Mortising Question

[Joe Tilson]

For years I have used half laps for my corners when building frames for cabinets. I also use them for table bracing and such. I see a lot of talk about mortising here, but fail to see the practical use other than beauty. They are not very strong joints, but they are pretty to look at. A few years back Wood mag did study on the different types of joining, and they found half lap to be the strongest. Let me know what you think, please.
Thank you,
Joe

[Sean Hughto]

I think you are mistaken in claiming "they are not very strong joints."

[Joe Tilson]

Thanks Sean, I should have said not as strong. They are a strong joint.

[David Weaver]

I think the tests I've seen of common sized mortises show break pressure in the thousands of pounds, and often the wood instead of the joint.

At any rate, the biggest benefit of the M&T joint is that there is no endgrain showing. Half lap joints do work well, and if you're painting something, they can be fine.

M&T on a cabinet is much nicer to me, though, because the end grain is only on one end and can be hidden a lot more easily. End grain is a lot like back hair, some people are not afraid to show it, but it's offputting.

[Adam Cruea]

I'm just curious how a half-lap joint (at least in my understanding) has much strength at all.

Woodworker's Guild of America has M&T as one of the strongest joints, and lap joints being "meh".

http://www.wwgoa.com/woodworking-joints-which-ones-should-you-use/

[Adam Cruea]

M&T on a cabinet is much nicer to me, though, because the end grain is only on one end and can be hidden a lot more easily. End grain is a lot like back hair, some people are not afraid to show it, but it's offputting.

*snerk*

Dude, your comparisons are hilarious.

[Sean Hughto]

David, your fetishes are a hoot. I may try to to come up with a cabinet that is all end grain - butcher block style and oysters all around - heh heh.

[Sean Hughto]

As we are all mammals, we are all covered in hair - that is one of our defining characteristics. You just notice it more on some than others.

[Joe Tilson]

The thought I had, the tenon is very narrow, and the test at Wood showed that is the weakest point and it begins to break out fairly quick when pressure is applied.
David, You're a nut!:D I like that in a man.

[Prashun Patel]

Practically, half laps might not be appropriate when joining parts of different widths that you wish to still be centered.

Conversely, half laps might be preferred to M&T when joining narrow parts of equal thickness, such as picture frames, where a mortise of any consequence may result in two too-thin side walls.

The aesthetics of half laps or through mortises are debatable and particular to the design. Personally, I often like exposed joinery.

[Sean Hughto]

Indeed. Any joint that can hold together without glue - dovetail, tongue and groove, mortise and tenon - I would argue is superior to alternatives that rely on the glue. A mortise and tenon has significant advantages over half laps in that the shoulders and housed tenon allow the joint to mechanically - not just by glue shear strength - resist racking forces. A pinned mortise and tenon does not even really need glue. I wouldn't put much faith in a pinned half lap joint.

[Joe Tilson]

288931I strung these pics together. I just wanted to show David exposed end grain that is still beautiful. I checked my back hair(one) and it is still there.

[David Weaver]

As we are all mammals, we are all covered in hair - that is one of our defining characteristics. You just notice it more on some than others.

Right, some people have mission style back hair (those being the type who have no qualms about wearing a tank top in a public place and making others very wary about whether or not that person might bump into them and make some unwanted backhair to skin contact), and others cover theirs up as if they were woodworking in the 18th century.

As far as an all endgrain cabinet, I think I'm going to contact bausch and lomb and ask them if they can make a coating for glasses that's similar to polarizing lenses, except that it would work by refusing to allow any light reflecting off of end grain to the viewers eyes.

They could work on glasses that don't reflect light off of back hair in public places after that.

[Sean Hughto]

some people have mission style back hair (those being the type who have no qualms about wearing a tank top in a public place and making others very wary about whether or not that person might bump into them and make some unwanted backhair to skin contact)

I believe the psychoanalysts call this "reaction formation" - a defense mechanism to hide one's true feelings by behaving in the exact opposite manner. ;-)

[Noah Wagener]

Those guys always take off their shirts and post you up when playing basketball.

[Joe Tilson]

This sure changed in a hurry. Why don't we talk about David's back hair.
Thanks for the input. This got very informative in a hurry. I really have nothing against Mortise & Tenon, but have used half lap as taught by my grandfather who was a master carpenter. I really think a lot of both styles. Have a good day!

[paul cottingham]

M&T on a cabinet is much nicer to me, though, because the end grain is only on one end and can be hidden a lot more easily. End grain is a lot like back hair, some people are not afraid to show it, but it's offputting.

Thats good stuff, right there.

[Pedro Reyes]

I think I saw that study, and being a mechanical engineer I called bull on it. I am not sure how the pieces were stressed. Also I don't recall how the M&T was cut. When M&T have shoulders all around (not just sides) then the joint is very strong against stress in multiple directions.

If you cut a tight M&T with shoulders on all 4 sides, you will have a hard time making it fail by hand even without any glue, how much will a glueless half lap hold?

So what was the test really of? Quality of the glueline? I gather machines can probably cut a tighter half lap over a M&T, after all even if marginally cut, when you clamp the half lap you insure good glue contact, not guaranteed on M&T.

just my 2c and an attempt to steer the convo away from back hair.

/p

[Jim Koepke]

Living on the west end of the continent gets me to the conversation sometimes after it is all done.

I like half laps and use them a lot when appropriate. Appropriate is in the eye of the maker or the person for whom it is made.

Just like the face of a piece, the end grain can be made to be very attractive.

A well known quote from Robert Kennedy, "Hang a lantern on your problem," can remind us, often the best way to hide something is to put it right out in the open.

jtk

[David Weaver]

In this case, hanging a lantern in front of the problem so that the light would blind you from seeing it would be a good idea.

Friends don't let friends show endgrain (unless the furniture is intended for the shop or outside, then it's permissible).

[Judson Green]

In this case, hanging a lantern in front of the problem so that the light would blind you from seeing it would be a good idea.

Friends don't let friends show endgrain (unless the furniture is intended for the shop or outside, then it's permissible).

What about end grain flooring and real butcher blocks?

[Jim Koepke]

In this case, hanging a lantern in front of the problem so that the light would blind you from seeing it would be a good idea.

The idea is quite different. It is to bring the "problem" out into the light of day.

1/3 of the faces of a standard piece of wood is going to be end grain. I do not want to take pride in only 2/3 of the surfaces of my work.

Hopefully it doesn't make me any less respected in your eyes because of my feeling end grain can be proudly highlighted as opposed to being hidden.

One of the things I like about Greene & Greene work is the proud display of end grain.

jtk

[Pedro Reyes]

There is a design adage which says something to the effect of "if you can't hide it, flaunt it"

I for one, do not dislike endgrain, the endgrain police's (aka "The Dude") opinion nonwithstanding, I think that cleanly polished endgrain and even the transitional (as in curves between endgrain and long grain, are simply beautiful. Non polished endgrain is ugly, yes.

/p

[David Weaver]

What about end grain flooring and real butcher blocks?

I understand the functional reason for an end grain butcher's block that actually gets cut on - it's ideal for that. Not a fan of end grain flooring at all. I suppose there could be a durability claim for it, but on the oak and maple floors I've seen, any damage done to them would occur regardless of the orientation, and anything superficial is usually just finish damage.

[Pat Barry]

. End grain is a lot like back hair, some people are not afraid to show it, but it's offputting.

Wow. Why all the negative talk about end grain? Your comment and someone's tag line really make me wonder? I can see not liking it because its hard to work, but otherwise there can be quite a lot of character and interest in end grain. After all, who isn't fascinated to examine the growth rings on any old tree that gets cut down. That's where the story is.

[David Weaver]

I definitely like to look at the growth rings on a trunk of a tree.

I definitely don't like to look at them on furniture that's indoors that's supposed to be high quality, which means that I really despise mission furniture and greene and green furniture, and anything else of the sort that intentionally shows you joints and end grain.

Just a personal preference, it is bad design to me and it looks interrupted and coarse.

Have a look at this clock and find the end grain:
http://www.merrillsauction.com/media/1147

Or this chest of drawers:
http://www.1stdibs.com/furniture/storage-case-pieces/commodes-chests-of-drawers/tiger-maple-chippendale-chest-drawers/id-f_348940/

There have been a lot of furniture movements since then, but a lot of them were movements alright...perfect for double entendre.

I never thought much about this stuff until I started paying attention to people who have a keen sense of design, and then those things started to bother me. When I first started, I just wanted to show all of my work like everyone else, but good work hides quality secrets and doesn't let them interfere with the lines - at least in my opinion.

The japanese also have been very particular about keeping unsightly joints and end grain out of view on fine furniture.

I do let dovetails show sometimes....

.... like on the box holding my chisels in the shop, or on the quickie saw till that I put in my shop. They are dovetailed because I literally don't know of any other free joint that would've held as well. But if they were on something in my house, I'd have covered them with a moulding - it just looks 10 times better, even if you think something looks good without it, when you put the mouldings on to cover up the joints, you realize how much better it looks. Nobody else cares if you can do dovetails or through tenons, anyway, except maybe another budding amateur woodworker who hasn't yet looked at quality furniture without compromises.

[Steve Voigt]

If a half-lap got a Brazilian, would it be a mortise and tenon?

[Brian Holcombe]

This is why prescriptive advice does not work well without a particular situation in mind. I use the joinery I feel fits the situation best.

[Ryan Mooney]

This is why prescriptive advice does not work well without a particular situation in mind. I use the joinery I feel fits the situation best.

Hear Hear! The voice of reason.

[Pat Barry]

For years I have used half laps for my corners when building frames for cabinets. I also use them for table bracing and such. I see a lot of talk about mortising here, but fail to see the practical use other than beauty. They are not very strong joints, but they are pretty to look at. A few years back Wood mag did study on the different types of joining, and they found half lap to be the strongest. Let me know what you think, please.
Thank you,
Joe
A half lap joint can be very strong. They are though a bit deceptive. You think, oh I'll do half laps and then when you put it together you realize, hey I need more clamps. Not only do I have to pull the joint together at 90 degrees but I also need to clamp each joint vertically to get if to bond properly. Lets say you are doing a picture frame. With half laps you are going to need 8 clamps to pull all the joints together. With MT you can get by with 2.

[Joe Tilson]

How did we get back on subject? I thought we were talking about David's(aka the dude's) hairy back.

When to use a particular type of joint. From what I see here the choice and beauty is in the eye of the beholder, and that is what happens through each of these types of threads, is it not?

[David Weaver]

I guess I'd ask one question about the M&T being a weak joint, etc, in all of this talk about joints this or that, and youtube videos where people put weights on the ends of levers, etc, to get joints to fail...

... how many of us have ever actually had a joint fail in furniture, or even tools? I've never had any fail. None. No matter what type they are.

If they do, all of my joints have been made with hide glue in the last 3 or 5 years, unless I'm doing something that I don't intend to repair because it won't last that long (like kitchen cabinets) or some kind of shop jig. But even in furniture my parents have (that is sometimes 200 years old or so), the only thing I've seen legitimately broken is stuff in drawers. Someone literally separated the dovetails from a drawer side in one drawer, and, of course, drawers have been worn out or with the bottoms broken out.

But structural joint problems in anything other than abused chairs? Never.

Even so, planning to make joints that can be cleanly repaired is more important.

[Sean Hughto]

Joe, what is your complaint? You have received several substantive answers. If there is something else you want folks to address in particular, ask a specific question.

If you are looking for some iron clad general rule as to when to use particular joints, I really don't think such things exist. Joint choice requires a context - specificity of application. And even then, there is room for more than one appropriate choice in most contexts. Grandpa liked lap joints and you like lap joints - nothing wrong with that. Have at it. Post some pictures of your furniture built with lap joints with detail shots to highlight their use and look.

[David Weaver]

I promise I will not take shots at specific things people show with exposed joint, it's partly in fun that I go on tirades about exposed back hair and exposed joints (which are essentially the same thing to me).

[Frank Drew]

Indeed. Any joint that can hold together without glue - dovetail, tongue and groove, mortise and tenon - I would argue is superior to alternatives that rely on the glue. A mortise and tenon has significant advantages over half laps in that the shoulders and housed tenon allow the joint to mechanically - not just by glue shear strength - resist racking forces. A pinned mortise and tenon does not even really need glue. I wouldn't put much faith in a pinned half lap joint.

Exactly; other than being a bit more work, the mortise and tenon joint is superior to a half lap in every important respect if strength and longevity are the concerns, IMO.

[Frank Drew]

Friends don't let friends show endgrain (unless the furniture is intended for the shop or outside, then it's permissible).

Many if not most solid wood table tops, dressers tops, etc. show a fair amount of end grain, with no loss of attractiveness. Also bed, chair and newel posts, cabinet door stiles, tool handles ....

[Doug Hobkirk]

How did we get back on subject? I thought we were talking about David's(aka the dude's) hairy back.

When to use a particular type of joint. From what I see here the choice and beauty is in the eye of the beholder, and that is what happens through each of these types of threads, is it not?

Fine Woodworking (my personal favorite magazine as a woodworking authority) tested joints strength (https://www.finewoodworking.com/tool-guide/article/joinery-shootout.aspx). (IIRC, they joined one end of two pieces of wood at a right angle and observed how much pressure it took to break the joint. Obviously there are many other types of joints.) I don't pay for web access, so I cannot review the article. I am quite sure they found the half-lap joint was actually the strongest joint. I believe they also found that box joints were stronger then dovetail joints. All because modern glues are so good.

I don't have enough experience to discuss Pat Barry's issue about clamping a half-lap joint. I've never had a problem, but I don't do this very often and I have never tested joint strength.

Aesthetics? Ah, I love the look of through tenons and dovetails. And I am such a child that I often prefer them with different species of wood - make those joints really pop visually!

[FWIW, I sort of "objected" to the FWW article. How dare they make such a claim?

[Brian Holcombe]

Joints are more purposeful than strength alone and beyond that, sheer strength alone. So, to add to David's point, how often is your furniture in a situation where it is loaded to it's yield in sheer. In my off the cuff estimation I suspect that it's more often racking that breaks down joinery over time.

In an armchair for instance, each m&t could be capable of 200lbs, and there are four legs, so 800lbs. Put and 800lb person in it and it's likely to break when they push away from the table.

I expect joinery to be specified by how it prevents certain movements from occurring. It's the reason why one would go through the trouble of making a housed cross having joint rather than a standard cross halving joint, for instance.

[Frank Drew]

I am quite sure [FWW] found the half-lap joint was actually the strongest joint.

As Sean pointed out earlier in this thread, it's not always the best practice to rely solely on glue strength for a joint; unlike a mortise and tenon, half laps have essentially no mechanical strength to supplement the holding power of the glue.

What FWW might not have considered is that, over time, glue shrinks, and also over time, the cross grain nature of a half lap will stress that possibly weakening glue line as the pieces shrink and expand (even if minutely) with the seasons.

I would make the same argument for dovetails vs finger joints in such applications as drawer construction; even an unglued well-fitted dovetailed drawer will hold together because the construction method anticipates the stresses of pulling open a drawer. Finger joints? Not so much.

IMO.

[Joe Tilson]

Just to let you folks know, I did not have any complaints about any style of joint. I just threw out a question to find out what others think. You have given some really great answers to this question, and it is appreciated very much. As far as the hair thing, my thought was just in jest only. If anyone got upset over this I am very sorry and did not intend to hurt anyone.
Thank you,
Joe