Hi
I am having a problem sharpening the blades on my hand planes. I am wondering how sharp I have to make the primary bevel.
I use a grinder with a white stone and Lee Valley guides to grind the primary bevel. Then using the scary sharp system I sharpen up to about 8000 on the sand paper. My question is….Do I have to use the sand paper on the primary bevel or just on the secondary bevel. Whenever I try to do the primary bevel, the jig is always off by a half degree or so and then I have to hopne for a few hours or so. If I just have to do the secondary bevel, it is easy to increase the angle by a couple of degrees.
I come up with this question after about 15 hours of sanding.
Not too quick.
Roger
Replies
Rog,
No. You don't need to polish the entire bevel.
The actual cutting edge is where the back and the bevel meet. The point of polishing the steel is to avoid having scratches in the steel make a serrated edge. On such an edge the "teeth" are not well supported and will break easily, leaving a dull edge.
Alan
Edited 12/3/2004 3:20 am ET by Alan
I am a beginner. I have finally gotten my planes working. I have found that a jig is necessary for me. I do not use a grinder. I use the coarse diamond or the 600 water stone and make certain the back is flat before a start on the bevel. If the back of my iron does not resemble a mirror I continue working until it shines. I mount the jig and start with my 600 water stone to form a 30 degree bevel. Next I use my 4000 water stone and finish with the 8000 water stone. I do not worry about secondary and primary bevels and my planes sing when in use. I spent last week flattening 5 cherry 11" x 8' slabs that I finished in my planer. I have an 8" jointer but I prefer flattening the wide boards with my planes. If it were not for my planes I probably would have gotten bored with machining wood.Keep it simple and use clear pine to test your planes. Eventually you will get them to work. It is worth the wait.
It sounds as if you've got it all figured out. The only suggestion I would make is that the secondary bevel makes honing and re-honing MUCH faster. Some honing jigs (the Veritas) have a built-in adjustment to create the secondary bevel. If yours doesn't, it's easy to do yourself. Just screw two little pieces of wood into either your workbench or a piece of plywood, both parallel t the front edge and one slightly closer to the front edge than the other. For the primary bevel, set the blade in the jig loosely and clamp it tight when the cutting edge of the blade is nestled against the little piece of wood farthest from the edge and the jig is against the edge itself. For the secondary bevel, do the same thing with the little piece of wood closest to the edge. This way you can perfectly repeat the placement of the blade in the jig without using those worthless angle measuring things. In fact, once you've set the little pieces of wood where you want them you never have to think about the angle of the bevel again.
damn Rog.... 15 hours..?????????
I don't use anything but handraulic waterstones and I've never spent longer than an hour on a primary bevel; the norm is around 10 minutes.
As for how fine to polish, the closer you can get the bevel to a mirror finish the better, although the quality of the back and secondary bevel are far higher than the primary bevel. I got the feeling that going from a grinder to scary sharp, you're trying to polish out a hollow grind..?? Strictly speaking that shouldn't be necessary; Straight off the stone, I'd set your guide to the desired angle of the secondary bevel and start to polish until you get that mirror finish.
With any luck that should save you a ton of elbow grease ;)
Mike Wallace
Stay safe....Have fun
Rog,
What is your grinding wheel's diameter? It should be grinding a "hollow" primary angle (25 degrees or so). Either by hand, or using a guide, all you have to do is let the hollow-ground plane iron rest on the sandpaper on the two "high points" - the sharp cutting edge where the hollow grind meets the lapped-polished "back" and the "heel" where the hollow ground surface meets the iron's front surface.
Resting on those 2 high points, you hone flats on the cutting edge and the heel. The hollow ground surface is between those flats. It shrinks as the flats grow. If your iron is thin, and you can't rest the iron equally on both the cutting edge and the heel, just address the cutting edge letting the heel almost get some honing. You don't have to create much of a flat. 1/16" is good. 3/32" is a lot. It should only take a few minutes all the way up to your finest grit. Then raise the honing guide to create a microbevel on the cutting edge (a few degrees) using only the finest grit. A few passes up and back - just a tiny line at the forward edge of the polished cutting edge flat.
Leave your honing guide set to that microbevel angle. As the blade dulls a little, rehone the microbevel. It will slowly grow across the face of the cutting edge flat. After 3 or 4 microbevel rehonings, it may take up a third of the flat. Time to rehone the flat(s) at the original sharpening angle, starting with your coarsest sandpaper.
The rehoning will only require that you remove the expanded microbevel. This will take a little longer than it took to create the flats the first time, because you are creating wider flats. Then create a microbevel and continue as above.
I usually get away with 2 rehonings. At that point the flats (combined) about equal the remaining hollow ground surface. Then its time to regrind on the wheel.
Since you are using the scary sharp method, try to learn to rest the iron freehand on the 2 high points and do the honing with a side-to-side motion of your hand, not up and back as a honing guide requires. With a little practice, you can hold the cutting edge and heel solidly on the sandpaper, with no rocking at all. Just a few side to side swipes at each grit. It seems to go much faster than when honing up and back with a guide. Then just tilt the iron slightly to apply the microbevel.
Rich
Edited 12/1/2004 12:07 am ET by Rich14
Edited 12/1/2004 12:08 am ET by Rich14
>> With a little practice, you can hold the cutting edge and heel solidly ...
With a little practice, some people can learn to hold the edge and heel solidly on the stone. I never could. When I rock the blade, I can tell when the edge and the heel both hit the stone, but as soon as I move my hand in any direction, I lose the feeling of the angle.
Good thing I never tried to apprentice as a cabinet maker. I'd have spent the entire seven years trying and failing to learn how to sharpen plane irons.
Professor,
If you could check my question in Breaktime- Paint sub price
-zen
Edited 12/1/2004 6:00 am ET by zendo
Uncle Dunc,I could NEVER learn to hold it firmly moving up and back. Which is the way I was taught. Very frustrating. Many years ago when honing guides became available (I still use the original Eclipse model I bought in 1970) they were called "cheaters." I always felt a little guilty using one. Well not TOO guilty!Then a few years ago I happened on one of the many WEB postings about the scary sharp sandpaper method. The pictures showed the guy hand holding his plane irons and chisels and using a side to side motion. It said that it was easy to lock one's wrist using that motion.Side to side! I had never heard of such a thing. My "teachers" never would have allowed it. Besides it was a motion that was not convenient on an oilstone (no waterstones in America in those days). Besides, in addition to the sharpening lessons, I remember being told about the up and back motion lining up the grains in the steel.That was all BS! The side to side motion really works! It IS possible to hold the iron steady that way. And it seems to polish the edge better.Anyway, Markroderick has described dispensing with honing the primary bevel completely and paying attention to only the secondary bevel. And starting at 600 grit?! Hmm. . . I gotta try that. I have always prepared the primary bevel (it dosen't take that long) and used that as the base for multiple secondary bevel honings. If all we ever really need is the secondary bevel, that's a real time saver. Film at 11.Rich
Let's say you've created the primary bevel with 80 grit sandpaper. Since the secondary bevel is only a 32nd of an inch wide or something like that, you can hone it very quickly starting with 600 grit sandpaper. All you're doing is getting rid of the scratches from the previous grit. Of course, if 600 doesn't work quickly enough (30 seconds of honing?) then back down to 220. The point is that with the primary bevel created the rest should go real fast because you're working with such a tiny sliver of metal.
By the way, I also agree that honing by hand using the side-to-side motion is even faster, but I wouldn't advise someone to try that until he had full confidence in his ability to hone with the jig. One step at a time. This is from an amateur who has suffered more than his share of defeats at the hands of the sharpening gods.
Once I get a glint of a secondary bevel on the fine side of an India stone I move to the finest stone I have to wrap up. Usually doesn't take that many strokes. We're talking just a very few minutes from a freshly ground primary all the way through forming the secondary and polishing it and removing the burr.
If Rog spent 15 hours I'm surprised if the blade has any meat left on it.
I recently visited the Shelbourne museum (village) in Burlington Vermont. There is a woodworking shop on the grounds where the professional woodworker makes chairs, tables etc. in live demonstrations for the crowd. There was a slow period and he took some time to show me how he sharpened his plane irons from grinding to about 8000 grit stone in under 5 minutes. First he ground it on a hand grinder, (hollow grinding) then to about 1000 grit stone and then 8000 ( it might have been 6000) grit water stone. 3 steps in under 5 min. and it was as sharp as anything I have been able to do in an hour. At my skill level that may not be saying much, but it seemed very sharp to me (shaving hairs off the arm and all that) and it served his purposes well and it looked like he was doing some fine work.
Frank
Mark,Here's a little feedback regarding your suggestions.I ground a Hock 2" iron on my 8" white wheel at 25 deg, then honed only a "secondary" bevel at 27 deg starting with 600 grit, 1000, 1200, 1500, 2000, 8000.Maybe its because this is the first time I've used this method, but the results were decidedly inferior to honing a primary bevel at 25 deg then adding the secondary microbevel.It was much harder to push the plane through maple, koa and mahogany. I just could not get a thin shaving at all. In fact, the iron seemed to be much more sensitive to setting and never found a good position. It either cut a thick shaving or would not take anything.I then rehoned, using my usual methods, and everything is back to normal. I get .002" shavings easily with my smooth plane.I might try again, but I'm out of ultra high grit sand paper now.Rich
I can't really say why it didn't work for you. The physics say it should, so something must have been out of whack.
The whole purpose, the only purpose, of the secondary bevel is to avoid needing to hone the whole main bevel. So if you are first honing the whole main bevel and then honing a secondary bevel, you are doing way much work TWICE. You can either avoid honing the whole main bevel or, having honed it, just stop there and not create a secondary bevel.
Good luck.
Mark,I can't agree with you about the purpose of the secondary bevel. The primary bevel is ground and honed at the optimun angle, taking into considerations a number of factors. These include the kind of cutting expected, end grain vs long grain, soft vs hard wood, the bed angle, the position of the bevel, even the type of steel. It's the angle that puts the sharpest edge on a cutting wedge for all those conditions.That sharp edge is prone to quick dulling as it's used. One remedy is to frequently resharpen it. If the angle is increased, the edge will not be as sharp to begin with, but it will maintain its initial sharpness much longer. It will be a little harder to push through the wood, the planed surface will not be as good, but it will be usable longer than the smaller angle blade before rehoning is needed.A second remedy is to hone at the optimal smaller angle, then hone a tiny microbevel, the secondary bevel, at a higher angle on the leading edge. The microbevel is not deep enough to adversely affect the sharpness of the primary angle. The blade still cuts as though it has only the primary honing. But the microbevel is enough to alter the leading edge to the higher angle configuration which resists dulling better.It's true that as the edge dulls, it's the micro bevel that gets rehoned the first few times. That's not to save rehoning of the primary bevel. It's because it's only the micro bevel that's been dulled (if the dulling hasn't progressed too far - if it has, then it IS necessary to rehone the primary). Once the microbevel has been rehoned several times, the condition equals a primary honing at that higher angle - time to rehone the primary at its correct lower angle.I hone the primary at 25 and the secondary at about 27-28 degrees. I have a feeling you are either honing what you call a "secondary" bevel, but it's at 25 degrees, in which case you are planing with a sharp, but quickly dulling edge which you frequently rehone, or you are honing at a higher angle and planing with an iron that has only that high angle edge and no decent primary bevel.In the first case, you are rehoning more frequently than I do, but assuring yourself that it's very easy to rehone that tiny bevel. In the second case you can't really be getting the cutting action that you would with a polished, lower angle primary and a higher secondary bevel. (That's what I encountered).If the only reason for the secondary is to avoid the need of honing the primary and if it then follows that no primary honing is needed at all, then all those experts who have microscopically studied blade behavior and who have just about universally described the technique of primary and secondary honing must have all been wrong. But I can't believe that's the case.I think if you had a chance to compare planing with a properly prepared edge vs yours, the first would be better.Rich
I think we may be getting tied up with semantics here. A sharp edge is a sharp edge, whether you call it a "microbevel" or a "secondary bevel" or a "primary bevel." The only edge that matters is the one that's cutting the wood. If I grind a "primary bevel" at 25 degrees and then hone a "secondary bevel" or "microbevel" at 27 degrees, I don't think it matters one bit whether the "primary bevel" was ground on 80 grit sandpaper or honed on a 15,000 grit waterstone. Am I wrong? Are we talking about two different things?
You are correct.
Mark,Yes, I'm afraid there is a little bit of semantic confusion going on here. It's because you have described your sharp edge honing technique as a "secondary" bevel. You are putting that single bevel on the front edge of a rough-ground surface that you are calling the primary bevel.That's not the way I understand blade geometry and the physics of the situation are a little more involved than simply saying "a sharp edge is a sharp edge." The rough grind provides the angle on which the primary bevel is formed, but the rough grind itself is not the primary bevel. But the semantic difference is not important.The real confusion is happening because you have not specified at what angle you are actually grinding the rough grind, and at which angle you are honing the actual sharp cutting edge.I have found that performance diminishes quickly as the honing angle increases. That's why it's necessary to keep the higher-angle secondary bevel honing very small - a MICRObevel. Otherwise its characteristics dominate the cutting behavior and it becomes the primary cutting edge. That's not wanted. Its only there to prevent rapid dulling of the sharper primary bevel. It's the underlying primary wedge angle that's doing the cutting. Since you say you are getting good cutting, I am assuming that whatever angle you are honing must be close to about 25 degrees for plane irons, maybe lower (which will result in an even "sharper" wedge). You are simply honing a single edge and that edge is your primary bevel, not a "secondary".If it's at about 25 degrees, you have a good cutting wedge but do not have the advantage that a higher angle secondary microbevel affords on the leading edge. If it is higher than 25 degrees, you are losing sharp cutting wedge behavior. The laws of physics apply in your shop exactly the same as they do in mine.At what angle are you actually honing your single bevel?
I sometimes use a single bevel at 25 degrees, and by that I mean the whole bevel is 25 degrees. I do that when I'm sharpening totally freehand, because I'm not good enough to create consistent microbevels freehand.
When I'm not doing it freehand, I generally use a 25 degree angle for the primary bevel and a couple degrees higher than that for the microbevel.
I really do get great results, but if there's a better way I'm all ears.
The one thing in your post that doesn't make sense to me is you seem to be saying that when you use a primary bevel with a microbevel, the angle of the primary bevel has some significance. I could be wrong, but I just don't see how this could be true. The only thing the wood "sees" is the angle of the microbevel, isn't it? Once the microbevel has sliced into the wood at 27 degrees, what does the wood care whether what comes behind is 25 degrees or 5 degrees?
Rich,
Don't get too hung up on bevel angle. I get the sense from your posts that you may.
I hollow grind the primary on a 60# wheel then don't touch it again - makes sharpening easier and quicker. Roughness doesn't matter on this one.
The secondary bevel is the honed one that contacts the wood. It's just a few degrees higher than the primary. If the edges folds or crumbles in use, hone the secondary bevel at a higher angle.
Eventually you'll hit the right angle through trial and error.
As a starting guide, primary bevels are ground to the following angles, secondary bevels are a touch higher
Paring chisels 15-20 degreesBench chisels and planes 25 degreesMortice chisels 30-35 degrees
But, as I said, these are a guide - change them as you need to if the edge crumbles in use.
Cheers,
eddie
Industry terminology attached in file. A microbevel is a tertiary bevel.
A cutting edge has 3 angles. The first is achieved on the grinder at about 25 degrees. The second- called the primary bevel is achieved on your sharpening medium, stones sandpaper whatever. This is elevated by 1 or 2 degrees, and only serves to quickly refresh an edge. The third is achieved on the finest grit of your sharpening medium, and is the actual cutting edge. This is a mirror band of polish about 1/64 of an inch wide and it is about 1 degree steeper than the primary bevel which is about 2 degrees higher than the angle of the hollow grind.
As you say there Peter - I'm trade trained.
Perhaps they used different semantics/methods when you were trained. I use a hollow grind.
I'm not going to add to the confusion by entering a debate.
Cheers,
eddie
Edited 12/6/2004 1:30 pm ET by eddie (aust)
The first angle- achieved on the grinder, naturally leaves a hollow grind.
The point behind honing a secondary bevel is to not hone the primary bevel at all. This saves metal as one is honing a very small secondary.
One grinds a primary bevel, then forms a secondary bevel using fine and ultra fine stones or whatever your choice of abrasives happens to be.
It is perfectly acceptable to forgo the use of a secondary bevel if one chooses to, but of course this necessitates honing the entire primary bevel each time the edge dulls.
I don't hone a secondary bevel on my mortise chisels, but wouldn't dream of working without a secondary on my bench firmers which are used constantly.
Why do you not hone a secondary on your mortise chisels?
They don't need honing often enough to warrant the procedure as a time saver/metal saver. Due to the geometry of a mortise chisel, I find it a little difficult to tilt the blade to put on a microbevel without rounding it. I register the primary, hone and go.
As an aside, I most definitely would never hollow grind a mortise chisel, but I don't hollow grind my bench chisels either. Some people do and have no problems. It's almost a matter of taste I guess.
But it litterally takes 2 strokes on your finishing stone to achieve what must take you dozens to polish the entire bevel.
Dozens? You're not serious I hope.
It appears it's time for some myth busting which I will get around to doing in a bit. In the meantime, consider that a mortice chisel is *relatively* narrow.
Edited 12/7/2004 9:53 am ET by cstan
To answer your question, you don't have to make the primary bevel sharp AT ALL. The only thing that matters is the secondary bevel.
Also, while you will eventually learn how to hone the blade freehand, DON'T TRY IT NOW. Use the honing jig. Thus, once you've ground the primary bevel on the wheel, switch to to the honing jig right away for the secondary bevel. Ten or 15 seconds with 600 grit, 1,000 grit, and 2,000 grit sandpaper and you'll have an incredibly sharp blade.
Also, feel free to change sandpaper frequently. It's cheap.
Rog,
I was having the same problem as you I think. It would get sharper and sharper and then dull again. The break through came by heading what Alan, Mark and others have alluded too...the back has got to be polished to the same level as the bevel (secondary or primary)...or else it's a serated edge.
Rog
If you are getting the angle within a 1/2d - STOP. You're done.
_________________________________
Michael in San Jose
"In all affairs it's a healthy thing now and then to hang a question mark on the things you have long taken for granted." Bertrand Russell
Hi Rog,
I have been reading all the excellent advice you are getting after your question on blade sharpening and I noticed that no one mentioned the BACK of your blades. It may sound obvious, but I just wanted to mention that no matter how good your bevels, you will not get a sharp edge if you dont polish that back to a mirror finish.
PSA backed adhesives on a flat piece of glass will make short work of it.
As you define the bevel, you must remove the burr on the back side as you go along or your edge will always have a burr that will be rounded and break away in chips.
Enjoy your polishing! Hope you hear those blades singing soon.
Treeman
I put the primary bevel on using a 8" fine grit wheel mounted on my lathe running at 500 or 800 rpm. I use a fine black felt tip pen to mark square on the back side then grind to the line. I have a water drip to keep the stone wet.
For the secondary bevel (which I do only for myself) I use 600, 1000, then 1500 grit wet/dry silicon paper glued to the back of my 1/4" thick steel diamond laps. Secondary bevel is only about 1/16" wide. After the last grit, I burnish using a hunk of belly leather and jewelers rouge. Final bevel takes only 10 minutes or so if it is a new bevel. 5 minutes for a touch up.
Seem to me that going to higher grits just caused them to dull that much quicker.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
Sharpening is incredibly easy, using a jig or by hand. Period. You do not need to polish the primary bevel at all. Not even a little bit. Hollow grind one time on your grinder, then hone a primary bevel by lifting the end of the blade slightly, do this on whatever you consider your 1000 grit sandpaper. Your bevel should be only enough to raise a burr on the flat side of the blade. This shows that you have achieved a new edge. After creating a burr along the entire cutting edge, switch to your finest grit of paper and raise the end of the blade a fraction more than on the primary bevel and take two strokes. You should now have a highly polished band about 1/64 of an inch wide. That is it on the bevel side. Now turn the blade over. From here I use the David Charlesworth ruler trick. Actually, I will skip the writing and just tell you to go to David Charlesworth's web site and get all the information required.
Hello Rog. When you sharpen you only need to go to the grinder every 10 sharpenings or so. So, after you grind a fresh angle on the grinder, place your blade in your jig, increase the angle slightly so that only the edge is making contact and hone until you feel a burr along the entire width of the flat side of the blade. You do this on your sandpaper that is equivilent to a 800 or 1000 grit waterstone. After you have your burr, increase the angle again just slightly, and hone for 2 or 3 strokes on your finest sandpaper. You will now have a mirror band of polish at the cutting edge, the only place that it matters on the bevel side. The next time you sharpen, forget the grinder, place your blade in the jig, and hone the bevel again until you feel the burr, then increase the angle and switch to your finest sandpaper again, and do 2 or 3 strokes. After 10 sharpenings or so, it will take to long to establish the primary bevel, the one on your 1000 grit sandpaper, so you will go back to the grinder. The back side of the blade is a whole different story.
This forum post is now archived. Commenting has been disabled