Thread: Why kill an edge

Interesting!

I'm in the middle of muddling my way through a Tuckmar that was NOS, and just does not want to form a nice edge to the bevel.

I can get it to shave okay, but never at the level of my other razors. Fresh off the hone it feels more like a razor with a week and a half under its belt.

Having spent a lot of time looking at the edge in between honing I've come to the conclusion that the edge might be over hardened due to evidence of likely chipping on the very edge of the bevel. Also in some areas the material near the edge looks like it had suffered corrosion at a micro-level. So I'm now taking off material from the bevel until I can get to shave off the 1k. The more material I take off using the 1k, the better the edge of the bevel starts to look,confirming my gut feel that was telling me I need to find fresh steel.......... If I eventually succeed then I'll be in 100% agreement with the 3 killed edge technique!

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I see this often on customs, that may be harder that production razors. It may be the heat treat, over heating the edge, work hardening or aggressive use of belts.

I also see this, when doing edge restoration, where a bit of the edge has been removed as in large chip removal. And with new honers. where low grit stones, Diamonds or lots of pressure and/or laps, will “overwork” an edge or cut deep into the steel.

Diamond plates are notorious for cutting deep and weakening the steel below, (even after the stria has been removed) and, I suspect some of the newer aggressive Ceramic belts can do the same. The razor may shave well, but maintenance stropping flexes the weakened edge and it eventually breaks off, causing a micro-chipped edge.

When I encounter this, I remove the micro-chipped edge and re-set it. Once the bevels are flat and in the proper angle, it is quick and easy, to bring the bevels back to meeting. As said sometimes the edge will have to be remove 2-3 times, the amount of material removed is still, microscopic.

How you remove the edge does not matter much. Running it on glass or other hard surface, rolls the fin and honing cuts it off, jointing on the corner of a stone, cuts the edge off cleanly, or you can also just hone it and eventually the edge will be removed, or add a layer of tape and create a micro bevel or new higher angle edge.

I like jointing on the corner of a stone, as I believe it is cleaner, quicker and leaves a straight edge that just needs to be brought back to meeting, a matter of just a few laps,10-15.

I often kill/joint an edge before going to the finish stone and reset on the finish stone, for a stronger edge.

If making a micro-bevel, try adding a layer of clear packing tape, it is thinner than electrical tape and stronger than scotch tape, that also works. Packing tape, (the clear one, not reinforced) is slick and very strong.

Exactly why this edge chipping occurs, I don’t think anyone knows for sure, Removing the edge and re-setting it is the cure.

My guess is that it both gets rid of a chippy edge and gets to better steel.
The times that I have killed an edge come from seeing chippiness on the edge when I have finished my regular honing routine to 16k.
I use an aprox. 500x scope to look at my edges. Once in a while the edge still looks chippy no matter what I do or how long I do it. Killing the edge and going back a step or two on the stones, then working back to finish has pretty much always worked for me in bringing back the total smoothness. Only on the rare occasion where there is deep pitting and really bad steel does it not work.

Pete <:-}

Originally Posted by JHBBlade

Interesting!

I'm in the middle of muddling my way through a Tuckmar that was NOS, and just does not want to form a nice edge to the bevel.

I can get it to shave okay, but never at the level of my other razors. Fresh off the hone it feels more like a razor with a week and a half under its belt.

Having spent a lot of time looking at the edge in between honing I've come to the conclusion that the edge might be over hardened due to evidence of likely chipping on the very edge of the bevel. Also in some areas the material near the edge looks like it had suffered corrosion at a micro-level. So I'm now taking off material from the bevel until I can get to shave off the 1k. The more material I take off using the 1k, the better the edge of the bevel starts to look,confirming my gut feel that was telling me I need to find fresh steel.......... If I eventually succeed then I'll be in 100% agreement with the 3 killed edge technique!

Sent from my SM-N910C using Tapatalk

Was it a Cell Rot razor?

Some of the Tuckmar scales were notorious for cell rot. If so remove the scales or the rot will continue and can spread to other razors.

If cell rot, continue removing the edge until and if, you get to solid steel.

I've recently learned this. After Glen told me about it and me forgetting (CRS), then another gentleman here told me the same thing a couple weeks ago (Sorry, CRS again), I've now learned that when restoring a blade this has helped get the edge I'm looking for. I've honed and honed to no end and not come out with an edge like I want. Then after killing a couple times, it comes out like it should.