Comparing grit - diamond versus waterstones?

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gidon

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Hi
I'm a little confused here. I have been flattening some plane iron backs on a "fine" DMT diamond stone. I'm unclear as to whether my 1000 grit waterstone is actually finer, or whether to go straight to my 6000 grit waterstone. I have found some (conflicting) information on the web comparing grits - but does anyone have a clear understanding on how say extra coarse (220), coarse (325), fine (600), extra fine (1200) DMT diamond stones compare to waterstones? Also does anyone know if an extra fine DMT stone will give a mirror finish. I find that the 600 grit fine gives a very bright finish but scratches are quite visible.
Cheers
Gidon
 
Gidon,

You seem already to have found the tables that compare grits so I won't suggest them. However I would observe that my green DMT stone (I guess this is what you call "extra fine"? ) does give me a pretty good mirror finish, close to but not as good as an 8000 grit waterstone which is what I use for finishing off my regular woodworking chisels and plane irons.

You can go one step better by honing/stropping with suitable gear but IMHO this is not worth the effort for normal woodworking tools (unlike carving tools as mentioned in another thread). If I have some very delicate paring work to do, I will then strop or hone a normal chisel further on glass or hard maple with a chromium honing "soap" .

It is not uncommon for a careless honing or stropping to round over ("dub") and edge and this screws up all the hard work to that point. If paring, then I will place a piece of maple, dressed with compound on the bench near my work and every few strokes, wipe the blade over the maple - carefully!
 
Hi Chris
Thanks for the info. The two sites I found were here:
http://www.ameritech.net/users/knives/grits.htm and here
So one seems to suggest a fine diamond is equiv to a 600 grit waterstone and the other suggests it'd be equiv to a 2000 stone (unless I'm reading it wrong!)
Yep green is extra fine - I may have to get one - I'm spending a long time on the 6000 waterstone at the mo.
I was experimenting this evening and found that just using the 600 grit fine diamond stone I got a very sharp edge (flattening an old chisel back and honing the bevel all with 600 grit). Passed my nail test pretty well. So am wondering how much the effort that I generally go to is really worth it?! I guess old Pareto's law comes into effect :).
Cheers
Gidon
 
gidon...I donno if this is any help.... but I'll say it anyway...

when I first started experimenting with hand tools, I sharpened with the only stone I had to hand at the time; traditional combination oil stone. I found that using proper guide assisted angles made a hellova difference to the edge quality, but overall, I wasn't impressed with having to stop and re-sharpen 2-3 times a day... I was given a pair of waterstones as a prezzy, 800 & 6000 grit... edges were transformed, hand planing became enjoyable but still, longevity of the edge was pathetic (Stanley steel....) Better steel cured the longevity and I was happy..... till recently....

After taking the better part of a full day to sharpen the primary bevel of my smoother, I figured it was high time I did the same with my jointer... only this time I'd get smart; add more stones to my range to try to speed things up some. I figured I'd be faster doing the bulk of the prep work with a course grit diamond stone... boy was I ever wrong; lapping out the old secondary bevel took forever on the diamond. I ended up using 3 course water stones, at 250, 400 and 800 grit todo the initial shaping, gradually working out the scratches left by the previous stone.

<cutting to the chase..

Evidently I still need to add a couple of intermediate grit stones; the transition from 800 to 4000 being too great a jump to gain an even polish in a reasonable time, but I got there eventually, carrying on through 6000 and 8000 grit... I'll try the blade at that before deciding if I want to go the whole hog, and polish down to 10,000 grit...
 
Thanks Midnight. Like yourself I've tried a fair few ways of shaprening my tools and am pretty happy with my current set-up - would just like something in between my 600 grit diamond / 1000 grit waterstone and my 6000 grit waterstone - really to save time. I have the extra coarse DMT stone and have to say it grinds my primary bevels pretty quickly (and flattens the waterstones) - but then I don't do that very often.
I guess edge longevity is another issue I haven't really been thinking about - that's another reason folks sharpen to the polish I think.
I'm still not sure what grit a 1200 green DMT stone equates to in waterstones though (and for that matter the 600 grit red)?
Cheers
Gidon
 
I think the problem is that waterstones, by their very nature, alter the grit size as you use them. I suppose to a certain extent perhaps diamond stones do too, as they become rounded and so forth, but that's just during the "breaking in" period I suppose. But the waterstone grit breaks down as you use it, hence the building up of the slurry just as you get towards the point of changing to the next grit up. At least, I would assume that would make comparison even more difficult.

Mike, d'you not have a grinder? :?

Cheers, Alf
 
Mike, d'you not have a grinder?

nuh uh.. purely handraulic guv.. :wink:

Truth be told. I don't have the shop space for one.. not even a lil one... as things are, my stone bath gets parked on a shelf 7' up when not in use..
 
Alf":3iya8f0a said:
I think the problem is that waterstones, by their very nature, alter the grit size as you use them ... At least, I would assume that would make comparison even more difficult.

I'm sure someone must have looked into this scientifically in the past. Will have to look at the FWW archives ...

Maybe I'll see if I can pick up a cheap 1200 grit diamond stone if I go to Yandles. Or maybe I'll just make do and stop thinking of excuses not to sharpen all those cutters I have lined up :).

Cheers

Gidon
 
FWW did a comparitive test a year or two ago, with Waterstones, Tormek, Scary etc. I'll dig it out if you want. Let me know.

Rgds

Noel
 
IIRC, they compared system to system rather than waterstones v. diamonds or whathaveyou. Frankly I'm astounded, in a good way, that no-one's come along with the inevitable "it's sharp isn't it? What else d'you need to know?" :wink: :lol: Ooops. I've just done it, haven't I...? :roll:

Cheers, Alf
 
Thanks - Noely - yes please - if you could dig out the name of the article I can get it from FWW - I have some credits left.

Alf - I don't think I explained my quandry very well. I have a 600 grit diamond, and a 1000 grit waterstone. My next finest stone is 6000 - and I'm having to spend too long on this stone. So want something in between. I'd prefer to get the 1200 grit diamond if it really is equiv to a 2000'ish waterstone. Otherwise I'll probably go for a Norton 4000 grit waterstone. Hence my query.

Cheers

Gidon
 
Tsk. You need a hand-cranked one, methinks

I'm not sayin I couldn't use one... (Tony's Rexon review hasn't gone unnoticed)... I just don't have the shop space for one... honestly...

I'm walkin sideways in there as it is....
 
You can still walk in? Plenty of room then. Ask Adam.

Adam cheats... there... I've said it.!! Draggin the table saw outside is definately cheatin...

<mutterin cos my saw canna fit through the damn door....
 
Midnight":12fwb6yr said:
<mutterin cos my saw canna fit through the damn door....

Well run a circular saw down the side of the shed, and voila, the door is suddenly a bit bigger :shock: . In all seriousness, its something I conciously designed in when i built the workshop = big doors are a lot easier....

Adam
 
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