Noddy
Statesman
Posts: 672
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Post by Noddy on Jul 16, 2007 15:12:22 GMT
The trouble with the bits for the down the hole hammer bits is the carbide buttons (actually cylindrical rods) are pressed into undersize holes in a piece of what I think is Mn steel. the steel is typically around 100mm diam (4").
It's a real shame because the carbide is a v tough grade (when atlas copco were developing cemented carbide rock drills, the quality control was to put the sintered insert on an anvil and hit it as hard as pos with a hammer (lump hammer I think), if it survived it was ok.
Tel, I've been out of action for a while, will send u a letter in next few days.
For scrap yards, quarries etc, try the little, privately owned ones. taking steel toed and soled boots, reflector vest and hard hat is always v. good idea (they're useful to keep in the car, you never know when you'll really need them...)
Was in a quarry last week that was operating 2 cat 988 shovels, those things are seriously BIG.
I've got some old diamond core drilling bits at home, been meaning to try the ammonium persulphate / ammonia mix on them as I think the matrix may be nickel based.
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