DIYbanter - View Single Post - How do you fit box tops? (Longer than it needs to be)

In article ,
(Arch) wrote:

I know and have used several ways for making an accurate "pop fit', but
all the methods that I know of end up with the sameole 'cutting &
trying' and a miserable success rate

How do Arch? I've learned to stop the fitting process before I get the
fit I want. I'll explain how and why later.

With the tenon on the lower portion and the mortise on the lid, I cut
and finish the lid first. Then trial fit the tenon to the morise. I
sneak up on it and stop even if the lid is too tight. As long as it fits
all the way on without undue (as in palm pounding persuasion or mallet)
force, I'm done with the tenon on the lathe. I go about working the rest
of the box to completion.

(When sneaking up on the tenon, I will make a superfine adjustment cut
on only half of the outer end of the tenon. This gives me a reference as
to how much I've removed (or left on the untouched portion) as well as
an opportunity to test fit the lid without the risk of taking the entire
tenon down. If the lid will mount on the smaller diameter portion of the
tenon, I'll just pare down the untouched portion - if the lid still
doesn't fit, I'll pare the untouched portion to the same level and trial
fit the lid anyway just to be sure - and start the 1/2 paring process
again. I start and stop the lathe a LOT during the process.)

After the whole thing rests for a couple hours I lap the lid to the
base. Making up my own homaid lapping compound as such: I skillfully
shape and build an aluminum foil tray. Then using two small sections of
wet/dry 320 sand paper, I rub the grit faces together over the tray so
that it catches the dust. Then mix in some furniture wax to make a small
amount of slurry and spread a bit on the tenon and mortise. Working the
lid on and off and twisting it in complete revolutions will, after a few
minutes, yield a perfectly fit lid. You can stop at the suction-pop
stage or else go just a bit further and stop at a fit that is a nice
friction fit but won't allow the bottom to drop off if the box is is
picked up by the lid.

TaaDaa, Viola and BobsyerUnkel.

--
"Sure we'll have fascism in America, but it'll come disguised
as 100% Americanism." -- Huey P. Long