Replies

1. 
   _mj_ | Jun 22, 2022 05:31pm | #1

   If the holes are pre-drilled and you glue it up the holes will fill with hardened glue and the dowels may not even go in. IMO the best use of the dowels is for drawboring the joint which can actually make the assembly process easier.

   I scanned the article and he did not mention his reason for the dowels or touch on them in the assembly process. I believe the M&T joints should hold up well w/o them so I'd feel safe just adding the decorative plugs.

1. 
   chancito | Jun 22, 2022 07:26pm | #2

   Thanks for your thoughts. Do you think they would provide any added strength if drilled and pinned after the rail glue-up?

1. 
   _mj_ | Jun 22, 2022 09:19pm | #5

   They would not add any strength to the M&T joint after glueup. You would have to put sample joints in a hydraulic press to measure any diff.

2. 
   joeinca | Jun 22, 2022 08:26pm | #3

   Drawbored joints, properly executed, are incredibly strong, and I agree with _MJ_ that dowels provide the greatest benefit when the joint is drawbored.

   I believe there’s nothing wrong with your suggestion to drill/install dowels after the mortise and tenon joint is assembled; if the glue in the joint fails over time, the dowels would prevent the joint from separating.

   Dowels should be long enough to engage the leg post on both sides of the mortise.

   If working time of your adhesive is a concern, consider using a different adhesive. Old Brown Glue, for example, has a 30 minute open time and is very easy to use.

1. 
   chancito | Jun 22, 2022 10:10pm | #7

   Thanks to all, very instructive. I’m going to look for articles/videos on the drawbore technique and consider this option with the brown glue to give me more time to execute something new. It’s great to have access to the wealth of experience in the forum.

2. 
   john_c2 | Jun 23, 2022 05:49am | #8

   I would have written exactly what joeinca wrote.

3. 
   mikaol | Jun 22, 2022 08:34pm | #4

   Draw boring is for strength. Dowels on pinned tenon are intended to show. That's part of the look. They're usually a different color than the surrounding wood for effect, common in 'Arts & Crafts' projects.
   Mikaol

4. 
   _mj_ | Jun 22, 2022 09:21pm | #6

   If anyone bought the plans for the settle please chime in... Were the joints drawbored? The article does not say.

5. 
   DRBWWing | Jun 23, 2022 09:53am | #9

   Draw boring is intended for an unglued joint, such as a bread board.

   The is 0 (zero) strength advantage vs. straight pinning if the joint is glued.

   Glue it up, drill for pins after its dried. Do the draw bores if you want the experience.

   What IS important for strength are nice hefty shoulders at the bottom and top.

1. 
   EdWeber | Jun 24, 2022 10:46am | #12

   +1,
   Draw boring is a time tested method of cinching a M&T joints together. It's a method of pulling the joint tightly together but it adds no more strength than a straight bored pin or dowel in a glued joint. The Joint itself, in this case a M&T, is what bears the load. The dowel or pin is only there the retain the tenon in the mortise, it's insurance. If designed an used properly, the dowel or pin should not be subject to any amount of pressure.
   If your joint has already been clamped and glued, it does not help. Sure you can pin it for aesthetics and it will hold in the unlikely event of glue failure but drilling offset holes and drawing things tight is not necessary in most glued applications.

6. 
   Rob_Sp | Jun 23, 2022 10:27am | #10

   I think draw bore joints are useful in timber framing and similar, where there is no practical way to pull the joints of large assemblies together.
   I see little to no value to them for furniture joinery.
   I rip straight grain square stock, (I never use dowels), the diameter of the hole, maybe a touch full, chamfer the corners to form an octagon and cut to length. Apply glue to mortise and tenons, pull the assembly tight with clamps, drill through the joint, apply glue to the pegs and drive them home, the assembly can be immediately removed from the clamps and set aside to dry.
   I have used this method over decades and countless furniture and millwork assemblies without failure.
   As with all things woodworking, if one enjoys the process and dosen't mind the extra time and trouble of draw boring, by all means have at it.
   In my opinion and experience it is a waste of time.

7. 
   Eideann | Jun 23, 2022 11:00am | #11

   As mentioned, drawboring is a great way to pull a m&t tight and make a strong connection, with or without glue, but does take some extra planning.

   Pinning doesn't necessarily add a ton of strength and does not pull the joint together, but that doesn't mean it doesn't serve a purpose beyond aesthetics - which they most certainly add too.

   - Glue and clamp together, and then drill through - typically through the entire assembly but certainly needs to be at least all the way through the tenon into the other side of the mortise wall.
   - Then you can add glue to your dowel/pin and hammer it through (it should be tight enough that you need to hammer). Once you do this, you can actually pop off the clamps (assuming you've got tight, square joints) and the pins will hold everything in place while it dries.
   This DOES add some strength to the m&t glue joint considering that it helps to hold things tight together.

   I have done this several times in building workbench bases where my long clamps are at a premium.

   There is a place for all of these methods depending on the project. For most things, adding the pins rather than drawboring is sufficient. In your project, the pins certainly are sufficient.

8. 
   EdWeber | Jun 25, 2022 12:34pm | #13

   Pinning a joint is designed to keep it from separating. In normal use the forces acting on the joint are never applied to the pin, dowel or peg. ONLY the joint is overly stressed.

   Draw boring is a method of mechanically tightening a joint. There is ALWAYS pressure on the dowel or pin used whether the joint is stressed or not.
   These are two entirely different circumstances. You need to understand the difference in the joinery and its planned use before you design your work.