Dear Marc,

I will try to make this easy to understand, our most popular knives for
cryostats are 22 degrees. For sectioning on a cryostat we sharpen with a 5
degree facet each side of the knife which gives us on a 22 degree angle
knife a total of 32 degrees. If the knife is used for wax sectioning then we
use a 7 1/2 degree facet each side of the knife. These facet angles can be
used and  added to whatever knives you use except 'D' profile. I would keep
to a constant angle settings as above as if you keep increasing the angle
you will have to spend some time and loose valuable tissue finding the
correct angle each time you resharpen a knife, and eventually the angle will
be too great to get sections off.

Please note that in time the facets get very large this can cause a problem
for removal of cryosections, and the edge is not as durable causing more
frequent sharpening. This can be over come by having the faces of the knife
reground ( refaced) this then will virtually bring the knife back to its
original condition when new, at a fraction of the cost of a new knife.

We can or alternatively Hacker Instrument or other knife sharpening services
may be able to carry out this regrind for you, it cannot be achieved on an
automatic knife sharpener.

Please come back to me if all is not clear.

Best Regards

Alan Bright

Bright Instrument Co.Ltd.
St Margaret's Way
Huntingdon
Cambridgeshire
PE29 6EU
England

Tel No:+44 (0)1480 454528
Fax No:+44 (0)1480 456031
Email: AlanBright@brightinstruments.com
Web Site: www.brightinstruments.com




-----Original Message-----
From: Marc Slotemaker [mailto:mslotemaker@yahoo.com]
Sent: 13 February 2001 16:14
To: histonet@pathology.swmed.edu
Subject: knife sharpening


Hello everybody,

I have a question about knife sharpening. It's a basic
question since we just started into histology. We have
our knives sharpened automatically, and the person who
is doing this for us increases the knife angle each
time time the knife is sharpened, for instance from 35
to 35.25 degrees. Other people say this is rather
strange and the angle should remain constant while
sharpening. Also, what exactly is this angle? is it
the total angle between the two facets of the knife?
thanks in advance

Marc Kropholler

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