In general, the suggestions and guidelines you are about to read hold true for sapphire knives of any age and made by any manufacturer. Where we are aware of differences of opinion regarding knife handling, we have made a note. Additional information regarding these differences can be obtained from the manufacturer of your knife. To use this guide, jump to an area of particular interest by touching items on the menu below or simply browse.
Your new sapphire knife is made by Linetek from synthetic single crystal sapphire. We can create a remarkably sharp and uniform edge on sapphire because it is extremely hard and its crystalline structure is very regular.
These characteristics also result in an edge that can be very delicate. To prolong the life of this edge, never touch it with any solid object.
The best sections come from a clean environment. Keep your knife clean by:
Using clean water, buffers or reagents in your microtome.
Rinsing and wiping the reservoir and stage of your microtome between
uses.
Preventing sections from drying on the knife.
Sectioning problems usually come in three forms: chatter, compression
and knife marks. As a general rule, vibratome sectioning with a sapphire
knife is done with high amplitude, slow approach speed and a knife angle
setting of about 23? You should spend some time learning the effects that
changes in these operating parameters have on section quality.
Chatter is the result of vibration during cutting and appears as regularly spaced thick and thin lines on the section perpendicular to the direction of cut. Too low a clearance angle, too fast an approach and too hard a specimen are several causes of chatter.
Compression is a crushing of the section as it is cut resulting in a section that is shorter than the original block face and thicker than the microtome setting. Too high a clearance, too soft a specimen and a dull knife can cause compression.
Knife marks are lines that appear on the section parallel to the direction
of cut. A dirty or damaged knife edge causes knife marks.
If you have sectioning problems, especially knife marks, a dirty knife may be one of the causes. Clean the edge by:
View the knife edge under
a dissecting microscope and press the chisel end of the stick against the
edge of the knife as though to split the stick. Using little force, wipe
the stick parallel to the cutting edge, never obliquely or at a right angle.
Move across the entire length of the knife edge then use a fresh part of
the stick and repeat in the opposite direction.
At Linetek, a large part of the cost of a sapphire knife is the extensive testing each one is subjected to prior to shipment. One hundred percent of the entire edge of every knife is examined at high power for imperfections in material and craftsmanship. New knives and sharpened knives must pass this rigorous standard before shipment to you.
As a result, we confidently guarantee that our sapphire knives, whether new or resharpened, are free from defects in material or workmanship. A knife thought to be defective for any reason should be returned to Linetek Co. We, in turn, will correct defects by repair or replacement, at our option. This guarantee is void if, in our opinion, the sapphire knife has been damaged due to negligence or misuse.
We hope that the information in this booklet has been of assistance, either in educating or reinforcing your knowledge of sapphire knives. The work in our laboratories, however, is not the only source for the information contained here. Many satisfied customers through the years have been involved with contributing to the contents of this manual. We welcome your contributions regarding applications, techniques, and care of sapphire knives, too.
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