Kinta je napisao:
Corto_1973 je napisao:
Ova moja su bila sa kobaltnim premazom i buseno je s malim brojem okretaja. Mislim da tu i lezi problem, jer su bila za celik. Za zeljezo bi trebala biti hss, ali me buni da li N ili E.
Cini mi se da mislis na titanski premaz. Ta svrdla ... ajde nisu tako losa ali samo ako ih mozes hladiti emuzijom.
Cobalt je inace u sastavu samog materijala i ako se to svrdlo nabrusi na 130 - 140 stupnjeva moze bez problema busiti sve od betonskog zeljeza do rosfraja ali i tu bi hladjenje bilo jako jako pozeljno.
mislio je na HSS-Co
Steels
Soft low carbon steel bits are inexpensive, but do not hold an edge well and require frequent sharpening. They are used only for drilling wood; even working with hardwoods rather than softwoods can noticeably shorten their lifespan.
Bits made from high carbon steel are more durable than low-carbon steel bits due to the properties conferred by hardening and tempering the material. If they are overheated (e.g., by frictional heating while drilling) they lose their temper, resulting in a soft cutting edge. These bits can be used on wood or metal.
High speed steel (HSS) is a form of tool steel; HSS bits are hard, and much more resistant to heat than high carbon steel. They can be used to drill metal, hardwood, and most other materials at greater cutting speeds than carbon steel bits, and have largely replaced carbon steels.
Cobalt steel alloys are variations on high speed steel which contain more cobalt. They hold their hardness at much higher temperatures, and are used to drill stainless steel and other hard materials. The main disadvantage of cobalt steels is that they are more brittle than standard HSS.
inace ako si busio na ruku nije ni cudo da je puko borer ..treba sve biti dobro fiksirano i malo loja stavi da ne "zagrize"
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