Hi Gayle,

Less challenging, but effective--use embedment rings.

Kathy



>===== Original Message From Gayle Callis  =====
>Per Sarah Jones's comments about the call for large cassettes. Been there,
>done that same as she has done, for big blocks other than megacassette
>size.  However, megacassettes ARE in demand, if they weren't, I don't think
>every cassette vendor would sell them.
>
>An ill designed, poor fitting megacassette has no place on the market or in
>our labs, especially when you need the depth of a megacassette to hold an
>eye or thicker sample for processing.  It is counterproductive, expensive
>and time consuming to use another regular cassette back to replace these
>expensive little gold nugget megamonsters in order to get a proper fit in a
>clamp!
>
>They sell DEEP metal molds for thick samples and megacassettes. However, in
>my estimation, there is a failure in the system - the infamous
>megacassette!  Seems to me, after previous discussions and complaints on
>Histonet and this tirade, someone would get it right - hasn't happened yet!
>
>Did some measurements.  Regular, everyday cassettes for 3 mm thick samples
>(on clamping side) measure 3.75 cm x 2.8 cm.  One megacassette measured 3.5
>cm x 2.8 cm, and when inserted horizontally into clamp left a 4 mm gap
>between corner of clamp and cassette corner.  This mega freely slid back
>and forth while clamped and fell out of clamp when reoriented in vertical
>position!   The other megacassette (same mfr as the regular cassette)
>measured 3.7 cm to outside of a little lid tab x 2.85 cm, but left a 3 mm
>gap, a tidge sturdier, but not 100%.  Both megas did not provide stability
>for sectioning.  I think that is obvious from other commentary.
>
>Me thinks megacassette design is/was based on a "traditional" regular
>cassette design with slanted edge for ease of slipping block into a clamp.
>IF you are working with a deeper block -  you can actually grasp the block
>face and shove it straight back INTO clamp if the cassette back is squared
>to fit into the clamp. I would opt for writing surface on side of cassette
>- same as routine, small cassettes.
>
>Had a discussion about megacassette problem with one technical product
>advisor from a well known manufacturer/vendor YEARS AGO (time frame
>obviously doesn't apply now) and his comment was -  "There is little demand
>for megacassettes and not worth expense (hmmmm, bother?) to change how they
>are manufactured".  This meant changing the plastic press mold.  Well -
>putting it mildly, PHOOEY! That way of thinking doesn't hold water anymore!
>If one sells a flawed, ill-designed product, then it should be corrected.
>I see megacassettes (with the same basic look/design/dimensions) sold by
>cassette vendors - labs are using megacassettes more now than they did 15 -
>20 years ago.  I truly appreciate vendor samples to try for comparison and
>ALL megacassettes have failed miserably after comparison! Sorry, folks!
>
>I don't think the mega problem has ever been carefully thought out and
>hopefully some vendors in contact with their manufacturers will take it to
>heart and redesign megas for cutting stability and correct FIT INTO CLAMP!
>The microtomes/clamps are updated, modernized, designed improved
>use/sectioning while megacassettes reside in the dark ages.
>
>Hello out there??? Is anyone who makes megacassettes - listening?   I
>CHALLENGE you! NO! DOUBLE DARE you to be the first to redesign a
>megacassette useful sans "the bad language syndrome". Our lab will be the
>first to buy these with glowing recommendations to others.
>
>Enough, but looking forward to a new, improved megacassette ----
>
>
>
>
>
>
>
>
>
>Gayle Callis
>MT,HT,HTL(ASCP)
>Research Histopathology Supervisor
>Veterinary Molecular Biology - Marsh Lab
>Montana State University - Bozeman
>S. 19th and Lincoln St
>Bozeman MT 59717-3610
>
>406 994-6367 (lab with voice mail)
>406 994-4303 (FAX)
>
>email: gcallis@montana.edu

Kathy Walters                                // 
Central Microscopy Research Facility        / /
85 EMRB                                    / /\
University of Iowa                        / /\ \
Iowa City, Iowa 52242                    / /  \ \
Phone #:  (319) 335-8142                / /    \ \
Fax #:  (319) 384-4469                ______   ((0))
email: Katherine-Walters@uiowa.edu     |__|    / /
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