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Thread: Twin mortise advise needed

  1. #1
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    Twin mortise advise needed

    I am going to build a night stand with four drawers. I built one a couple of years ago and need to make the second one. The first was built basically as an experiment in pocket hole joinery. It looks good and has held up well. Sorry for the sideways picture.

    image.jpg

    Now I want to build one with real, hand cut joinery. I've been practicing some on twin mortise/tenons to connect the drawer dividers to the legs, but am finding it awkward to cut a 1/4" wide by 3/4" long mortise. There is little room to lever chips out.

    Is this best done by drilling out the waste instead of doing it all with a chisel?

    Should I consider a different joint? Perhaps a stopped sliding dovetail?
    Last edited by Gary Focht; 12-30-2018 at 11:58 PM.

  2. #2
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    Go ahead and use a 1/4 inch mortising chisel. It will be a bit delicate, but just try to avoid chopping the ends until last. You can lever out a lot of chips with a bevel edge chisel or a pocket knife - but be careful the knife doesn't close on you. Mark

  3. #3
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    Now I want to build one with real, hand cut joinery. I've been practicing some on twin mortise/tenons to connect the drawer dividers to the legs, but am finding it awkward to cut a 1/4" wide by 3/4" long mortise. There is little room to lever chips out.
    For removing the waste what is called a lock mortise chisel or a swan neck chisel is very helpful. For a small 1/4" mortise a 1/8" wide lock mortise would work.

    On ebay the smaller ones are sometimes listed with carving chisels alone or in sets. They show up often in my saved search for > buck brothers chisels <.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  4. #4
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    I often make small twin mortises many only an eight wide. I have found what works best for me is to start in the middle, I don’t normally do this on larger mortises. I keep the bevel positioned toward the center and the chisel vertical. The bevel will usually cut the chips free making them easy to get out. When you get to the end you are already vertical. Small chips and a couple of passes works well. This works for me I’m sure others do it differently. I tried drilling and found it lacking. Jim is correct about a swan neck being of some help at times.
    Jim

  5. #5
    This is a case where a sash mortise chisel would be much better than a heavy joiners mortise chisel. The joiners mortise chisel, now often called "pigsticker" or "English oval bolster mortise chisel", was developed in the late 19th century, at a time when most furniture was made in factories by machine. Some have said that the sash mortise chisels are designed for shallow work, but where they excel is in deep short mortises where clearance is an issue. That is why they are much better for a cabinetmaker. We often do deep mortises.

    I would say that work on your technique will be rewarded; if you can make these mortises skillfully with a chisel your longer mortises will go more smoothly also.

  6. #6
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    I have tried both a Narex mortise chisel and a bench chisel. I’m going to keep practicing. I got a decently tight joint, but am bruising the ends/sides trying to remove the chips.

    Thanks for all the help.

  7. #7
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    I don’t usually lever out the chips, just spin the chisel 180 and chop them again. The chips then begin to lose their integrity and can be vacuum or knocked out.

    I haven't found drilling to be helpful, it seems counter intuitive but it usually ends up taking about the same or more time with drilling.
    Last edited by Brian Holcombe; 12-31-2018 at 2:12 PM.
    Bumbling forward into the unknown.

  8. #8
    Quote Originally Posted by Gary Focht View Post
    . I got a decently tight joint, but am bruising the ends/sides trying to remove the chips.
    That's what the shoulders are for.

  9. #9
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    Quote Originally Posted by chris carter View Post
    That's what the shoulders are for.
    True, but based off of pictures I've seen it looks like the twin tenons tend to run the full height of the divider typically. Probably to maximize glue surface on such a small, 3/4" high tenon. Of course no one will see it if I don't get a perfect joint since the drawers will cover it up.

  10. #10
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    Gary, Sounds like your digging instead of chopping. Brian said it above. Chop those chips loose so you can lift them out. I usually use my index finger behind the chisel to bear against, that should be enough on those small mortises. Sneak up on the ends like you do to a dovetail base line. Don't dig only chop and lift.
    Jim

  11. #11
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    I put a full shoulder on most joints anymore, it hides the line created when the wood shrinks in the winter.
    Bumbling forward into the unknown.

  12. #12
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    Again I agree with Brian. I usually put shoulders on tenons. On small ones maybe a sixteenth. It’s not going to weaken it much. Think sash mortises, they take a fair amount of abuse.
    Jim

  13. #13
    A few more notes. 7/8 is traditional for drawer dividers and would give a little more room, a little more strength. And one technique I have used for removing chips: chop straight down a little off the line, then reverse the bevel so that the bevel surface is now now straight down in the same hole. Hit the chisel lightly so that it is still in loose material and then lever the loose waste out. starting from this angle allows a larger arc for the chisel to lever. For this type of work you want a single flat bevel and for the heel of the bevel to be down inside the mortise. double bevels do not work very well for mortising.

    I took a flashlight and looked inside a 200 year old slant lid desk with this construction this morning. The tenons are the full thickness of the dividers. The mortise gauge lines extend well beyond the mortise and there is some scarring at the mortise ends, everything in plain view. I had not looked inside for thirty, forty years or more.

    The great thing about this desk is not the care the craftsman took in hiding mortises, but the care he took in stock selection and placement. The care he took in his line inlay and cock beading.both of which help the figured wood in this desk look more refined. The care he took in planing the figured wood. If you are looking to see if the back of the drawer is finished, the drawer front might be rather ho-hum.

  14. #14
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    Quote Originally Posted by Gary Focht View Post
    I am going to build a night stand with four drawers. I built one a couple of years ago and need to make the second one. The first was built basically as an experiment in pocket hole joinery. It looks good and has held up well. Sorry for the sideways picture.

    image.jpg

    Now I want to build one with real, hand cut joinery. I've been practicing some on twin mortise/tenons to connect the drawer dividers to the legs, but am finding it awkward to cut a 1/4" wide by 3/4" long mortise. There is little room to lever chips out.

    Is this best done by drilling out the waste instead of doing it all with a chisel?

    Should I consider a different joint? Perhaps a stopped sliding dovetail?
    Great spot to use a 1/4" bevel-edged chisel. Most 1/4" chisels sold these days, unless you have a premium brand, are more like straight-edged firmers which people have used to chop mortises for hundreds of years. Even a sash mortise chisel can feel a little cramped in the size mortises you're contemplating. Cut practice joints with the chisels you have to decide what works best. A hole is a hole. It just needs to be straight with reasonably clean walls. Use what works best for you. I like a butt-chisel length chisel for the kind of mortises you need to cut. But that's a personal thing.

  15. #15
    A couple of pictures sure would be nice Warren. Hint Hint
    Dave Anderson

    Chester, NH

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