Replies

1. 
   RANGERP75R | Nov 21, 2003 10:05pm | #1

   jab

      I prefer pinned on a work-bench. Cut the mortice first, then cut the tenon slithtly over-size. Trim it down to perfect fit with a shoulder plane or chisel. The pin acts as a safety net if the glue were to release in the future. Legs on my design are 3 1/2" x 3 1/2" and the mortices are 1 1/2" x 3". That is quite a bit of glue surface, but you never know. Since it not show quality, I add the pin "just in case". Kind of like bringing your seat to an upright position and fastening your seat belt on take-off and landing in an aircraft.

     The below pic uses pinned tenons. Not likely the glue will break, but the pin is there to keep the joint together if it does.

   Good luck...

   sarge..jt

   Proud member of the :  "I Rocked With ToolDoc Club" .... :>) 

   
1. 
   JBentley | Nov 21, 2003 10:48pm | #2

   SARGE,

   Your bench rocks! Is that a half-lap joint on the center beam of the base? Does that help stiffen the top? Nice twin screw! Veritas? All maple?

1. 
   RANGERP75R | Nov 21, 2003 11:07pm | #3

   jab

      Yes, the joint on what I refer to as the "whale-back" is a half-lap or open bridle that is pinned. It does add additional strenght, but also adds under-neath support to the heavy top. By adding it in the center, you actually cut the weight of the top in half.

      Again yes on the Veritas twin-screw. You cannot see the face vise well in the pic, but it is German hardware. Both vises have front and rear jaws made from laminated scraps.

      All maple. Nope... This was a pet project made of 90% short peices of maple scraps finger-jointed to make a core for the top. This was sand-wiched between solid maple I did purchase for $30.

      The base is made of a single 30' Doug Fir beam I recovered from a warehouse (civil war era) being torn down here in Atlanta. Ripped, sliced and diced and re-laminated and glued into the appropriate base components.

      This is an experimental "economy" bench. With the expensive bench hard-ware I have about $270 in the entire bench. As I said, economy model but a "blue-collar" work-horse. ha.. ha..

   Have a good day and welcome aboard...

   sarge..jt Proud member of the :  "I Rocked With ToolDoc Club" .... :>) 

1. 
   JBentley | Nov 21, 2003 11:22pm | #4

   Wow! Excellent bench and a great price. You used some ingenuity there. Thanks for the pictures and for sharing!

2. 
   mudman | Nov 22, 2003 08:42am | #12

   Sarge,

   From my readings, and experience, the pin is not to "back up" the joint. The size of pin typically used would do little to hold a failed joint together. The purpose of the pin is to draw the joint together more securely during glueup. The holes for the pin should not line up perfectly, they should be offset slightly (1/16 or less). The pin should be chamfered on the tip so that as you drive the pin it actually pulls the two pieces tightly together. This is very useful on a large joint where it can be difficult to draw the pieces together with clamps. Again the pin is not to reinforce the joint.

       Wedged joints are stronger because using wedges you can create an impossibly tight fit. Once when test fitting a wedged M&T I tried to knock it apart with a dead blow hammer and (although I didn't hit it too hard for fear of denting the wood) it wouldn't budge, with no glue at all! Make sure the wedge is perpendicular to the grain.

   Having said all this (way too much I'm sure) I agree that bolts work great. Lee Valley sells some specifically for work benches. But I admit that when I see a bench assembled  using "real" joinery I'm jealous.

1. 
   RANGERP75R | Nov 22, 2003 07:17pm | #13

   mike

      What you have described with the pin is absolutely correct and probably stems from timber-framing methods. I have my bench pinned with 1" pins but they are inserted straight through. In my case they are just their for deco. I have no problem getting the joints pulled together as I have capability of clamping to 20'.

      The mortices are rather large on my bench. I designed the thing as three separate components that act independently for expansion purposes, but interlock as a single unit for strenght. Your point about the wedged tenons not coming lose with a dead blow hammer blow was interesting.

      I said that I could not glue the two diagonal ends of my design and it would still not wobble. The reason I stated that is two weeks before I did glue it, I needed my bench to finish a project for my wife. I dry assembled it without any glue. The joints locked into place and the bench wouldn't budge. I got my teen-age son and 5 of his friends to see if they could budge it. Offered them $20 apiece if they could. They are still penniless as usual.

      So in my case the pins are there in those particular four motices for decoration, back-up if the glue fails and a toronado happens to take a direct route through my shop. Not likely, but you never know for sure so I added them "just cause".  ha..ha..

      BTW, I took a week off from work years ago to watch some Japanese carpenters build a high-end steak house here in Atlanta. Those guys don't use glue either. Don't use nails, bolts or anything else we consider standard. I learned a few things about timber-framing from those guys. I also learned they love Amercin hot-dogs with chili. Hold the onions. :>) 

   Regards...

   sarge..jtProud member of the :  "I Rocked With ToolDoc Club" .... :>) 

1. 
   mudman | Nov 22, 2003 10:48pm | #14

   Sarge,

     That is very impresive about your unglued table! I still have trouble dialing in perfect M&T joints when they are really large. I have a tennon jig, but that dosn't work so well for large tables. Ha Ha. So I resort to hand saws. I get aceptable results but not the kind of quality consistant with my other work. They look great but dont fit like yours must. So how did you make them...machines or by hand?

    I am amazed by the Japanese joinery. Post pics if it isn't too late.

   Mike

1. 
   RANGERP75R | Nov 23, 2003 12:12am | #15

   mike

      Keep in mind the M&T's are glued now and pinned. All I was saying is the bench was designed in a manner that all three components are independently sturdy and when joined they become almost indestructible. Yep, the table will function without the glue at those mortices connecting the side rails to the legs. The legs sit in 5" deep through mortices on a 5" high, 6 1/2" wide foot. With the shelf glued and pinned into an 1" rabbet on the inside of the  3 1/2" x 3 1/2" side rails and then the support on the ends of it are M&T'ed to the inside of the legs.

      At this point you might still get some play. But add the H component (whale-back rib down center attached to the top end rails that sit in the saddle of the bridle joint and the play disappears. Even heavy pushing won't allow movement at this point. Then sit a 140 lb. top on top of the H component and things get even more re-inforced.

      What you don't see is 10 bullet headed 1" radius X 1" exposed above the stock dowels ( One on each leg top and two evenly spaced on the top rails, then two on the whale-back rib itself). The underside of the top has reciever holes drilled corresponding to the exposed bullet headed dowels. You have just locked in all three components into one unit. Is the pins and glue neccesary? Not really, but it does add a bit of bullet-proofing to the already strong joint, design combo.

      Mike, there are no Japanese joints on this bench. They do very complicated joints that are quite amazing, but the very large mortices with large shoulders are sufficient here. My bench is basically a small timber-framing job. I was referring to what I learned from the Japanese about design. Not their eloborate, intricate, sturdy joints themselves but their framing technique. Their techniques allow a number of joints that will work without any added re-inforcement. The key is the design. The design is self-supportive with adequate,  properly cut and properly places joints.

      Hopefully that kind of gives you some ideas that could be useful. Either that or I have confused you beyond recovery. If you have any questions as I am not an accomplished communicator, feel free to ask.

   Regards...

   sarge..jtProud member of the :  "I Rocked With ToolDoc Club" .... :>) 

2. 
   mudman | Nov 23, 2003 09:41pm | #16

   Hey Sarge,

      I understood that the bench was glued up and that you didn't use Japanese joinery on the bench. My over worded question was how did you make the large M&T joints? Machine or by hand. I have probably made 12 or so by hand (not counting the practice cuts) and I have always had a tough time getting them to fit the way my smaller machined joints do. I generally use a PM tennon jig and a router. My hand tool collection is somewhat limited, though I do have a good tennon saw. I have thought about trying a Japanese tennon saw. I wonder I they are easier to keep on target. I seldom do these kind of joints but when I do they need to be solid, so I am shooting for a kind of perfection I have yet to achieve. The way you describe the stability of you bench (before glue) I know that those M&Ts must be well fitted. But reading your last reply I think you are saying it is the upper assembly that locked it together. How solid was the base before you added the upper brace?

      I know that when it comes to hand tools practice is the important thing. However I am always hoping to pick up some techniques that will help.

       Japanese joinery amazes me. When used properly the various members are designed to perfectly handle the stress (tension, compression, torsion, etc.) that they need to. Most admirers don't realize that the joint aren't fancy for show, they are very specifically engineered for the exact purpose they serve. This is especially true for their timber framing. I have been to Japan several times and have never seen any real examples in person. If I found out they were building a restaurant in my area using traditional techniques I would be there every day!

   Mike.

3. 
   RANGERP75R | Nov 24, 2003 01:11am | #17

   mike

      These mortices were cut by hand. I do have a morticer, but these are 1 1/2" x 3" x 3 1/2" deep. A tad big for the  morticer bits I have. I prefer cutting anything over 3/8" by hand anyway. I have morticing chisels up to 2" (over 1" is timber-franming size) as I have assisted with a few friends building log homes.

      Use a dual pin mortice gauge and set the pins to the width of blade (picked this idea up from ian). Then mark your mortices. Outline them once marked. I use a 90 degree faced block as a fence on one this size. Clamp it on and you cannot cant the chisel outside of the outline as the block will keep it dead 90 degrees. At this point I drill out with a under-sized drill bit for one this deep. Saves a lot of levering. Once drilled the remainder is cut with the chisel making sure to back the piece with hard-wood on the exit side.

     I cut the tenons on this application with a home-made tenon jig I built with dual slides that fit the two left mitre tracks on my modified Table Saw. The jig is a bit over-size and I can run up to 5' strecthers or rails on it. Anyting taller than that I would use a tenon saw. The tenons are cut over-size after the mortices have already been cut. That way if the mortice is slightly off it won't matter. The tenon is trimmed down to size with a shoulder plane and chisels after the mortice is cut. Always...... And yes, this produces a piston fit mortice (borrowed the wording for that from Boss-Crunk, ha).

     How stable was the top before the two remaining components ( H component and top ) were added. Visuallize a stance that you would use pushing a car that won't start. With that exertion about 1/4" to 3/8". When the H is added it won't move at all. When the top goes on it would take a natural "act of God".

     The restuarant is a piece of work. It is timber-framing art and the prices their reflect the craftsman-ship that went into building it. If you examine some of the joints closely you might even be able to find a chili stain. The good news, I happen to be one of the few that know where they came from. The bad news, I lost a weeks pay finding out. ha.. ha..

   sarge..jtProud member of the :  "I Rocked With ToolDoc Club" .... :>) 

2. 
   AlanTurner | Nov 21, 2003 11:41pm | #5

   My 2 cents -- For the stretcher to leg connection, I favor a through bolt to a trapped square nut, which can always be tightened.  Make a very shallow tenon (3/8" or so, mortise to 7/16", and have your shoulders be quite narrow, to increase the size of the plate that the bolt is pulling together.  This will allow disassembly, if needed, and is, IMHO, a bit stronger than either a wedged or pinned tenon.  It permits seasonal tighening. 

   As to the Leg into foot joint, M&T, wedged, is to me the stronger joint.  The top of the leg to cross brace is an open bridle joint.

   Have fun.  A good bench is a critical and enjoyable tool.

   Alan

1. 
   JBentley | Nov 22, 2003 12:03am | #6

   s4s,

   Thanks for your response. Yet another way to do it. I kinda have my heart set on a bench that looks like David Charlesworth's bench. The British guy who wrote Furniture-Making Techniques. I just love the look of that bench but I am kinda scared to make wedged tenons. I might prototype the joint a few times and see if I can do it or go with the pinned "Sarge" type bench.

1. 
   AlanTurner | Nov 22, 2003 12:35am | #8

   The wedged tenon is not difficult.  Cut a straight through moritise, then go to the back side, where the wedges will  go, and enlarge the ends by about 3/16" or so, in a fairly smooth taper to near the front.  Then, on your tenon, cut two slots, about 1/4" in from the ends.  The wedges are oriented to push against the end grain.  (If you do it the other way, you will split the wood.)  You can drill the tenon at the end of the kerf to stop any run.  Frid shows this.  Then make 2 wedges, with the fat part about 1/4" wide.  Fit the wedge to the side of the tenon to get the right slope.  Then, when you go to the glue up, glue as usual, plus fill the kerf with glue, clamp it, and  then drive the wedge home.  This joint will not come apart or loosen.  There are only 4 to do, so it is not too difficult.  A sharp paring chisel will make a huge difference.

   I think the pin is decorative, but not strong.  If the glue gives way, the joint will be loose.  The pin will stop the tenon from coming out, but will not tighten it.  Your bench will wobble.

2. 
   RANGERP75R | Nov 22, 2003 03:36am | #10

   jab

      If you want your bench to look like David Charlesworth's, take s4s's advice and use the wedges. You can build them as they are not difficult. If you don't feel confident, glue some old 2 x 4's together and practice cut on them till you do.

      s4s is correct in that the wedges are stronger. A pin is not designed to be strong. It is just a decorative safety valve as I originally stated. The way I designed it the piston fit of the tenons have over 25 sq. inches of glue surface per mortice on the four where the side stretchers enter the legs. I have built five of this design and over a 20 year span not one glue joint has failed. I still add the pin "just cause" as I stated before.

      I believe that the design I use would allow for two diagonal corners to not even be glued and it would still not wobble. If it did, not much. Even under the heavy torque of hand planing. And I am speaking of the upper bridle joints not glued on those corners also. Bold statement?  Yep.. I'm sure I will be challenged on that one. ha..ha..

      If anyone disagrees, let it be known. I will post a pic of the base before the top was added to give a better look. Look at it carefully and give it careful thought.  I will add that all legs, stretchers, rails and the "whale-back" is 3 1/2" x 3 1/2". Don't overlook the shelf on the bottom. That would be a mistake. Then present your argument and I'll tell you why I have concluded what I have. Hey, I'm on vacation this week and having a little fun.

   Learn to cut wedged tenons, jag.... you can!

   sarge..jt  :>)Proud member of the :  "I Rocked With ToolDoc Club" .... :>) 

   
1. 
   BobSmalser | Nov 22, 2003 05:22am | #11

   Looks fine to me.

   The advantage of the drawbore is a better glue joint than most at the shoulder, not raw strength, which is mostly in the tenon.  But wedges do the same thing.  I'd be looking for a joint that didn't loosen under variable stress of pounding on  that bench, and I think either one would work just fine...but the wedges look better.

3. 
   jeffreysherow | Nov 22, 2003 12:09am | #7

   I looked at Sarge's workbench, I'd do whatever a guy that can make a workbench like that does.  That bench is sweet. 

4. 
   BobSmalser | Nov 22, 2003 12:35am | #9

   I do drawbore tenons often like in the pic below when I'm not using sliding dovetails...look for the untrimmed pointed dowel end.  Bulletproof joint.  Excellent for tool stands and tables that get a lot of racking stress in use....makes those glue joints hold up longer.

   Make and dryfit your M/T...drill the the mortise cheek until the drill bit just touches the tenon enuf to make a mark....disassemble and drill the tenon a tad offset toward the shoulder.  Finish the hole thru the mortise.  Point an overlong dowel, lube it with glue, and drive it thru your assembled joint.

   Example