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Thread: Only one mortise chisel?

  1. #31
    Join Date
    Mar 2019
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    I was taught that mortise chisels, except for really deep mortises more than 2" or so, are unnecessary. The thicker frame resists racking and bending while levering out chips, which is really not an issue with 90% of all mortises. I have a set and honestly there is no difference in the cut or the time spent chopping them out. Save your money unless you are timber framing.

    Paul Sellers' Opinions on the Subject: https://www.youtube.com/watch?v=q_NXq7_TILA
    Regards,

    Tom

  2. #32
    Quote Originally Posted by Thomas McCurnin View Post
    I have a set and honestly there is no difference in the cut or the time spent chopping them out. Save your money unless you are timber framing.
    Mortise chisels are thicker to withstand repeated striking, I was never under the impression the cut quality would be any different.
    Timber framers typically hog out the bulk with an auger bit and use a heavy firmer chisel to clean the walls. It's just an efficient way to work unless you like chopping.

    Everyone has their own philosophy on this

  3. #33
    Quote Originally Posted by Edward Weber View Post
    Mortise chisels are thicker to withstand repeated striking, I was never under the impression the cut quality would be any different.
    Timber framers typically hog out the bulk with an auger bit and use a heavy firmer chisel to clean the walls. It's just an efficient way to work unless you like chopping.

    Everyone has their own philosophy on this
    Mortise chisels are somewhat thicker than they would need to be to resist the forces. The reason they are thick is that they are self jigging: the chisel is held straight by the previous excavation. A thin chisel is much to free to wobble around and wander. The thickness is what yields precision.

    I watched Paul Sellers make a mortise with a bevel edged bench chisel. I got the impression that he did not have a lot of experience making mortises by hand.

  4. #34
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    Feb 2004
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    More in agreement with you than not, Warren. I do believe that Sellers has a large amount of experience, however he seeks to appeal to an audience of beginners rather than traditionalists. He would rather that they spend on his courses than on tools.

    Here is a video of his using both types of chisels for morticing ...

    https://www.youtube.com/watch?v=q_NX...el=PaulSellers

    And another by Peter Follansbee ...

    https://www.youtube.com/watch?v=N1bo...elsenToolworks

    We would all be interested in your comments.

    Regards from Perth

    Derek
    Last edited by Derek Cohen; 05-28-2022 at 6:57 AM.

  5. #35
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    Quote Originally Posted by Charles Guest View Post
    cosmetically to cover any bruising of mortise arrises.
    An important point Charles.

  6. #36
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    What infuriated me was the mortising chisels I bought were made in Germany, so they got be good, right? And were advertised as imperial sized, but ...

    The mortise chisels were consistently oversized, e.g., wider than their imperial counterparts. Not much, but wider enough that the mortise chisel would not fit into bench chisel's hole, so I spent an hour with the set on diamond stones and a caliper to get them right.

    I don't use them much, and I seem to get a smoother cut with a bench chisel. If one uses the age old technique taught by Sellers, and in turn taught to me at the school where he taught, one is only taking out about 1/8th inch of material at an angle and levering it up, hardly enough to bend any chisel. Again, if one limits the amount of material to about an 1/8th, the chisel never turns or racks on me. Finally, using two sets of chisels simply means that I have to make twice the trips to the diamond stones during the course of the day.

    But there is certainly nothing wrong with using mortising chisels to cut a mortise, if one likes using them.

    And yes, his philosophy is that older used tools, if properly tuned and sharpened perform as wells as the modern Veritas and Lie Neilson brands. I particularly enjoyed a couple of his videos where he took a $5 chisel and turned into a razor sharp instrument of death to wood in about 20 minutes using only his hands and diamond stones, with no fancy jigs. He is old school.
    Regards,

    Tom

  7. #37
    Quote Originally Posted by Warren Mickley View Post
    Mortise chisels are somewhat thicker than they would need to be to resist the forces. The reason they are thick is that they are self jigging: the chisel is held straight by the previous excavation. A thin chisel is much to free to wobble around and wander. The thickness is what yields precision.

    I watched Paul Sellers make a mortise with a bevel edged bench chisel. I got the impression that he did not have a lot of experience making mortises by hand.

    For the most part, yes but this is not true of all mortise chisels.
    Some, like Narex, have slightly tapered sides to avoid binding. You can not rely on the previous cut to automatically register the nest. The bulk of the chisel is there to withstand striking while chopping down accross the grain, not to ensure alignment or "self jigging".
    As I said, everyone has their own philosophy on this.

  8. #38
    My sorby mortise chisels are designed the same way and they cut straight. You register the back of the chisel in order to cut forward, not the front. They're still thick though...

    Edit: to lend a little clarity to my statement, the chisels may be tapered but still run true and straight due to their mass. Imho of course

  9. #39
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    I have the Narex mortise chisels and they are definitely not what I expected. My first attempt making a rather large mortise in white oak was barely usable. My expectation of the chisel taking care of things was wrong. I've had better luck with bench chisels. That said, I need to use them more and learn how to use them properly. I was given a lot of good advice here. I think, on that particular mortise I would have been better off using the drill and pare method.

  10. #40
    I have a set of Narex and all I can say is to just register the back, don't rely on the sides. Use them much as you would any other chisel. I always score the layout of my my mortises for a clean opening, it also serves a bit of a guide to keep you from wandering which many people seem to do with these chisels.

  11. #41
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  12. #42
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    Hmmm..Hmm... I have the brown handled one 9

  13. #43
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    May 2021
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    Spartanburg South Carolina
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    Chopped a lot of mortises while making a traditional window this weekend. I do prefer a mortise chisel but regarding size, it is important to select a size that matches the sash pane profile. This means you may need more than one size and possibly a mix of imperial and metric to get a good match.

  14. #44
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    Every replacement, exact reproduction sash I've made here has 3/8" and 1/4" mortises. The stiles and rails get 3/8", and where the muntins and glazing bars mortise into the stiles and rails, but any intersection of muntins and glazing bars get 1/4". I wouldn't want to cut all those 3/8" mortises with a 1/4" mortising chisel, so I guess I'd have to carry more than one size of mortising chisel.

  15. #45
    Quote Originally Posted by Jason Sellers View Post
    Iíll try and rephrase it: Why do woodworkers like Chris Schwarz say that all you need is a 5/16 mortise chisel when table legs 1 1/2 inch are common, and you should size to 1/3 the width of the leg, I.e., 1/2?
    Because they need readers or ads revenue will never come.

    Seriously though, Chris said it in the context of people just getting started. The explanation is that we tend to work with one, maybe two, rarely three different standard thicknesses: 3/4", 7/8" or 1" and 1 1/2". Within a single project all mortises are usually the same width assuming this particular piece was designed by somebody experienced. Just fyi, in timberframing only one mortise width is used throughout the project, and framers usually own just a single chisel. So most of the time only one chisel gets most of the work, Chris calls it a "jack chisel". Same logic is applied to other tools sets: bench chisels, plow plane irons, etc. Indeed it's possible to build all the projects with just a single plane, two bench chisels and one mortising chisel, but personally I would rather have a set that sits unused most of the time than not having the right tool when it's needed. Even if it's once a life time situation.

    One person said that the mortise should be sized to the TENON stock
    This, as well as "rule of thirds", is just a mnemonics, a "rule of thumb". It's a bit more complicated than that.

    The actual rule is "to weaken both members as little as possible". After a certain size the "rule of 3" doesn't work: on thick and wide members excavating one third of thickness will weaken mortised part too much. To prevent this a double tenon is employed (my preference is a 1/4" double tenon over a single 1/2" tenon when possible). On small pieces an absolute difference between 1/3 and 1/2 is negligible, and a 1/3 tenon might be too thin. And as you correctly noticed, on different thickness pieces the rule might be not applicable at all: when mortising a 1" rail into 3" stile, what should be my basic unit, the rail or the stile? The answer is neither, most probably I'd size my tenon and mortise to 3/4".

    There's quite a detailed overview of the M&T sizing in the "Modern Joinery" by Ellis, which was advertised by Chris in his LAP blog. Ironically, it calls for a good variety of the mortise chisels and contradicts his earlier advices, but whatever, it's just an opinion, not a law.

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