Floating Tenon Problem

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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.
Why is this? Is this a common problem?
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"Garage_Woodworks" wrote:
> When I make floating tenons the tenon stock is always more tight fitting in

Don't have a clue, but why sweat it.<G>
Plane stock for each tenon application and move on.
Lew
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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.
Odd, to be sure.
Let us know what you figure out.
Joe
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Garage_Woodworks wrote:

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.
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Garage_Woodworks wrote:

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.
Rick http://www.thunderworksinc.com

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I was beginning to think it was me. Looks like I need to invest in a 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.
Thanks.
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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.

I like your website, Rick. I checked out your audio cabinet, and it is really a nice piece of work. I particularly liked the use of the box joints under the top to mimic dentils. Your idea?
Liked that Lone Star cabin-ette, too.
Great work.
Robert
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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:
http://www.e-woodshop.net/images/MSS3.jpg
... 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.
http://www.e-woodshop.net/images/MSB7.JPG
Great way to make a case that should "stand the test of time" for these types of applications.
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OK, with these eyes, I can see some joint detailing on the corners. 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.

Again, the details make the deal. I don't think you should hide your 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?
Robert
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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. <g>
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:
http://www.lawrence-mcfadden.com/stain.php
... 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!
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I can never find my scissors. That's why I use colored masking tape that has a dovetail and pin patterns alternately punched onto it. I can have perfect dovetails in minutes! And it comes in four popular colors, too!
Some say it looks like the old fashioned shelf paper, but hey... who's looking that close!

I was only familiar in passing with the case build method, and was really interested in what you were doing. In the end, the finish product is beautiful. No kidding, beautiful.
But... as an aside, if the big one gets dropped when I am in Houston I'll race you for a spot inside! ;^)
Since I was brought up in the carpentry trades, I have difficulty getting off the path sometimes. I am a carcass builder, tried and true. I don't have any problems learning something new and enjoy doing it most of the time, but "the time" is a problem. I just can't learn it all, but that doesn't quell my interest.
Outside of a magazine or book, I didn't see any one else pursuing that method of construction when you started on your project, and haven't seen any mention of it since.

?
Prototype? More coming soon?

So will you go to 1/2" and use the interiors to keep it all straight and square, or will you use 3/4"? Sitting here thinking about it, I guess the skin would make the difference as the 3/4" seems to have as much movement as the 1/2" anymore.

Hmm... I would never have thought to buy anything like that from Rockler. I have had good luck with their products, but never looked at finishing materials. I would swear from that picture you used some toner, though. No one colorant will get what I think I am seeing.

Tried and true for too many years to count. Good old bug spit.

Surely you jest....
3# Zinsser (off the shelf) cut 30% with anhydrous alcohol shoots a glassy finish that will make you wonder how you got so good. Use the 1.4mm aircap with the air control about 1/3 to 1/2 open, the flow control at about 2/3 open, and the aircap shooting in the vertical position. Adjust the flow and air until joy arrives.
Hold the gun a perfect 10" (maybe 12) off the surface (the convergence point of the airstream and material reach perfection between those numbers) and you are there, dude.
Seriously, if you are confident with a high pressure sprayer, you are well on your way. Even a CAS gun is a great choice. Think of it this way, the more material that goes on your project, the less is in the air.
The industry says it breaks down like this:
Rattle can: about 20% material on target
High pressure: about 30% to 35%, depending on material used
CAS (conversion compressor powered guns): about 60% to 65% material on target
True, single purpose turbine powered HVLP: Well... they lie. Manufacturers say they get as much as 90% product on target, but I don't think so. Maybe if they unhooked the gun and poured it out of the cup. I think a good number based on the amount of drift we clean up would be about 80% to 85% (these are just guesses).
I came up with the HVLP number with a friend of mine after we decided to calculate the amount of product it took to get a 3 mil finish coat on smooth wood. We actually measured the material, took out the thinner, etc. to get that.
I don't know why, (maybe others can chime in here) but the older finishes seem to like the CAS guns better than the HVLP gun. I am guessing it is because they were designed for the old high pressure formulas. Those were the days of metals in the paints, and using VPMT and Japan drier in the formula.
You had to have a pretty good idea of what you were doing. I made a painful mess of some finishes before I got the hang of that stuff. You do learn quickly though to mind every detail, as there is no such thing as a touch up on a sprayed oil finish. Touchup on oil based is actually called "refinishing" or "topcoating".
But you know, when finishing metal doors, I still go down and get that stuff and mix it up and shoot it with my CAS gun. A good oil finish blended with some "stuff" will dry extremely hard, abrasive and solvent resistant. Nothing else will do that right off the gun.
But today's finishes are a different breed, and they are all made to be spray friendly/compatible, if not spray only/recommended. And they are formulated for easy use in HVLP. Look at Barry; what could be easier than taking off the can lid, swirling the finish around and loading the gun? With a 4 stage, no thinning needed. I can shoot my conversion lacquer out of the can as well with no thinning, I don't though. (I am not trying to downplay Barry's skills, just make a point about the actual finish itself.)
Actually, it was at the Houston woodworking show where I met you and Leon that I tested the Turbinaire and sprayed unthinned latex enamel. That was the end for me, I knew I was going to jump in. I just didn't know which machine.
I don't want to diminish the fact there is a curve to learning HVLP, but it is NOTHING like learning high pressure guns shooting oils. If you are already used to thinning, mixing and shooting, you may already be on the road to another tool purchase.
However: fear not. Festool does not make a HVLP system yet. (Whew..!) But I'll bet if you talk nice to Leon he will paint some Gremlin green stripes on whatever system you buy. ;^)
Just funnin' Leon.
Robert
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<snip>
I was being facetious OK, but about the gel stain, Robert! :)

Yep, that's exactly the shellac cut I shoot with my little el cheapo HVLP rig from the BORG.
On that note, I've saved every post that you and Mike Marlow have posted the last few years on spraying but have never had a rig good enough to put most of the info into practice ... one of these days.
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I didn't actually think you were going to run out and buy a new system... but you never know!
The stains that have won my loyalty over the last few years are the Old Masters gel stains. They seem to have just the right consistency, just the right amount of pigment, and their colors are really good. You can use them as toners as well as stain. They stick to everything, and when I was doing a lot of door finishing for a company here, I even used them to color fiberglass doors.

AHA! And here I thought you were a high pressure man.

Wow... that's pretty flattering. Seriously.
I think that exchanging ideas with Mike and Barry (and everyone else as well) are a great way to stimulate the brain to learn other things you didn't know about what you do. The internet has given us all a marvelous opportunity to take a look at just how others do things, in detail.
I have been really pleased to see someone like Charlie Belden ( charlieb ) come along that is a worse wonk than I am. When I get going on something, I have to know everything I can to speed the learning curve along. I don't mind sharing what I find, and sometimes typing it all out helps me define my thoughts. I like the stimulation of helping others, as well.
Like I have said before, I got into finishing by accident/necessity. It was imperative that I hit the ground running. I had NO idea that it could be as interesting or challenging as it is to be a really good finisher. There are just so many aspects of finishes, materials, etc., that there literally is no end. And like woodworking, since there is no end to the learning, and that is a very good thing.
I might add here too, that you have been very generous with you own time to just about everyone. And certainly the website you have put up has been a really valuable tool as to how things are done to a lot of us.
A tip of the hat to you as well.
Robert
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You say you shooting shellac now...
With what ???
Swingman wrote:

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snipped-for-privacy@aol.com wrote:

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.

Thank you very much. Rick
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"Rick" wrote

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.
Leon?
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"Swingman" wrote

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.

factor as well.
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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.
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I test fit the tenon stock the same day it was made. The mortises are cut on the same day, but earlier (day before) than the tenon stock.

In your case it could be the tenon expanding. My tenon stock fits one mortise well, but not the other.

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the results are.
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