When I make floating tenons the tenon stock is always more tight fitting in the rail (end grain mortise) than in the side of a leg (cross grain mortise). Why is this? I use an upcut spiral bit and use a jig for the end grain mortise. For both mortises I am using the same 1/4" upcut solid carbide bit.
Both mortises are cut with increasing depths with multiple passes. If I make the tenon stock fit to the cross grain mortise it will be VERY tight in the end grain mortise. If I make the tenon stock fit the end grain mortise it will be too loose in the cross grain mortise.
That seems really odd. The only idea I have is that you seem to say that you use different setups for the two cuts. Is there possibly some slop in the cross grain mortise jig. I'm assuming you have a jig for cross grain, you don't specifically say so.
My other idea was that maybe one cut was leaving a washboard surface inside the mortise, but this would be more common with a dull straight cutter and you're using a spiral bit.
The end grain cut is cleaner because of the orientation of the bit to the wood fibers (parallel). Same reason that a rip groove cut on a saw is cleaner than a groove cut cross wise using a rip blade.
In my experience, yes, it's common. I use loose tenons frequently and there is usually a difference in how the bit cuts in end grain vs. long grain. The only real variable is "how" the bit cuts the grain, and while I can't explain the physics of the cut, there clearly is one. It also seems to me that any arbor bearing slop, if your router has any and most do, will contribute to slight runout and differing mortise dimensions if the bit is indeed cutting slightly differently in the two grain orientations.
My solution is to fit the tenon stock to the fatter mortise, glue in that side, and then plane the other end to fit the smaller mortise.
shoulder plane. I'm glad my description of the problem made sense. I think I should have said 'long grain' instead of 'cross grain' in my description, but you got my meaning anyway.
I think there is also another physical aspect of the wood to consider, but wouldn't know without a moisture meter. Bear with me on this.
When you turn a handle for a socket chisel, you always blunt the end of the cone going into the socket for two reasons. 1) the repeated pounding will force the wood to a smaller diameter and 2) left alone unused, the handle will shrink, no matter how dry the wood appears to be and become loose. A couple of taps to drive it in further into the socket and you are fine.
When making "classic" neander tool handles where you bore into the end grain to mount it into the handle like a forged chisel or carving tool, you always use slightly green wood. This allows the wood to grip the wood as it continues to dry. I know of not one traditional tool maker that makes these types of tools that uses epoxy, ferrules, etc. Some even speed this along by heating the tang (this goes back to the blacksmithing days) and jamming the hot metal into the end grain so that it will literally shrink around the tang.
It is not uncommon for woodturners to make small tools and handle them without the above mentioned ferrules, etc, as just a little moisture in the center of our turned piece will keep it from coming loose.
Obviously... all of the above won't work if the wood is completely seasoned all the way through and has achieved the same moisture content through the piece.
I am wondering when this happens if we are cutting into a larger sized piece of wood (1 1/2 thick or so) that has seasoned on the first half inch all the way around, enough to be stable, but not enough to be completely seasoned. That could easily make up a few thousandths of shrinkage when exposed to air. I know when I turn green wood on the lathe, just a few minutes exposure of some woods will make the wood crack from the immediate exposure to air.
Most turners have turned pieces of "stable" wood that were green that were literally cracking while we were turning because they were drying so fast.
Just a thought.
I just put the end grain side on the sander for a second or two before I even glue.
is really a nice piece of work. I particularly liked the use of the box joints under the top to mimic dentils. Your idea?
Could be mistaken, but I think what you're looking at is an old "casework" construction method, used quite often for chests of drawers, like the following, except with box joints instead of dovetail joints:
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makes for an extremely strong case that resists sagging and racking over time. Just add dividers for drawers/doors, legs and aprons.
Same concept was used for this, except the end panels were veneered, which hid the corner dovetail joints.
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way to make a case that should "stand the test of time" for these types of applications.
You could be right, but I experience the same differential in mortise dimensions even when using loose tenons on material that are the same dimension and dry to 7-8% mc, so I don't think that differences in mc are the culprit.
Actually, what you are seeing is a through dovetail joint where the tails are in the top board, and the pins are the sides - somewhat unorthodox, but mimics visually a box joint if you can't see the top, which in this case, you can't. The top is elevated above the dovetailed carcass by a mitered frame approximately 3/8" thick and set back from all edges so the top "floats" above the cabinet a bit - hope that makes sense. Hard to describe. The floating top concept is one that one of my teachers, John Fox, has used extensively. I make no claim of originality.
I also experienced this occasionally when using router mortising jigs for loose/floating tenon joinery, and don't with the Multi-Router ... which makes me wonder if it is not more "method" than "material"?
It would be interesting to know whether the Domino user's have experienced the phenomenon.
Box (?) I assume after reading your comments on the site. But with the same picture on your site, it was small enough (even with my glasses!) that it looked to me like you just edge glued it. I knew there was more, but I never saw it until you linked to a bigger pic.
Heh, heh. Edge glued....
Sorry.
Firefox can make the text bigger, but not the pics.
You know, I remember you posting away about that process, one I certainly have never tried, and then it seemed to me you quit giving updates. I just missed it, I guess. I didn't know you had finished up the project.
nice work with small pictures. That looks like a really exceptional piece that has a lot of details that fellow woodworkers would like to
I have no doubt. And I hope you have a long bloodline in your family that will appreciate that piece (as well as other fine pieces you have made) over the generations. I also hope you are marking your pieces someway with your name, date, etc.
On the last piece I made as a gift (sometime back!) I went to the trophy shop and had a small lacquered brass made with the pertinent information on it and they even gave me little nails to attach the plaque. Boy did that little brass plate class things up. I put it inside a door like some old furniture make did a million years ago. (That's actually where I got the idea) and it was almost the favorite part of the piece.
That piece sure merits something along those lines.
One more thing... what kind of stain did you use? Did you tone and stain, or just stain then finish?
With the multirouter, the router is locked into a carriage. This is much more stable when cutting than when hand held. Also, the stock is is clamped very securely with the multirouter. There has to be some kind of a slop factor when using jigs that are smaller, less expensive, etc.
And Charlie B, didn't you post some kind of message that describes how the domino cuts the mortise? If I recall, it does NOT cut it in the same fashion as the garden variety router. It could be that the domino addresses another issue that conventional routers are found lacking.
I am wondering of wood selection or the size of the joint would play a factor as well.
Well, no I have not. But then I have mostly been using the 5mm tennons and those have to be tapped in with a hammer regardless of where your mortise is cut. The larger tennons, 6,8,10 mm, tend to fit a bit more loosely but about the same in tightness again regardless of where the mortise is cut.
I guess the million dollar question to ask Brian, OP, did you test the fit immediately of did you wait over night? I can cut stub tennons to fit a grove perfectly. The next day, not so good. Thinking about how wood expands and contracts, it seems to me the end grain may tightenshrink more so than the edge or face of a board if humidity plays a roll.
Damn, you caught me! I butt jointed the ends and pasted on cardboard cut-outs of dovetails for the shop pictures ... gotta do something with those shop scissors besides making paper dolls all day long.
The basic tenet of that type of casework: "if a case part joins another at a corner, dovetail it; if one part meets along another's length, use multiple through tenons."
Follow that simple maxim and you can build hell for stout.
Thankee ... Actually, I still think of that piece as an experiment/prototype, although it is a solid and functional piece of furniture.
On the next one the "casework" will be out of cabinet grade ply instead of a secondary wood. That sucker is H E A V Y! as it sits now.
I've taken to using Rockler "Mission Oak" gel stain, which is actualy made by the Lawrence McFadden Company, IME, makers of excellent stain products:
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followed by three coats of sprayed, amber shellac, to get an overall darker feel.
If you haven't tried any of their stuff, give'em a try.
(Now, if that HVLP rig of yours will "shoot" that stuff, you sold me on buying one!
I would, but this isn't the first time I have noticed this. It has happened with maple and cherry as well. I just thought I would finally post and see if I am the only one that has experienced this, AND it looks like I am not alone (see Rick above).
I believe it is an issue of differential compression -
Suppose we have a block that measures 2"x2"x2", and try to compress it.
The block will compress less when the force is applied to the end grain.
I suspect that then you are cutting the end grain mortise, the forces of each cut (yes, they are happening fast, but they are really a series of individual cuts) compresses the stock more than when cutting into the cross grain. After each cut, and the compression it causes, the wood springs back to its original position. Because of that differential, the end grain mortise is smaller than the cross grain mortise, even though they are cut with the same setup.
These things are hard to describe. I hope that what I've written makes some sense.
That could could have some validity, except that those using the Multi- router find that to be untrue. Same exact approach to the application except the difference in the jig. If they don't squeeze up on the Multi-router (read: tank-like jig) then I am thinking as mentioned above it could actually have to do with the cutting itself.
It isn't a hard stretch to think that (especially a mortise cut with a router) would deflect away from one side or another. And if you clean up the middle as you go, the bit might lean a thousandth or two towards the empty area, away from the solid sides. Remember, if it only leaned ONE thousandth in on each side, that would make it two thousandths in aggregate, and that would make a really snug fit.
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