Thread: What do I do with a warped blade ?

I am trying to learn how to hone my razor, but with limited success so far. A bit about the materials I have:

- A DOVO black star razor (bought it new),

- a two-sided waterhone labeled 800/6000. I bought it in japan and have read the designations used there are different from those used in the west (something to the extent that it's the average rather than smallest particle size that determines the grit size).

- a barber hone of some sort. It is fairly long (about 6" or 16 cm) and narrow (1.5" or 4 cm). I believe it may be made of slate. It is dark gray but lighter in colour than charcoal.

- a TM four sided paddle strop, a TM red latigo strop, a DOVO strop and another TM strop I don't remember the name of (the light, very smooth horse leather) (yeah, I know I've got plenty of strops but I like them and the dollar was cheap so I bought an extra)

When I press the razor flat on the hone and hold it to the light I can see it does not touch the hone evenly. Depending on which side of the blade is held against the hone it either balances on the middle or there's a gap in the middle. So it seems the blade is bend ever so slightly.

This is confirmed by my result from doing the permanent marker test:When I use a permanent marker to colour the bevel and give it 1 or 2 strokes on each side on the newly lapped japanese waterhone (lapped using wet sand paper on the back of a fairly thick mirror) some colour remains on the bevel: on one side it remains coloured in the middle but not the sides, on the other the colour is gone from the bevel in each end of the blade but not from the middle section. This just confirms it has a concave and a convex side.

Now my question is what I do about it ?

If I keep honing to flatten it I'm afraid the bevel will not end up being equally wide along each side and between the two sides. Is that a problem ?

As an experiment I tried to use a few strokes on the edge on the hone - now concentrating all pressure at one point as opposed to the whole edge/shoulder resgin on the whole width of the hone should mean a much greater pressure on the point touching the stone, but at the same time would ensure honing of the bevel is equal on both sides (if the two stroks are performed symetrically of course). This immediately got the razor much sharper, which again leads me to believe the uneven contact with the stone is the problem.

It does get sharper when I use the higher-grit and much narrower barber hone I've got, but it will still not pass the hht, though I can get it to pass the thumb pad and nail tests (to my knowledge at least).

I have a TM paddle strop (3.0, 1.0, 0.5, 0.25 diamond) but I cannot get it as sharp using this as I can on the barber hone.


All comments welcome !

If you hone on one side and it touches the middle, and on the other touches the heel and toe, that is a classic warped blade. I would look into sending the razor back where you got it--if it is that warped.


It's funny.

I have a Dovo that I have trouble with, too. It has some kind of defect that causes it to jump in the middle of a stroke.

Personally I am staying away from Dovo razors at the moment.

I get these $12.00 razors on Ebay and very few of them have any problem like this. On the other hand, I've got a couple of Wade and Butcher meat axes that do not hone comfortably. They have wierd places in the stroke where they suddenly shift to a different angle.

I don't have any that are bent like yours, though.

Are you sure it is the razor?

Has you hone been lapped?

Warped blades though not the norm are not unusual. A person would do well to learn the proper method. It is not that difficult if you are given help with the technique or have the properly sized hones.

Urleebird said: http://straightrazorpalace.com/showt...ght=straighten

"Warped blade are not as uncommon as you may think. The heat treating process does it. The thinner the steel, the more likely it will warp. I'm pretty sure razors were either only partially ground or not ground at all before the heat process took place. After they were tempered, a different process, then they were ground. No way could they have been ground to their normal thin profile and then heat treated.

I have knifemaker friends who do their folders this way to ensure the blades do not warp. Warped blades can be fixed. Use a big vise.

Put the blade parallel to the top of the jaws near the surface. Vertically insert one wood dowel on each "low" side of the blade at the spine. Then insert a vertical dowel on the opposide side of the blade at the tangent of the "high" side on the spine.

Crank the vise shut until you go a little past the curvature of the bend. Practice on some junkers first. Do a little at a time and keep checking to see if the blade is straight.

Tip: Tape the dowels in place on the blade because you will need 5 hands otherwise to get them where they need to go."

I'm going to try it on a WB - has anyone tried this method? What were the results?

Originally Posted by DEwey

Urleebird said: http://straightrazorpalace.com/showt...ght=straighten

"Warped blade are not as uncommon as you may think. The heat treating process does it. The thinner the steel, the more likely it will warp. I'm pretty sure razors were either only partially ground or not ground at all before the heat process took place. After they were tempered, a different process, then they were ground. No way could they have been ground to their normal thin profile and then heat treated.

I have knifemaker friends who do their folders this way to ensure the blades do not warp. Warped blades can be fixed. Use a big vise.

Put the blade parallel to the top of the jaws near the surface. Vertically insert one wood dowel on each "low" side of the blade at the spine. Then insert a vertical dowel on the opposide side of the blade at the tangent of the "high" side on the spine.

Crank the vise shut until you go a little past the curvature of the bend. Practice on some junkers first. Do a little at a time and keep checking to see if the blade is straight.

Tip: Tape the dowels in place on the blade because you will need 5 hands otherwise to get them where they need to go."

I'm going to try it on a WB - has anyone tried this method? What were the results?

Generally speaking razors are more brittle than most knife steels so the risk of cracking the razor is greater. I know that Bill did one for someone here and it worked. However I would practice on a junker first!

The Dovo video gave me a good idea why their razors warp. It is the method of quenching that they use. It is an oil bath ( no problem) but when they immerse the 50 plus hot, soft steel blades into the oil they swish it around! Most knifemakers will tell you that is a no-no, it warps the blades.

Yep, I pressure test with my fingers first to get a feel of how much I need to flex the blade to get it to hopefully line up. This method is also a great way to make junkers.

thanks again for your comments and suggestions.

I've been experimenting some more this evening. Following Randy's instructions and using the two narrow hones I have managed to get my razor a lot sharper than previously. It is not quite there yet, but it is getting very close, and I'll give it a full test shave tomorrow.

One thing, though, is that it seems to work better when using lather than water or slurry - is that a sign I'm doing something wrong ? It seems to get more difficult keeping the razor flat on the hone the less pressure I apply. I've tried repeating the movement many times in an attempt to 'get it into the hands', and that seems to make it easier to do with less pressure...

Originally Posted by Kenrup

Yep, I pressure test with my fingers first to get a feel of how much I need to flex the blade to get it to hopefully line up. This method is also a great way to make junkers.

Hey Ken,
Would you say that Sheffields, with their softer steels, would be more successful candidates for straightening with the vise? Or does the age impair the ability to bend without breaking?

Originally Posted by toolarts

I get these $12.00 razors on Ebay and very few of them have any problem like this. On the other hand, I've got a couple of Wade and Butcher meat axes that do not hone comfortably. They have wierd places in the stroke where they suddenly shift to a different angle.

Of all the razors I see in antique shops that look un-used, about 90% have some small warp to them. I assume that's why they look new -- because they were hard to hone and they were gotten rid of!

Most of the ones I see that are well used have been so well used that the bevel is very wide and the spine has a large flat section from all the honing.

The trick is to find an un-used vintage razor that is not warped!

E