6/22/98

In our vast knowledge base does anyone have any suggestions for making long edge glass

knives, i.e. ~ 25mm or so as used for histology or rotary microtomes, with an LKB knife

maker or glass breaking pliers?



Obviously, ideally we'd like to use a 'Ralph Knife' maker as sold by several vendors,

but the $2k price tag is prohibitive presently (sorry guys) ... unless some has one

gathering dust some where they'd be willing to part with....?





Richard E. Edelmann, Ph.D.

Electron Microscopy Facility Supervisor

352 Pearson Hall

Miami University, Oxford, OH 45056

Ph: 513.529.5712 Fax: 513.529.4243

E-mail: edelmare@muohio.edu

There is a Hayat ref. to a paper on making Ralph knives by hand: Bennett

et al., (1976) Stain Technology 51:71



I haven't tried it; don't even have the paper, but I'd like to hear from

anyone who has as to how successful they were.



Tamara Howard

CSHL

Tamara Howard <howard@cshl.org>

Hi Richard,



I used & made this type of Ralf Knife around 20 years ago.



1. Start off with a 3 X 1 inch slide and diamond score using a small set

square at the desired position.



2. Place a wood toothpick on the opposite side of your score line offset

from the line by say 2mm, this distance is critical and may need to be made

larger or smaller depending on the profile you achieve. Take care and wear

leather gloves and protective goggles, carefully press down on the slide

and you should have your Ralf Knife.



3. To use the knife on a microtome, I placed a standard steel knife in the

holder with a piece of sheet metal under the steel knife to act as a ledge

to support the Ralf Knife. Make your Ralf Knife a few mm. longer than the

distance from the edge of the knife to the ledge at the base of the knife.



4. To fix the Ralf Knife onto the front face of the knife, paraffin wax

was used by slightly heating both knife and Ralf Knife, and then waiting to

both cooled down.



I hope this information is of assistance to you, please say if you need

anymore information.





Best Regards.



Alan Bright



Bright Instrument Co. Ltd.

St Margarets Way

Huntingdon

PE18 6EB

England



e-mail: Bright@dial.pipex.com

Tel: +44 (0) 1480 454528

Fax:+44 (0) 1480 456031

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