Workbench joint designs

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I have referenced all the books I can find and they all showcase the typical joints for woodworking like lap, biscuit, mortice and tenon, rabbet, dado, etc etc, but none of them seem to handle joints with multiple pieces that cross each other like I am dealing with in this design for my built-in workbench. I have identified the 7 different joints in the illustration and started designing different types of joints that are possible for the upper post cross joint. I would like to get feedback on which would be the best from a strength standpoint. Of course any other things I may need to consider are also welcome and encouraged. More joint designs for the other 6 joints will be posted later. The 2x4's will be anchored to the walls. Keep in mind also that the flat bench top will be laid on top of this of course.
http://www.realeyz.com/misc/bench_joints.jpg
[img:d2c0ea2d9e]
http://www.realeyz.com/misc/cross_joints.jpg [/img:d2c0ea2d9e]
It seems like the best choice is the screwed lap joint. The quad corner tenon lap joint I realize is a bit silly and not really practical for this.
thanx for any and all advice!! - todd
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realeyz wrote:

If you fasten it to the walls, racking won't be an issue and you could probably get away with just about anything.
Also, 4x4 is vast overkill for your posts. A 2' vertical section of standard 2x4 can hold 4500lb in compression.
Chris
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Todd,
You asked for advice and ideas before about this and none of those that you indicated would be incorporated are reflected in the drawing you're showing. Unless you'll be throwing engine blocks up on the bench, do away with the 4x4's and use 2x4's. Change the drawing then come back. Simple lap joints (glued, doweled or screwed) will suffice for most joints here. If this was a free-standing workbench subject to racking forces and heavy loads then I would use 4x4 legs (actully laminated 2x4's to make 3x3-1/2"). You have over-engineered this and making it way to expensive for what you need.
Bob S.
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I'll agree with Bob. I recently made a movable table for my old table saw, and I used nothing but 2x4s and lap joints. I can sit on the table anywhere without seeing deflections. I did use screws "till the glue dries". The table saw weighs about 250 pounds. Jim
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On Tue, 13 Dec 2005 16:02:14 GMT, snipped-for-privacy@spam.invalid (realeyz) wrote:

So change the design. You don't need those joints, they're a pain to make and they're less strong than staggered joints. Everything you need for a workbench you can do with M&Ts, either wedging them, pegging them, or (if you want to be posh) half-dovetailing them and using a wedge to lock the other half of the dovetail. http://www.jarkman.co.uk/catalog/furnitur/bench.htm
If you really must do 3 or 5 way joints, look at Japanese techniques, as described in Nakahara's "Complete Japanese Joinery" <(Amazon.com product link shortened)>
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On Tue, 13 Dec 2005 20:27:01 +0000, Andy Dingley

I can't see how this joint works? Shouldn't the wedge come from the other side?
-------------------- Steve Jensen Abbotsford B.C. snipped-for-privacy@canada.mortise.com chopping out the mortise. BBS'ing since 1982 at 300 bps. Surfing along at 19200 bps since 95. WW'ing since 1985 LV Cust #4114
Nothing catchy to say, well maybe..... WAKE UP - There are no GODs you fools!
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Sorry, it's a friend's site and I posted the link because it's what I had, not the best illustration of the joint.

In lots of wedged M&T joints you have to insert the wedge from the outside end of the tenoned member, but for these you do it from the inside. If your primary goal is to make a "box frame" where the wedges are inserted from "inside", then the wedged half dovetail is a useful choice.
The basic joint begins with a M&T Then the lower edge is cut at an angle (both parts) to make half of a dovetail. This dovetail has a "steep" angle on it, I think we used 1:6 for these hardwood joints.
Above the tenon the mortice upper face is also slanted at an angle, but _not_ the tenon. This angle is shallow compared to the other (important!), maybe 1:8 or 1:10 for this bench. It's also cut in the "opposite" way to how you might expect a dovetail. Matching locking wedges are cut at this same angle. There's wood removed right through the depth of the mortice so that the locking wedge protrudes through both sides, and also so that there's enough spare height with the wedges out to allow the joint to be assembled.
The joint now fits together quite loosely as the tenon is free to move up and down. Don't assemble it by titing the tenoned member, or you'll find that you can assemble one, but not two - make those wedges thick enough to give space. Once assembled, drive in the wedges to lock it. As always, drive wedges with a light hammer, not a maller (you can hear when they bottom out more easily)
The racking strength of the joint depends crucialy on having a different wedge angle for the "dovetail" and for the wedge. So long as the wedge is much more shallow, then it's possible to get a good lock on the dovetail part.
This is a fairly common joint in Japanese joinery as the shitage-kama and has aspects to recommend it for wider use. If you can cut the angled mortices (a wedge on the morticer table is all you need) then it's an easy joint.
It's not in Kiyosi Seike, it is illustrated in Graubner (not a great drawing though) and it's described in Sato & Nakahara . All three of these books are worth having (Graubner is OOP and S/H prices are insane - Nakahara is a better book anyway)
<(Amazon.com product link shortened)>
<(Amazon.com product link shortened)>
In Japanese work (and Japanese timber) the angle for the "dovetail" part is typically steep and the other side of the mortice is cut square, with a very shallow peg (typical of Japanese timber-framing work). This is a good joint for house carpentry, but it doesn't have the resistance against moving under racking stresses that it does if you cut with two angles and a less steep dovetail.
It's also cut in Japan as a blind mortice (hard work to cut) or with the dovetail only cut on half the tenon's length.
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On Sat, 17 Dec 2005 12:24:31 +0000, Andy Dingley

The thought of a different wedge angle came to me this morning...since the "weakness" I saw in this joint seemed to be the wedge and tenon coming out at the same angle. The wedge angle makes more sense.
I can see this joint being a very good choice for something to be knocked down.

Thanks for the excellent answer.
-------------------- Steve Jensen Abbotsford B.C. snipped-for-privacy@canada.mortise.com chopping out the mortise. BBS'ing since 1982 at 300 bps. Surfing along at 19200 bps since 95. WW'ing since 1985 LV Cust #4114
Nothing catchy to say, well maybe..... WAKE UP - There are no GODs you fools!
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I notice that the joints and drawers took a long time to make. How long did it take to get the bench 'covered in crap'? :o)
BTW, interesting joint and links.
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I see others have boo-hooed the 4x4 but I like them for legs. They add mass and reduce bounce when I hammer something stubborn. As for the joints, a simple half lap that I epoxyed then screwed have help up for twenty years without any problems or loosening.
Dave
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If your interested in the quick and dirty, go to the hardware store and look at the selection of Simpson products. They are a common brand name for joist hangars, but they also manufacture many other metal connectors to join things together. --dave

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Here are some of the lower corner joint designs:
http://www.realeyz.com/misc/lower_corner_joints.jpg
I think the inner miter dado joint looks the easiest and strongest. I also like the way it looks put together with two different toned woods. What do you guys think?
-todd
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realeyz wrote:

Any of them will do the job, given that you don't need to worry about racking stresses.
In this application glued and screwed butt joints would probably be sufficient.
Chris
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Todd, You indicate elsewhere that you have very little woodworking experience. You'll find these joints much more difficult to make with actual wood than they are with computer programs. You will quickly ruin some of your wood and be going back for more if you attempt such complicated joints without more experience under your belt. All of us make mistakes, beginners make more of them. I don't care how smart you are, there are skills involved here you simply haven't learned yet. I assure you that wood glue is plenty strong to hold your bench together with only the simplest joints and a few screws.
DonkeyHody "Good judgement comes from experience. Experience comes from poor judgement."
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DonkeyHody wrote:

Wouldn't it be better for him to learn this constructing something for the shop than something for the living room? Let him try. This is exactly where he should become adventuresome.
Pine is a hell of a lot cheaper than cherry.
--
Mortimer Schnerd, RN

snipped-for-privacy@carolina.rr.com.REMOVE
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Mortimer Schnerd, RN wrote:

Your point is well taken. I'd just like to see him make some simple half-lap joints before he starts trying to get fancy. I see great potential for him to become frustrated and quit if he bites off more than he can chew.
Reminds me of the time we took the neighbor's 13 year old kid skiing. He had a snowboarding video game and was very good at it. He thought he would be doing jumps and flips right away. That's about all you see people doing on TV, right? By the end of the first day, he was totally demoralized and wouldn't try it again.
DonkeyHody "Good judgement comes from experience. Experience comes from poor judgement."
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"DonkeyHody" wrote in message

Sometimes it is more tragic than that.
I was raised on a horse farm and, at one time in my "yoot", spent a good part of my time astride, from steer roping in rodeos, to riding hunter/jumpers on the SW show circuit, and even got into training for a period after getting out of the service.
One of my mentors was an old man who had owned a thriving stables since the turn of the century, when horses were still a major means of transportation in this part of the world. It is safe to say that Mr. Vaughn Parrish died knowing more about horses than most self-styled horseman today will every know, and was a damn good example of what constitutes a "horseman", by any definition.
So I had to initially laugh last year when a friend told me about this "expert" horse trainer she was letting "train" her show horses ... a 14 year old girl. This girl "had all the horse movies and training videos" and "really knew horses" ... until she put herself, and a horse, in a position that no remotely knowledgeable horseman would have considered.
As a result the young lady is now a quadriplegic, from an unnecessary accident caused by poor judgment and ignorance.

... and the fact that this friend is an MD just further illustrates the state of a culture that hasn't even considered that little bit of wisdom.
--
www.e-woodshop.net
Last update: 12/13/05
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wrote:

Reminds me of an early driving lesson I was giving my daughter. Around the block, and we're approaching the driveway. I wait for her to slow down, we're getting closer to the driveway. I don't want to be overbearing, so wait an instant or two more. We're doing about 20-25 as we approach the driveway. "You have to slow down" I say, and she does - to about 15 for a 90 degree turn. Next thing I'm grabbing the wheel to keep us from climbing the bank beside the driveway, and telling her to hit the brakes. After we stop, I told her you can't turn that fast. Her response: "You can in _Need for Speed_" (video game). Yeah, darlin' but that's a Ferrari, this is an Aerostar.
(She's gotten better over the past five years.)
Ricky
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Thanx guys - here is the assembly with the mortise and tenon construction:
http://www.realeyz.com/misc/mt_bench.jpg
I know I have no experience with with this kind of wood joinery - I plan to practice on old wood before really using any bought material for the bench. I may use big 1 1/2 dowels for the tenon instead of trying to cut square mortises - those look tough. This way I can just cut the holes with a big forstner bit. In any event I will practice the methods before diving in. If it turns out to be too tough I will just revert back to using doubled up 2x4's
Thanx for all the ideas and encouragement - it is much appreciated!!
- todd
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On Thu, 15 Dec 2005 04:02:15 GMT, snipped-for-privacy@spam.invalid (realeyz) wrote:

Throw away the CAD, pick up a pencil and do some reading first. That design is beautifully rendered and very poor mechanically. Look at any other similar piece of framing and study the joinery used and the proportions of the tenons. As a quick clue, mortices shoudl be longer than their width - square is bad, and tenons should have two shoulders, not four.
I suggest reading "The Workbench Book" for starters, and probably something (Tage Frid?) on how to design good proportions for joints.
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