Hmmm..go for it...
Jack plane rehab, bad edge.JPG
Made by Sargent Co. never been sharpened since it was sold....
Actually, I'm still not following. How are your removing the wire edge before progressing to the next grit?
I mean, what technique? I have been only doing this as a final step after working on the 10,000 grit then I pull the blade from the sharpening jig and rub the flat back for 6 or so strokes on the 10,000 grit waterstone.
Erich,
Through a process known as "chasing the burr". When you are finished with a stone the last process is to chase the burr by pulling the cutter back side then bevel side, repeating as needed until the burr is removed. It is kinda hard to do with the cutter attached to a jig. Jigs are pretty limiting, about the only good use of one is if your freehand skills are not that good, you do not have a grinder and you need to reestablish the bevel. It takes a little time and some effort but one of the best things you can do to improve your wood working is learning how to sharpen free hand.
ken
Can you explain in more detail? The iron is in what orientation? Bevel flat on stone, then back flat? Or...?
I've picked up that you are an advocate of free-handing. I'll admit it just feels too imprecise for me. I do understand that this is what wood workers did for ages. Just don't see how the edge can be as precise. I do free hand sharpen my kitchen knives, and they cut just fine. But I feel like I'm not able to keep a consistent enough angle moving up grits.
Erich,
Yes, just as if you were working the back and the bevel only now you are using light pressure and only pulling the iron.
Free hand sharpening is a matter of a grip that lets you keep even pressure on the bevel so the stone is cutting the bevel evenly. When you start learning, a hollow grind on a thick iron can help you get the feel.
ken
Yes. Bevel flat, back flat. Rinse, repeat. Repeat. Repeat, etc.... There are nuances. (And variations.) Typically, less pressure each iteration. (One variation is edge leading strokes, with extremely light pressure.) Basically you don't want to carry a large burr forward to a stone that won't deal with it well. (Many argue a small burr is OK. I've probably done it both ways, 'cuz I'm not that good at this! )
For me the key is a jig limits degrees of freedom. Cutting edges come in all forms. What works for chisels might not work for a cambered plane iron. Something that "rocks" to do the cambered iron can screw up the chisel. Then you get to a carving gouge or hook knife (or most kitchen knives) where the curves are more complex. It's a tradeoff. It seems to me you're either mastering a difficult task (I'm told it easy, but...) or you are chasing an increasing list of jigs. Or doing some of both. No one way is wrong, only not best for you. Or for me.
When a burr has been created across the full width of a blade, The back of the blade is pressed lightly across the stone and pulled. Depending on the size of the burr or wire edge it will either be worn away by the stone or more likely have some wear and some bending to the bevel side of the blade. For the second stroke the blade is turned over, set on the bevel and then pulled across the stone.Actually, I'm still not following. How are your removing the wire edge before progressing to the next grit?
This is repeated until no burr (wire edge) can be detected on either the bevel or the back of the blade.
For me, this is mostly done on the stone that created the burr in the first place. With softer water stones a heavy burr from a coarse stone my inflict scratches on a finer stone. This so far hasn't been a problem with oilstones.
Note: Across the short side of the stone instead of the length.
Here is something to possibly help those who want to try to learn freehand sharpening. If you have a video camera set it up to record your sharpening from the side. You will see if you are keeping your blade at a constant angle or not. This should help to detect and correct any unwanted variations in honing angles..
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
When Ken described this to me, it dramatically improved my results with my Arkansas stones. It also helped me with my water stones, but it was more obvious with the Arkansas stones.
I just keep switching sides and going lighter and lighter. I had not previously done that on any stone.
If you can sharpen kitchen knives successfully then chisels and plane irons are cake. You don't have to draw a long edge across the stone or follow any curve- just hold it in one position and rub. And sure, the jig is more precise technically, but that isn't adding anything in terms of sharpness.
Like I said earlier, my plane irons are hollow ground, but I sharpen on a diamond hone and will lift the iron to put a micro bevel on it and it works.
When the iron need it, I will simply re-hone the bevel.
And the "after"..
Jack plane rehab, stropped.JPG
Chipbreaker was tuned up, and polished, along with making the fit gap-free...test drive?
Jack plane rehab, test bed.JPG
25 degree, flat bevel, flat back, chipbreaker set 1mm back from the edge of the iron....not too bad, for a Jack plane?
Jim, I meant to respond to this a couple of weeks ago. I had tossed off that the amount of the back affected by the ruler trick is "about a millimeter." It's actually about half of that. But your question about the chipbreaker is important. A chipbreaker usually has a bend of about 1º or even more, to allow its edge to contact the iron's back firmly. The angle created by the ruler trick is about 0.5º, so the chipbreaker can make contact regardless of how close to edge it's placed. does it contact the true flat area or the little ruler trick sliver? If the back is shiny flat to begin with, it won't matter. Either way, the ruler trick is an ingenious notion, designed to save time.
Then you asked if periodic regrinding makes more back-flattening work. I don't think it does. The other question that was raised here is whether the ruler trick takes away the need to flatten the back. It doesn't, exactly because it only affects such a thin sliver of the back. So we want a good half-inch of mirror-flat to work with, to last through many resharpenings and even regrindings.
But that half-inch regenerates itself as you go. Every time you finish honing, you rework the back to take off the wire edge, using the ruler trick over the 8000 stone, maybe fifty short strokes, to reestablish the little ruler trick sliver as the last step. All this takes seconds to do and minutes to write down. The reestablishd sliver makes contact with the mirror-flat back you established when you first bought the iron.
When you need to regrind because the secondary (800 grit) bevel is getting wider than you want, it's true you'll grind away a bit on the half-inch of flat back, but it will take many regrindings to run out of this surface. So yes, eventually you will need to reflatten the last half-inch or inch on your well-used iron (mirror-polish off the machining marks). But that was always going to happen if you use an iron so much that you grind it down significantly. It's an argument in favor of polishing an entire inch in the first place.
Last edited by Bob Jones 5443; 08-10-2020 at 4:13 PM.