Argh - Can't get centre of blade sharp

S

Sigurd

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11
I'm trying to hone an Ebay special, but I'm struggling with the centre of the blade. The razor is a C.W. Engels from Solingen-Foche.

I have a King 1000/6000 waterstone for setting the bevel, and I'm using the 1000 side. The razor was pretty dull when I got it. The edge has a slight smile to it. I don't think it is warped.

I've marked the bevel with a magic marker, and after a few strokes the marker was gone. Yet I can't get the middle of the edge sharp. Only the heel and toe pop hair off my arm. The middle of the blade doesn't pop hair, it even glides right over my nails.

I've tried doing circles on 1000 grit, guess I've done about 50 circles on each side of the blade. I've also tried the swooping X-stroke, the regular X-stroke and the 45 degree X-stroke, but the edge stays the same.

I've also lapped the hone, but it didn't change anything.

Are there any other techniques to try? Does anyone know what might be causing this?
 
Assuming that you aren't taping the spine, inspecting the hone wear on the spine might help. If the wear in the middle is markedly less than at either end then the spine might be warped. This usually is accompanied by a thick bevel in the middle on one side of the blade and a thin bevel on the corresponding area on the other side of the blade. With a smiling blade it is a bit easier to overcome this, but the easiest way is usually to go to a narrow hone - say 1 inch wide. Hva a look at the spine wear and let us know what it looks like.

Regards,
Neil
 
Thanks.
The spine wear looks nice and even on both sides. If needed, I can take a picture when I get home today, but I remember checking this yesterday. I'll make sure to double-check the spine when I get home.

By the way, when I was doing the circles on the King hone, I concentrated on the middle of the blade, since the King is too narrow to do circles on the whole length of the blade at once. Don't know if this makes any difference, though.
 
Honing a smiling blade isn't as straightforward as honing a blade with a straight edge. Concentrating on one part may lead to a frown, so try to avoid that. You must also make sure that the King is lapped flat.

I usually use a rolling X stroke, making sure that by lifting/rocking the blade that all parts come into contact with the hone. Watching the way the water behaves helps - it should ride up the blade as you hone, not go underneath it. Also, honing at a more extreme angle than usual helps - by that I mean laying the blade on the hone at a 45 degree angle or so, so that it is well raked back as you hone.

If the blade is passing the marker test, you need to look at with a high-powered loupe - say 20x - 30x - to see that the bevel is set. If it is not then you have more work to do. If it is set, then the blade may have had the temper damaged at some time in the past and it will never take a good edge again.

Finally, make sure that you are not overhoning the edge - if you have formed a fin then it must be removed by backhoning, or preferably by dropping down to a lower grit.

Had any work been performed on the blade when you got it? Was it cleaned-up, polished, have grind marks on it? Was there any discolouration near the middle?

Regards,
Neil
 
Thank you, I'll try your advice tonight.

I'm not sure if the blade had been worked on before I got it, but I think it might. The is some slight pitting on the blade, and there was some rust around the pivot pin. The seller might have removed the rust on the blade, but didn't bother with the pin-area. What puzzles me is that the original "grind lines" appear to be intact, and the blade was discoloured, but not rusty. When I say discoloured, I mean like it had been stored for a long time, not from excessive grinding. I'm not sure what to make of it. There was no discolouration near the middle.

I'll start with backhoning, and then proceed with the rolling X.

Are you saying that the blade might develop a bevel, but that it might be bad due to temper damage? How would such a bevel feel when testing it on a nail or arm hair?
 
If the blade was kept moving and occasionally cooled down the temper should be OK, but if someone concentrated on one point for too long and the colour of the metal changed - blue - that would ruin the temper. However, the discolouration can be buffed-out so its hard to tell. The metal becomes softer at this point and its ability to hold an edge is seriously compromised, but some sort of edge should be detectable by testing - it just doesn't hold up that long.

Some oxidation/tarnish can look like the colours left by heating the blade (blue/lilac petrol film like colours) but they are harmless and nothing to worry about.

If the original grind lines are still visible then it's unlikely that the previous honer generated enough heat in getting the pit-marks reduced to afect the temper.

Have you looked at the bevel under magnification to see if the pitting has infiltrated it? This sometimes leads to edge crumbling, and you have to hone back to good metal - takes hours sometimes.

I'm still tempted to think that the bevel is not fully-formed yet, though.

Another check for any deflection on the spine is to tape it and hone normally until the tape begins to wear through - if it wears at toe and heel and not the middle, that's causing your problem. I have read that some people put a bit of tape on the low point, but have never tried it myself. I have taped over the worn tape to achieve the same effect, though.

If the spine has no issues I would put a couple of layers of electrical tape on the spine - maybe even three - and hone it on a diamond plate (325 0r 600 grit) just to establish a new bevel - the tape will elevate the blades spine a bit and make up for any metal lost during previous honing, plus make the bevel itself a bit more acute.

Regards,
Neil
 
Unfortunately, I don't have a loupe, so I need to rely on testing with my nails and arm hair. :geek:
I have several tricks I can try now, hopfully I'll get some results.

I'll take a picture of the razor ASAP, so you can see the spine and hone wear.
 
Here are some pictures of the offending razor:

back.jpg


stains.jpg


Spinewear2.jpg


pitting1.jpg


Spinewear1.jpg


pitting.jpg


CW.jpg


The pictures get snipped lengthwise, so please look in the original album: http://s385.photobucket.com/albums/oo294/sigurda/CW Engels/

The pitting looks worse in the pictures. :roll:
 
Well, the flattening along the spine looks regular enough from what I can make out. The smile has been flattened-out somewhat with your circles though - try to bring the toe into line with a bit more work to re-establish the gentle smile.

The pitting at the toe end looks ominously near the bevel - can't really tell if it has affected it or the rest of the bevel, though. You really should get a high-powered illuminated loupe or a USB microscope if you intend to do much of this type of work - inspecting the bevel tells you so much.

I might be wrong, but a lot of the grind lines look extra to original, like the whole blade has been worked over at some time. Lets hope a steel brush wheel wasn't used!

I take it that the light we can see under the spine is due to the scales lifting it at one end and that when just the spine is laid flat on the stone no light is visible. That leaves three main possibilities: the bevel is not formed properly in the middle, pitting has compromised the bevel, or the temper is shot. Let's hope that it is the first one!

Due to the spine wear I would tape the spine - two thicknesses of tape - and start again. Watch the pressure - you will need some to get the work going, but tail it off before the bevel is fully formed. Make sure the King is lapped flat, too - you may need to lap it more than once during establishing the bevel. And do get some sort of magnification - you need to be sure that the bevel planes have met all along the bevel and that they are free from pitting and overhoning artefacts.

Good luck!
 
Well, I just spent about 50 minutes honing this thing, but it's still dull in the middle. Tried different strokes and backhoning. Used two layers of tape on the spine. I need a rest now, might give it a shot later on. As for now, I think it's a POS razor. :x
 
Desperate times call for desperate measures.

I'll be drummed out of the straight razor honing corps in disgrace for suggesting this, but it has worked for me in the past.

Tape the spine with one layer of electrical tape. Using the most corse hone you have (I use a DMT 325 grit), reset the bevel by using your off hand to apply light pressure in the middle of the blade. Continue until the blade will pop arm hair, then hone normally, leaving the tape on the spine, for the rest of your progression.

There, I said the unthinkable. The fact is, however, that the razor will never shave until the bevel is set properly.

Pressure is normally not recommended, but on rare occasions pressure can and will save hours of time.
 
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