Drawboring

[Bryan Schwerer]

A while ago I was researching drawboring because I wanted to use it with an Arts and Crafts style bench with M&T joints. Most of the Google'd info was demo's of the Schwartz resurrected method, but one was from an older text because it had old scanned drawings more in an older fashion. I can't find that reference anymore but, according to ig, when you were putting two pins in a joint, only one should be under tension, i.e., you would only offset the tenon whole for the top pin, then put the drawbore pin to tighten up the joint, then drill the other tenon hole that would leave that pin untensioned in a tight joint. IIRC, it seem to be done that way to deal with wood movement. I can't find that reference anymore and all other we references are post-Schwartz and don't seem to mention it. Has anyone else seen this method? Is that the correct way to do it?

[Jim Koepke]

Just now a Google search came up with similar results.

Then I clicked on the "books" link on the left side of he window and came up with some new books and a few old books. One was from 1895, "English Mechanic and World of Science."

That may not be the one you for which you are looking, but it is a start.

jtk

[Trevor Walsh]

I've not read the article you're referring to, but it doesn't make sense to me. Only half of the joint would be pulled tight, the other wouldn't be as tight. On a short tenon maybe there isn't noticeable difference, but then I'd use only one peg. What wood movement would it be helping? Either the thickness (depth-way) of the leg/mortise shrinks and the "not-drawn" peg forces a gap at the shoulder or the thickness swells making the "not-drawn" peg tight, and the "drawn" peg even tighter.

Sounds like it may be an old wives tale that reduces the abound of marking and offset drilling. Of the pegged M&Ts I've done the joints that were drawbored are tight, the ones assembled drilled and pegged do not remain so.

[Sean Richards]

A while ago I was researching drawboring because I wanted to use it with an Arts and Crafts style bench with M&T joints. Most of the Google'd info was demo's of the Schwartz resurrected method ...

"Drawboring Resurrected" - that is pretty funny. I might write a post about how I have re-discovered the mortise and tenon joint - that would be an equally valid statement


but one was from an older text because it had old scanned drawings more in an older fashion. I can't find that reference anymore but, according to ig, when you were putting two pins in a joint, only one should be under tension, i.e., you would only offset the tenon whole for the top pin, then put the drawbore pin to tighten up the joint, then drill the other tenon hole that would leave that pin untensioned in a tight joint. IIRC, it seem to be done that way to deal with wood movement. I can't find that reference anymore and all other we references are post-Schwartz and don't seem to mention it. Has anyone else seen this method? Is that the correct way to do it?

That doesn't make a lot of sense to me and I don't have any first hand knowledge of anyone doing it like that

[James Taglienti]

Looks like the fuse has been lit yet again on the oh so controversial and downright explosive topic of ... Drawboring. Im glad this isnt a political discussion forum we would be kicking down each others front doors over any topics heavier than exactly how to stab and or twist a piece of metal through a board.

[Sean Richards]

Looks like the fuse has been lit yet again on the oh so controversial and downright explosive topic of ... Drawboring. Im glad this isnt a political discussion forum we would be kicking down each others front doors over any topics heavier than exactly how to stab and or twist a piece of metal through a board.

Nah not really - just find it a bit amusing sometimes all this stuff that has been "rediscovered" and "resurrected" etc. Happy drawboring ...

[Derek Cohen]

according to ig, when you were putting two pins in a joint, only one should be under tension, i.e., you would only offset the tenon whole for the top pin, then put the drawbore pin to tighten up the joint, then drill the other tenon hole that would leave that pin untensioned in a tight joint.

If you drawbore for two pins that will sit alongside one another, once you have inserted the pin into one hole, the other set of holes will have "pulled up" and effectively present in an untensioned manner. If you do not set them up for drawboring, the second hole - if pre-drilled - will not line up. I drawbore both holes.

Regards from Perth

Derek

[Bryan Schwerer]

"Drawboring Resurrected" - that is pretty funny. I might write a post about how I have re-discovered the mortise and tenon joint - that would be an equally valid statement
t
BTW, I did not make that up.

http://www.wkfinetools.com/contrib/cSchwarz/z_art/drawBoring/drawBoring1.asp

[Sean Richards]

BTW, I did not make that up.

http://www.wkfinetools.com/contrib/cSchwarz/z_art/drawBoring/drawBoring1.asp

Bryan aplogies if you thought my comment was directed at you - wasn't at all. I was referring to the title of the blog post in the link you just posted. I should have made that clear in my post.

Cheers, Sean

[James Taglienti]

Bryan aplogies if you thought my comment was directed at you - wasn't at all. I was referring to the title of the blog post in the link you just posted. I should have made that clear in my post.

Cheers, Sean

Oh man that was a genuine title? that IS irritating. Almost like calling any tool chest an anarchists tool chest, even if it is 100 years old

[Jack Curtis]

... according to ig...

And I can't find any reference to "ig." It's short for what?

Thanks

[James Taglienti]

And I can't find any reference to "ig." It's short for what?

Thanks

ig looks to be a misspelling of the word "it"

[Sean Richards]

Oh man that was a genuine title? that IS irritating. Almost like calling any tool chest an anarchists tool chest, even if it is 100 years old

Yup really pushes my button that sort of thing - to claim that you have "resurrected" a technique as commonplace as drawboring should be pretty amusing but I have to confess I do find that quite irritating.

[John Coloccia]

Sounds fishy to me. Of all the joinery techniques available, the only one that seems to survive more or less forever is drawboring...at least as far as I know, save perhaps for some of the fancy shmancy Asian joinery that's been kicking around for centuries as well. I think this is one of those techniques that is easy to over complicate but there's really no need to as even a mediocre drawbore m&t, and even one with no glue, is quite sturdy.

If there's a better way of doing it, I'd love to know it, but I'd also like to see some data to back it up.

[Jim Koepke]

Since this is a thread on drawboring, I am curious about the methods and wisdom of others.

Marking the tenon is fairly easy. My method is to dry fit and then mark the tenon with the lead screw of the auger bit used to bore through the mortise. Then the tenon is pulled out an a hole is bored a little toward the shoulder from the mark.

How do you determine your offset?

Is it different for soft woods than for hard woods?

Is it different for different pin and bore sizes?

Do you make your own pins or use standard dowel stock?

jtk

[Sean Richards]

How do you determine your offset?

Normally its a smidgen or a skerrick or some other suitable unit of measurement


Is it different for soft woods than for hard woods?

A bit less/more for hard/soft wood


Do you make your own pins or use standard dowel stock?

Most of the drawboring I have done was in restoration work and used cleft oaks pins - nominally square section.

Cheers

[Jim Koepke]

Cheers

Thanks Sean.

jtk

[Bryan Schwerer]

Well, I can't find any reference to it anymore. It may have been through one of those sites I hit from the web archive, although the ones I usually hit are Jeff Gorman's and shavings.net and neither one of those have a reference to it. It was a few months ago and it struck me as unusual at the time.

I will just go with the accepted way.

Carry on.

[Bryan Schwerer]

Bryan aplogies if you thought my comment was directed at you - wasn't at all. I was referring to the title of the blog post in the link you just posted. I should have made that clear in my post.

Cheers, Sean

No foul. As I was going through all the Google hits, it definitely occurred to me it was a bit egotistical. Although you can definitely find more online demonstrations of draw boring after Schwartz wrote the article. He has a pretty big online following and you can definitely measure the impact. I wouldn't have heard about it if it wasn't for him.

[Jim Matthews]

I was under the impression that the drawbore pins are only to check the joint for square, not for assembly.

At a class, it was mentioned that the offset should be no more than 1/4 of the hole's diameter.
In practice, I offset about 1/16" (1.5mm) because I can't see lines smaller than that on my ruler...

If you offset too much, the end of the tenon (away from the shoulder, insided the mortise) can give and lead to failure of the joint.
I wonder if all species are equal, in the amount of offset required to lock the shoulder down but not blow the works?

jim
wpt, ma

[Zach Dillinger]

Oh man that was a genuine title? that IS irritating. Almost like calling any tool chest an anarchists tool chest, even if it is 100 years old

Ha! Glad to have met you the other day at the auction!

[Andrae Covington]

...I wonder if all species are equal, in the amount of offset required to lock the shoulder down but not blow the works?

When the peg is a much harder wood than the mortise and tenon pieces (say, oak into pine), I think it best to err on the side of caution with the offset. Wonder how I found that out?:o

227575

[Karl Andersson]

I had a similar experience to Andrae when making pine frame and panel doors - so instead of drawboring (on the second set of frames :mad:), I used bar clamps to pre-compress the joint and drilled and pinned straight through the M&T. The doors have lasted 2 years without any failure, so it appears to work. I've seen the technique mentioned in several older books, and it makes sense that softer woods would benefit from it to avoid blowout.

Maybe precompression will be the next "lost" traditional technique to be rediscovered...

[Megan Fitzpatrick]

From Moxon's "Mechanick Exercises" (but you'll need a 17th-century shilling):

"Then with the Piercer pierce two holes through the Sides, or Cheeks of the Mortess, about half an Inch off either end one. Then knock the Tennant stiff into the Mortess, and set it upright, by applying the Angle of the outer Square, to the Angle the two Quarters make, and with your Pricker, prick round about the insides of the Pierced holes upon the Tennant. Then take the Tennant out again, and Pierce two holes with the same Bit, about the thickness of a shilling above the pricked holes on the Tennant, that is, nearer the shoulder of the Tennant, that the Pins you are to drive in, may draw the Shoulder of the Tennant the closer to the flat side of the Quarter the Mortess is made in. Then with the Paring-chissel make two Pins somewhat Tapering, full big enough, and setting the two Quarters again square, as before, drive the Pins stiff into the Pierced holes."

(I pulled this from Jennie Alexander & Peter Follansbee's new book, "Make a Joint Stool from a Tree" – lots of good stuff in there from their research into the form.)

Megan

[Pat Barry]

Is a shilling about the same as a dime or a quarter?

[James Owen]

A 17th Century Shilling is approximately 1/16" thick.

[Bryan Schwerer]

A 17th Century Shilling is approximately 1/16" thick.

I couldn't find one of those on ebay.

[Sean Richards]

I couldn't find one of those on ebay.

Don't worry someone will probably start making a bronze version ...

[Bryan Schwerer]

Don't worry someone will probably start making a bronze version ...
I think I will hold out for the aircraft aluminum machined to .0001" version.

[Jim Matthews]

A 17th Century Shilling is approximately 1/16" thick.

Like I said...
It must be my accent, it dinnae hae heft tay me wards...