Thread: Lapping Shapton w/ DMT D8C

Originally Posted by bevansmw

That makes sense. So the DMT is about .025mm (= .001") flatness and GDLP .001mm, so the question is 24 thousandths of a mm really perceptible?

This flatness argument, especially the DMT vs. Shapton GDLP has been around for some time. My opinion is summation is:

There is absolutely no direct SHAVING advantage from the Shapton stones being lapped to .5 micron versus the DMT lapped stones to .001". None. Skin is pliable and conforms to a keen shaving edge. So....zippo, no advantage on this front.

HOWEVER...............There IS an advantage (the degree of which can be debated) to having each honing stone in the grit progression used being .5 micron flat vs. .001". Less surface variation or greater flatness from stone to stone makes for faster removal of the prior stone's scratch pattern. If I hone a razor that lies flat as it should on both sides of the blade, I've found that it takes less passes on the finer grit stone to remove the prior stone's scratch pattern since I've been using the GDLP rather than the DMT. I attribute this to the flatness factor.

With that said, are we talking about a world of difference in time? Does the DMT's flatness at .001" mean the DMT can't do the job as a lapper? Of course the answer is no on both counts.

There are so many areas of interest in life where those that are deeply interested and even obsessive about an interest will debate the most minute points of the smallest advantage of one thing over another ad nauseam. It's no different with us.

I like my GDLP and think it's great. Not only for it's flatness but also for it's non-continuous surface which reduces stiction. That said, I would never advocate that DMT is crap and everyone should drop a big chunk of change on the GDLP. Both will do what they're supposed to do. The GDLP is there for those of us find an IDEAL is worth spending $280 when we all know or should know that spending a lot less on a DMT is just fine.

Just my 2 cents. One more thing to add; I don't think anyone who buys or is contemplating buying a DMT D8C for lapping should ever feel they'll NEED the GDLP at a later date. There's nothing wrong with DMT.

Chris L

Originally Posted by bevansmw

That makes sense. So the DMT is about .025mm (= .001") flatness and GDLP .001mm, so the question is 24 thousandths of a mm really perceptible?

Is it really perceptible? Yes! If you mean when sharpening razors, then no. I think we keep forgetting that Shapton hones were never designed for straight razor sharpening.... I bet the folks at the factory are downright amused at this newfound source of customers! Back to the flatness issue... when honing bevels on traditional Japanese planes and bevels on chisels and the like, flatness really does matter. The larger the bevel, the more material needs to be removed and the longer it takes. If one hone is slightly dished and the next finer grit is the opposite, it can take a loooong time to polish that bevel if you are up in the 4k 8k and beyond grits as they really don't remove much material. On the other hand, hollow ground razors are much less affected by such trivial flatness errors such as 0.001" so that it would not be noticeable at all. I seriously doubt it would be noticeable on a wedge for that matter. And while we are at it, DMT claims 0.001" max variation, NOT that it WILL be 0.001" out of whack. Ditto for the Shapton unit... the differences between any two samples will vary.

There is a secondary and much larger issue is the ability of the operator to flatten the hones with these plates.... The correct way to compare the two would be to measure the difference on the flattened hones and not the diamond plate used to flatten them. If one constantly turns the hone end for end while flattening, using the full surface of the diamond plate, the effect of a .001" bump or hollow would not be measurable on the hone that was flattened, particularly when you consider the water and slurry between the two items in use having it's own moderating effect. I personally would not expect myself to do better than 0.001" with either diamond plate.

HAD is a frightening affliction though, it really can mess up a gents mind to the point that a $250+ diamond flattening stone starts to look like an irresistible good deal and is sure to shave years of honing time off the next time you have to touch up the edge of a straight razor..... I should know, I'm fighting the urge to order one and I'm not winning! I mean... they look so damn cool!

Regards

Kaptain "Who said logic and common sense had anything to do with the hobby of straight razors?" Zero

Like Chris said, there is nothing wrong with a DMTC for lapping. And like Kap Zero said HAD is a helluva affliction So I have both the DMTC and the GDLP. It reminds me of one of those motorcycles that is built for both road and dirt. It will do both but not as good as a dedicated sure enough road bike or dirt bike. The DMT is made for sharpening. It works for lapping and if you don't mind the stiction it will get the job done but the GDLP is to lapping like a Husquvarna is to riding dirt. It is made for it and does a superior job IMO.

For the record, I lapped the 4 Shaptons that arrived in the mail today on my D8C and I had zero problems. Total time was about 15 minutes including cleanup which was about the same as when I did my Norton 4k/8k.

I'm really torn now about the DGLP. Doing the math on the difference between the DGLP and the D8C in regards to accuracy tells me the DGLP is not worth it. On the other hand, the DGLP looks really cool, will have less stiction and did I mention it really looks COOL. To be honest, the D8C is fine for flattening not only the usual hones but the Shaptons as well. The only thing in my crazy world that does not make sense is HAD and I've got it.... big time!

Regards

Kaptain "I'm as broke as the last hone I dropped on the basement floor" Zero

I did end up having a bit of a problem. My hones that I lapped feel really smooth after lapping them, I tried setting a bevel on one razor last week and noticed no swarf was coming up at all and I was getting a lot of stiction, the razor was like a vacuum to the hone. I e-mailed one of the guys at shaptonstones the other day asking about it as I got a little worried that I had managed to take off all of the ceramic, he said it was unlikely and I probably just smoothed it out while lapping, said the GDLP helps to preserve the sharpness of the ceramic while lapping so it isn't smoothed out. I think I may end up buying a GDLP now just to make sure

Unless someone with a gdlp wouldn't mind me mailing the stones to you to have them lapped ? I could pay both ways shipping and that, just to make sure it will restore the sharpness to the stones.

Well, diamonds are diamonds... I don't really see how Shapton could do anything special when attaching diamonds to their glass plate that isn't done when DMT attaches the diamonds to their metal plates. The difference is the way they are adhered. Shapton probably uses some sort of adhesive similar to the stuff they use making up their hones. DMT simply uses the nickle plating process to bind the diamonds to their hones.

The stiction you are feeling is the agressive cutting action of the Shapton hone and probably some stickiness from the binder which is some sort of non-permeable resin. My DMT is very worn already after a rather drawn out affair with a Spyderco UF. The diamonds are still there and work fine for flattening hones but a large surface area cutter made from hardened tool steel just glides over that hone with hardly a scratch. If I run the same cutter over my 1200 grit DMT the cutting is fast and furious.

You have not harmed your Shapton hones, mine are glossy as well but the difference is that water does not bead up. If water begins to bead up, you need to lap again to clean the surface. The ones flattened with a Shapton DGLP will not be any different but if you wish to test an alternative, why not lap your hone using good old wet/dry paper on glass or a polished marble/granite tile. 220 grit or higher if you wish should be fine. Dr. Moss used that method on his Shaptons before switching to the DGLP and the result was simply that the flattening goes faster with less of a mess when using the DGLP.

By the way, what grit hone were you trying to set your bevel with?

Regards

Christian

I agree that your D8C should not be a factor or have contributed in some negative way to what you're experiencing. I don't see how the D8C could have screwed up your Shaptons since they're solid material all the way through.

Shapton ceramics, especially the higher grit very smooth hard stones can be prone to stiction and chatter depending on your honing technique. When I hone I always skew the razor with toe leading in addition to doing an X pattern. This eliminates any stiction problems (well, that and I've also been known to use a two handed method somtimes; shhhhhhhh......don't tell anyone).

Do you skew your razors when making your passes? What stones were you having those issues on?

Chris L

I know, I know this is a crazy question. You said: "The lapping went fine but took some time as the glass is a lot harder than a coticule or a norton stone."

I'm pretty sure you meant glass as in Shapton Float Glass, but with the trouble you describe I simply must ask: Are you sure you're lapping the ceramic face?

My Shaps are from the pro series and like many I started with abrasive paper. I use a DMT plate now and have lapped some seriously abused stones from knife polishing. I just cannot imagine spending an hour on a new one using 325 grit diamond

It was about 20 - 25 minutes or so each, I was lapping the right side the clear face of it and I was using a 1k shapton. I lapped four, so it took about 1 hr for two each time I lapped them.

Originally Posted by bevansmw

It was about 20 - 25 minutes or so each, I was lapping the right side the clear face of it and I was using a 1k shapton. I lapped four, so it took about 1 hr for two each time I lapped them.

Uhh... sorry, but that explanation did not clear things up for me.... There is a clear glass side and a white ceramic side to the Glass Shaptons... It is the white side that is the honing surface, the other "clear" side is only the glass base and you can see the identification marks through it as in the grit mesh and micron size.

If you were lapping the white side of the hone, I cannot help but think that if you spent that much time on one hone, you must have accidentally used the wrong DMT plate or there is something terribly wrong with your DMT such as virtually no diamond grit. For me it was a matter of a few minutes with a almost instant white slurry being developed as I lapped the hones. The Shapton 2000 grit took the longest, my Shapton 16000 grit took the least amount of time which is to be expected as the diamonds have better access to the binder as the finer hones have smaller sized grit.

Regards

Christian