Really cheap diamond stones

[ivan]

Last month a slim package arrived from China; a selection of diamond sharpening stones ranging from 400 to 3000 grit. You can find these on ebay, and they are around £2.50 each, about the same a sheet of lapping film. No typo, they're about 3 x 6 1/2" (74x170mm). The reason for the low price, they're a mm or so thick. This is no real problem if you use them on a flat surface - you could polyurethane glue them to glass if you wish. They are plenty big enough for hand sharpening. A bit small for use with a guide, but as they don't wear like a waterstone, a short stroke is a small price to pay when you think of the price! The main snag is that you probably shouldn't use water, WD40 is better; the stones appear to be sheared from a larger sheet of steel, so the edges are unplated and presumably will rust. Been using them for about 6 weeks now, finishing up on a fine waterstone. There are 6" and 10" discs of the same material available too. Have a look! (grits from 60 to 3000)
PS. there are some cheap 10,000 grit waterstones to be found on Amazon in the kitchen department - £15 not £100! Not tried these, though.

 

[SVB]

Some links would be really appreciated.

Thanks

Simon

 

[Rorschach]

Yes links would be great

 

[bugbear]

+1 on links please

BugBear

 

[Phil Pascoe]

As an aside, Ivan says WD is better than water - I've found on my fine stones and diamond plates that isopropyl is cleaner than any sort of oil.

 

[transatlantic]

http://www.ebay.co.uk/itm/Thin-Polishin ... 2037450454

 

[RogerP]

As an aside, Ivan says WD is better than water - I've found on my fine stones and diamond plates that isopropyl is cleaner than any sort of oil.

That's interesting. I have 5l container of the stuff given me, I must give it a try.

 

[Phil Pascoe]

It softens hot melt glue as well.

 

[D_W]

I haven't liked some of the Chinese made synthetic Waterstones, but the decent quality diamond hones and sheets have been fine.

George Wilson mentioned to me that he likes the large discs that work on polishers, and they last just fine. For about a 20th of the cost of replacements from the distributor of the machine.

Some of the high dollar plates are made in China, anyway.

 

[Rorschach]

What kind of grits are the discs? I am thinking these would be good for my carbide lathe tools.

 

[D_W]

What kind of grits are the discs? I am thinking these would be good for my carbide lathe tools.

They can be just about anything, same as other diamond hones - I've seen them with 60 grit and with grit ratings into the several thousands.

 

[ED65]

For those who recall my thread from December last asking for people's cheapest honing setups, these plates are larger and cheaper than the one I linked to in that thread.

Re. lubricants for diamond plates, over the years I've regularly used them dry and I can't see much difference using any lubricant I've tried, be it watery or oily (with a definite step down in cutting once you get to something the viscosity of liquid paraffin). So don't be afraid to try using them dry if that might suit, even the finer ones don't seem to load up or glaze enough that a wipe with a wad of kitchen paper doesn't sort them out.

 

[ivan]

Suggesting WD40 - which I've been using - is just to prevent the edges of the "polishing plate" (which look unplated, just cut) from rusting. Previously always used water on diamond, as don't see any benefit other than corrosion protection with WD40. Paraffin or white spirit would do, but not kind to skin. Rapeseed oil from Tesco etc is probably more economical. The plates might be stainless, but I doubt it. If used dry, some like to clean off with a pencil rubber; not tried this, but crepe rubber block for unloading clogged abrasives might be worth a try.

 

[Rorschach]

Hmm can only find diamond discs for angle grinders.

 

[graduate_owner]

Would something like 10000 grit be finer or coarser than honing soap?
Or to put it another way, does anyone know what the equivalent grit would be to green honing compound?

K

 

[D_W]

Would something like 10000 grit be finer or coarser than honing soap?
Or to put it another way, does anyone know what the equivalent grit would be to green honing compound?

K

.25 micron diamonds. They sometimes assign a grit number to them, but go by microns.

1 or .5 is more practical.

 

[graduate_owner]

Thanks DW, but how do microns compare with grit? I was wondering what grit stones to get, and there would be no point using an abrasive soap if it is coarser than the diamond grit already used. Is there some means of calculating grit size from micron?

K

 

[D_W]

Thanks DW, but how do microns compare with grit? I was wondering what grit stones to get, and there would be no point using an abrasive soap if it is coarser than the diamond grit already used. Is there some means of calculating grit size from micron?

K

There are several, and that's part of the problem. The other issue is that a micron of diamonds affixed to a metal substrate (like the diamond hones sold on the market) will do something different than a micron of loose diamonds on wood.

The best comparisons I've seen of those nosebleed tiny things is the perceived effect on a straight razor, but at the same time, your sharpening for woodworking doesn't have to go to that level. I think 1 micron diamonds (loose - which are cheap) make a very good final step.

A diamond hone that states that it's 10,000 grit will probably be 2 micron diamonds, which will also be fine, but it won't be as fine as the green compound you've described, despite the fact that the green compound may have stray large particles in it.

In my experience with *razors*, which should only be taken as advice for razors, and not for woodworking tools, I can tell the initial sharpness of green chromium oxide powder (which is pure and of a specific grade - 0.5 micron for the type I bought) honed edge is about the same as 0.25 diamonds, but even at half the size, the diamond edge has a bit of bite, which suggests that it's more ragged.

Because of that, i think collective perception from a group of people is more accurate than comparing charts and numbers.

 

[custard]

When my DMT 600 grit stone was getting tired I followed DW's advice and tried an Atoma diamond stone (available in Europe from Dichter Tools), so far I've been delighted with it and I'll switch over other DMT stones to Atoma in due course. The Atoma seems to give a bit more user feedback than the DMT plus it's better at clearing the swarf. It's very flat and the fact that it's bonded to an aluminium plate rather than steel makes it lighter and handier without compromising stability. Dichter separately sell the actual thin diamond plates that are bonded to the aluminium base block, there's a small cost saving there but probably more significant is that you could make up any double sided configuration you wanted. Dichter also stock Atoma diamond sheets bonded to thin, flexible copper, so you could make up shaped hones for more specialist tools.

https://www.fine-tools.com/diasharpener.html


A few months ago a local woodworker that I'm friendly with brought in some amazingly cheap Chinese diamond stones to see how they compared to the DMT stones. Initial reaction was pretty positive, but he tells me that subsequently they've shed some of the diamonds along an edge.

Incidentally, I'm sceptical about using quoted grit sizes for comparison between different types and brands of stones. To give just one example, I've got an XX Fine DMT diamond stone that's rated at something like 8,000 grit, but it doesn't deliver a polished edge like you'd get from a 6,000 or 8,000 grit water stone. I don't doubt that DMT have accurately graded their product, but it's evidence of the way different sharpening media have different characteristics. Actually, when it comes to most woodworking tools I'm not completely convinced of the need for a polished edge anyway. Don't get me wrong, I value a polished edge as much as the next guy, but I suspect it's psychological more than real. Nothing wrong with that, the greater part of woodworking is all about confidence so confidence in your tools must play a part too. If a polished edge gives the confidence to cut a tricky joint without hesitancy then it's done its job.

 

[ED65]

anyone know what the equivalent grit would be to green honing compound?

Why not just use that? The green honing blocks usually work well (most are not pure chromium oxide in case you don't know, but they're commonly 'adulterated' with aluminium oxide and this is not a bad thing).

If you really want to try something finer it's worth experimenting with any fine polish you might have in the house that'll polish steel. If you have to buy new Simichome, Flitz, T-Cut or Peek are all viable choices, each one has its fans for loading a strop.

...how do microns compare with grit?

Headsup: this is a rabbit hole if you want to explore if fully. Unfortunately you can't do a direct comparison across the board, various tables have been drawn up by obsessive fans of sharpening gear and it's clear that manufacturer ratings and many published equivalence tables don't agree.

Plus there are further things that come into play, since some abrasives break down (become smaller particles), some round off, along with the various ways different sharpening media break down and form a slurry the results from two abrasives that are the same grit (i.e. they were the same originally) can be wholly different.

This is the kind of thing that accounts for some of the difference in results from two waterstones sold as 8k, a waterstone and an oilstone of the same grit (whatever it is), and diamond plates versus everything else.