Hello Matt,

Pen mills offer an important advantage over using a sanding station to
square the ends of your pen blanks prior to mounting on the mandrel... If
your drilled hole is not straight, centred and true - relative to the
squared pen blank, the pen mill will correct the ends and give you a 90
degree interface for your bushings to mount against.

The pen mill inserts inside the pen tube, following the drilled axis of the
hole, off centre or not, to give you the proper 90 degree ends on your
blanks. For the best fit of your completed pen, you want a true 90 degree
end on your pen blanks, relative to the drilled holes axis.

If you use a sanding station, you may well have a square blank and get a 90
degree end on it with your sanding jig, but if the drilled hole is slightly
off centre, you will not get an exact 90 degree face on the ends of the
blank, relative to the off-centred drilled holes axis. This may cause you
fitting problems when you go to assemble your pen, due to the slight gap
between the metal and wooden components.

Of course, you can use a sanding station, but I do not believe it is the
best approach to take if you want the most accurate and best fitting pens
possible, IMHO. As far as sharpening the pen mill cutters, yes they will go
dull after a time, but they are easily sharpened with a small diamond hone -
a few strokes and you're back in business.

The length of time between sharpening varies, based on the material you are
making your pens out of... Obviously, harder, more abrasive
species/materials will cause more wear than less abrasive types. Having said
that, I typically get about 100 pens out of my mill before I touch up the
cutters. It's easy to tell when you need to sharpen them, the cutter will
begin to chatter on the end grain surface when it needs dressing.

As for a technique to use with the sanding station, I'm not much help
there... I used this approach years ago, but abandoned it in favour of the
pen mill based system. To reduce the cost of the pen mills, look for systems
that offer interchangeable guide shafts. (Craft Supplies USA offers an
excellent system and is the one I use www.woodturnerscatalog.com) These
maintain the same cutter head assembly, but you change the shaft for each
style of pen you need to mill. These interchangeable systems are much
cheaper that purchasing the complete mills in the sizes needed for each
style of pen you desire to turn.

I should also mention that I have been using the same pen mill system for
the last six years or so... The cutter head has been sharpened many times,
but still performs flawlessly. I would think it would be hard to wear one of
these out in a lifetime. It has stood the test of time in my production
studio, which is no easy task for any tool. Take care and all the best to
you and yours!

P.S. Make sure you maintain the factory rake on the cutter head's cutters
when you sharpen them with your diamond hone. Compromising the rake angle
will cause degradation in cutter head performance, excess heat during the
cutting process and premature failure of the sharpened edge. Its simple to
sharpen the cutter head with a small DMT diamond hone. I use the ones that
are mounted on a plastic handle and measure about 1" x 2". Simply line up
the face of the hone on the same angle as each of the the cutter head's
teeth and give them a few light strokes... You're good to go for another 100
pens or so.

--
Better Woodturning and Finishing Through Chemistry...

Steven D. Russell
Eurowood Werks Woodturning Studio
The Woodlands, Texas

Machinery, Tool and Product Testing for the Woodworking and Woodturning
Industries

³Woodturning with Steven D. Russell² Volume #1 CD ROM * Available for
Shipment, ² Volume #2 CD ROM/DVD Video * Available Soon


On 8/10/04 2:31 AM, in article , "Matt"
wrote:

I have heard some say that barrel trimmers/pen mills get dull rather
quickly. I have been using a disc sander to square up the end, but by
looking at the pictures in the catalogs (craft supplies, psi) it seems like
a pen mill or barrel trimmer would do a nice/better job.

My dilemma is this:

1. I hear they need sharpening often
2. They are rather expensive - I want more than just 7mm. I would like 'O',
maybe others.


If #1 is true, then #2 is even worse because I'd be buying an expensive tool
that needs sharpening too often - i might as well stick with the sander.

Can someone with experience with these and/or disc sanders give me their
opinion?

And with regard to disc sanders, what technique do you use? I use a block
of wood with a hole in it. I place a drill bit in the hole(snug) and the pan
blank with tube over the exposed drill bit, then hit the sander with it. I
*have* taken off some of the tube by accident, but not much and it doesn't
seem to affect the pen's operation at all.