Thread: Drawboring

You can also watch Chris Schwarz's video.

YouTube - LieNielsen's Channel part 1

YouTube - LieNielsen's Channel part 2

Hi Derek,

Congratulations on another great tutorial, very clear and concise and well illustrated, I only have a couple of questions, are these joints glued as well?

The draw bore pins from TFWW I think are straight on one side and tapered on the opposite side so that just twisting pulls the joint up tight. From what I can tell on the Veritas web site the veritas draw bore pins are evenly tapered on both sides.. perhaps you could have a look at the ones you have and see..

Ok, I found a link to the article I was thinking of.. http://www.toolsforworkingwood.com/M...html&BlogID=78


Regards
Ray

Hi Ray

Questions such as yours make me aware of the points I omitted!

The great thing about drawbored joints is not just their strength - and yes they can be used without glue - but that they turn an OK gap at the join into a terrific gap since they squish the parts together better than any clamp can do.

I am aware that Joel (at TFWW) argues for a oval cross section so that twisting the shaft causes it to tighten the joint. I think that Chris Schwarz says something similar, but he uses round pins (which he made). The Veritas pins are round. Not having used the TFWW pins I cannot say that they are better/worse. In fact I know some that argue that one does not even need a drawbore pin to make the joint. That is true (as I have does this as well) but the pins do make it easier to check out whether the joint is going together as desired.

Regards from Perth

Derek

The French, whom I think historically, own this joint use a square peg. The pegs are 250 - 300mm long tapers cut on the band saw. This long tapered square draws the joint gradualy, forms a mortise gradualy and is almost the same size front and back. Depending on the timber you can drive it to get a perfect joint on the back as well as the front. The pegs are sawn off proud and pared proud and left proud. All finish planing or sanding must be done before this operation. The pegs are driven in, oriented like diamonds to minimise split. You'll get the occasional split, but that's "Provincial" furniture and you get a bit of that.

Derek, as you say, drawbore pins are unessential to the process of draw-boring. Small, handled draw-bore pins seem to be a 19th century invention to equip the middle class Victorian Gentleman woodworker with yet another gadget in a tool-yearning phase similar to the one we are currently experiencing.

In your article, you state "Now you can grab a drawbore pin and use it to pull the boards together in preparation for inserting the drawbore pin." I presume the last reference to "drawbore pin" should read "wooden peg".

Also, I think you are confusing two distinct types of joinery; draw-boring and dowelling. Drawboring uses roughly hewn pegs to secure the tennon within the mortice and round dowels are used as a substitute for tennons. What's more, in your example, the use of an undersized dowel in place of a faceted, tapered peg has resulted in the dowel incompletely securing the joint.

In your article, you state "Now you can grab a drawbore pin and use it to pull the boards together in preparation for inserting the drawbore pin." I presume the last reference to "drawbore pin" should read "wooden peg".

Thanks WW. It was an error of the pen. To be corrected.

Also, I think you are confusing two distinct types of joinery; draw-boring and dowelling. Drawboring uses roughly hewn pegs to secure the tennon within the mortice and round dowels are used as a substitute for tennons.

Traditionally, drawboring may have used tapered pegs, but in the modern translation the use of riven dowels is commonplace. The latter work very well, and are certainly easier to make. Note that they are tapered at the end that is inserted first.

What's more, in your example, the use of an undersized dowel in place of a faceted, tapered peg has resulted in the dowel incompletely securing the joint.

Are you inferring that the dowel is "undersized" because it is not tapered? Or that the joint is not secured because one might find a gap on the back side? I do not see either of these features present here. The method may be slightly different from found in the origins of drawboring, but the "modern" method works very well indeed in my experience.

Thanks for raising these issues. I plan to add to the article (which started as a pictorial) more historical information, along with a wider perspective of methods used in the past.

Regards from Perth

Derek

Originally Posted by derekcohen

Traditionally, drawboring may have used tapered pegs, but in the modern translation the use of riven dowels is commonplace. The latter work very well, and are certainly easier to make. Note that they are tapered at the end that is inserted first.

Riving the peg stock is certainly not a modern technique; it's been done this way since at least the 14th century. Dowels created with a dowel plate are invariably undersized and crooked whether made from riven stock or not. Using a round dowel in place of a whittled peg is a possible area for failure, especially if the joint is assembled without glue. Round pegs aren't afforded the same grip as irregular shaped whittled pegs. The corners of whittled pegs bight into the parent wood and are virtually immovable - even with a hammer.

Originally Posted by derekcohen

Are you inferring that the dowel is "undersized" because it is not tapered? Or that the joint is not secured because one might find a gap on the back side? I do not see either of these features present here. The method may be slightly different from found in the origins of drawboring, but the "modern" method works very well indeed in my experience.

You are matching a smooth round 3/8" dowel to a 3/8" hole. There's little retaining the dowel in the hole other than the deformation it endures as it snakes through the off-set holes. A bout of dry weather or rough handling could see that peg fall out. I've seen it happen in well made period furniture. Ideally the peg should be large enough to well and truly engross all of the holes; any voids will weaken the entire joint. This obviously requires a very long, slow tapered peg and minimal off-set. The point at the tip of the peg is purely to enable it to navigate the off-set.


If your personal experience has been positive, then that's all that matters.

...This obviously requires a very long, slow tapered peg and minimal off-set. ...

Thanks for the reply WW. Your description of the peg is very interesting .. from the point of view that, while described, I have not seen dimensions suggested for such pegs.

Let's say you were adding a peg to the example I provided, could you draw/make a peg and show us what it would look like/how it is dimensioned? That would be most helpful in this learning process.

Regards from Perth

Derek

Great article.

Is the past participle of rive, rived, or riven?

edit: Never mind, I see you use both.

Originally Posted by derekcohen

Thanks for the reply WW. Your description of the peg is very interesting .. from the point of view that, while described, I have not seen dimensions suggested for such pegs.

Let's say you were adding a peg to the example I provided, could you draw/make a peg and show us what it would look like/how it is dimensioned? That would be most helpful in this learning process.

Regards from Perth

Derek

I'm not sure a photo would show the amount of taper, but the concept is fairly elementary. The 'outer' end of the peg needs to be larger in diameter than the hole (being over-sized is what packs the hole and acts as a natural 'stop') and the business end (above the pronounced lead-in) needs to be of a diameter equal to the width of the ellipse described by the sum of the off-set holes as viewed through the assembled joint.

The trick is not to overload any single element of the joint. The off-set need only be a hair's breadth (assuming your joinery skills are up to scratch and there aren't any gaping miss-fits between rail and stile), any more than that and you'll be putting unnecessary strain on one or more of the components. The object is to create sufficient tension to prevent movement in the assembly – anything more is butchery.

I've belted pegs in with a goodly hammer, but I'm very familiar with the processes. It's akin to torqueing a nut on a bolt. There's a sweet spot – not enough preload and the fastener could rattle loose, and one twist too much could see the threads stripped. Pegs can easily be beaten in despite overly large off-sets, but they can subsequently break inside the joint if the off-set is too great or the peg to bore fit is inadequate.

An inconsiderately draw-bored joint is more of a liability than a plain mortice and tennon joint.

Hi WW

That is excellent. Thanks. I will looking into this further to provide a fuller explanation and methodology of drawboring practice. Would you mind my quoting your comments?

Regards from Perth

Derek

Originally Posted by derekcohen

Hi WW

That is excellent. Thanks. I will looking into this further to provide a fuller explanation and methodology of drawboring practice. Would you mind my quoting your comments?

Regards from Perth

Derek

I'm not sure any more needs to be written on the already over romanticised subject, but if quoting me helps, then by all means...

I've found the following article very interesting for an alternate view on how to make a drawbored joint, without being obsessive about micron fits and squared all sides timbers.

It starts with the photo of a cross section of a 17th century joint as an introductory illustration.

Drawbored M & T Article (Greenwoodworking)

Originally Posted by Fuzzie

I've found the following article very interesting for an alternate view on how to make a drawbored joint, without being obsessive about micron fits and squared all sides timbers.

It starts with the photo of a cross section of a 17th century joint as an introductory illustration.

Drawbored M & T Article (Greenwoodworking)

I noticed the peg in the cross-section of the 17th century joint is actually broken!