Jasahan Posted March 13, 2012 Report Share Posted March 13, 2012 I am building "farmhouse chairs" for a cafe. So they will get lots of use. I don't have plans, just a picture of a chair we like. I found some plans for a farmhouse chair that used pocket screws to join the bracing. I'm wondering if mortise and tenon joinery would last longer. Anyone know? Quote Link to comment Share on other sites More sharing options...
TheOneHandedHandyMan Posted March 13, 2012 Report Share Posted March 13, 2012 I would bet that 99% of people here would highly advise you to use M&T. It is worth the time in the long run. Pocket screws are great, but you don't want to mess around with weight bearing structures. Quote Link to comment Share on other sites More sharing options...
tdale51@yahoo.com Posted March 13, 2012 Report Share Posted March 13, 2012 mortise and tenon jointery is much stronger than pocket holes. Wood magazine did an experiment on the strength of different joints a couple years ago. I'll have to go through my back issues to see if I can find it. I don't remember the exact numbers but I think it was in the neighborhood of 10 times stronger than pocket holes. Quote Link to comment Share on other sites More sharing options...
ddg Posted March 13, 2012 Report Share Posted March 13, 2012 Fine Woodworking tested joint strength by making up various joints using two pieces of stock 2-1/2" wide, 8" long, and 3/4" thick. Their results for breaking show: 3/8" M&T - 1444 lbs 5/16" M&T - 988 lbs 1/4" M&T - 717 lbs pocket screws - 698 lbs Domino (1) - 597 lbs I have not seen any studies showing joint strength over time. Quote Link to comment Share on other sites More sharing options...
CessnaPilotBarry Posted March 13, 2012 Report Share Posted March 13, 2012 On chairs, I join the M&T choir. Quote Link to comment Share on other sites More sharing options...
dwacker Posted March 13, 2012 Report Share Posted March 13, 2012 Depends on the design. Some do fine with screws some need M&T. Got pictures? Don Quote Link to comment Share on other sites More sharing options...
STL Woodguy Posted March 13, 2012 Report Share Posted March 13, 2012 Fine Woodworking tested joint strength by making up various joints using two pieces of stock 2-1/2" wide, 8" long, and 3/4" thick. Their results for breaking show: 3/8" M&T - 1444 lbs 5/16" M&T - 988 lbs 1/4" M&T - 717 lbs pocket screws - 698 lbs Domino (1) - 597 lbs Interesting, especially on the Domino, as they're trumpeted to be much stronger (than biscuits). However, would stand to reason that multiple Dominos would better support the weight, no? Quote Link to comment Share on other sites More sharing options...
Jasahan Posted March 13, 2012 Author Report Share Posted March 13, 2012 Thank you all so much. Mortise and tenon it is! Quote Link to comment Share on other sites More sharing options...
dwacker Posted March 13, 2012 Report Share Posted March 13, 2012 Interesting, especially on the Domino, as they're trumpeted to be much stronger (than biscuits). However, would stand to reason that multiple Dominos would better support the weight, no? The domino is a floating mortise and tenon. Comparing them to biscuits is an apples to oranges comparison. These test have been done for years and the results have always swayed toward the side of the standard M&T or to the side of what ever the tester was bias to. Every joint has its place and there is no one joint for everything. A domino or floating tenon is every bit as good as an equal sized standard mortise and tenon. European furniture makers have used floating mortise and tenons for many decades. They are just somewhat new to the US with the sudden influx of domino users, but are really no different than horizontal mortisers found pro furniture shops across both US and Europe. There are many that swore by dowels like Sam Maloof. I think you need to look at the design and use the appropriate joint for the job rather than picking a joint based on a magazine strength test. Don Quote Link to comment Share on other sites More sharing options...
ddg Posted March 13, 2012 Report Share Posted March 13, 2012 I didn't go back and read the whole article again to get the tone, so I don't know if there was a favorite before they started the FWW study: A few others of interest were: Higest - half lap - 1603 lbs My surprise - miter - 1374 lbs They said this number is expected to go down over time with seasonal movement. Beadlock - 836 lbs 3/8" dowels (3) - 759 lbs biscuit - 545 lbs Lowest - stub tenon - 200 lbs (less than half of a butt joint - 473 lbs, another one that would go down over time with seasonal movement) Quote Link to comment Share on other sites More sharing options...
rodger. Posted March 14, 2012 Report Share Posted March 14, 2012 M & T is really your best option. Pocket screws are great for face frames, and a few other tasks, but when it comes to Uncle Joe leaning back on a chair after X-mas dinner, I don't want a few screws to be the only thing separating him from the floor! Quote Link to comment Share on other sites More sharing options...
rodger. Posted March 14, 2012 Report Share Posted March 14, 2012 My surprise - miter - 1374 lbs They said this number is expected to go down over time with seasonal movement. The author said there was an issue with this. Something with the way the pressure was applied to the joint artifically exagerrated the mitre's strength. Most of us can snap a mitre joint (without re-inforcement) with our bare hands. Quote Link to comment Share on other sites More sharing options...
STL Woodguy Posted March 14, 2012 Report Share Posted March 14, 2012 The domino is a floating mortise and tenon. Comparing them to biscuits is an apples to oranges comparison. Right, I do understand the domino is a floating tenon (been wanting a Festool Domino, but more want than need right now). Just scratching my head on how/why it doesn't appear much stronger than a biscuit, and not up there with the traditional M&T. Although with that miter joint thrown in (and it's stated issue), that makes things a little suspect too. Quote Link to comment Share on other sites More sharing options...
dwacker Posted March 14, 2012 Report Share Posted March 14, 2012 Right, I do understand the domino is a floating tenon (been wanting a Festool Domino, but more want than need right now). Just scratching my head on how/why it doesn't appear much stronger than a biscuit, and not up there with the traditional M&T. Although with that miter joint thrown in (and it's stated issue), that makes things a little suspect too. Its just a comparison I wouldnt put much thought into it. Just board writers that cant come up with something better to write about. Alot of it is just plain common sense. You cant compare a tiny domino to to a M&T three or four times its size. A dowel is nothing more than a round loose M&T but its a waste of time comparing them to a standard M&T many times its size. Jumping into the M&T bandwagon without knowing the design and selecting the proper or adequate joint is just as much a waste of time. There are plenty of areas in many chair designs that would lend themselves well to pocket screws and others that should have some sort of M&T be it traditional floating or dowel. The design and use dictate the joint, limiting yourself to a single joint only limits your work. Take a look at the dowelmax strength test http://www.dowelmax....ntstrength.html These debates and test are about as useful as the sawstop conversations. Don Quote Link to comment Share on other sites More sharing options...
wdwerker Posted March 15, 2012 Report Share Posted March 15, 2012 I think the domino in the test was small and only 1 domino in the joint. I started making my own wider and widest domino stock which lets me control the size and fit. Quote Link to comment Share on other sites More sharing options...
Jasahan Posted March 21, 2012 Author Report Share Posted March 21, 2012 So first, i should say I've only been working with wood for about two years, most of that being really basic stuff. My only real experience with mortise and tenon joinery was a set of five stools I made a few months ago, and a coffee table and two end tables. I don't own the stools, so I don't know how they've been holding up. I'm wondering what an appropriate size for the mortise and tenon would be for these chairs. I'm going to use 2x2 (actual size) for the legs, and likely also for the stretchers going from front legs to back legs, creating the frame of the seat. I'm doing that because we make all our stuff from recycled pallets, and we have WAY more 2x material than 1x. Should the mortises be centered? What is a good range of sizes for the mortise and tenon? The pallets are all hardwood, and mostly oak. Quote Link to comment Share on other sites More sharing options...
williaty Posted March 22, 2012 Report Share Posted March 22, 2012 Right, I do understand the domino is a floating tenon (been wanting a Festool Domino, but more want than need right now). Just scratching my head on how/why it doesn't appear much stronger than a biscuit, and not up there with the traditional M&T. Although with that miter joint thrown in (and it's stated issue), that makes things a little suspect too. I own a Domino and like it a lot, so I'm not a hater bashing it. There's a lot of ways to make a bad joint with a Domino. It's a high precision machine. Use it right, and the results are very strong. Fiddle with something a bit wrong and you can make a very poor joint. First and most obvious is just making sure the size of the dominos used and the total number of them is apropreate for the work. Second, you need to work precisely enough to use the "no slop" mortise widths. You can make your life easier by selecting one of the two "sloppy fit" settings. Obviously, this massively reduces strength. Quote Link to comment Share on other sites More sharing options...
SomeGuyNamedPaul Posted March 23, 2012 Report Share Posted March 23, 2012 Another screw in the coffin for pocket screws http://woodgears.ca/joint_strength/index.html Quote Link to comment Share on other sites More sharing options...
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