Making diamond glass cutter

Bob, you fracture me with your colorful remarks.

--Winston

I googled around too. They're called "Active Braze Alloys". I was unable to ascertain whether they were simple alloys containing titanium or if they were mixed or coated with the hydride.

I had always assumed that a good deal of the strength in soldered and brazed metals came from a metallic bonding of the parent metal and the braze alloy, where they actually share electrons. Sort of an alloy a couple of atoms thick.

But brazing down ceramics and glass seems to indicate that the process is more like superglueing two things together.

I will have to do more research on this.

Paul K. Dickman

And please let us know what you find. In years past I've studied soldering glass and brazing of many types, always to get surprises about the actual bonding mechanisms. Diffusion bonding, intermetallic problems, and a whole host of things can crop up. It's interesting and it's pretty deep stuff for hobby metalworking, but it's important if you're going to be able to plan and execute good bonds.

My problem is that I read it and maybe understand it for a while, and then I forget the whole damned thing and have to start over the next time I pick it up.

-- Ed Huntress

I've been interested in soldering of glass using Indium based solders but unfortunately have been put off by the cost, I worked out with a mate that the cost of the Indium solders in the UK is about the same as gold gram for gram.

Will do, but don't hold your breath waiting for the Readers Digest condensed version.

The list of things I have to do more research on already reads like Diderot's Encyclopedie and gets a couple of pages longer every day.

Paul K. Dickman

Hmmmm! I have always been able to read Bob's posts, but of late they are not appearing on my computer, although quotes of his comments are. What the hell's going on?

Well, he didn't say that wasn't a possibility. I feel somewhat vindicated. :-)

Harold

Bort is the toughest of diamond forms. Often used as Grinding wheel dresser. Will it have a sharp enough edge for glass ?

Martin

Mart>>> I have a few carats of diamond bort here and I've wanted to make a

Oh, yeah. As they come out of the ground, they can be in many forms, but most of the ones I have look like really dirty and cloudy glass that was melted into lumps with a torch. I also have a couple of black opaque ones.

I have a little case-hardened hammer my uncle used for crushing them into lapping grit. Once you crack one, the edges are sharp.

-- Ed Huntress

My problem (and many others here I'm sure) too, don't feel lonesome. The trick is either to work with it a lot more or at least remember where it was that you found it.

It seems to be a curse for the curious minded of us :)

Amen! Or, "Build it, and it will come to you."

-- Ed Huntress

I did a patent search for "diamond" and "brazing" in the title. There were 13 hits. The most recent patent to come up is 6,889,890, which is right on point. The titanium appears to be essential.

Joe Gwinn

Granted. Compression fracture will find a flaw.

But my Mineralogy book stated the bort is the toughest of all diamond forms. None are as on a finger until split and ground. I suspect the best way is to place it in a hole of sorts to hold it - in a wood stick - and then with a sharp edge place it and whack a corner or edge off. That preserves the bulk and creates an edge.

Think of turning a cutter into work a bit hard and the lip layer shears or fractures off.

I suspect the case-hardened hammer allowed some give so the hammer wasn't hurt!

Martin

Mart>> Bort is the toughest of diamond forms. Often used as Grinding wheel >> dresser.

Well, it's standard, old gagemaker's tool. You put the diamond piece on a steel plate (used here as an anvil), and lay a piece of leather with a hole over the top of the diamond, so the diamond is in the hole. Then you put a piece of paper on top, and rap away. The diamond chips are trapped in the hole in the leather, and the paper keeps them from flying around.

Then you take the diamond grit, pour it into a bottle of olive oil, and shake it up. With a pipette, you draw off the diamond as it settles to the bottom. The size of the grit relates to the time you let it settle; I forget the drill, but you draw it off into different vials, and let *them* settle. Then you charge a lap with the grit that settles to the bottom of the vials, selecting the size you want.

That's also how precision toolmakers used to make internal grinders for precision internal grinding, for making master jigs and so on, boring and grinding them on a lathe. Instead of a lap, the grinding tool was a mild-steel rod, into which you'd drive the diamond with the hardened hammer.

It was a tedious business. Thank goodness for plated-diamond points and jig grinders, eh?

-- Ed Huntress

Now you're getting somewhere. Is the titanium part of the brazing alloy?

-- Ed Huntress

Yes.

Joe Gwinn

Replacement prongs, with a layer of solder in place on the underside, are stock in trade for jobs like that.

Building up with solder is just pounding more heat into the customers jewellery, than is wise.

Some "easy" solder on a replacement prong cap requires far less time as well as risk of having to fix a mess.

Only requires a quick flat filed surface, for the ones I saw.

Cheers Trevor Jones

That kind of super-delicate work always amazes me. Perhaps you get used to working at that scale when you do it every day.

-- Ed Huntress

Titanium is added to some stainless steels to prevent the growth of chromium carbide at elevated temperatures, which leads to intergranular corrosion. As I understand it, the titanium has a high affinity for carbon, so titanium carbide is formed in preference to chrome carbide.

Perhaps this affinity for carbon at elevated temperature is the reason for the Ti "flux".

So where would one get a chunk or two of diamond bort?

BTW, my father described the same method years ago for shattering tungsten carbide for making glass cutters and scribes.

Tony