Thread: DMT dilemma

Originally Posted by Chrisl

Holy smoke! What hone were you using to lap the 12K for 30 hours if I might ask? If it was a DMT, that concerns me that it took that long (not questioning your lapping ability in any way, I say it concerns me because I'm wondering if maybe you're DMT is more broken in than mine and maybe I'll have to prepare to work mine that hard as time goes along). I got a 12K from Woodcraft just last week and lapped it on the DMT 325 grit. It took me an hour (I did lap only one surface and added beveled edges), about as long as it took for me to lap my Belgium Blue. Sure an hour isn't a long time in comparison to what you guys are describing, but it's alot longer than lapping a Norton!

I was using a DMT 325 that previously had lapped a Swaty, 2 carborundums, a norton 1000, a norton 4000, and a norton 8000. My 12K was convex--the center faces were highest in the center. That means as I lapped, the center became smooth and the edges were untouched. As lapping proceeded, the smooth center got larger and I was therefore lapping a progressively larger area and the progression out to the edges became slower. That is why I stopped when all but the last 1/2 inch of each corner was polished--the greater the polished area, the slower the lapping was going. Because I like to hone on narrow stones, on both the 12K and all three nortons were honed on a wide side and a narrow side.

Originally Posted by Utopian

I was using a DMT 325 that previously had lapped a Swaty, 2 carborundums, a norton 1000, a norton 4000, and a norton 8000. My 12K was convex--the center faces were highest in the center. That means as I lapped, the center became smooth and the edges were untouched. As lapping proceeded, the smooth center got larger and I was therefore lapping a progressively larger area and the progression out to the edges became slower. That is why I stopped when all but the last 1/2 inch of each corner was polished--the greater the polished area, the slower the lapping was going. Because I like to hone on narrow stones, on both the 12K and all three nortons were honed on a wide side and a narrow side.

Thanks for the clarification. My 12K was convex as well, but not nearly what you describe. I did experience the same thing you did in that the last 1/2" of the edges took about as long if not longer than lapping the entire surface up to that point.

You must have single Norton grits rather than the combo stones. I liked that idea when I had my Norton combo, but buying a single 4000 and a single 8000 were out of my price range at the time. There's a place called toolsforworkingwood.com that sells single grit Nortons rip sawn lengthwise into 8"x1.5"x1" for half the price. I thought about buying those for narrow hones but haven't yet.

[QUOTE=You must have single Norton grits rather than the combo stones. I liked that idea when I had my Norton combo, but buying a single 4000 and a single 8000 were out of my price range at the time. There's a place called toolsforworkingwood.com that sells single grit Nortons rip sawn lengthwise into 8"x1.5"x1" for half the price. I thought about buying those for narrow hones but haven't yet.[/QUOTE]

You're right. I liked the price of the combo stone but the ability to hone on the narrow side, and the fact that they will last much longer, won me over to the single stones. I absolutely don't regret it.

I don't know squat about these particular hones however I will tell you that any diamond stone or for that matter any diamond cutting implement does it work with very little pressure. Most diamond saws use a gravity feed type mechanism so very little pressure is applied. The achilles heel of any diamond cutter is the ability of the diamonds to be worn away very easily but diamond cutters simple do not require much pressure to do their job anyway.

Seriously, if I had to lap my hones for 70+ hours I would
give up and use a different product. Luckily my Spyderco
hones have been flat enough out of the box -- that is, they
impart a great edge on my razor.

- Scott

I'm kinda' stubborn. I figure with 70 hours plus invested , I might as well finish up at least one side of the UF, otherwise I've wasted a lot of time for nothing. It is now close enough to flat to polish an edge. Pictures available of all three (with visible grid pattern and detailed runout dial indicator measurements) if anyone is interested.

Measurements referenced to my sine-bar/plate, accurate to w/in 0.0001" flatness (the sine-bar, not the runout) The runout indicator is accurate to w/in 0.0005". That's overkill though, the UF is now flat enough to put a decent edge on a flat razor, without seeing too much gap between the two. In practical terms, just looking at the grid pattern that the DMT D8C is not hitting yet is usually sufficient while eyeballing the gap between a straightedge and the hones low spots.

I will be selling the Spyderco medium and fine as soon as I replace them with a D8EE (I will guarantee at least one side of each to be flat enough to work an edge). I'll keep the UF so I can compare it to a Chinese 12k later. The UF just put a wicked edge on a wedge and a full-hollow last night, as is. I've spent so much time with the UF that I see it as an old friend now, instead of an enemy...

The hardness is kinda' cool, I bet it'll be a very long time before the fine or UF need to be lapped again. These Spydercos have also been an excellent test of the D8C's lapping abilities and durability; for me. It's been informative.

DMT update: I used HEAVY pressure (over 40 pounds) on the D8C last night, for the first time, using the Spyderco UF. Yes, it did start to pop diamonds off one edge. Moral: Use light pressure as DMT recommends and let the diamonds do the work. I normally use either the weight of the hone itself, or about one pound for the items weighing less than 2 pounds.