Oh goodness lapping.

[the gato]

I think my arms are about to fall off.

So this past week I got my norton 220/1k and 4k/8k as well as a C12K. I also got a DMT D8C to lap them with. It's taken about 3 hrs per grit to get completely flat.

Is that normal? I ask because my D8C arrived and the box front had Extra Coarse marked. The original UPC was labeld D8F (Fine). The actual stone said Coarse though.

 

[azmark]

http://badgerandblade.com/vb/forumdisplay.php?f=80

Watch my video I just posted.

 

[the gato]

I'm watching them right now...and it's making me think my DMT is mislabeled.

 

[TheMist]

Do not forget running water, otherwise DMT will not cut

 

[azmark]

Do not forget running water, otherwise DMT will not cut

Not true. As long as there is water it cuts but doesn't have to be running.

 

[honed]

The C12K is notouriously hard to lap.
But with a fresh DMT coarse it shouldn't be that hard. Hmmm.

Make sure you don't press down to hard, let the diamonds to the job & make sure there is plenty of water in between.
Hard pressure actually slows down the process a lot.

 

[the gato]

The C12K took about the same amount of time as the Nortons. I've been using the technique shown in azmark's video. It's just taking me like 50 times as long. I wish the DMT stones were sold locally so I could compare. Maybe I just got some unlucky Nortons.

I should also double check, I am looking for a uniform surface right? I find when I'm trying to elimnate the rather troublesome spots that the pencil marks wash away rather quickly.

 

[honed]

The C12K took about the same amount of time as the Nortons. I've been using the technique shown in azmark's video. It's just taking me like 50 times as long. I wish the DMT stones were sold locally so I could compare. Maybe I just got some unlucky Nortons.

I should also double check, I am looking for a uniform surface right? I find when I'm trying to elimnate the rather troublesome spots that the pencil marks wash away rather quickly.

You could try switching to some wet/dry sandpaper ~320 or 400 grit & put it on a flat surface.
If that makes it much easier, you DMT is infact mislabeled.
But I have never heard of a mislabeled DMT before, but just to be sure.

For the C12K you could even go down to 120 paper & once flat get rid of the scratches with a quick session on the 320.

Nortons are pretty soft stones so they shouldn't cause problems even on a 600 DMT...

 

[azmark]

Wow, Nortons shouldn't take as long as C12's at all. It's fair to say the finer grit hones take longer but a Nortong under 8K should be a breeze. In the past I've noticed that when you use pressure it distributes uneven so the stone begins to wear uneven. So you have to take longer to fix the spots you created.

 

[the gato]

Yeah I've done my best to not put any pressure on it, I haven't gotten any new or surprise spots to fix. It's just the ones I'm working on take forever. It was generally one or two corners that were extremely problematic.

I'll pick up some sandpaper tomorrow and give that a try.

Thanks guys.

 

[Slash McCoy]

A new Norton is also fairly flat, so not much stone should have to be removed. I don't even bother to lap a new Norton combo stone. If anything, I will rub two similar ones together in the sink. I am thinking that your DMT is probably way finer than you want for initial lapping of a hone. I can't imagine that it is variables in your technique that slow down your progress, as long as you are using light/moderate pressure and plenty of water.

 

[jeness]

My norton was way out of true, I lapped both sides for more than an hour and the corners are still a bit low. So if you got a bad one, it can happen that you have to lap a lot.

 

[Utopian]

Please be aware that the DMT 325 is not designed for lapping. It is meant for steel removal. If you use it for lapping you run the risk of the hone grit undercutting the substrate that holds the diamonds. DMT considers that the 325 can be used for waterstones, but not natural stones like the Chinese hone. Now, you might get away with it, but you also might trash your plate. If you want to do any serious lapping of natural hones or barber hones, then you should get the DMT 220 or 120 grit plates.

 

[dnullify]

^ what he said.

That, and the d8c isn't all that coarse.
I'd suggest running water, and let the diamonds do the work. It's probably a lot easier to strip diamonds off the plate than it seems, so don't force it.

I think it is pretty unlikely that the plate is mislabeled, but it would be worth contacting dmt.
Personally I am rather satisfied by wet/dry paper and a marble countertop. It's cheap, disposable, and you can do a progression to smooth out harder stones. Then again, I haven't had to lap anything too difficult...

 

[professorchaos]

I lapped a Chinese 12K once. Once.

Either use coarser sandpaper, as others have mentioned, or get a lapping plate. I use the Norton I got long ago with my first set of hones. It is cheap and has taken care of every hone I've thrown at it. Only drawback is that it is a little coarse; the surface it leaves needs a little smoothing.

 

[Loric]

My C15k was tough to lap even with the 120 DMT XXC, though after the Spyderco UF even the C15K still fet like I was cheating. I would also so suggest getting a more coarse plate next time.

 

[the gato]

After giving it a cleaning with comet I tried to use it on the Norton 8K (which is almost flat). It was just floating on the plate and would barely start cutting as the water dried out. Is that normal?

One of the big things I noticed in comparison to azmark's video is the water on his plate turns milky almost instantly. It took me 20+ passes before I would start noticing milkiness.

I've sent my plate to DMT, their customer service was very nice and straight to the point. I'll get the verdict whether I got a bum plate or I'm an idiot. Not going to count out either option. I promise i'll post if it's the latter.

 

[Neurotopia]

I lapped a Chinese 12K once. Once.

My fadda hung me on a hook once. Once.

 

[azmark]

After giving it a cleaning with comet I tried to use it on the Norton 8K (which is almost flat). It was just floating on the plate and would barely start cutting as the water dried out. Is that normal?

One of the big things I noticed in comparison to azmark's video is the water on his plate turns milky almost instantly. It took me 20+ passes before I would start noticing milkiness.

I've sent my plate to DMT, their customer service was very nice and straight to the point. I'll get the verdict whether I got a bum plate or I'm an idiot. Not going to count out either option. I promise i'll post if it's the latter.

Oh yeah there is something up. My plate isn't old but I've lapped two Nortons lifetime.

 

[Jim]

Spending some time easing the edges of the stone first can aid in getting it flat.

Best of luck with DMT. Keep us posted.