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A girl's best friend

PostPosted: 24 May 2022, 08:40
by Dr.Al
At the risk of getting a bit close to a banned topic, I thought some people on here might be interested in a cheap source of HUGE diamond plates. Big plates make things a bit easier in my (limited) experience. DMT diamond plates are bigger than most (8" x 3", so about 200 mm x 75 mm), but they're very expensive.

After spending an unreasonable amount of time searching ebay, I found these thin diamond plates for less than £9 each. They're 230 mm x 80 mm, so even bigger than the DMT ones, but only about 1 mm thick, so can't be guaranteed to give a flat surface. However, you can either stick them down to some plywood or, as I did, buy some 10 x 80 mm aluminium flat bar, saw it to length and stick the plate down with some Loctite 603 or similar. For about £55 (or £26 if you don't buy the aluminium), you can get three huge diamond plates in whatever grit sizes you want.

There are cheaper versions (about £6 each) that are a bit smaller (170 mm x 75 mm) and very easy to find on ebay (search "diamond plate"), but I wanted something a bit bigger and they're harder to find.

I've been using mine for a month or so now and they seem very good. I don't know how long they'll last compared to DMT's ones, but as a hobbyist I suspect they'll probably do me for a very long time.

I wasn't sure whether to post this as I was worried it would turn into a sharpening thread; if mods think I've gone a bit close to that topic, then feel free to close the thread!

Re: A girl's best friend

PostPosted: 24 May 2022, 10:55
by Andyp
At that price they seem worth a punt.

no problem with the post from me

Re: A girl's best friend

PostPosted: 24 May 2022, 12:00
by Argus
I've heard varying reports of these very thin plates....... apparently they don't stand up to repeated use as the solid ones do, but at that price......

One question.
At 1mm thick, how flexible are the plates?
What's the smallest radius that they can be curved to?

My reasoning is that, if they will curve uniformly to a small radius, I'd consider using them as a glue-on on a former to make a slip-stone for gouges.

Re: A girl's best friend

PostPosted: 24 May 2022, 12:09
by Dr.Al
Argus wrote:I've heard varying reports of these very thin plates....... apparently they don't stand up to repeated use as the solid ones do, but at that price......


As you say, the price makes them seem worth it. If they only last one tenth of the time the DMT ones do, they work out as the same price. Glued down with Loctite 603 it should be easy enough to remove them from the aluminium (with acetone and/or heat) and replace with a new plate when they wear out.

Like most diamond plates, they started off seeming a bit coarser than advertised. After the first few rubs they settled down to a more consistent (and as expected) grit. DMT's instructions suggest that's true for DMT ones too.

Argus wrote:One question.
At 1mm thick, how flexible are the plates?
What's the smallest radius that they can be curved to?

My reasoning is that, if they will curve uniformly to a small radius, I'd consider using them as a glue-on on a former to make a slip-stone for gouges.


Not very flexible at all; I doubt they would work for gouges to be honest. If you put them onto a gently curving surface and pushed hard (think car tyre radius or thereabouts) they would follow the curve (and possibly plastically deform), but they're not going to bend much tighter than that I imagine. I haven't tried to bend them much though: I just glued them down to the aluminium backing plate straight away.

Re: A girl's best friend

PostPosted: 24 May 2022, 12:20
by 9fingers
Interesting list of places that they won't send to
I can understand dodgy areas but they exclude USA and China where they almost certainly come from.
They exclude Aus but will allow NZ??

Bob

Re: A girl's best friend

PostPosted: 24 May 2022, 12:43
by Lurker
Does anyone remember years ago, trend offloading supposed substandard plates via their e bay site?
IIRC it was three for a fiver.

I bought loads thinking that they would quickly die and still have unused spares.
They were glued onto a plastic base but removal revealed a finer surface overleaf.
I embedded one of these into a lump of thick MDf but dead level with the plate so I can overshoot the runway so to speak. I am still using the first two course and fine.

Re: A girl's best friend

PostPosted: 24 May 2022, 13:00
by Woodbloke
Interesting, but my guess is that even when glued down to a substrate of some sort you couldn't guarantee the flatness, 'specially if used for general plane and chisel sharpening where there's a possibility that you could do a lot of 'damage' to the edge which could take some effort to rectify. A DMT plate, although smaller is as flat as a flat thing and from the Ax page they say...'The DMT D8EE Dia-Sharp precision engineered diamond surface will stay flat throughout all your sharpening'
So yes, tempting idea but I'll pass - Rob

Re: A girl's best friend

PostPosted: 24 May 2022, 14:38
by TomTrees
I epoxied mine (the cheaper ones with the grid pattern) onto some granite on the convex side for those reasons.
Haven't found issue doing so, although I have fancier hone for afterwards so only used as an initial
prepper.

Re: A girl's best friend

PostPosted: 24 May 2022, 16:21
by BucksDad
I guess as this is kind of related to sharpening. What's a recommended grit for primary bevels? I don't really want to spend the money on a bench grinder for the occasional primary bevel... hand power sounds just as good even if it takes a little longer

Re: A girl's best friend

PostPosted: 24 May 2022, 16:58
by TomTrees
A used bench grinder could work out cheaper than what could be a rabbit hole, prob 20 quid would get you something useable compared to other methods by hand
i.e abrasive on float glass, and a really good tool to have around.

Although ED65 has some posts on possible links to some cheap ones, which had much more aggressive grits than the 400g and 1000g cheap card plates with cross pattern on them available everywhere, which I'm not sure of compared to a non patterned one, due to getting chips of the edge on rough work or garden tools after the grinder that is :)

Re: A girl's best friend

PostPosted: 24 May 2022, 17:23
by Woodbloke
BucksDad wrote:I guess as this is kind of related to sharpening. What's a recommended grit for primary bevels? I don't really want to spend the money on a bench grinder for the occasional primary bevel... hand power sounds just as good even if it takes a little longer

Pretty much as coarse as you can find! The idea is to remove a lot of metal with the minimum amount of effort. As an example, if you were to go to Workshop Heaven you buy some 100 micron PSA sheets which are about as coarse as you can find. I've used them in the past and they're good but the grit doesn't maintain the 'bite' for very long and however you slices it, it's still hard work and a long and tedious process.
End of the jour, anything really coarse will do as long as you can stick it to a flat surface - Rob

Re: A girl's best friend

PostPosted: 24 May 2022, 17:49
by Dr.Al
I was looking around for reviews of the plates (in terms of longevity) and found this: looks like St Paul has had the same idea (albeit with the smaller plates):

https://paulsellers.com/2020/03/edge-sh ... -under-10/

Oh, and I thought it wouldn't hurt to post some photos since it seems to be the done thing :D

IMG_20220524_174037 - Copy.jpg
Three "stones"
(43.46 KiB)


Close-up showing the aluminium plate I chose to use (Paul Sellers just uses birch plywood) - I stamped the grit into the aluminium as it isn't written on the plate anywhere (just on the bag it came in):

IMG_20220524_174051 - Copy.jpg
(21.2 KiB)


(The detritus you can see on the coarser plate is just bits of tissue from where I wiped it dry).

Re: A girl's best friend

PostPosted: 25 May 2022, 08:00
by Woodbloke
The only Sellers I pay any attention to is:

download.jpg
(7.55 KiB)


...is this one - Rob

Re: A girl's best friend

PostPosted: 25 May 2022, 14:29
by Woodster
I’m not sure using plywood is a good idea. Offcuts of thick plate glass should be pretty flat or you could use pieces of porcelain or stone tiles. In spite of claims for flatness of the very expensive diamond plates I doubt a few thou out will upset your tools? Certainly worth a try given the cost.

Re: A girl's best friend

PostPosted: 25 May 2022, 15:04
by Dr.Al
Woodster wrote:I’m not sure using plywood is a good idea. Offcuts of thick plate glass should be pretty flat or you could use pieces of porcelain or stone tiles. In spite of claims for flatness of the very expensive diamond plates I doubt a few thou out will upset your tools? Certainly worth a try given the cost.


I wasn't convinced by plywood either. Tiles or glass sounds like a good idea though. Ideal would probably be some flat (stainless?) steel bar as the glue wouldn't be under any strain from thermal expansion. I went with aluminium as it's cheap and easy to cut.

Like you, I'd be gobsmacked if it ended up being far enough from flat to have any issues with woodworking tools. The (aluminium in my case) base will keep it flat overall and any wear of the plate itself is going to be tiny compared to the wear that you'd get within a handful of strokes if you were using a waterstone and waterstones seem to work for a lot of people.

Re: A girl's best friend

PostPosted: 25 May 2022, 18:01
by Just4fun
I tried some cheap plates about the same thickness, although smaller. They were nice while they lasted but they did not last long.

Re: A girl's best friend

PostPosted: 25 May 2022, 18:05
by Dr.Al
Just4fun wrote:I tried some cheap plates about the same thickness, although smaller. They were nice while they lasted but they did not last long.


Interesting. How long did they last? I realise it's very dependent on how much one uses them, but I'm curious nonetheless.

Re: A girl's best friend

PostPosted: 25 May 2022, 18:58
by Mike G
TomTrees wrote:.........i.e abrasive on float glass......


Just as an aside, it is very difficult to buy anything other than float glass. You have to actually go out of your way these days to buy something that isn't float glass. Further, even float glass can be out of flat if you get toughened glass. So, so long as it is thick enough, virtually any old thing out of a glazier's scrap bin is going to be suitable.

Re: A girl's best friend

PostPosted: 25 May 2022, 21:18
by TomTrees
I went to a large glazier, and the thickest stuff they had was 6mm, they looked at me like
I was asking for the moon and didn't have a clue where I'd look for thicker stuff. :?
Also didn't know toughened glass was still called float glass aswell.
Something else to keep in mind!

Never found something to suit in the end, and scraped me own.

Was really hoping the granite stove hearth stuff would be decent, but every piece I have the polished face as pretty convex, which equated to around 1mm when checking something 3" tall.
Very evident with a pair of squares butted against each other which will show up when pushed.

Though not important for just working a primary bevel, if needing to buy something
then I'd be wanting two for one for the toolmaking aspect.
Could use just melamine for the job of that ala Klausz, provided you can support it.
He said the same about the glass, but wasn't clear about what type it was.

Can't argue with that, as it's probably a good thing to assume the thing isn't flat to begin with.

Tom

Re: A girl's best friend

PostPosted: 26 May 2022, 06:44
by Mike G
TomTrees wrote:..........didn't know toughened glass was still called float glass.....


It's not called it, but that is the method of making it. To make toughened glass they take ordinary glass, which is float glass, and heat it up.

Re: A girl's best friend

PostPosted: 26 May 2022, 14:53
by Lurker
My glass plate is as flat as a flat thing :D

Re: A girl's best friend

PostPosted: 26 May 2022, 19:27
by Vann
Lurker wrote:My glass plate is as flat as a flat thing :D

I'd take that straight back to the seller and demand your money back if I were you. If that's supposed to be 1/2" thick you've been robbed 0.1mm :!: ;)

Cheers, Vann.

Re: A girl's best friend

PostPosted: 26 May 2022, 20:39
by Lurker
Vann wrote:
Lurker wrote:My glass plate is as flat as a flat thing :D

I'd take that straight back to the seller and demand your money back if I were you. If that's supposed to be 1/2" thick you've been robbed 0.1mm :!: ;)

Cheers, Vann.


Difficult as I “borrowed it” from an employer who is now no more.

Re: A girl's best friend

PostPosted: 12 Jun 2022, 17:33
by RogerS
Just got a couple to try and they're very handy. I simply clamped mine to the bench.

Now I ought to know the answer to this but I don't ...
diamond plates ...do you use them dry ? Or 'wet' and if so, what with ?

Re: A girl's best friend

PostPosted: 12 Jun 2022, 17:38
by 9fingers
RogerS wrote:Just got a couple to try and they're very handy. I simply clamped mine to the bench.

Now I ought to know the answer to this but I don't ...
diamond plates ...do you use them dry ? Or 'wet' and if so, what with ?



Use something vaguely oily but very limpid. you don't want to clog the cutting process just to allow the debris to flow away.
Paraffin, diesel, white spirit, wd40 all suitable.
Bob