I am considering building a door in which the design is for each rail to be joined to the stiles using floating tenons. Just wondering if I should modify the design and cut the rails about 4″ longer to allow for milling a 2″ tenon at each end.
Is there a benefit for using floating tenons?
Greg
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Replies
In one way, floating tenons are supposed to be easier and faster than contiguous tenons. You don't have to be fussy about cutting the tenon shoulders square; just get an accurate square crosscut and you have the foundation for the joint's strength. But the substantial downside, if you've never done one, is that you need ot mortise into both parts.
On a door it will be critical to line up the mortises so the frame will be flush, so a jig would be useful. I guess some of us would say that aligning two mortises with the same tool setup is easier than aligning a tenon into a mortise. It's a matter of what you're used to.
If you can get a hold of Gregory Paolini's A Classic Case article from FWW Sept/Oct 2005, pp 32-37, there is an adequate treatment of floating tenons.
Personally, I prefer the old fashioned tenon. I find it easier to cut a tenon than a mortise, and easier to mortise into a part's side than its end. However, I am planning to make Paolini's case, and I'm going to use the project to get some more practice with the floating tenon technique. I've already made the jig to cut the mortises. Because this case's rails are recessed into the legs, aligning the mortises is not a serious concern.
Greg,
I think in almost any kind of furniture there is no difference in the performance of floating tenon construction vs standard M&T. That is, it's impossible to stress the joints enough to reveal the slight additional strength that a M&T MIGHT have IF it is made with very high precision.
In a scientific test, though a correctly made M&T joint will probably always show some higher degree of integrity.
And it's in door construction that the most stress is placed on the joinery and where potentially weak joints are going to fail. In fact, for heavy doors, just M&T construction is not enough, and the variant, haunched M&T gives better results.
But it all depends on the type of door you are making. Is it a heavy door for an entry way or for a small cabinet?
Rich
Entry way. Pretty heavy door when made from solid wood.I saw a Woodworks show last night and David Marks was building an entryway door our of Jarrah I think. He used floating tenons. But then he seems to be the king of floating tenons with his multi-router.Alignment of the traditional M&T or mortise & floating tenon is not an issue.Does a haunch really add much strength to the joint? I thought the haunch was just to fill the space created by the dados for the panel.Greg
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Greg,The haunch provides a solution to the fact that in a M&T joint of the kind you will need, the correct proportions and placement of the tenon on the end of the rails to maximize strength leaves too much unglued and unsupported wood above the tenon. This is very hard to describe or visualize without pictures. And I can't supply any this morning, but I'll try to scan a few in later.The very best resource for this information is Taunton's, "Fine Woodworking on Joinery." Get a copy and you will have information on every aspect of M&T construction, especially as it relates to doors.This book contains priceless information by masters. It is truly a treasure. It's profusely illustrated. All its articles appeared in FWW issues, some from the first few.There is an article by Ian Kirby, "The Haunched Mortise and Tenon." Another, "Locking the Joint, Tenons tusked, draw-pegged or wedged will hold without glue." And, "The Frame and Panel, Ancient system still offers infinite possibilities.""Entry Doors, Frame-and-panel construction is sturdy, handsome," by Ben Davies is indispensable.Tage Frid shows, "The Right Way to Hang a (very heavy) Door." He also has many more articles in there.Solid wood doors are covered and much more. And while you're at it, I recommend "Boxes, Carcases and Drawers," for related information.I'd like to see pictures of your doors when you're done.I have a project which I won't be able to start for about 6 months - a wall of "French Doors." There will be 3 pairs of doors. They are 9 feet high, spanning about 22 feet. Each one, a simple frame, no middle rail, with a single, large panel of double-glazed glass. I hope to post images when I'm done.Rich
Edited 7/3/2008 10:57 am ET by Rich14
Rich,Thanks for the detailed reply. I will look up those articles over the weekend.GregGreg
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Rich is right about haunches. If your door is framed up with square edges, then the haunch also provides another seal/surface for glue adhesion. I'm a fan of mortise and tenon. Particularly cope and stick mortise and tenon. The glue surface is much higher with cope and stick, and the joints are superior when teamed with the M & T. A thing of beauty. As for the loose tenon, you will have twice as many joints to make (half of which will be in end grain), and if joint failure is a concern, twice as many opportunities for such failure. Forming the tenon on the ends of the rails is historically easier than making a mortise, so economy dictated things evolve the way they did. Dave S
http://www.acornwoodworks.com
In my small shop I find it easier to make cope and stick doors (entry or passage) with floating tenons or dowels as my shaper is not big enough to push a cutter stack which can create an integral tenon and cope cut in one operation. I would not use dowels for exterior work, generally only for passage doors.
Cinc,To add to what has been said before, a haunch does provide additional long grain gluing area, and thus strength to an M&T. This may or may not be important depending on the application- often it is not. It might be helpful in a place where a double tenon might be required- these are more work, and a bit fussier to make. If you make a single tenon too large, you can end up with problems with wood movement.For a large entry way door, a haunch provides additional benefit: it helps to prevent warping and racking. Such a door is supported by its hinges at points, and the weight of the door and the forces on it- particularly opening and closing- can twist it out of plane. Haunches help to keep the rails and stiles in register better than a non-haunched M&T would, and better than a floating tenon would. The frame of the door is really the skeleton that supports the whole business- the panels contribute an anti-racking effect, but frame is not unlike the frame of a car in its importance to structural integrity. If you dry fit a floating tenon and then attempt to twist the rail and stile, you see right away what I mean.For a small (cabinet) door, haunches are probably not necessary, but for a heavy entry door, I'd use 'em.Glaucon
If you don't think too good, then don't think too much...
I have been building doors for years using loose tenons. Most of the time I make the mortises about 4" deep and 3/8" wide/ I use a double row of tenons that are not more 2.5" wide. That width and a double row gives a lot of glue surface area. When using rounded loose tenons it allows me to make tenons and then round the edges easily. If I made the stiles longer then it would be harder to deal with the tenons.
Greg,
Another consideration - What material are you using for the rails and stiles? Solid wood? An "engineered" sandwich of internal plies and face veneer skins?
Are you familiar with "stave core" construction?
Rich
The rails and stiles of the garden gate will be made from Spanish Red Cedar.I am undecided about the choice of wood for the exterior door. I am thinking Oak or Mahogany. One of my wood suppliers recently told me about Eucalyptus, but I know nothing about price or availability.10 years ago, I built one interior frame and panel door. That is the extent of my door-making experience.I have never heard of "stave core" construction. I will look it up. What can you tell me about it?Greg
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Greg,If made from solid wood, it is very difficult, if not impossible to keep the stiles and rails of a large door from moving in one or more dimensions, resulting in twisting and deforming of the door so that it no longer lies in a flat plane. It doesn't take much twist so that opposite corners are unacceptably misaligned and the door won't close, or it actually becomes visual apparent, sometimes to a great extent.Using plywood would help, but that's not the answer in a high-quality door.Stave core construction has been used for a very long time to produce a stable sandwich of materials to use for the stiles and rails. It's essentially an "engineered" wood product.Staves are glued up so that their vertical grain is in the direction of the thickness of the door, as is the edge banding. The whole construction is covered by face veneer of about 1/4" thickness. The staves are typically lower quality hardwood, or even softwood while the face veneer and edge banding is the "show" wood of the door.See the attached PDF and do a Google search for "stave core" or "stave core door." Stave core products can be bought from commercial suppliers, or constructed yourself, if you have the facility to do the glue up for required length of stile pieces.Rich
Is there a benefit for using floating tenons?
I do both kinds. I use mostly routers so I usually have 'floaters' Especially if I forget to glue em'..
As one time I made custom doors for very old houses. Big mistake.. I hardly come out ahead. However most had router cut floating tenons. NOBODY EVER called me saying the door fell apart. Usually just a finish problem...
In the entry doors I make, I typically run out the cope and stick joints with a shaper. Then I make the mortises 4" deep in both the stiles and rails. I would find it very hard to make tenons 4" long with rounded edges on a piece of tenon of the end of a piece of wood. That is the reason I use loose tenons. I use a double row of tenons and mortises that that 3/8" wide and 4" deep. That give me twice the gluing area of one piece of wood used to make the tenon. To make loose tenons with rounded edges I use a shaper or router table to round the edges. Using loose tenons allows one to make full use of the wood especially if there is a likelihood of a shortage of length.
"Then I make the mortises 4" deep in both the stiles and rails. I would find it very hard to make tenons 4" long with rounded edges on a piece of tenon"
As a matter of interest: what are you using to make these 4 inch deep mortices?Philip Marcou
I use longer and longer 4 flute end mills then I drill the ends of the mortises and use long end mills to clean out the middle section. I have also used long drills that I have changed the point on them to a flatter cut on the end instead of a V point. They are more aggressive than an endmill. Because the mortise is deeper it seems to not present and problem.
That all sounds like a real fuss. To the best of my knowledge a "long " series four flute end mill of around 1/2" diameter is 3.75 inches long overall.
So are you doing this in all cases: what if you need to make a number of house doors? (At the barest minimum this would mean at least 10 mortices per door for rails and muntins).??
And what machine are you using for this?Philip Marcou
Edited 7/5/2008 11:42 pm by philip
I get my end mills from MSC Industrial supply. The stock them up to 6" in overall length. If I use a 3/8" mortise I will make a total of 40 mortises and make 20 tenons. I use a machine I made using an old horizontal mill that was modified to accept a horizontal mandrel on top that I spin at about 4000 RPM. I am able to move the work on a horizontal table. The machine allows me to drill holes and mortise.
Edited 7/6/2008 1:48 am by gb93433
G, I thought you may be doing something like that , in the absence of a reciprocating head morticer or fixed head slot morticer with moving table. Please let us see a picture of your machine.Philip Marcou
I do not have a picture of it at this time. All of my machinery is in storage at the moment. It is quite similar to the mortising machines at http://www.crfinefurniture.com/1pages/shopinfo/mortisers.html
I did a new front door a while back out of walnut and used floating tenons. One of the advantages is that it saved 5" in length for the horizontal sections of the doors. If your working with solid wood that can actually save some money. I figured I saved about 2 board feet of wood. The door turned out ok and still works well so I think it is a way to go.
Troy
i just built a cherry interior door with loose tenons after i had the rails and stiles glued up i drilled 1/4 inch holes in the end grain of the stiles approx 3 inches deep so that the holes also went into the loose tenon and blew glue into the holes with my compressor and drove in 1/4 inch dowels you will never see the dowels because they will be at the top and bottom of the door after it is hung
For all that, might just as well drawbored them...http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=smalser&file=articles_608.shtmlGlaucon
If you don't think too good, then don't think too much...
Glaucon, Thanks for that link. Very helpful .
why would i need to do that the joint is allready clamped tight it would not need to be drawn together and i dont want to see the dowel on the face of the door, i put the dowels in to help streghthen the loose tenon joint
Interesting. I don't recall ever seeing that joint strengthened like that. You mention blowing glue into the tenon with an Air Compressor. Is this because the tenon was not correctly fitted into the mortise, or not properly glued and you are attempting to get glue around the tenon? Or are you just wanting to get glue completely in the dowel hole before pinning it?BTW, I'm assuming you're pining the loose tenons in both the rails and the stiles. If the tenon fails, won't the dowel tend to split the long fibers of the stiles?Greg
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