# Diamond paste sharpening ...



## gidon (12 May 2006)

Not that much exists on the details of diamond paste sharpening. But this is quite a nice summary of the whys and wherefores of what the authors refer to as loose diamond sharpening:

http://www.woodcentral.com/cgi-bin/hand ... read=89166

I still find the number one issue with this method of sharpening is the right substrate. I use hard maple and have tried Plexiglass and other flat surfaces in my workshop. Maple works ok for me but can be frustrating if there's any burr on either side of the edge and you end up scraping or digging into the surface. Still if you are careful it is a very nice and quick way of putting a nice edge on your tools. And if I could get hold of those recommended cast iron plates they mention it would be even better .

Cheers

Gidon


----------



## Neil (12 May 2006)

gidon":3mhcs0st said:


> And if I could get hold of those recommended cast iron plates they mention it would be even better .


Would the plate out of this kit be any use, Gidon? Doesn't seem too expensive even the powder is no use. Maybe steel would be too hard though?

Cheers,
Neil


----------



## gidon (12 May 2006)

Thanks Neil. Answer is I dunno! That's what's a little vexing about this whole business - there are no real answers, only speculation albeit based on some thorough testing. I have seen some comments on woodcentral on those steel plates (Kanaban's) - but can't remember what the verdict was. Toolsforwoodworking seem to recommend them so that's something ... I have been tempted before to give them a try and am again now you've reminded me! 
What would be nice is if someone like DMT or Norton actually offered these diamond pastes with a suitable substrate which they'd researched. The fact that nothing is available backed by a manufacturer must mean something. I think those chaps as woodcentral appear to say there is no one perfect substrate - although cast iron is preferred.
Cheers
Gidon


----------



## Chris Knight (12 May 2006)

Gidon,

I got a cast iron lapping plate from these people http://www.homeandworkshop.co.uk/misco200.htm who have one on the page in the link. It is not cheap at £65 - I seem to recall I paid a good bit less for mine but it was so long ago, I have totally forgotten. It may be worth trying secondhand dealers near you.


----------



## Alf (12 May 2006)

I gather the steel lapping plate isn't much use - too hard so the particles of diamond get picked up by the thing you're trying to lap/sharpen and you end up honing the plate. #-o The cast iron issue is annoying; 12x12 is a leetle bit big for normal use, even if it wasn't 65 quid. You can get hunks of cast iron okay it seems, it's just getting them machined that might be the stumbling block. :?

Cheers, Alf


----------



## gidon (12 May 2006)

Well - just looked at WC again - and it seems it was our very own bugbear [Edit: sorry mistake - it was someone else - think I read bugbear's reply ) who had tried the Japanese plates and wasn't impressed. Ah well.
Chris - thanks for that - a little pricey and big for my needs but good to know something may be available. Do you use that for diamond paste sharpening?
Sorry Alf - keep getting interupted with work whilst writing this so missed your post - I'd wondered what the reason was the steel plate was not recommended - at least for the finer grits which is what I'm interested in.
Hey a few of us could get one of those and cut it into 8 6x3 inch lapping plates with a hacksaw??.
Cheers
Gidon


----------



## bugbear (12 May 2006)

gidon":2fe9uclw said:


> Hey a few of us could get one of those and cut it into 8 6x3 inch lapping plates with a hacksaw??.
> Cheers
> Gidon



Not without residual stress turning the results into pretzels (on a 1 thou scale that is)

BugBear


----------



## Jarviser (12 May 2006)

Alf":1h7rcd5a said:


> You can get hunks of cast iron okay it seems, it's just getting them machined that might be the stumbling block. :?



Maybe an old no 5 1/2 or 6 plane sole upside down in a bench vice would make a good lapping plate? We know how to flatten those nicely, and they are cast iron. They occasionally turn up in flea markets and car boots without frogs or with worn out mouths etc.


----------



## gidon (15 May 2006)

BB - shame .
J - I have tried that with an old plane I already have. Trouble is it's not flat enough. And it's a lot work to get it good enough for flattening other stuff. I may try it again though - or try and pick up something flatter ...
Cheers
Gidon


----------



## Rob Lee (16 May 2006)

gidon":2lsjedy2 said:


> BB - shame .
> J - I have tried that with an old plane I already have. Trouble is it's not flat enough. And it's a lot work to get it good enough for flattening other stuff. I may try it again though - or try and pick up something flatter ...
> Cheers
> Gidon



Hi - 

How flat do you want it? Not a facetious question...just looking for what people find acceptable....

We can easily make a plate.... but what size would people want - how flat, and what price? (note - those are not independent variables!)

Cheers - 

Rob


----------



## Frank D. (16 May 2006)

Hi Rob,
8" by 3", within a few thou, as cheap as possible.
My condolences for the Senators :wink: .


----------



## gidon (16 May 2006)

Hi Rob
Well my DMT Duosharp's are meant to be flat within 0.003" - and they seem plenty flat to me. I agree with Frank 8"x3" would be perfect. For me yep as cheap as possible - I personally wouldn't really want to pay more than £20 for something like that. Especially since if you want to use more than one grade of paste you'd need a plate for each. I may stretch to £30 I suppose .
Would be absolutely brilliant if you could produce something like this - and for those starting out perhaps some tubes of pastes too? And while I'm at some of those nice clear Veritas instructions that would clear up some of the mystique of diamond paste sharpening .
Cheers
Gidon


----------



## Rob Lee (16 May 2006)

Hi - 

Ok - it's been on the queue for awhile... so we'll see if we can push it ahead...

Tolerances will not be an issue - economically, we can do a 14" x 14" plate to within +-.0005"...

How - you ask?

On a great big diamond lapping machine (due soon!) 8) 

Cheers - 

Rob


----------



## Alf (16 May 2006)

Rob Lee":2k2q3uiv said:


> On a great big diamond lapping machine (due soon!) 8)


Now look what you've let happen; he's been able to gloat. #-o

Cast iron plates of any size would be lovely indeed, but I fear for the shipping cost... :? Would they be "Veritas" badged, and thus BriMarc-able...?

Cheers, Alf


----------



## Rob Lee (16 May 2006)

Alf":2asy8pgq said:


> Rob Lee":2asy8pgq said:
> 
> 
> > On a great big diamond lapping machine (due soon!) 8)
> ...



Hi Alf - 

Not sure just yet... they're still a twinkle in some designer's eye....

:wink: 

Cheers - 

Rob


----------



## Alf (16 May 2006)

Well I just thought I'd mention it in the hopes of guiding the twinkle in a beneficial direction... 

Cheers, Alf


----------



## gidon (16 May 2006)

Rob - great stuff - please keep us posted if you can - cheers. Diamond lapping machine eh? Don't let bugbear see you're getting one of those . 
Is that the criteria for something from LV being available through Brimarc then - it has to be badged Veritas?
Cheers
Gidon


----------



## beech1948 (16 May 2006)

I just had a look at the G&M web site for cast iron plates...loads of used for prices from £50 to £120...lots of sizes...maybe thats a source


----------



## gidon (16 May 2006)

Thanks - I spoke to the people on Chris's link - they had some too - different sizes. But I'm a little unsure about this plates - they have a textured surface I believe which I wouldn't think would suit the small micron paste? Plus they were a little vague on the accuracy of the plates - being second hand there were no guarantees. I may just wait for Rob now .
Cheers
Gidon


----------



## Wendell (16 May 2006)

Rob Lee":2ldcn080 said:


> Hi -
> 
> How flat do you want it? Not a facetious question...just looking for what people find acceptable....
> 
> ...


 
I've been using 12" x 3" polycarbonate pieces for diamond paste sharpening. It works well for the lower grits (45 & 15 micron) but I really want to try cast iron for the higher grits. Based on this my preference would be 12" x 3". I'd be willing to pay up to $50 a plate just because it's coming from a source I could trust.


----------



## bugbear (16 May 2006)

gidon":1ifbosio said:


> Diamond lapping machine eh? Don't let bugbear see you're getting one of those .



Heh. I have all the flattening kit I need; 1 surface plate, some blue crud, and some metal removing tools (files, scrapers, scraps of AlZi)

It's enough to do rather accurate work, as it turns out.

BugBear


----------



## Rob Lee (16 May 2006)

bugbear":2cchni3y said:


> gidon":2cchni3y said:
> 
> 
> > Diamond lapping machine eh? Don't let bugbear see you're getting one of those .
> ...



Ah - but ours is (will be) "sweatless"... turn it on, walk away, and come back to a 10u finish..... 8) 8)


----------



## Wiley Horne (16 May 2006)

In my experience, the surface finish of the iron plate matters, especially when you get down into the 1/2- and 1/4-micron meshes. You want smooth. How smooth?--I dunno, real smooth, about like a plane sole. Smoother is better. Price point: $50. Length: 8" real good; 10" better.

Wiley


----------



## Philly (16 May 2006)

Axminster do this plate.
Any good or too expensive?
Philly


----------



## Jarviser (17 May 2006)

gidon":1rtwgl8i said:


> BB - shame .
> J - I have tried that with an old plane I already have. Trouble is it's not flat enough. And it's a lot work to get it good enough for flattening other stuff. I may try it again though - or try and pick up something flatter ...
> Cheers
> Gidon


Sorry I didn't respond - I'm still not getting any notifications.
To flatten other things, yes you need a surface plate. 
To hone a blade it needs to be flat across the width, but in the length it doesn't have to be flat at all. You can hone a blade on a curved surface if you use any wheeled holder, the ultimate curve being a Tormek wheel. I would have thought the surface of a typical DIY plane would be flat enough for honing.


----------



## gidon (17 May 2006)

Thanks Philly - again it's that textured surface that won't be any good for the fine paste. And too big really - just need something the size of a standard sharpening stone ...
J - I never get those notifications either (well not reliable) so don't bother with them anymore. If the plane was flat across its width yes it'd be fine for honing I guess (as long as you kept your strokes straight up and down). But I still wouldn't want my nicely polished backs touching an unflat surface. As it is it's not reliably flat in any direction .
Cheers
Gidon


----------



## Javier (18 May 2006)

I think I've read somewhere that the iron plates are soft enough to allow the 
diamond particles to become imbedded. Does this sound right?


----------



## gidon (18 May 2006)

Javier - I think's that's it. That's why it's quite tricky finding a substrate with the right balance. You want the diamonds to stick, but not sink! So although Maple works ok - it's still porous so you need more paste plus the cutting action is meant to be slightly less aggressive because the particles are more embedded than with say iron.
In this article, the author tried Maple, MDF and steel - and found steel gave the worst results followed by MDF. And Maple was best. She was looking at the results under an 700x microscope. unfortunately she didn't try iron. But I know for a fact that maple does give good results even if you do need more paste. But as I mentioned earlier the problem for me is ruining the nice flat surface by digging in the blade or scraping with the burr.
Cheers
Gidon


----------



## Miles968 (23 May 2006)

A good source of info on lapping (for precision machining, and polishing gemstones) is Kemet International http://www.kemet.co.uk/about_kemet.html - there is a specific composite material they make that is supposed to be even better than cast iron, but CI is also on their catalogue. Lots of diamond pastes too - I suspect they would be a good choice, better than going via some non-specialist supplier. When I get a moment I'm going to try some...

On Woodcentral we had another little discussion like this, and I got a quote from Kemet - they do circular lapping plates (cast iron) for about £60, or sheets of the Kemet GP4 for £14 each but with a 10-off minimum order. Any chance that people here would want to get together and order a stack (2 sheets each I reckon, for a coarse and a fine grit)? I would do admin.

It's my feeling that getting the right grade of substrate is important if you really want to assess the performance of this technique - if ordinary steel doesn't work quite right, but CIron does, then a specialist supplier who does nthing else is at least going to supply the 'right' grade of CI which can serve as a reference for substitutes.

Miles


----------



## gidon (23 May 2006)

Miles
Thanks for the information. The paste I have is from Kemet and I have spoken to one of their chaps before. Unfortunately although he was helpful you seemed to have gleaned some more useful information from yours .
It does sound interesting. I would be interested into one of the composite plates for £14. Do you know how flat they are? And will the material stay flat? What size / shape are they - on the web they look like discs which wouldn't be so handy for sharpening. What grits are the GP4 plates intended for - I'm personally only really interested in used the finer paste (<=1 micron) on mine. Sorry for the questions but will save me finding the right person to speak to if you already know the answers.
Cheers
Gidon


----------



## Miles968 (23 May 2006)

Gidon, this was the quote I had from Kemet - I think the cast iron plates are circular - probably fine for hand lapping, just have to learn a slightly different stroke - for running a jig on, not so great but of course one can always mount them in a larger area of something to run the roller on (as I already do with my DMT so I can use the full length) 

I think GP4 is suitable for all grits, no info to the contrary yet, we could check. Jeff Brown was the guy I spoke to at Kemet. It's a shame they don't sell other shapes/sizes of plates - maybe they would be willing to just supply some rough cast iron of the right grade, we can machine/lap it ourselves if we want to 

342743 6" Cast Iron Plate £51.00
342705 8" Cast Iron Plate £61.60
E04069 Kemet GP4 Sheet 6" x 2" x 18mm Thick £14.38 Each 
Please note item 3 has a minimum order quantity of 10

A 'full sharpen' for me (new primary bevel) means I go from 80grit on a belt sander (not a worn belt) to a 15 micron (red) DMT (quite worn now) to blue compound on leather - gets a fine polish in only a few minutes start to finish. I sometimes use an oilstone instead of DMT but DMT is usually faster, and seems not to cause any problems. Now I'm honing at the end I am finally getting 'shaving sharp' edges much better than without. The very slight rounding towards the edge from honing is probably a good thing for edge life (the back is still as flat as I can keep it, I can hone on a hard surface like MDF). 

Using loose diamond rather than DMT will just mean never having a worn-out middle stage abrasive in this sequence... 

happy sharpening

Miles


----------



## gidon (23 May 2006)

Thanks Miles. The 6x2 inch plates sound ok - although a little small for my plane blades. I still favour Rob's plates to be honest - but from his earlier comments they could be some way off (do you have a ball park figure Rob if you were to go ahead with them?)
Could they send you a sample piece of this GP4 before comiiting to an order. Even a small piece would confirm (or not) its suitability?
Cheers
Gidon


----------



## Alf (23 May 2006)

On WoodCentral Rob gently chastised me for getting folks' hopes up (in a very roundabout way) and pointed out they were only doing next Christmas's stuff now, so presumably not until next year at the earliest? 

Dunno if you got my email, Miles? Anyway, I'd be willing to give the 6x2 plate a shot - it'd be nice to know which grits it's suggested for, though. If it's across the board then two would make sense, as you say, for the highest and lowest grits I have and use most. 

The cast iron is really a bit steep for an less than optimum shape for our purposes, IMO. I dunno, what are the varieties of cast iron? If anyone has access to a means of flattening it, is the stuff offered here (for example) any use?

Cheers, Alf


----------



## bugbear (23 May 2006)

Alf":1wv8tymz said:


> If anyone has access to a means of flattening it, is the stuff offered here (for example) any use?



Ooh, ooh! Flattening! Ask me, ASK ME!

BugBear


----------



## Alf (23 May 2006)

bugbear":3o984vgo said:


> Alf":3o984vgo said:
> 
> 
> > If anyone has access to a means of flattening it, is the stuff offered here (for example) any use?
> ...


Let me re-phrase that. #-o

A means to flatten _economically_ and reasonably _quickly_ without having to learn a whole new skill or technique....

Yes, the BugBear at the back of the class? You think you have the answer? Alright, put you hand down, lad, before you pull something. :roll: :lol: 

Cheers, Alf


----------



## Miles968 (23 May 2006)

Alf's source looks very economical, and we should make the link between the type they are supplying and what Kemet say is preferred for lapping.

Once we have N plates, then it should be possible to either have them machined and polished (or we polish them against each other in the classic A/B/C method until they are fine enough for use, or get BB to scrape them all in his spare time for the next couple of years). 

The key point for me is to get an economical source without having to go with something of unknown character. Is there something special we need to know about or will 'any old iron' perform well in this application? Once we know this, the maddening confusion will be forever reduced!

Alf, can you ask your source for the grade/source/type of material they are selling? We can then check it and go from there.

I would be willing to buy up to 4 Kemet composite sheets, if we can find volunteers to take on 6 between them then we can have a go with this alternative. 3 each, Alf and Gidon, what about you BB? 

Miles


----------



## Alf (23 May 2006)

Miles968":34m5k7bp said:


> ...or get BB to scrape them all in his spare time for the next couple of years


Gets my vote... :wink: 



Miles968":34m5k7bp said:


> Alf, can you ask your source for the grade/source/type of material they are selling? We can then check it and go from there.


Not likely. "Guv, there's some daft bird asking what kind of cast iron it is" "Women. :roll: Tell her it's the heavy sort". I can see it all too well. I need to have a vague idea what the hell I'm talking about first! :lol: I just thought cast iron was cast iron, to be honest.  

Cheers, Alf


----------



## gidon (23 May 2006)

OK Miles - please put me down for one if you go ahead.
From most of the posts I've seen I think any bit of cast iron is ok. What I'm not sure about is how smooth it needs to be. I think for the fine grits the answer must be smooth - the roughness can't be proud of the embeded diamonds? 
Maybe we should be speaking to Axminster? They should be able to knock this sort of thing up (or source it at least) I would have thought if they think there is demand?
Cheers
Gidon


----------



## Miles968 (6 Jun 2006)

Gidon, thanks for stepping up to the plate.... (I can't belive I wrote that before realising what a bad pun it is!) - Alf, are you game too? BB, can we persuade you to chip (in)? 

I will try to get Kemet to ease up on the minimum order - can't really see why they shouldn't, it's not a complicated one to process. If I can find out more about 'good' and 'bad' cast iron (e.g. how modern ductile iron compares to classic cast iron) as far as a lapping substrate goes, I'll pass that on as well.

Seems to me that we could do with a few of the metallurgists who hang out on the knifemaking forums, endlessly discussing steel and edge holding properties, to tell us more about cast iron and diamonds - presumably knifemakers also sharpen from time to time?

cheers 

Miles


----------



## DaveL (6 Jun 2006)

Miles, 

I probably don't need one, but am hopelessly on the cast iron slope, put me down for one. :roll:


----------



## Alf (7 Jun 2006)

Yeah, go on, Miles, put me down for one. If it's a case of needing just one more to get the order then put me down for <wince> two.

Cheers, Alf


----------



## Anonymous (7 Jun 2006)

I just read all posts and what a fascinating thread. I was sorely tempted to jump in and order with the rest but the thought struck me 'why?'. 

What I mean is why use paste on difficult to source (and clearly expensive) substrate when DMT and Trend diamond stones are flat, and ready made and, I would imagine, cut equally well as they too use industrial diamonds.

I guess one could argue that DMTs etc. wear out, but I have only had to buy one adn it is still going storng after several years use.

So, why go for the paste option?


----------



## gidon (7 Jun 2006)

Tony
Absolutely agree - but diamond stones only go to 1200 grit. Diamond paste goes to <0.25 microns .
If DMT came up with a 1 micron (fixed) diamond plate I would buy it an instant.
There are other arguments for diamond paste through the whole grit range but I already have diamond plates up to 1200 grit so am not so concerned with trying the larger grits.
Cheers
Gidon


----------



## Chris Knight (7 Jun 2006)

Gidon,
In your search for a perfect edge, I wonder if you have examined the effects of time/usage on sharpness? I can see the point in striving for the very best possible edge only if it lasts long enough to be useful. 

It would be great to see a graph of sharpness expressed in some meaningful way (like the force needed to take a decent shaving versus number of strokes). I suspect (pure speculation here) that the super-sharpness benefits disappear after a few strokes and then the blade will behave in a "normal" way. In other words, the dulling gradient is very non-linear.


----------



## gidon (7 Jun 2006)

Chris 

I'd love to see a graph like that too! 

It's not I'm so concerned about the _perfect_ edge - it's more that I am after a mess-free method with few variables. I've mostly used waterstones in the past and whilst they give me very good results, I can't be bothered with them - especially since I have no running water - just too messy and too many variables (ie keeping them flat). 

I'm pretty happy with diamond stones - satisfy both my criteria. But you can't argue with the difference between an edge coming off the 1200 grit stone and one polished on a <=1 micron paste / or microfinsishing film? And that edge lasts for a me a decent amount of time (would be very hard to quantify) before it gets reduced to the 1200 grit edge. All for the sake of a less than a minute of polishing. 

To be honest I find that a bit of microfinishing film (.5 micron) slung on the DMT stone for polishing works pretty well. But would be nice to effectively have a <=1 micron diamond stone.

Also with such a graph - you'd need one for all the different varieties of metal out there . You need to find a metallurgy student looking for an interesting PhD thesis to look at this properly .

Cheers

Gidon


----------



## mudman (7 Jun 2006)

Which plates are you talking about ordering? Is it the Kemet GP4 Sheet?

One thought though, does the composite stay flat in use? If it wears quickly like a waterstone, then I can't see them being much use.


----------



## Miles968 (7 Jun 2006)

Yes, it would be the GP4 sheet. It sounds like funny stuff, with a mixture of metal particles and a binder matrix. I suspect it is quite hard, to give good support to the diamond particles, but I have not had time to find out more. 
Are you interested in getting some to try it - it would help to get towards our minimum order size!

cheers

Miles


----------



## mudman (8 Jun 2006)

Go on then, sign me up for two.


----------

