From the book by V. Shishkin "VyatSU: pages of the biography", 1998.
«... What is the best way to connect two metal parts firmly? Probably the best way is to solder or to weld them. But in the middle of the 70s associate Professor Ivan Nikolaevich Yurkus decided to glue them.
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At the department of the mechanical engineering technology he started to work at using special glues for manufacturing different cutting tools: cutters, drills, milling cutters, taps, rose bits, reamers. High-speed steel is too scarce to produce tools in whole. One can certainly make a cutter of ordinary steel and attach a plate of a hard alloy to it. And the producers used this method- they welded and then soldered it. But there was a problem. There was an internal tension in a cutting plate due to the different coefficients of the thermal expansion of metals in both cases. It led to microcracks. The cutter began to crumble and broke in the end. Besides the holder metal was annealed and the tool lost its rigidity.
That’s why it was better to avoid the “hot” connection methods. And the researchers applied glues. The kirovites, of course, did not formulate glues themselves. The glue laboratory of Moscow research-and-production association of plastics sent readymade glues to them. The task of Kirov scientists was to find appropriate glue to a certain tool, to find and to justify the optimal thickness of the glue layer, optimal roughness of the surface on which this layer was applied, and to develop the technology of gluing- time, temperature, etc.
The resistance of glued cutters processing high-strength steels was one and a half to two times higher than of soldered ones. This conclusion of Kirov researchers was confirmed by the producers involved in industrial testing of the new tool. The specialists of the plant “Mayak” and the machine building plant of the XX Congress of the Communist party assisted I.N. Yurkus and his colleague A.V. Gaida. Later the mass production of glued cutters started there. Thanks to the application of this innovation the economy of 44,5 thousand rubles was reached at the plant “Mayak” for 3 years.
Soon the Department made a folder to record the requests of various companies in the country to the new technology. Then it made another one: the first was full of records. It was not a surprise because the last entry in it was made under number 1663».
