Windsor Chair Resources

Windsor chairmaking tips-tools

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 TAPERED/NON-TAPERED MORTISES

Has anyone tried using non-tapered mortises in the seats to receive the legs? In my first chair I was able to drill the 5/8 inch holes accurately but when I taper reamed them I ran off. I was thinking about drilling 7/8 inch holes and not reaming them . I'm not so much concerned about shrinking and loosening of the legs but I'm more concerned about being able to assemble the legs and stetchers without having the tapered holes to facilitate getting the legs to enter the seat. I'd hate to turn the legs with straight tenons and then find out I couldn't assemble them into the straight mortises. K. 2/22/01

Reply: It is easier assembling a chair with tapered legs. Though I made a few chairs early on with straight tenons and don't recall having any real problem getting them together. I still make windsor candlestands and tables this way. I don't believe straight tenons makes as strong a chair, but it may well be strong enough. Looking at old chairs should make it obvious the the shrinkage problem can't be completely discounted, I make sure my legs are throughly dried. One of the main reasons I use tapered socket is the ability to fine tune the leg angles. Which seems to be the opposite of your experience. If I were you I'd try a few chairs and see what you think. JT 2/25/01

Reply: Do yourself a favor and get some practice with the reamer. Your chair will stand the test of time; if you want the quality chair you get with straight sockets as opposed to tapered, why not just head down to Ikea?  There is no replacement for a locking tapered leg and socket joint which is wedged. I do know about you, but I want the chairs I make to hold together for 100 years or more; without the taper there is not a chance. PB 2/26/01

Reply: I have used both tapered and straight tenons. I do not use the 7/8" as often as the 3/4" straight tenon. After more than 25 chairs dated 20 years or older, I have not seen failures in the seat tenons like I have in the stretchers.

Note: I conducted a test to see how much the tapered tenon and the straight tenon legs spread when a 250 pound weight was placed on the seat without stretchers in place. The difference was not measurable. The bad news for both tenons is the surface the legs rest on. Chairs that live on carpet will have much less spread than those on wood(varnished) floors and the worst is linoleum. Here lies the biggest trouble for longevity and chairs in the 21 century(lack of surface friction).

Straight tenons: Once you have fitted the legs, cut off most of the excess tenon (leaving a 1/4") and chamfer the edge of the tenon (prevents tear out). This will help when you fit the stretchers and drive the legs in from the bottom. I put tension on my stretchers as I assume most builders do as well. Make sure you turn a good shoulder at the base of the tenon and house the shoulder to fit the bottom of the seat much like the tapered entry. This will help the tenon a great deal.

Additionally, I have found the straight tenon gains more even expansion from the straight edged wedge than the tapered tenon. I can only get a 5/8" wedge and a little in the tenon from the top of my tapered tenons. Its a tough call. I think either tenon will do a good job if you fit them carefully. D.O. 2/27/01

Reply:With regard to the amount of wedge (5/8?) that you can get into the tapered leg. The integrity of the tapered joint is do to several factors; the lock gained by the taper itself, the glue, the self tightening nature of the joint (each time the chair is sat in), the spreading of the leg in the taper by the wedge, and the "keying" effect of a properly sized wedge.

The wedge needs to be wider than the diameter of the leg it is driven into; so it extends beyond the diameter of the leg. When the wedge is driven into the leg it partially penetrates the seat; the wedge is now "keyed" into the seat. If the leg cannot rotate the "lock" created by the tapered joint is less likely to be broken. I like to use a wedge approximately one (1) inch wide which may be overkill but I think you get the idea. PB 2/27/01

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