I am curious about jointing or killing an edge. Terms I have heard of.
Interested in knowing when this is used: grit levels; also how, do you do more strokes on the same stone after jointing or move on to the next stone?
Thanks,
Joe
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I am curious about jointing or killing an edge. Terms I have heard of.
Interested in knowing when this is used: grit levels; also how, do you do more strokes on the same stone after jointing or move on to the next stone?
Thanks,
Joe
Hey binder,
There are several conditions that have me killing an edge. One is to remove any false positives on a blade that does not shave well and needs more lower or mid level work. Another is when the edge is developing at different rates at different places, mostly so that my "V" develops evenly at the same time all along the edge, and that is most often done on a cranky razor that has been slow to get a full bevel. The most common time that I kill an edge has to be when I have done a lot of work sanding and buffing a blade and there is some deep damage that shows up in the higher grits in terms of chips, the bevel looks clean on the 4K and then on the 8K it gets chips, so I kill it and go back to the 1K. Also some cranky blades are chippy on the 8K even though the blade has not had a bunch of work and those ones need to go back and forth in the grits as well. I do not always got back to the 1K, in the case of a full hollow that is chippy I will go to the 4K and regain my bevel. Generally if I kill and edge I go back to where it will be quick to get my perfect "V" back, which can be either the 4K or 1K depending in part how hard I kill the edge. For example a light pass on my thumb name to kill a chippy edge is a pretty light kill, and effective for lightly chippy thin blades. A big wedge that has had extensive work and has larger chips forming at the 8K might get killed on the edge of the 1K, which would be a very hard kill. So it does vary a little and is complicated to try and explain all the situation where it might apply.
I'm a recent convert to jointing but I think that it works great and have incorporated it into my routine. I joint after 1K and 4K and then after any higher grit stone if I see evidence of microchips or a feather/wire edge. I don't recall having to do it after any of my finishing grade stones.
The thumbnail is a great tool with minimal "kill" as you say. Plus it allows me to check the edge at the same time. Lightly on glass is a very light jointing also but you don't get the feedback like a nail can produce.Quote:
Originally Posted by RezDog
Jointing is different from killing an edge on glass, though they may be used for the same reason.
Killing an edge on glass, take the edge and rolls it over so it will not cut. You must remember that the edge, the true edge cannot be seen even at 400 x. It is a thin, foil edge. Some kill an edge when starting to hone, just to ensure that they create a whole new edge.
I kill edges with a 1k diamond file, to remove the edge when working on a blade for safety, especially when buffing.
Jointing, is or can be used to remove a burr or flash when too much pressure has been use to hone, on low grit stones, or to remove steel that has micro-chipped. It can also be used, to get a straighter edge on a low grit stone, than is normally possible by edge forward honing.
You can joint an edge on the stone face, stone side, the stone face edge or vertical corner. I use the upper corner of the stone. The razor edge is dragged lightly on the stone to remove just a bit of steel, off the edge. It is not a sawing motion like a bread-knife, but a very light single stroke.
Often if the edge is ragged or has a small chip you can feel the it. Usually one or two strokes will straighten the edge and get to solid steel.
Once a bevel is flat, a jointed edge can be brought back to meeting with just a few strokes, depending on the grit of the stone.
I often joint after a 1k, especially if a lot of material has been removed or the edge was reshaped. Then bring the bevels to meeting on a 2 or 4k.
I also typically joint at the 8k and the last laps on the finish stone, to ensure the edge is as straight as can be and that there are no chips. I also strop on a Chrome Oxide pasted canvas strop before going to the finish stone, for the same reason.
It is not something that is needed all the time, but it also does not take a lot of time or remove a lot of steel. It is a good technique to use on chippy edges and I feel builds a stronger edge.
Try it on a 1k, set the bevel, look at the edge, it will be ragged, now joint it straight and reset it on the 1k, with very light laps, 10-20. Look at the edge again.
So, if the goal of honing is to get as straight an edge as possible for comfort, why not joint the edge straight, then hone to that edge?
Glass, corks and thumbnails do similar things, but jointing on a stone cuts off the edge cleanly, instead of tearing it off or rolling it over.
I would like to add one thing to what these very knowledgeable guys have stated as they have covered it quite well, however:
Not all blades need it, nor do you have to do it every time you are at the stones.