DIY Diamond Abrasive Coatings

**GlennR** · Mar 14, 2015, 06:38 PM

Does anybody know how I can apply diamond abrasive grit to metal bits, wheels, etc. ?

I know some are plated & some a glued, but I don't know how to do either. I see cheap diamond abrasives on Alibaba, but asking the Chinese how to use them is next to impossible. I've been using a diamond product made by Scomac that is in the form of thin copper sheet imbedded with diamond grit; the copper is easily cut and glued onto bits. It is relatively affordable and works pretty well, but the copper strips can break loose. I recently bought a new supply of the copper/diamond and recoated a bit, but it's stopped grinding and I'm wondering if I got a bad batch. I really wish I knew how to apply the diamond grit directly onto my bits.

The bits are relatively large and made of steel. They are a tapered cone shape, about the diameter of a soda can, that I used to countersink my blown glass sinks.

I wonder if I can braze the diamonds on? The bit is has quite a bit on mass (think of a solid steel hockey puck), so it would take a long time to cool and I don't know how to keep the grit in place while it cools. Maybe that isn't an issue? I guess I could test the process on a horizontal piece of flat steel plate, using a cheaper grit than diamond.

Any ideas or tips?

**GlennR** · Mar 22, 2015, 08:47 PM

I've found diamond abrasive segments available from a company in China. They're brazed to tools, like cup wheels. I want my bits to be reusable, so I don't think I would want to braze them on. From what I've read brazing is a permanent process, but soldering is weaker than the base metals and recyclable.

I haven't contacted the company yet, but hope they have something that will work and will sell, or give, small quantities for me to test. I'll also search a little to see if I can find the segments in the US first, since it would be easier for me to communicate with them.

**DIYer** · Mar 23, 2015, 04:27 AM

I haven't come across homemade diamond abrasives/grinding bits before. Sorry can't help you, but I'll be following along as it's a bit of knowledge that I may possibly use in the future.

**GlennR** · Mar 23, 2015, 07:58 AM

Here's one of the suppliers that I found. I'll send them a photo of my countersink bit and tell them it's for glass and see if they have any stock segments that I can try.

Buy and Custom Made Quality Diamond Segments - Diamond Tips

**Bill Dancliff** · Aug 4, 2015, 11:39 PM

I have been working on a method to grind valve seats using diamond powder and so far I have the powder. The actual process involves a slurry of ceramic clay mixed with diamond grit that is poured into a mold and fired in a kiln used for ceramics. The diamond grit I bought is synthetic diamond so that the stone I produced could be dressed by a real diamond or maybe carbide, but it is all theory at this point. You can buy diamond paste for polishing. I just wanted a tool to chamfer small valve seats at various angles. It is doable but you need a kiln or know an art studio for clay throwers.

**jhovel** · Aug 5, 2015, 04:17 AM

Just remember that diamond is pure carbon. It burns! So if you are planning to solder or braze diamond coated segments, you need to stay well below the ignition temperature of carbon....
On the other hand, why does the diamond need to be fixed to the countersinking tool? You can get diamond paste ina all kinds of grades. It's essentially diamond grit in grease. You can coat your countersink with that and wipe it up to reuse each time.
I also came across special glass sink drilling and coutersinking tools with diamonds fixed in nickel plating. Maybe those tools are what you are looking for?
Cheers,
Joe

**mikeyrocks** · Aug 17, 2015, 07:32 PM

Well a newbie to this forum but I have a fair amount of knowledge in this area which I have been working with for almost 20 years now as a lapidary (stone cutter). There are several methods to use diamond powder (bort). Sintering is diamond mixed within the metal. Plated onto the surface of the metal in a plating process which traps the diamond particles for a while. Resin bonding is glueing, either in a thin coating or a very thick coating. Diamond paste or simple loose diamond bort. Next and very important.....there are various diamond borts available. Basically there is plain bort, then there is bort that is prepped for resin bonding or gluing, bort that is prepped for sintering, and so on. So get the correct bort for the application you wish to work with and you should get better results.>>>>>Now for this discussion here:-there is a diamond welding rod available which is brass tubing filled with diamond bort for torch welding. You can buy it or make your own. Generally looks a bit crude after it is done though.>>>>>Here is a method that you might find appealing though for making shaped diamond tools for grinding. Make an arbor from steel, attach a piece of old growth Redwood to it then cut/grind it down to the shape you want to grind with. Apply diamond paste and go to work, recharge as needed. When charging or recharging rotate the tool slowly so you can work the diamond into the wood rather than fling it off, Initially I presumed that a hard wood would be appropriate and some do use maple but an old experienced hand at this, Daniel Lopatki (of Lopatki Lapidary Supplies) out of New Mexico set me straight . The softer Redwood absorbs the diamond particles better and surrounds them more easily....making a better tool.>>>>>>Now for those wanting to glue diamond...get the properly prepped bort then try to find some phenolic resin of the correct hardness. Eastwind Diamond Abrasives makes the best diamond discs, belts, wheels and pads, etc. that there are, in my experienced opinion. And makes them here in the USA in Vermont. He settled on phenolic resin because it's strong enough to hold the particles in place. He found the right combo, hard enough to not wear out too quickly but soft enough to wear down and expose fresh cutting diamond particles. So keep that in mind as you try various epoxies, filled epoxies, etc. for your own experiments. Steel filled might be too hard to do a good job. I don't have a recommendation for you yet and I am still experimenting in this field. I've even tried zinc rich spray paint early on. I don't know if any here knows about the phenolic resin family but I am all ears. Mohan lapidary supply in China is making belts and discs using a more rubbery resin than Eastwind I have just started trying them a few months back...my initial reaction is they are too soft or gummy. I am withholding my final opinion on these yet...not enough usage yet. Oh I use diamond bort from 36 grit particles down to 50,000 grit.

**Darla** · Apr 2, 2016, 04:45 PM

Old time lapidaries used to make diamond saw blades with metal can tops with slits cut in the edge with a tin snips and using lipstick and diamond grit to charge the saw blade.

**Rixster** · Jan 18, 2018, 11:48 PM

Originally Posted by mikeyrocks

Well a newbie to this forum but I have a fair amount of knowledge in this area which I have been working with for almost 20 years now as a lapidary (stone cutter). There are several methods to use diamond powder (bort). Sintering is diamond mixed within the metal. Plated onto the surface of the metal in a plating process which traps the diamond particles for a while. Resin bonding is glueing, either in a thin coating or a very thick coating. Diamond paste or simple loose diamond bort. Next and very important.....there are various diamond borts available. Basically there is plain bort, then there is bort that is prepped for resin bonding or gluing, bort that is prepped for sintering, and so on. So get the correct bort for the application you wish to work with and you should get better results.>>>>>Now for this discussion here:-there is a diamond welding rod available which is brass tubing filled with diamond bort for torch welding. You can buy it or make your own. Generally looks a bit crude after it is done though.>>>>>Here is a method that you might find appealing though for making shaped diamond tools for grinding. Make an arbor from steel, attach a piece of old growth Redwood to it then cut/grind it down to the shape you want to grind with. Apply diamond paste and go to work, recharge as needed. When charging or recharging rotate the tool slowly so you can work the diamond into the wood rather than fling it off, Initially I presumed that a hard wood would be appropriate and some do use maple but an old experienced hand at this, Daniel Lopatki (of Lopatki Lapidary Supplies) out of New Mexico set me straight . The softer Redwood absorbs the diamond particles better and surrounds them more easily....making a better tool.>>>>>>Now for those wanting to glue diamond...get the properly prepped bort then try to find some phenolic resin of the correct hardness. Eastwind Diamond Abrasives makes the best diamond discs, belts, wheels and pads, etc. that there are, in my experienced opinion. And makes them here in the USA in Vermont. He settled on phenolic resin because it's strong enough to hold the particles in place. He found the right combo, hard enough to not wear out too quickly but soft enough to wear down and expose fresh cutting diamond particles. So keep that in mind as you try various epoxies, filled epoxies, etc. for your own experiments. Steel filled might be too hard to do a good job. I don't have a recommendation for you yet and I am still experimenting in this field. I've even tried zinc rich spray paint early on. I don't know if any here knows about the phenolic resin family but I am all ears. Mohan lapidary supply in China is making belts and discs using a more rubbery resin than Eastwind I have just started trying them a few months back...my initial reaction is they are too soft or gummy. I am withholding my final opinion on these yet...not enough usage yet. Oh I use diamond bort from 36 grit particles down to 50,000 grit.

There is a company in West Jordan, Utah named Anthon Engineering that does custom diamond tooling, wear parts, and other stuff. They manufacture a brazing rod in a few different grits of diamond so you can make your own tooling. This is commonly used in the lapidary field to turn plumbing fittings called "bell reducers" or reducing couplings into cup wheels for sphere grinders. It can be used on steel "cores", and even removed, as the brazing alloy has a lower melting point than steel. you can take any steel tubing that has a higher melting point than this brazing rod and coat one end, and make a core drill out of it. I've seen HUGE homemade DRAG SAWS that used this, or used diamond segments from HANS Lapidary, in China, to saw 4 or 5 foot diameter rocks in half! If there's a need, and where there's a will, there's a way!

P.S. Thanks a bunch for sharing your expertise and your experience with me!

**Rixster** · Jan 18, 2018, 11:58 PM

If you use steel cores for your bits, you can go ahead and braze the segments on. I have done this on steel core drill bits with the same type of segments. The segments, and a high silver content brazing rod, say 15% silver and up, will bond those segments to steel fairly easy if you have a little brazing experience and use the right flux. Those segments, if properly applied, would outlast the diamond impregnated copper sheets by over 100 times.