

And a cheap import reamer will do more carb bushings than you are likely to
wear out in a lifetime.  We're not talking about production machining of
thousands of parts or even turning the reamer with a machine.

-- Randall 



More information about the Triumphs mailing list