Science/Engineering/Technical forums

I have a couple industrial diamond wheels that I use for grinding tungsten electrodes and carbide tooling. They're flat face wheels, so not real useful for other work, but I can do a few tests on alumina and see how they survive. I'm heading to Harbor Freight tomorrow to get some of the cheapo wheels and see what kind of damage I can do to my quartz.

They work great for me. I spin the work in the lathe, 60 rpm or so, the wheel at a few thou rpm, use an eyedropper with water for coolant (it really helps, and keeps silica out of your lungs in the bargain) and even sometimes use the auto infeed (slow). I just put my hand out and catch the cut off piece, or better, check a rod in the tail-stock that goes up inside it for that. Works pretty much 100% and the wheels last a long time doing that kind of thing. Since they have diamonds on the sides too, you can then chuck the cut off piece in again and make the end perfectly flat off the side of the wheel. I use the little dremel diamond bits in odd shapes they also have sometimes to chamfer the hole, so it's easier to insert an O ringed plug in the end. That whole process is now "in the bag" here.

Doug, thanks for the tips on cutting quartz! I ran the the cut off blade in my dremel just holding it by hand, since I don't have a functional tool post grinder, but it still worked fantastic. After chamfering the piece I cleaned up the last of the chips on the scotchbrite wheel.

I've now bitten the bullet, bought some BN from McMaster (wow is it ever expensive) and made a feedthrough out of it. The stuff works like magic and seems to suffer no damage in hot D+. Other things sputter onto it, but are easily wiped off with one swipe of 320 grit paper. Since it's not particularly airtight, and is very slippery - I used it inside a piece of 1.5" OD thick-wall pyrex, which only extends a couple inches into the tank - the rest is just BN with a copper rod for the conductor.
It's easy as pie to machine FWIW. John F warned me when he saw a pile of its dust on my lathe to get it off of there, as it will ruin the ability to do things like lock a tailstock down. He was right.