Page 75 - The Strad (February 2020)

TRADE SECRETS

Adjust the cross slide The reamer in the lathe
to the desired angle

Chuck the reamer blank into your lathe and turn it down to the desired size, matching the taper of a standard endpin reamer. On most
5 metal lathes there is an angled cross-slide that can be adjusted to cut at an angle. I set mine about 40 years ago and have never touched
it since. The cross-slide is also good for turning down endpins when you want to make them smaller rather than reaming the hole larger.
Once the reamer is turned down to the correct shape, it is a good idea to seal the wood with some varnish or shellac to prevent it
from deforming with changes in humidity and also to help in removal of the abrasive paper when you need to put on a fresh piece.

The next step is to prepare a paper template for the spiral shape of
6 the sandpaper. The accuracy of your template is important, as it will
ensure that the sandpaper will wrap around the core with no gaps. It usually
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Trace the template on the abrasive paper and cut it out with an old knife.
It is also possible just to glue regular sandpaper to the wooden core, but if
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Adhesive-backed sandpaper and template

The spiral wrapping of the sandpaper
7 prevents it from having an edge that
might catch and tear when using the
reamer. Begin at the larger end of the cone,
wrapping it around in a spiral fashion. The
key is to start at the correct angle in order
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is also important to prevent the paper from
unwrapping when the reamer is turning. Wrapping the sandpaper round the reamer

Using the reamer
I recommend using a fairly strong drill with a good speed
8 control. I have found that it works best at a medium speed.
It must be fast enough to get some momentum going, but not
so fast that it catches violently when it jams. If you can have
Omobono hold the cello securely, that would be a huge help.
Otherwise, clamp it in a cradle to the bench for good support.
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to true up the hole or to correct the angle. Check the alignment
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correct. Try not to build up too much heat as this will compromise
the adhesive on the sandpaper and cause it to unglue. Proceed
slowly and carefully, and you should have excellent results.
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