RE: blades in general

From:"McCormick, James" <>

Dear Blade Complainers, Having grown up with a hone and strop, I know what a
keen edge looks like when observed under 100x magnification...a thin light
reflective line without any visible defects (nicks, however fine) at the
cutting edge. If disposable blades are Teflon or otherwise coated there will
be a different light reflex as you move the image back from the edge bevel,
and this coating edge must be  "broken" to expose the true steel cutting
edge. If you wish to be sporting, like an old fashioned barber, (not
recommended) you may run the back of your thumb nail down the edge. This
will tell you by neurosensors that the edge is free of nicks and also wipe
away the coating from the treated steel cutting edge. A better way, and much
safer, is to use a pencil eraser or swab applicator to swipe down the
cutting edge.  A cotton applicator wet with xylene is an excellent tool for
this "edge treatment" because it will remove oil that is a
lubricant/antioxidant on most disposable blade packaging and also peal away
the finite deposit of Teflon that, while well intended, is in fact
preventing the cutting facet from engaging the paraffin that it intends to
cut.  After cutting some quantity of sections the applicator wipe is an
excellent way to regenerate good sectioning. The fact is that blades that do
not engage calcium salts or shoe leather, or over processed (over dehydrated
collagen)will last thru many hundreds of blocks. Adjusting the proper
cutting angle and having a clean cutting edge will do much for permitting
good sectioning and ribboning. There is nothing like thin sections coming
straight off of a clean cutting edge to start and keep the day going well.
Good cutting...J.B.McCormick M.D. 

-----Original Message-----
From: Connie McManus []
Sent: Tuesday, June 19, 2001 1:24 PM
To: Histo-Scientific Research Laboratories; Jim Ball; Histonet
Subject: Re: Dura Edge Blades

Primarily, I use Surgipath teflon coated blades and have no problem with
them at all.  However, I also use Leica blades from time to time and I have
noticed this last shipment of blades has not been very good.  Some blades
fresh from the dispenser  cut just like something I would discard!  I
prefer the Surgipath blades over the Leicas because they last longer and
cut much nicer sections, but these Leicas are worse than usual.  Is Leica
and Dura Edge made in the same plant, maybe???

Connie McManus

At 07:50 PM 6/17/01 -0400, Histo-Scientific Research Laboratories wrote:
>Dear Jim,
>DITTO!  We are having the same exact problems with our latest shipments of
>DuraEdge.  It is happening on all of our microtomes:  Our Leitz, Leica,
>Reichert, Microm.  We have been having a real time of it--I also will be
>calling DuraEdge to file a complaint!
>Beth Poole
>137 South Main Street
>Woodstock, VA  22664
>fax: (540)459-8217
>----- Original Message -----
>From: "Jim Ball" <>
>To: <>
>Sent: Friday, June 15, 2001 1:57 PM
>Subject: Dura Edge Blades
>> Our institute is in the process of trying to find a reason for the poor
>> sectioning we have started to experience, after receiving a new shipment
>> dura edge blades. The trouble sectioning is not isolated to just one tech
>> the whole histology section is having problems. There has been no change
>> any of our processing. The lot number we are having a problem with is
>> 003, 1135 006, 1135 007, and 1135 008. I have been sectioning tissue for
>> plus years so the answer to everybody first question is yes I have tried
>> adjusting the angel and while this helps a little the blades do not seem
>> hold an edge and I am going thru about twice the normal amount of blades
>> usually use. We have send one shipment back and the story from the
>> distributor is "No one else is having any problems with our blades." They
>> replaced the shipment with the same lot numbers and we continue to have
>> same problems
>>                                           Thank you in advance
>>                                     James L. Ball
>> _________________________________________________________________
>> Get your FREE download of MSN Explorer at
Connie McManus
Veterinary Diagnostics Lab
Utah State University
Logan, UT

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