OK I’m really new here. You may have seen my latest project in the gallery “Combination Bookcase & Table”. My next project is a Morris Chair, as you know there are several mortise & tenon joints where the tenon penetrates all the way through the leg and the arm of the chair. I’ve already decided to make the tenons through the arms “flush”, to the horror of the purists I know, but hey it’s my chair.
What I am asking is this: How do you cut the mortise with the precision needed to make this joint look awsome! Wood filler is not acceptable, the end grain of the tenon needs to mate the surface grain of the arms & legs perfectly. I’m thinking I’ll start with the tenon, cut the mortise 1/8 small with machinery then finish with chisels? Are there any tricks? What about chiseling from the top down removing material a little at a time until the tenon starts to fit then finish up with a fine file? This might take a month per arm but would probably work.
I work with wood all the time as a Handyman for a living but 45’ing trim together is different than this stuff, any help is certainly appreciated.
Replies
What tools are you planning to use? Once you tell me that, I'll be glad to tell you what I can. As a general matter, it is easier to shave teh tenon to size than the mortise - i.e., make the mortises FIRST. If construction sequence won't allow that, I have tips for that too, but it's more complicated.
Some recent through tenons of mine:
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Greetings Samson,
Great table! Well my Delta mortise attachment for my drill press is going to Ebay if that says anything. Making my combination bookcase/table I had good luck using my Bosch 1617 router with plunge base and upfeed bits. I had thought that since the Morris Chair uses a stub tenon that I would fit to the tenon but this is negotiable.
The Delta drill press attachment is a POS.
If you think you may stay in this hobby, a benchtop mortiser sure is nice to have. Like most tools, it doesn't do anything other tools can't, but is makes it easier and faster.
You want the legs to go through the arms from below, right? Like on my cabinet (looks like a table to you in the pics)? In order for everything to come together smoothly on that project, I had to the tenons on the legs first and then use them to mark the mortise positions on the bottom of the "table" top. Do you anticipate needing to do this, or can you make the mortises first and fit the tenons to them?
By the way, where are you?
Edited 3/23/2009 11:03 pm ET by Samson
I'm in Hastings, MN.
I've been at this for awhile, I've mass (in a small way) produced a few dozen stile/rail doors and other projects for people when what they need was not available commercially. Basically I'm new to the mortise & tenon work.
You understand perfectly what I'm trying to do as it just like your cabinet, my apologies it really looks like a cabinet the second time through. ;<)
I'm really not sure what I'm asking here, but any suggestions on lay out tools, wide or narrow chisels, will a get a better cut pushing from the top down or by clamping a backer board to the arm top and chisel from the bottom.
Johnny, someone who has actually built the chair you are building will no doubt come along and tell you that I'm all wet and thet the way Morris chair makers do it is X. But for what it is worth, generally here are the things I would tell you.
- marking should be done with a marking knife. The cut lines are much more precise than a pencil and give you something very fine to pare to.
- keep in mind the show side - that's the only part that has to be pretty and tight - that thought should guide you in your fitting
- Coming from underneath and making the mortise second, is much more difficult than cutting the tenon to fit the mortise
Here's what I did on the top for my cabinet. ithink something similar might work for you:
In this picture the legs are attached to the sides and the top is positioned so that I can mark the mortises with a knife from below:
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Now I know where the mortises have to be going in, but, of course, the show side is still a mystery, and that is where you really want to have your lines be right.
So I used a piece of tracing paper - carefully positioned / keyed to pencil marks spanning the edge of the top and blue taped in place to trace the mortise marks. I then used an X-acto to slice out the box. You need to flip the paper when you place it on the other side and key it to the marks again. You can now use a marking knife and straight edge to incise the box on the show side.
Work from the top / show side. Remove most of the waste in whatever method suits you, and then use chisels to sneak up on the incised lines. I find it easier to use relatively smaller chisels and shave at an angle when working the inner cheeks of mortises, but some people use the widest possible chisel and try to shave straight down. That never works for me because after the first inch or so, the chisel stops cutting unless you tilt it a few degrees. Once you do this, it's easy to lose square on the inside of your mortise.
Keeping the show side in mind, if the mortise is going to be at all loose (and I mean like a few sheets of paper thickness loose not 1/16th) is should be at the entry side/the part that will be hidden by the tenon shoulders.
I don't know if this was very clear, but i'm happy to anser any questions.
One thought is that you might find some wiggle room for yourself if you leave the arm board rectangular and slightly oversized until the mortise and tenons are done. Then you can cut its shape or notches for meeting the back or what have you to precisely fit where the arm ends up in space after the M&T operation, as opposed to having no room for error. Does that make sense?
Absolutely that makes perfect sense. I've spent the day thinking about this and while I use a grinder to sharpen carpenter's pencils to a fine point I'm never really happy with the accuity of my mark, and when it gets to fine the line gets lost in the oak grain.
Thanks alot and I'll be posting as I go.
You already got great advice on how to make crisp mortices. You probably want to keep them that way too: Relieve slightly the top edges of the tenons when dry fitting. With some woods more than the others, sharp edges can splinter the edges of the mortices. Tight tenons, before you pare them down for a snug fit, are pretty good at that <g>. A trivial advice, but could save you some grief.
Best wishes,
Metod
On the Morris chair drawings I've seen where the legs go through the arms, the through tennon is not the full size of the leg -- there is a shoulder on the leg formed by the tennon. That shoulder, besides supporting the arm, will cover any blowout you may encounter if you work the mortise only from above. (BTW, IMHO, E-Bay is a great home for your mortise attachment. Some folks like 'em, but I'm no fan.)
You can either use a router with a template if you are so inclined (but you'll still need to finish the corners off by hand) or simply drill out the major part of the waste and trim to the line with a sharp chisel. I'd do the latter. Not all that tough. Don't try to file -- you'll only round the edges. Either way, careful layout and marking is key. If you elect to chisel, so long as you get the mortise cut cleanly to the layout line at the surface, you can undercut just a bit without worrying about the fit.
Mike Hennessy
Pittsburgh, PA
Thanks Mike I'll be posting as this project gets going, I've had some really nice curly red oak for several years waiting for a project and to me the Morris Chair seems like a good fit. Potentially this could really be great but these two joints are going to make or break it, I think anyway.
Round corners yes, but otherwise, routing can get get you there.
Pretty much what Samson said. I just finished a front entry door that had mortises that were 3" deep. The furthest the bit in the hollow chisel mortiser would go. Actually it was the first time I used a Hollow Chisel Mortiser and despite them being a popular tool I must admit I am only moderately pleased with the results and find it a rather crude way to make a rectangular hole. I much prefer the router or a slot mortiser which will leave clean walls.
Ted
Hi there, I'm curious to know what type of mortiser you had the not so great expereince with. Was it a bench top or floor model. My first was a drill press attachment, frustrating at best. My next was with a powermatic floor model with the x and y table and vice type clamp of which I would gave me fits when the bit kept getting stuck in the work piece. It took some time to figure out the correct technique which for me was to make shallow passes while moving the table from side to side gradually deepening the mortise to the desired depth, much like plunge routing. With out the clamp and table with adjustable stops I can not imagine these machines being anything but crude.
As for the clean walls I guess that is a personal preference .
Tom.
We have a Multico PM20 in our shop. As far as benchtop machines go it's one of the better ones. I just prefer the clean smooth walls that I can get with a router bit or a slot mortising machine especially when it comes to through mortises.
In the days before I had access to a slot mortiser I use to use a horizontal boring machine outfitted with end mill bits. With practice, patience and a steady hand I can also get pretty good results.
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