Lap Spyderco UF on DMT 8EE?

Newbie honing question here: I just bought a DMT Dia-Sharp 8EE and a Spyderco UF as my honing stones, in part because I had read they don't need lapping. However, the Spyderco does have some slight surface variations that I can feel, and since then I read elsewhere that it may need lapping if you really want something for straight razors (as opposed to knives). I was wondering if it would do any harm to lap the Spyderco on the DMT? (I don't want to ruin the DMT while fixing the Spyder!) Or, do you have any other suggestions that don't involve buying a lapping stone? Would sandpaper work? What grit?

Thanks!

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Originally Posted by BurnBeGone

Newbie honing question here: I just bought a DMT Dia-Sharp 8EE and a Spyderco UF as my honing stones, in part because I had read they don't need lapping. However, the Spyderco does have some slight surface variations that I can feel, and since then I read elsewhere that it may need lapping if you really want something for straight razors (as opposed to knives). I was wondering if it would do any harm to lap the Spyderco on the DMT? (I don't want to ruin the DMT while fixing the Spyder!) Or, do you have any other suggestions that don't involve buying a lapping stone? Would sandpaper work? What grit?

Thanks!

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Trying to lap something on the DMT 8EE would be a waste of time. You would need something significantly courser like the DMT 8C or XXC.

Thanks, heavyduty. I'm not planning on buying any more stones for some time, so would like a solution that is at least as cheap as sandpaper (possibly including doing nothing -- I will probably try that first and see what happens to my razors.)

Sydercos do not need lapping according to the manufacture

Pretty sure Spydercos use an alumina ceramic with a closed cell structure making them impossible to lap. It also means that the UFs never wear out.

Well, there appear to be two schools of thought on that. In the same thread on B&B, I have seen some folks say they are guaranteed by Spyderco and will be replaced if not flat (see post #9 on that thread; I saw no such guarantee in writing with mine), and other folks (see posts #83 and #84) showing how un-flat they are and claiming that the flatness Spyderco guarantees might not be good enough for straights.

Since I can actually feel some variations on the surface of mine, I was assuming the second opinion must be true, but maybe the stone doesn't need to be so flat for the finishing?

I lapped my UF. It can take a very long time if yours is near the 0.020 inch tolerance. Spyderco told me you will void your warranty if you lap the UF.

I lapped all three of my Spydercos (M, F, and UF). Total time was just over 80 hours. Whatever room you decide to lap in, consider installing cable TV...:eek:

Edit: I used a DMT D8C coarse. All three hones still work ok for me. If I ever lap another one I will acquire the coarsest diamond hone I can find...

I have heard that Spyderco will also replace a UF hone that is within the guaranteed 0.020 inch tolerance. Don't quote me on that one.

Steven,

I believe you were the one I quoted above on the B&B thread who showed the nice pictures of the results of lapping the UF.

Were you having trouble with it before you lapped it, or did you just lap it on principle?

Do you think any kind of sandpaper might do the job? (I'm trying to avoid buying another hone right now.)

For the record, I lapped my Spyderco UF after reading multiple posts by several gents including Dr. Moss. I used my D8C and it took forever. Now, even though the D8C still works very well for lapping my hones I've discovered that it is useless for honing my scraper cutters that are made out of high speed steel (still works fine on knife edges and such though). These cutters are about the area of a silver dollar and I usually hone them on a diamond hone... After the Spyderco incident, my D8E hones those cutters waaaay faster than my D8C!:rant:

For me at least, in the end, it was all for not. I didn't find the Spyderco to work any better after lapping than before and I continue to prefer my Belgians with a Chromium Oxide pasted bench strop for a finish. To be honest, I found the Spyderco didn't give me enough feedback, I much prefer the feel of the Natural stones, so I sold the UF and I'll be ordering another D8C which will be reserved for honing steel until the old one gives up the ghost.

Regards

Christian

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Originally Posted by BurnBeGone

Steven,

I believe you were the one I quoted above on the B&B thread who showed the nice pictures of the results of lapping the UF.

Were you having trouble with it before you lapped it, or did you just lap it on principle?

Do you think any kind of sandpaper might do the job? (I'm trying to avoid buying another hone right now.)

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From what I've read so far, you'd need a large stack of sandpaper before your UF was flat, in which case a DMT8XX would be cheaper.

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Originally Posted by Bruno

From what I've read so far, you'd need a large stack of sandpaper before your UF was flat, in which case a DMT8XX would be cheaper.

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I did give sandpaper a try when I decided to lapp my UF, it's rely an waste of time IMHO, didn't do much, so get a DMT C if you decide to lapp it.

BTW, my UF works better for me after I lapped it, it may have something to do with removing the circular pattern on it, but I'm not sure.

I looked back at what Steven (Sticky) had said on the B&B thread I quoted above about the manufacturer's tolerance: 20 mils over the length of the stone (where did you get that number, Steven?). For comparison, 20lb printer paper is 4 mils thick, so that's like 5 sheets of printer paper. The variations I'm feeling are certainly less than that, I would guess 5-8 mils, so I think my stone is within manufacturer specs. However, the variations occur over short distances making little ridges on my stone.

So now my question is, do you think this is good enough for finishing the edge on a str8, or will it mess up my razor? I guess I'll have to just try it and see... Might be a good reason for folks considering what finishing stone to buy to go with a Chinese 12k + lapping stone instead of the Spyderco UF.

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Originally Posted by BurnBeGone

I looked back at what Steven (Sticky) had said on the B&B thread I quoted above about the manufacturer's tolerance: 20 mils over the length of the stone (where did you get that number, Steven?). For comparison, 20lb printer paper is 4 mils thick, so that's like 5 sheets of printer paper. The variations I'm feeling are certainly less than that, I would guess 5-8 mils, so I think my stone is within manufacturer specs. However, the variations occur over short distances making little ridges on my stone.

So now my question is, do you think this is good enough for finishing the edge on a str8, or will it mess up my razor? I guess I'll have to just try it and see... Might be a good reason for folks considering what finishing stone to buy to go with a Chinese 12k + lapping stone instead of the Spyderco UF.

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The 20 thousandths of an inch is stated on a sheet included inside the UF's box (also in the M and F's box). Was in my purchases, anyway.

My stone was within manufacturer's specs, barely. It still wouldn't put a very good edge on my razors. The flyer in the box states " .020" of flatness over their 8" length ". It does not say PER 8 inch. In inspection terms that means it can be .020 difference w/in a 1 inch length as long as the ENTIRE hone is w/in .020 overall; as opposed to something like " .005 per 2 inches ".

After lapping, my UF performs acceptably. Before lapping, it did not.

Try sharpening without lapping it first. If it doesn't perform acceptably, either lap it or return it to Spyderco. In my opinion the Spyderco is just as good as the Chinese 12k, in terms of practical razor sharpening ability (meaning ability to give you an acceptable shaving result). Some users do not need to lap the Spyderco. Luck of the draw. The Chinese 12k and the UF both seem to come from the factory with different levels of surface flatness, which is rather normal for most manufactured items. Personally, I lap every hone I get (except DMT's), whether it's for razors or knives.

Good luck either way.

EDIT: I'm with bjorn, avoid the sandpaper on the UF or Chinese. Sandpaper would take forever. DMT's are more cost-effective and faster by far.

it took me a while using 3m 400 ahd 600 grit wet paper,but it is flat

Did it take many sheets?

more than i care to mention