|a scriber for metal work and marking pretty much anything|
ralph klimek VK3ZZC
whats so special about just another scriber ? This is no
ordinary scriber. It will scribe glass, sapphire, tool steel or
frozen butter. You cannot buy one of these for your metal
shop, you have to make it. The origin of this very usefull tool
came from a tungsten carbide PCB drill bit that I had carelessly
broken. What to do with the remaining shank ? I
drilled a supporting hole in a 6mm brass rod and then brazed it !
It came a a bit of a surprise to me to thus discover that
tungsten carbide can be brazed with just ordinary 2% Silver brazing
alloy and standard pottasium hydrogen flouride and borate flux.|
The point is ground down on a standard alumina grinding wheel, which takes quite a long time as the carbide is harder then grinding wheel. The point is brought to a needle point by a cheap diamond hone. This scriber will mark "anything" and rarely requires resharpening.
Just for the record, "tungsten carbide" is not actually tungsten carbide ! It is an emulsion of highly refined tungsten carbide powder suspended in cobalt ( and proprietary other) metals by a powder metalurgical process. This is why it can be brazed, it is actually a cobalt metal "alloy". Actual pure tungsten carbide is extremely hard but also extremely brittle.
|Thu May 26 18:58:45 EST 2016|