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Electron Microscopy Sciences

DiATOME® Diamond Knives

PDF Downloadarrow13Introduction, Manufacturing and Characteristics

diamonds for knivesarrowIntroduction

DiATOME® Diamond knives:
Development, Manufacturing and
Customer Service since 1970

What have we achieved in this period?

  • ultra 45, the first diamond knife with an absolutely score-free, hydrophilic cutting edge.
  • semi, the first diamond knife for alternating sectioning ultrathin/semithin.
  • cryo, the diamond knife for sectioning at low temperature.
  • histo, the first diamond knife for semithin sections for light microscopy.
  • ultra 35, the diamond knife for optimized sectioning results in almost all applications.
  • STATIC LINE II, the ionizer for eliminating electrostatic charging in ultramicrotomy.
  • cryo-P, a cryo knife with a patented platform for section pick up.
  • cryo immuno, the optimized cryo diamond knife for the Tokuyasu technique.
  • ultra sonic, the oscillating diamond knife for room temperature sectioning.
  • cryotrim, 45° and 20° optimizing trimming with diamond blades.
  • ultra AFM & cryo AFM, the first diamond knives for AFM at room and low temperatures.
  • cryo 25, for sectioning frozen hydrated specimens.
  • trimtool 45° and 20°, trimming tools for both room and cryo temperatures.

These developments were possible by the cooperation with you, our valued customers. We are convinced that our future developments will allow diamond knives to be used for many new applications.

What services can we offer you?

  • Technical assistance in all fields of ultramicrotomy.
  • Free sectioning tests for all types of samples.
  • Make use of our many years of experience in perfecting our knives.
  • With a telephone call, an e-mail or a fax message we can inform you of any details you require.
  • Click here to view our special DiATOME Diamond Knife Programs and Trade Ins.

We are looking forward to hearing from you soon!

Your DiATOME Team


The Raw Material:

The manufacturing of high quality knives, like ours, begins with the selection of the highest possible purity diamonds with a regular crystal structure, which are pale yellow in color. The crystal orientation of the diamond that we have chosen permits a final polishing parallel to the cutting edge, which gives you an extremely sharp, scorefree, durable cutting edge.

Precision in Grinding and Polishing:

Our precise pre-grinding and polishing techniques assure you the perfection in a diamond knife that you expect. Each one of our stones is ground strictly in accordance with its structure, with an accuracy of +/- 2 degrees being maintained in the crystal axis.

Loss of weight during this preliminary grinding amounts to 80%.

In contrast to the methods of others our diamond knives are ground parallel to the cutting edge. Some of the reasons for doing so are as follows:

  1. The cutting edge life of a diamond tool used for processing a tough metal such as beryllium bronze can be appreciably lengthened, if the diamond is oriented in such a way, that the grinding direction is at a right angle to the subsequent working direction. If we wish to apply this knowledge to the manufacturer of diamond knives, then the grinding direction will be parallel to the knife cutting edge. This is crucial in the cutting of bone or metals, for example.

  2. The diamond knife cutting edge is formed from the polished surface which is turned towards the trough and the ground surface which forms the clearance angle with the block. Since the sections pass over the side turned towards the water, this surface is subject to much greater use than the clearance angle surface, and if it has been badly polished, the areas with polishing ridges in the cutting edge give rise to stripes and streaks in the sections, some more visible than others.

The same thing would occur if we turned the ground surface towards the water and its grinding ridges were not exactly parallel to the cutting edge. It has been demonstrated that the steeper the grinding ridges are to the knife cutting edge, the more pronounced is the formation of stripes in the sections. According to this, grinding or polishing at right angles to the cutting edge would represent an extreme case.

The streaks in the sections can be seen in the stereomicroscope of the ultramicrotome or in the electron microscope.

In the course of time the effects of irregularities in the cutting edge can be increased through polymerized embedding material. Knives that have been supplied by us in perfect condition have come back to us after complaints and have been found to be cutting with streaks, even though there
was no damage visible under the microscope.

The Cutting Edge:

The sharpness of a DiATOME knife edge can not fully be shown in a light microscopy photograph, however, it has been shown that the radius of curvature of our knives is less than 2nm.

Quality Control, Optical Checking, and Section Testing:

The final step before any of our knives leave the plant is our own extensive testing that each knife, new or resharpened, is put through. Only if these knives perform successfully will they be sold. During the polishing process the edges of the knives are inspected at 500 to 1000x magnification. Very small irregularities that could not be found by light microscopy are detected during the sectioning test in accordance with the range of the different knife types (sections are checked by light and electron microscopy).

Only knives that cut perfectly over this range are accepted for delivery to the customer.

arrowCharacteristics of Diamond Knives

  • DiATOME knives are compatible with all ultramicrotomes.
  • The boat is designed in such a manner that the water surface is horizontal when the clearance angle is set. This results in a stationary water surface and good reflection.
  • The shape of the boat offers you the advantage of easy pick-up of the floating sections.
  • The surfaces of the DiATOME diamond knives are hydrophilic. This property allows an easy wetting of the cutting edge, even with a very low water level (important for sectioning Lowicryls and other hydrophilic embedding media, as well as for water sensitive samples.)
  • The diamond is fastened in a metal shank which is securely screwed into the boat.
  • The cementing material seals boat and knife. It is hydrophilic and aids the easy wetting of the cutting edge.

Quality Guarantee for DiATOME Diamond Knives arrow13arrow13