"Gerald Ross" wrote in message

Maxprop wrote:
Having adopted Andrew Hilton's method for honing tools between
sharpenings,
ie--fining them on a disc made of MDF with a 6" PSA sanding disc
attached to
one side and a method of attaching it to the spindle on the lathe on the
other, I've run into a snag.

I used a 3" faceplate on my first such disc, but tried a second method
of
attachment after someone suggested this: turning a partial-thickness
recess
on the back of the MDF and gluing a nut (1x8 in this case) in the recess
for
attachment to the spindle. After two attempts at this, it's been a
failure.
In both cases I turned the backside hole slightly undersized for the
nut,
then seated the nut into the hole with a brass mallet while gluing with
gap-filling cyanoacrylate adhesive (super glue), and then applying a
fillet
of epoxy around the flats of the nut to fill the gaps between the nut
and
the hole sides. I even scruff sanded the flats on the nut to bond to
the
epoxy better. In both cases the nut eventually popped out of the hole,
sending the disc flying. I was not honing a tool at either time, and
the
lathe was set to its lowest speed--roughly 450rpm.

Any ideas as to why the nut won't stay in the hole?

Max


Did the nut seat on the shoulder of the spindle? If not, when it tries
to go further onto the spindle the end of the spindle will push on the
MDF.

I used a nylon washer between the nut and the shoulder of the spindle and
checked for any protrusion of the spindle before assembly. It was okay.

Try making a sleeve to go on before screwing on the nut/disk so
that you can actually tighten it a little against the sleeve without the
end of the spindle putting pressure on the MDF. Or if the remaining
thread is small, a couple of washers instead of a sleeve.

Another answer would be to drill a hole the size of the spindle all the
way through the MDF. The Paper will still stick and it shouldn't
interfere with the sharpening process.

I've been giving this some thought as well. I guess I didn't believe it was
necessary at first, but am considering a two step hole with the nut inserted
from the sandpaper side and the spindle protruding through a just-big-enough
hole in the back of the MDF disc. Of course I'd have to place a large
washer between the shoulder of the spindle and the MDF to keep it from
crushing.

Max