Chisel out of square
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27 July 2017 at 8:01 pm #314079
Managed to get my 12mm chisel for mortise chopping out of square by hand sharpening.
Tried to get it square on abbrasive paper grit 60 but seems I’m touching all side of it.
Is it possible with abbrasive our only with a grinder?
Was finally back working on my workbench, but my mortise don’t meet each other in the middle (working for 2 sides). Could this be caused by the unnoticed unsquare chisel? (Got to unworkable mortise holes in 2 legs of the workbench :-(….)
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You must be logged in to view attached files.27 July 2017 at 8:41 pm #314082And I’m curious if the out of line mortise can be fixed or I need to throw the legs away. Or just leave the legs with a extra hole and flip them over.
For now I go back to practice wood and first make 4-6 practice mortise and tennons. Try to see if it’s the layouting or my chisel or my lack of skill 🙂
Try to grind it back using a sandpaper autobahn, if you understand what I mean. A long enough piece of thick glass and some 60-80 grit sandpaper.
You could benefit from an angle guide of sorts, like the eclipse ones. If you don’t have access to one, even a block of wood with the correct angle could work.
A grinder will probably overheat the chisel too much and you’ll loose that hard edge.
That said, you have a bahco chisel, I have only one and find it harder and thus more difficult to sharpen, even on diamond stones.If you do manage to get it back to square, see This thread, not so long ago…
Good luck
Diego29 July 2017 at 10:03 am #314130yes already working on 60 grit autobahn, but the progress seemed kinda slow. Also on the soft steel Lidl chisel.
I think where it goes wrong is indeed to much pressure on a small chisel. On larger chisel/plane i dont have this or less.
Will try to continue fixing it on 60 grit and in the future will use the honing guide more often!
Thanks for the feedback!
29 July 2017 at 4:54 pm #314135even a cheap oil stone and honing guide will bring it back to square in no time, if you are going off line from side to side i would recommend using a mortise guide as demonstrated by Paul in some of his videos
I’m not sure if you have a reply about whether being out of square (chisel) could cause the through mortise not to line up. If you are using Paul’s mortise jig, then an out of square chisel shouldn’t matter too much as long as you stay snug to the jig. I find that being out of square can make the chisel want to twist, which is something you’ll need to deal with even if you have the jig and sometimes even if the chisel is square. Without the jig, I’m not sure what to say. Perhaps it could affect things, but it seems more likely to me this is more a matter of sighting square and keeping control of the chisel. Just as likely is a layout problem, perhaps losing track of which face was the reference face or resetting the gauge between marking the two sides of the through mortise.
29 July 2017 at 6:39 pm #314140Never heard our Deen anyting about a mortise jig from Paul. Not in his books our Youtube?
Maybe I missed it.On smaller mortise never had issues, some maybe it’s the size. And my experience.
29 July 2017 at 6:43 pm #314141And I double checked my layout on the second mortise i tried:-)
But I also notice that woodworking that you do for a quick half hour as it makes sure you make mistakes:)
30 July 2017 at 9:35 am #314145Paul uses the mortise jig in some of his projects, you can see it for example in the dining chair episode 2 video (around 24 minutes in).
I agree that out of square chisels can cause the mortise to wander – when registering the chisel to the wood just before you make the chop, I find myself pushing the cutting edge to the wood. So if the chisel is out of square, I push the chisel somewhat out of square to the wood. At least, that is what I have found.. Also I can imagine that when you chop, the chisel rotates a little around the high spot.
Probably your approach of cutting a bunch of test moritses is best, to get a feeling for the chisel.
My 2 cents.
Mic
Amsterdam30 July 2017 at 9:41 am #314146As for resharpening it square – you are building a bench so i guess you’re taking woodworking serious. I would suggest to consider getting 3 diamond plates and mount them as Paul did. Sandpaper on glass works fine, but using diamond plates is a bit more user friendly and makes fixing/sharpening chisels a bit more easy.
I have out of square chisels. I get the hang of fixing them by consciously trying to sharpen them out of square the other way. Apparently that’s what my muscles need to sharpen squarely 🙂
Another 2 cents,
Mic30 July 2017 at 10:08 am #314147And a thought on the legs: could you change the mortise into a bigger, squared and aligned mortise? Making a new crossbeam with larger tenons seems less work than making 2 new legs..
M
30 July 2017 at 10:49 am #314148Hi Mic,
I already have the 3 diamond plates in a holder. But i don’t want to ruin my coarse stone and i assume grit 60 works faster as a coarse 250. But it still seems kinda slow. Not sure on the pressure etc.
Yes i indeed wanted to create a bigger mortise but any tips to proceed on that?? as i can’t use Paul’s method for this anymore?
thanks for the jig tip, i will check it out!
I’ve not tried this, so it’s just theory, but if I were trying to fix up a misaligned mortise, I’d start by figuring out the new width that is needed to get everything to line up. Knife or gauge that new layout into the work. Triple check it. Now prepare a block of wood with a squared face/edge and clamp it to your project along the new layout line. Use it to guide a chisel to pare the mortise to your new layout line. Take thin paring cuts. You may need to move the block a couple times if you are out by very much. Your goal is to have perfectly square paring cuts from both sides meet in the middle of the mortise. (If your eye is good, you may not need the guide block.)
Your mortise is now wider than you planned. If you you’ve already cut the tenon, you will need to carefully use your router plane to flatten and true the tenon cheek. Then, cut a shim that covers the full cheek and glue it on. Now, resize the too-fat tenon to fit the mortise. Since this is a through mortise, you are going to be able to see the shim in the final work.
Before you do all this work, pause after doing the layout work and decide whether you are making a mortise that is too close to the edge of the material. If the walls are too thin, you must start over with new material to avoid weakness.
Again, I’ve not done this, but that’s what comes to mind.
Think about whether you want to pare in from both sides, meeting in the middle, or if you want to pare from the inside face (where the tenon should sits) all the way through to the other side. This risks breaking out fibers on the other side, but it also eliminates the possibility of a layout error. If you are really careful when you reach the other side, and if the material isn’t crazy thick, you could probably accomplish it without breaking out fibers. Be gentle and slice/shear rather than push so that you’re really taking the final fibers running along their length. Good luck and let us know if it works.
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