I am in the process of starting to build some chairs using Pine (the customers preference, not mine) and it has been awhile since I built these types of joints but expect to be using this type of joint heavily in the future.   I would like some advice from some of the experts on this type of joint about the relationship between the size of the tenon and mortise to allow for any expansion and the addition of the glue.  My tenons are ¼” x ¾” with a depth of ¾”.  How much larger should the mortise be?  I have seen in some places where the difference should be 1/16” on and sides and the depth.

 

I am a long way from an expert, but I have always tried to make the joints as tight as possible. The most of the expansion that you should have would be in the length of the piece. Some of the real experts should be along shortly to set us both right.

I am far from knowledgeable about this joint but would`t the size of your wood dictate the size of the joint ? In other words larger structural wood , larger joint , just asking ?

I'm not a pro, but the mortices and tenons I've done have always been snug fitting. You don't want to have to hammer the joints together. They should be able to fit by squeezing the pieces together with your hands and possibly light tapping with a mallet. Loose fitting joints depend heavily on glue to fill voids and hold them together. I'm with you in the wood selection. I would definitely prefer a hardwood over pine.

Jim, have made some small table and chairs out of pine. Don't recomend it, they don't hold up well, tend to split out no matter what type of joint. Would strongly suggest a stronger wood, that will take the ware and tear that chairs get.IMO..... But what ever the customer wants.
THOMAS(handy)

I would have to agree with all the above. When I made the night stands I made the tenon 1/3 the thickness of the piece. Since I was using 3/4" oak, that means the shoulders were 1/4" and the tenon was 1/4". The mortise I cut I made about 1/8" deeper than the tenon to allow for glue and expansion. http://www.handymanclub.com/forums/...fnp/254979

Where are these joints at?



From that point on - we can help you a lot based upon our experiences.

It all depends where these are.  Leg to seat base?  Back to seat base?  Arm to back - or maybe even the arm to seat?

Where?

The joints are in chairs, back slats to back legs, slats for attaching the seat to, and slats between legs as braces.   In other words all of the chair parts other than the seat are connected with M & T joints.v

This is Jim again to clarify, the 1/4" x 3/4" x 3/4" are the back slats to back legs. They don't have to be as strong as the ones for the seats because they don't have weigh bearning down on them.

The tenons should fit snugly into the mortise. To allow for glue the mortise should be only slightly deeper about 1/16"  to 1/8" than the length of the tenon.

Where did the idea come from that pine will not hold up ?? I made a pine rocker almost 50 years ago and it is still fine -- whaddahey nothing will hold up if you beat the crap out of it ! One nice thing about pine if it does start to show some wear it only looks rustic as opposed to worn. I will say with pine I prefer hardwood dowels instead of small mortises. As you can guess I am not an "expert" so excuse me but what I have made in the past is still around.

Posted By Horace Puckey on 08-30-2011 10:43 AM
Where did the idea come from that pine will not hold up ?? I made a pine rocker almost 50 years ago and it is still fine -- whaddahey nothing will hold up if you beat the crap out of it ! One nice thing about pine if it does start to show some wear it only looks rustic as opposed to worn. I will say with pine I prefer hardwood dowels instead of small mortises. As you can guess I am not an "expert" so excuse me but what I have made in the past is still around.

Bill!  Jelly beans, man.  Jelly beans.  One handful should ease ya up.

Pine is a strong wood.  Afterall, it's the dominant choice of lumber in framing our homes and is the substrate in many pieces of furniture with a stiucker/decal on it to make it appear to be cherry, rosewood, or whatever.

The problem with pine is that most folks have been brainwashed/brain damaged into thinking that finished furniture must be made from oak, maple, mahogany, cherry, walnut, etc.

I am right with you Bill and Craig. There is a whole lot of expensive furniture out there that is pine stained and veneered to look like something that it is not--meaning pine.

I was always told that M & T joints were "NO LESS THAN 1/3" ....
I try to make the sholder as small as possible, leaving 1/3rd or more for the tongue (more is better)

Pine is by far the most popular wood for furniture. You just need to select the pieces properly, watching out for knots, cracks, etc.



eeyore

I think we could discuss the preference of hardwoods over pine for ever but I believe that pine is a relatively good wood to build with, not great but good.  I personally prefer one of the hardwoods but sometimes we are forced to make a choice based on the financial aspect of a situation.  My customer decided on the cheaper route.  They will be  used strictly indoors away from the elements.  When I was in high school I made a complete bedroom suit using Birds-eye maple.  That was in 1954 ( I’m telling my age) and I sold that it for $500.00 in 2006 when I sold my parents home and furniture.  There were no nails used, only screws for hinges, dowels and a lot of glue, clear varnish and 5 coats of lacquer.  It was still rock solid when I sold it.

Call me brainwashed - or brain damaged if ya want.... it may just be true... LOL

EZ, What about "Putz"?

One thing you will find with pine or any other soft wood furniture, in order to last, grain orientation and selection is key. I'll have to agree with EZ's last post, although many fine antique chair designs were built of pine, the way they are constructed is key, and hardwoods such as oak, will wear and stand up longer with fewer parts.