How Coarse Does Diamond Lapping Compound Get?

[Paul Alciatore]

I am playing around with some diamond lapping compound and I got an assortment from 0.5 to 40 micron sizes in syringes. But I was wondering if it comes any coarser? I found a chart on the internet (Gesswein, Canada) that puts the 40 micron around 400 grit equivalent. I was wondering if you can get the diamond compound any coarser than that for more rapid material removal? Like 200 micron/200 grit? Or 150 micron/100 grit? Or is 40 micron the limit in the coarse direction?

Or do you just use other abrasives for faster material removal? It seems like with the 40 micron diamond paste you are removing split tenths at a time. Although I think I knocked down a two or three tenth high spot on a 1-2-3 block with it with two goes.

[Mark Rand]

90 micron==200 grit is available.

[1-800miner]

I suppose you could throw the wife's engagement ring into the mix. That should be quite abrasive.

[vpt]

At around 1.5 carrots it starts to get cost prohibitive.

[Paul Alciatore]

Where is it available? Preferably a US source.

Have you used it? How fast does it cut compared to 40 micron? Is it usable to pull down a high spot that is 2 or 3 thousandths high in CI? Or am I going to have to scrape or even mill that? I am trying to learn and get a feeling as to what can and can't be done.

90 micron==200 grit is available.

[nickel-city-fab]

By way of suggestion, I would use a 2nd or smooth cut file to knock down most of the height, then start with about a 600 grit. That would be a #2 or #4 file in european systems.

The reason why I say this is because I have been doing some exercises in filing lately, and its surprisingly slow and controllable to knock off even 2 thou. It takes a while and a bit of sweat, but its very controllable. I would lap after filing something as big as 2 or 3 thou, instead of trying to do the entire amount with lapping. I think this way would also preserve the part geometry better, as far as parallelism etc.

[Mark Rand]

Where is it available? Preferably a US source.

Have you used it? How fast does it cut compared to 40 micron? Is it usable to pull down a high spot that is 2 or 3 thousandths high in CI? Or am I going to have to scrape or even mill that? I am trying to learn and get a feeling as to what can and can't be done.

Norton list it. Don't know of a US supplier, but I guess one of the more specialist lapping suppliers would have it. To be honest, I'd use my surface grinder or Biax scraper to remove that sort of height. I'd only use lapping compound for polishing. I've got 5x100 carat bottles of loose grit from 60 micron down for when I get to the point of re-lapping my surface table, but I hope I don't have to do 2-3 thou.

[Lee Cordochorea]

Where is it available? Preferably a US source.

Typing "200 mesh diamond powder" into Guggle Shoping gives four eBay results, one of which is actually valid. I'm fairly amazed, Guggle Shopping has recently been yielding only garbage for me. Guggle must like you.

[rmcphearson]

Synthetic silicon carbide lapping compound is available in 60,80,120, and 150 grit from Foley United. No diamonds but might be close enough?