Quality control and "warped" razors

OK, before I get into this, let me put a disclaimer up front: I'm not Dovo bashing here. Dovo makes good razors, which is a good thing, 'cause they're pretty much it when it comes to new blades. That said...

Right now I'm honing a seven-day set of new Dovos for a member. He was frustrated with several of them because the heel just wouldn't seem to get sharp.

So far I've worked on Monday, Tuesday, Wednesday and Thursday. On all four of these blades I found the same issue. When layed face down on a lapped hone, that is, with the Dovo logo facing down, the heel of the razor wasn't touching the hone at all. The severity of the gap varied from almost nothing to 1mm or more.

Basically, an inch of the heel doesn't get honed on one side of the razor if you use a normal X pattern. If you don't change your stroke to accomodate this, you end up with a wire edge on the heel that will continue to redevelop even after it's removed.

I have noticed this same issue on other Dovo razors and on a lot of vintage blades that I've honed. It's almost like the blade has a slight twist to it. It always seems to be the same side of the blade, too.

So I finally decided to contact Dovo about this. They responded very quickly, less than eight hours later. Here's what I was told:

Dear Josh,

Thank you very much for your email. I will gladly try to answer your questions. Prior to the final honing of the straight razor, which is done on a Belgian waterstone, the blade is subjected to grinding on a horizontal wheel, which is slightly convex on the surface. Hence the razors will not be completely even when put on a flat surface. Since that wheel grinding is done by hand as well, there will not be two razors absolutely identical. This has been done that way for many decade, so the vintage razors show the same "uneven" shape.

This is why we strongly recommend for the "untrained" user to stay away from sharpening. It takes skill and a long time of practice to NOT damage the blade in the process.

I hope I could answer your question to your satisfaction.

Best regards,
Anne Rothstein

Very courteous response, I thought.

But it leaves me wondering, why does this seem to happen so frequently, and in the same pattern? I'm curious as to whether it might be because most of the grinders are right-handed, so if there's any unevenness it would tend to reoccur in the same fashion over and over...

Has anyone else noticed this? Do most of your razors lay flat on the hone?

Just looking to gather some data... :)

Josh

I don’t know too much about the DOVO line but something I HAVE noticed is that TI (also new blades) are always straight and flat. Just FYI.

Mason

So basically they are saying 'Our grinding method sucks, so you better not try to correct it because this could ruin the blade'.

Most razors I tried do not lie 100% flat on the hone. I even have one W&B that is as warped as a banana.

That is why I prefer half hollow and quarter hollow razors for honing. Even if they are not 100% straight, the blade is thick enough to make the edge straight on a properly lapped coarse hone.

Only rarely is a full hollow truly straight (but then again, I have not honed hundreds, and I have not honed high end expensive ones).

I've noticed it, but maybe not to the same extent as you've seen Josh. My first straight was the Dovo "Best Quality" - probably their cheapest new blade. It was the first blade I ever honed, and I found it tricky for the reasons you say above (although I didn't know that at the time). My FIL gave me an old Bengall about the same time which was slightly warped too, and I inadvertently learned how to do the rolling X pattern....

I'll freely admit that nowadays when I hone my Dovos (got the B-L too now) I get them almost there on the stone with a rolling stroke and then just take them to the pasted hanging strop. The latter seems to speed things up and even things out - I guess because the leather is a bit flexible.

That response from Dovo is interesting and thinking about it makes some sense I guess. Maybe I'm not visualising it properly (having never ground a razor myself), but if that convexity of the wheel is the culprit, why is there not a similar issue on the toe? Is it because the shank and tang get in the way at the heel end? :shrug:

James.

Actually, if you flip these razors over, the toes do come up off the hone. But this is easier to correct with a normal X stroke, so I think it's not as noticeable.

Josh

Quote:

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Originally Posted by JoshEarl

Actually, if you flip these razors over, the toes do come up off the hone. But this is easier to correct with a normal X stroke, so I think it's not as noticeable.

Josh

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Ah, yes. That makes sense - cheers Josh.

James.

As a newbie, it sounds as though you are saying we should avoid DOVO blades if we expect to do our own honing. Not forever mind, but until we become VERY experienced.

I can't speak for Josh, but I wouldn't say you need to avoid Dovos if you're only new to honing. Knowing there's the potential for the heel issue is half the battle, and I'm sure some are better than others in that regard.

James.

It may be half the battle but I've not yet survived the skirmishes. :(

At the moment, I think my TI blade is winning. I won't cop out and say its because of anything but me, myself, and I. But to address a whole new set of complications doesn't exactly seem prudent at this stage.

Actually, due to an outbreak of RAD, undoubtedly from this site (my attorney will be updated :rolleyes: ), I plan on sending Josh :bow several blades including my TI. My hope is that at least in regards to the TI he may be able to do his CSI thing and tell me what I'm doing wrong.

I wouldn't steer anyone away from Dovo razors, either, although I'm partial to vintage blades...

If you're just learning to hone, I do think it's best to get them honed up first. I think the heel issue would be less of a problem for touchups than it is for the initial honing. If it's been honed properly once it should be easier to get it back once it dulls...

Cabo, I'm ready whenever you are... :D

Josh

Hi Guys,

I have honed a couple thousand Dovo's and some hone up very easily and some take a little more effort. The problem with the final grind can be seen if you look at the shoulder of the razor. It also seems like the cheaper models are the most problematic. In any case, Dovo's have always been very nice shavers and overall pretty easy to hone, even for beginners.

Have fun.

Lynn

Well, I guess I better even it out a little and do some routing for Dovo!:p

My Bismarck is the easiest to hone in my collection, is completely flat. Always a pleasure to hone!:tu

To Lynn's point, the Dovos I'm working on are lower end models, I think.

FWIW, I honed a Dubl Duck Goldedge tonight, and the blade layed perfectly flat. Took a fantastic edge, too. :)

I'm going to check some other razors and see what I find...

Thanks for your comments,
Josh

I have to say - Dovo's are relatively hard to hone, and of the several I have honed and even more that I have examined, very few lie flat on the hone. Initially I thought that the razors were no good, but like others have discovered, that is not the case, since they do shave well and hold their edges well. The only issue is getting them sharp enough, given that Dovos have curved edges and almost never lie flat on a hone. Try the marker test for proof.

For that matter, any curved edge can only contact a flat hone at a point, unless you want to go postulating that the edge angle varies along the length of the edge. This follows from the theorem that two planes (in this case the two edge planes) must intersect at a straight line. It is therefore a violation of the laws of mathematics to expect that a curved (smile shaped, for instance) edge will ever lie flat on a hone.

This would naturally imply that if you want to hone your curved razor, a narrower hone would work better, just like Allen at Ross Cutlery uses (the half inch coticule). I suspect, without any basis in experiment, that a rod shaped hone (like a rod-shaped ceramic steel) would work best, but like I said, this is only conjecture.

To Echo what has been said by Josh and Lynn and myself on another thread...
I had the same issue last week. I actually went into Trumpers asking for a low end Dovo. They agreed that the blade should be flat so i brought in a block of glass and went through their entire stock of low end razors before finding the single 1 (of 7 or 8) that lay apparently flat.

OTOH, the higher end Black Star razors didn't seem to have any problems. I emailed Dovo about the same issue last week and have yet to get a reply but I get impression that it's more a case of poorer standards and quality control on the cheaper models.