Drawboring

[Mike Holbrook]

I have been planing to use this technique on sawbenches and workbench projects I am about to start on. Mortises & Tenons locked in with drawbore pins seems like a reliable way to get tight joints for legs and stretchers, particularly on surfaces that will see as much heavy weight & pressure as woodworking surfaces.

I see that Tools for Working Wood is offering Ray Iles drawbore pins for sale. The unique feature of these pins is they are eccentric, not quite round or cylindrical. The benefit of the eccentricity is suppose to be that turning the handle on the pin can loosen or tighten the joint, depending on whether a wider or narrower section of the pin is engaged against the wall of the hole. Joel with his normal tireless attention to historical technique found that old versions of these pins did not show hammer marks leading him to surmise that the tool was twisted into the joint instead of hammered. I am thinking of buying a set of these pins as I am hoping Ray has worked out the details of how much eccentricity needs to be built into these pins.

I am interested in any experience or wisdom fellow Creekers may have had using this joint building technique.

[Jerome Hanby]

No real experience, but I bought the punches from Sears that the Schwartz blogged about turning into draw-bore pins. Someday I'll find them in my shop and actually make the handles for them and give them a try <g>. I know they are round in cross section...

[Chris Griggs]

You don't need drawbore pins to drawbore. You just need a strong hard pointed/tapered dowel and a hole in the tenon cheek that is 1/32 to 1/16 (no more) offest from the dowel hole in the piece with the mortice.
This will draw the tenons in as you hammer it in. I did this when I built my bench. That said, I presume pins would make the process easier and decrease the chance of blowing up a dowel as you hammer it in, can't say though since I've never used drawbore pins and I've only drawbored on one or two projects.

I did have a couple dowels split/blow up when I built my bench, but I just kept hammering and everything worked out.

[Mike Holbrook]

I have heard/read that one can simply use a wooden dowel but the argument was this method can introduce issues in checking or proofing the joint prior to actual assembly. Removing a trial dowel might, for instance, ruin the dowel or the hole. An eccentric pin might enable one to twist to test and then twist the other way to disassemble, providing the worker a chance to make a small adjustment if needed before assembly. Chris apparently makes his own drawbore pins from white oak. He apparently splits them off with a pocket knife so he gets good straight grain in the pins.

[Jack Curtis]

Their eccentricity may make them unique today, but I think that's a requirement to be called a drawbore pin. It's great that Iles/Joel are providing smaller diameters, my old big ones border on being too large for furniture.

Jack

[Chris Griggs]

Correct, if you want to test fit than no you can't just hammer the wooden pegs in. They'd be pretty hard to get out, so in that case metal drawbore pins would be advised. Then again you don't necessarily need to test fit with the pins. The tenon shoulder should close up without them just as any M&T should. Generally, at the point you are driving in the wooden pegs the intent is that they are there for good.

I'm not saying metal pins and the ability to test fit with them wouldn't be helpful, it surely would. Not trying to talk you out of getting them either, just saying that they are not required, particularly for shop projects.

Someone correct me if I'm wrong, but I believe the Schwarz method you are referring to is not for removable pins. I think he's referring to the pins/dowels he drives in permanently. My understanding is that the metal pins mainly help pull things together tight to align and possibly stretch the holes so its easier to actually drive the wooden dowel/pin/peg. Hope I'm not just confusing things here.

BTW have you seen these videos of Schwarzs demoing drawboring with pins.

http://www.youtube.com/watch?v=Qa8K_CH3eaI&list=PL76ED2FC43576D6AF&index=27&feature=plpp_video

http://www.youtube.com/watch?v=SaEO7WkmQ-Q&list=PL76ED2FC43576D6AF&index=28&feature=plpp_video

[Trevor Walsh]

I drawbored a bed and a workbench so far, on the bed I glued and drawbored the footboard. I was confident enough to forgo glue in the other joints. Pegs were 3/8" riven oak/ash for the bench. The bed was oak and had maybe a heavy 1/16th offset. The workbench was pine and had more like a heavy 1/8" offset. Make a sample joint, and do maybe three holes or so to get a comfortable idea of the offset. if you have a springyish wood you can go heavier on the offset, if it's something like oak you don't need to go as much, I've found that pointing the ends is really important and helps the peg snake around, I did not use drawbore pins.

[Mike Holbrook]

Ok, ok to be honest I am most interested in drawbores because Schwarz says they can make a not so great mortise & tenon last for a few hundred years even if the glue rots away. Which is to say if my skills are not exactly perfect, drawboring the joints I will be making in my first real workbench will lock the joints together solidly and cover up at least some of the imperfection.

I ordered a set of Ray Iles drawbore pins mostly in the hope that they will provide me a little more ability to test my joints and make them work even if they are not perfect. The other reason is, at least in my case, getting on in years creates a certain attraction to building things that might still be around and working a few hundred years after I am gone.

Chris, yes I have seen the Schwarz videos. Good info.

[Harlan Barnhart]

Mike, I have draw bored a few joints (maybe 75 or so) and I have not felt much need for proper pins. (However they do look like nice things to have on hand and I wouldn't discourage anyone from a good hand tool...) The best trick I have discovered so far is to insert a regular wooden pin in backwards the first time. Don't hammer it all the way in or it won't come out easily but you can tighten it up enough to check the fit. This "eases the way" for the final pin and reduces the chances of blowout on the backside. For small projects I split the pins and carve them to shape with a chisel, but if I need more than a handful, I rip blanks on a table saw and round them with a router. It works just fine, make sure you choose straight grained stock and rip along the grain lines. Make a few "test joints" first to learn the appropriate offset for your specific joint/wood specie.

[Michael Peet]

I have a set of the LN drawbore pins, and found I could not use them on deep joints like those on my bench because they were too wide for the 3/8" holes. Just something to keep in mind...

Mike

[Zach Dillinger]

I drawbore just about every mortise and tenon I make. On my window sash, I'm extra careful to make sure that I don't do any damage to the tenon, as they are usually quite thin and made from softer woods. I, therefore, always use a drawbore pin (made it myself from a drift pin, ala Schwarz) to open up the path just a hair so I don't split the tenon. When combined with tapered wooden pegs (always split, never sawn, and rough rounded with a chisel, never perfectly round as they come out too easily), my joints are almost always perfect.

The pics below show a quick and dirty sample sash corner I made a week or so ago. You can see the power of drawboring. The first pic shows the tenoned piece seated into the mortised piece just with hand pressure. Not a good fit, right? Drawboring makes that a very tight fit. This sample sash piece took approximately 30 minutes, from rough stock to finished joint, because I had to stop to take the photos. The rest of the photos are here: http://galootcentral.com/index.php?option=com_copperminevis&Itemid=2&place=thumbnails&album=643

217551217552

[Dave McCammon]

I used a phillips screw driver to test the joints when I built my workbench.:)

[Joel Moskowitz]

The whole point of drawbore pins (real ones not drift pins) is to allow you to easily test fit a M+T with a drawbore without distorting the joint. It's like using clamps to test fit only orders of magnitude easier and faster. They still use them in the steel industry with big wrenches, to bring beams into alignment. The point of a draw bored joint is that the jog you get in the joint puts pressure on the joint so that when the wood shrinks in the stile there is still clamping pressure that will close up the joint. If in fiddling with a drift pin you distort the joint one of two things are happening, you are removing the offset that makes the draw bore pin work, or you have too thick a pin or too much offset to begin with and you need the remedial action for the joint to work. If you do it right you have just enough offset so the joint goes together without the tenon being destroyed, but it's near impossible to get the pin out once hammered in.

[Zach Dillinger]

I like to use drawbores for several reasons, including what Joel said above. Another nice benefit, for me at least, is that I don't clamp my sashes, which can easily draw a frame out of square unless you are very careful. My sash tenons are usually only 1/4" thick and in white pine. This makes them especially prone to damage. But, as you can see in my pictures, my use of my drawbore pin doesn't remove the offset needed to make the joint essentially bomb-proof. I have no doubt that the TFWW drawbore pins work well, as do my shopmade ones.

[Mike Holbrook]

Great info. guys. I am studying Zach's pictures, visual aides are a big help. I figure Ray Iles put some time into figuring out exactly how to make his pins. I imagine I could make pins that worked decent with a little trial & error. I decided it was worth the price of admission for me to get Ray's proven pins so I ordered Joel's offering a couple days ago. As always I will report back after I have had time to try them out. Joel offers 3/8" & 1/2" drawbores. I was a little unsure what size to order but finally went with the 3/8" ones as I believe that is what Schwarz suggested for a Roubo bench. I am trying to figure out if a given drawbore only works a specific size hole or a range of hole sizes?

[Jack Curtis]

...I am trying to figure out if a given drawbore only works a specific size hole or a range of hole sizes?

For sure, the smallest diameter can't be bigger than the hole.

Jack

[Steve Branam]

I was a little unsure what size to order but finally went with the 3/8" ones as I believe that is what Schwarz suggested for a Roubo bench.

The first time I tried drawboring was when I built my Roubo, and it's one of those "Holy crap!" moments. The result was so rigid, the tree might as well have grown the M&T joint. It was one with the wood. Those things will never fail. Peter Follansbee and J. Alexander have studied a number of drawbore joints from the 17th century and later, and they are still solid.

I did manage to blow out the far side of a mortise on a project one time when I didn't point the pin well enough. As it deflected from the offset, the edge caught the mortise end grain. Make sure your pins are straight and pointed enough, and definitely make sure you split them out of straight grain. There's a lot of strain on them, and any short grain is likely to fail.

[Terry Beadle]

Mr. Kingshott has a segment in his Mortise n Tenon video that covers how to do draw bore MT's. He also shows a trenail ( tree nail ) from HMS Victory that he obtained.

His video is not expensive and it covers the MT joint very well.

Sure do miss him.

[Jack Curtis]

Mr. Kingshott has a segment in his Mortise n Tenon video that covers how to do draw bore MT's. He also shows a trenail ( tree nail ) from HMS Victory that he obtained.

His video is not expensive and it covers the MT joint very well.

Sure do miss him.

Me, too. Might want to pick up his dovetail video, too, mastery in action, both videos.

Jack

[Mike Holbrook]

I found both Kinshoot's DVD's, Mortise & Tenons and Dovetails, about $18 each. Is he showing hand tool techniques? I see his books too but $70-$130 ea on Amazon, ouuch!

[Jack Curtis]

I found both Kinshoot's DVD's, Mortise & Tenons and Dovetails, about $18 each. Is he showing hand tool techniques? I see his books too but $70-$130 ea on Amazon, ouuch!

Yes, it's all hand tools on those dvd's, get them while you can. You don't need the Making Tools book untill you start making infills and the like; but the other two (Sharpening and Workshop) could be nice, only $1-5 used. The Joints book is very good, but only if you have big questions about joinery after watching the dvd's.

Jack

[Steve Branam]

I've recently bought all of Kingshott's DVDs new, and all his books except Making Tools used. The used prices are very reasonable, the new prices reflect some kind of limited supply insanity. I'll be doing a review of the whole slew soon on my blog. All the material is excellent. He's an engaging teacher. There's some repetition between the books because they were written over several years, not as a particular set. The DVDs are all hand tools. The books are mostly hand tools, with some machine info (how to sharpen machine blades, use of machines in the workshop, etc.).

Kingshott appears to have been quite a treasure, and he's left us a fine legacy. What I find particularly interesting is that he came up in the English apprentice system just after World War II, so in some ways he was the among the last of a breed. He also liked to use Japanese tools, but shows primarily English tools in his books and DVDs.

[Mike Holbrook]

Thanks for that info Steve. Do you think the Mortise & Tenon & Dovetail DVD's are the place to start then? I am most interested in drawboring. I have found quite a few free videos/instructionals on dovetails and mortises & tenons at places like Derek Cohen's Blog page.

[Steve Branam]

The M&T DVD is excellent, though on drawboring doesn't show any more than Derek does. The one difference is that Kingshott marks the tenon by inserting his bit and turning the brace backwards, so it marks the position of the hole in the mortise without actually drilling, whereas Derek uses a brad-point bit. Other than that, the information is the same. Kingshott also uses a similar drawbore pin, which appears to be round in cross section.

[Howard Klepper]

If Joel is still around, I'd like to pursue the way an oblique cone works. Since it is round in cross section at any point on the shaft, it cannot draw the joint tight simply by being rotated. But it could do so by having its axis tilted as it is pushed and twisted. I think (not having used one) that the idea is to first push in the pin with the straight side contacting the tenon and the tapered side contacting the near side of the mortise. This will cause the axis of the pin to tilt a bit relative to the axis of the bore. Then if the pin is simultaneously rotated 180º and pushed in a little bit , and pulled to the same axis as the bore (a complex three-dimensional move, but probably feels natural and the user only is thinking about the twist) when the straight side of the pin is against both sides of the mortise and the taper side against the tenon and the axis of the pin aligned with the bore, the joint is drawn tight.

Is this making any sense? I am not skilled with drawing programs.