It shouldn’t be the case.
What kind of curve do you have in the back?
Also, are you doing this on sand paper? If so and if you kept your larger chisel to the end, perhaps you should change your paper.
Final question: are all your chisels of the same making?
That the chisel is 1″ should not make too much difference. True, more metal has to be removed than on a 1/2 inch chisel, but a lot less has to be removed than on a plane iron. And if the back is flat and polished, and the bevel on your chisel is already established (often 25 degrees to 30 degrees — though I never actually measure mine), not much metal has to come off to get the edge for it to be sharp.
Are you sharpening using Paul’s method? When I find I did not get a sharp edge, it is often because I simply did not sharpen all the way to the edge. I often take a quick look at the edge after the coarse stone to make sure the scratches are all the way to the edge and square across (to make sure I am not sharpening out of square). You should also be able to feel a burr, unless the course stone simply broke it off already, which I find happens. In any event, if after the medium stone, you still cannot feel a burr, you did not sharpen all the way to the edge. No burr, no sharp edge. It does not have to be large, but it must be there. That burr gets polished off on finer stones or, on Paul’s method, on the strop.
If you used your stones correctly, there is a second way you might get a poor edge. You might have a great edge and then round it off on the strop. You have to PULL the blade across the strop being careful not to raise the blade us so as to blunt the edge.
You mention a sanding belt. Are you just using that, laying flat on a benchtop or whatever, to flatten the back? Or are you doing some sort of power sharpening with the belt to establish the basic edge before turning to stones? That was not clear from your post.
One difference between a 1″ and a smaller chisel is that it takes more hand force to push a 1″ chisel than a narrower one. Think of it as similar to pressure….force per length of blade. If your next size down is 1/2″, then the 1″ will take twice as much force to push through the work. Thus, the 1″ may not be different from your smaller chisels, but may reveal the degree of sharpness you are achieving overall.
One way to test this is to try to take paring cuts in the end grain of pine. Especially in construction lumber, if the chisel isn’t perfectly sharp (and without good technique), the grain between the growth rings will crush and tear and this will largely be independent of the blade width. So, it is a good test of sharpness. But be warned, you can drive yourself insane with this. Like I said, construction lumber is very difficult to pare without tearing and requires a degree of sharpness that you do not need in other wood, including in _good_ pine. So, don’t drive yourself crazy with this test.
The “belt sander” has be a bit terrified. You can destroy a chisel in the blink of an eye with a belt sander. My experience with them, despite what some people say, is that they do not flatten the backs of your chisel…they make them into a curvy mess and do so fast enough that it can be hard to correct by hand. If you are using sandpaper by hand, maybe a belt, make sure it is glued down to a flat surface. Not just on it, not just sort of stuck down with some water, but glued down. Othewise, what I find is that the paper creeps as the blade passes over it and can dub over the edge from the back.
Finally, for some reason, I find it harder to get the burr off of wide blades than off of narrow, so maybe you just aren’t getting the burr off?
A low quality photo of a 7/8″ chisel, showing that it is quite thick, with a corresponding long bevel. So, it will require more work to sharpen it compared to a ½” one, which also will have a shorter bevel.
A few “for-whatever-they-are-worth” thoughts on aids on grinding and coarse sharpening.
3M offers sandpapers with adhesive on the back. They stick very nicely to a granite slab (rightmost on photo below) or float glass. In addition to the need of all sandpapers to frequently be cleaned from ground off iron, they are also not inexpensive. Re-mountable photo glue on the back of ordinary sandpaper is a less costly alternative. Clamps can of course also be used. The paper will wear down, but my DMT 120 grit diamond stone did that as well.
Centre of the photo shows a belt sander designed for tool sharpening. Thanks to that the belt speed can be varied, sparks can be avoided, though even so intermittent water cooling is required. It’s quick compared to manual work on sandpaper and thanks to a honing guide the results are no less accurate. It’s a useful machine for shop-made irons. As long as one is prepared to change belts from coarse to very fine, it can replace the Tormek next to it for final sharpening.
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Can you use your belt sander to flatten the back of a chisel? That was my concern. Also, I suppose what I had in mind was a hand-held belt sander which some people clamp in place and then try to work tools on. What you show might be called a linisher, which are quite useful, but again I did not think they would allow the refinement needed for the back of a blade. Is that incorrect in your experience?
Should of course have used linisher, but an internet query returned substantially bigger machines.
Yes, one can flatten irons safely and easily. The bed can be angulated from flat to 90°; and the arm can be moved up, down, forward, and backward.
With the bed flat and the arm down, I placed a blade for a southpaw dovetail chisel across the belt resting against the arm, set the direction of the belt to run into the blade and arm, and – with the help of a small piece of wood glued to the blade (cyano acrylate) – applied a light pressure to the plane iron to be. A well used 120 grit belt did a good initial job, so I dared to move the arm along the belt, allowing for grinding its entire length, then changed to a fine grit belt for an improved surface, and was done.
Sadly, the steel – also after hardening – turned out to be too soft to hold an edge over any length of time.
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