Draw-boring tenons

[newt]

Just been reading the article by John Lloyd on draw boring tenons in the latest issue of British Woodworking. On page 31 pic 4 he suggests that you could put a 1mm spacer between the stile and the rail shoulder (on the tenon), and then drill straight through the mortice and the tenon, this will give the correct offset on the tenon of 1mm. Surely this would put the 1mm offset in the wrong direction. Or am I missing something. Found the article interesting particularly rubbed joints.

 

[Chems]

That is the wrong direction. What a cabbage!

 

[OPJ]

Haven't seen the magazine yet but, it doesn't sound right to me, either.

 

[Benchwayze]

George Ellis says:

Drawboring is a way of pulling together a through-mortice and tenon joint when you don’t have a long enough cramp to span the work. The tenons are left about 1.5 inches longer than required.

Drive the tenon home, and mark the outer edge of the stile on the tenon.
Take the joint apart and bore a 3/8” hole through the tenon, dead centre on the line.

When the joint is pushed home again, the hole will project half-way outside the stile. Using a drawbore-pin, tap down so it draws the tenon closed whilst the glue dries.

George also says:

The hole in a tenon for a ‘draw-pinned’ joint should be about 1/16”
(App. 1.5mm) nearer the shoulder. (Got that wrong 1st time around. )

I’m not going to argue with George, so:

Using the spacer method would make it 1mm further away from the shoulder and would push the tenon out when you pinned it. Yes?

Someone isn’t thinking right. Of course, it could be me! ](*,)

John

 

[JoinerySolutions]

The article is incorrect.( based on what is in the OP)

The offset is always towards the shoulder of the tenon so the peg or dowell pulls the shoulders tight to the morticed material.
The amount of offset will depend on the timber species and sizes of components and in timber frame structures an allowance is made for whether the peg is riven or not.

Rob.

 

[ByronBlack]

This is part of the reason why I no longer read british mags. Poor effort.

 

[Paul Chapman]

Some stuff by Chris Schwarz on draw-boring http://www.youtube.com/user/LieNielsen# ... AkWMHDKB-E

and http://www.youtube.com/user/LieNielsen# ... G1jNQzwvQ8

Cheers :wink:

Paul

 

[matthewwh]

If you read the article itself it describes how to do it correctly - nicking the tenon with the tip of the bit, disassembling and then moving the centre of the hole towards the tenon shoulder. The Article is right and the photo is right, it's just the blurb underneath the photo that is incorrect. I'd hesitate to point the finger at John for this one.

There are a couple of other inaccuracies, frinstance on p10 they give an update on the Clifton Anniversary planes and woodwork repetitions should be woodware repetitions (and he missed a supplier....:wink: ), on p51 they have Axminster selling LN fishtail chisels for £6w each!

Having said that, editing a mag of this quality and running the company that produces it, and being a roving reporter and writing articles for it yourself is a very tall order and I reckon Nick does a cracking job considering the massive workload he is under.

 

[Streepips]

Well reading some of the above, notably a point made by George Ellis, that John is not going to argue with, I will take it upon myself to at least question if not argue..
He states that the offset used in a drawbore should be 1mm, then goes on to equate that with about 1/16"
Now as a near enough guide there are 25.4mm to the inch... so that means an inch is 25.4 1/16ths
Or the other way round:
and inch is 16mm...........

Even as rough guides this is appallingly bad advice, especially if taken literally by novices, which often it is.
Who is this G Ellis?

Oh and by the way, if a 1/16" is all the offset you are going to use I wouldn`t even bother.

 

[Benchwayze]

Well Pips,

I spent my entire schooldays and a good chunk of my working life with
£ s d, inches, feet and yards; miles, chains rods and perches. ( Not necessarily in that order ).

I am not much of a metric person and I find the system clumsy. In fact I did read that it was originally based on an incorrect measurement from the North Pole to Paris? That may or may not be true! Oh… I did have ten years talking in fathoms, knots, cables and leagues, but that’s by the by.

I apologise for not being able to visualise metric measures; (a centimetre looks near a half inch to me. (App. as I said before), but I suppose it isn’t so.

I do know, give or take a whisker, there are 25mm to an inch, and there are 10mm in a centimetre, but that's about my limit. I have to read the rule for the rest I fear. The rule I have is a bit worn... :wink:

And the 1/16” distance from the shoulder to the ‘drawbore’ is just about right for softwoods. Any more and you might find the shoulders distort the joint and it looks as if it’s cramp-bound. Hardwoods might stand a little more of course.

So, I’m sorry I mucked up my post.

Now I am going to have a cup of Horlicks, don my nightcap and bedsocks, and hey ho for an early night. I clearly need my sleep, having made such a glaring error, by calling a millimetre 1/16th of an inch!


TTFN :lol:

Edit...

I just saw your query on George Ellis. He was the author of 'Modern Practical Joinery', (Not so modern now of course). In his day he was as much an authority on Joinery as was Alan Peters on cabinetmaking.

Methods change. Our material doesn't and we still have work with the same stuff. if you can get this book from the library, I'm sure you would find it interesting, even if there isn't much you could learn from it.

John :wink:

 

[ByronBlack]

1/16th = 1.57mm

Either way it aint that much, but if reversed will produce one ugly gap.

 

[Streepips]

.John,

Please realise that no inference was intended that the error was yours, it was the statement by George Ellis that I was commenting on.
I too was brought up with Imperial measure, right back to farthings and hundredweights, half crowns and yards, so I find the metric system a bit of an imposition too but I keep certain comparisons in mind, 3 m is 10 feet, 1.8m is 6 feet , 2.4m is 8 feet, 18mm is 3/4" and so on. Not absolutely accurate I know, but near enough for a visualisation.

I generally judge the overlap by eye, about a 1/3 in softwood and less in hardwood. and often use square pegs. Yes square pegs in a round hole. Obviously whittled for a starting taper. These serve two functions other than the original one. The sharp edges tend to cut in and relive any undue pressure so the wood gives until it is "comfortable" with the pressure, and it is certain not to rotate and so any chance of the joint racking is minimised.Point two is that the square pegs are decorative as well as being functional.
I often to use oak pegs as well, whatever I am working in. If its a clear finish the oak end grain is far nicer to see than a softwood dowel end.
As for over pressuring the joint and giving a "cramped" effect, I have never had that and most of mine are on the side of tight draws, and I have found that any that happen to go in with minimal effort allow the joint to open a little due to tangential shrinkage of the stile, whilst this of course effects the tenon as well the ratio of the length of the rail and the length of the tenon means the shrinkage of the tenon tends to tighten and pull in rather than allow the rail to shrink away from the stile.
I made a stable door that has lasted for 25 years put together with just drawbores, no nails screws or glue and as far as I know its still in use, if it is then its 30 years

 

[timesale]

I just discovered your forum, and saw the topic on draw boring. I just tried draw boring for the first time, and found myself drilling the hole slightly off. So I came up with an offset punch, it made it a little easier. I took a 1/4 inch piece of steel, and drilled a 1/16 inch hole off center. Then tapped it into the hole to mark the tenon.

I tried to post a picture, but I'm having a little trouble getting it to post.

My apologies

 

[CHJ]

I tried to post a picture, but I'm having a little trouble getting it to post.
..

Welcome timescale, Forum anti spam software will block your attempts at picture posts or url links until you have made 3-4 posts.

 

[timesale]

Thanks CHJ, I guess I'll get the hang of it. I usually don't post much in other forums since I seem to learn a lot more than I have to offer. I'm glad to find another woodworking forum to read.

 

[woodbloke]

I missed the bit about the draw boring but picked up the machinery review of the Charnwood W650 tablesaur. I emailed Nick yesterday about it and he confirmed that he was much taken with it when he reviewed it, as I was when I saw it at Yandles in April
Edit - as it's far too early in the morning to envisage this, I made a little model out of a couple of Post-It notes and tried it...definitely poor info, the shim idea moves the tenon the wrong way - Rob

 

[Derek Cohen (Perth Oz)]

Mark the position of the hole for the cheek about 1/16” closer to the shoulder. This distance is arbitrary. It depends on the bend characteristics of the dowel. A hardwood will flex less and so you would not want to offset the holes more than neccessary.

http://www.inthewoodshop.com/Furniture/Drawboring.html

Regards from Perth

Derek

 

[Karl]

Edit - as it's far too early in the morning to envisage this, I made a little model out of a couple of Post-It notes and tried it...

:lol:

That is exactly what I did yesterday!

Cheers

Karl

 

[OPJ]

Having said that, editing a mag of this quality and running the company that produces it, and being a roving reporter and writing articles for it yourself is a very tall order and I reckon Nick does a cracking job considering the massive workload he is under.

I quite agree. Even though mistakes like this do happen with some regularity... Admittedly, this is a bit worse than a mis-spelling like "Competion" (last issue :wink but, people don't always acknowlegde the fact that Nick does pretty much all of this by himself and it's funded by his savings (though, I think he tries to be quite modest about it). When he's not working on BW, there's still Living Woods and Small Woods as well. :shock:

It is disappointing to see this happen in other British mags though; particularly where they have a larger editorial team and an external publishing house on board. Individuals have offered to proof-read Good Woodworking in the past (though, I haven't noticed any glaring mistakes for a few months...) but, would anyone really want that job, even if it payed? By the time the magazine hit your door mat, you possibly wouldn't feel like reading it...

Sorry, I'm answering a question that nobody has asked!

 

[woodbloke]

Edit - as it's far too early in the morning to envisage this, I made a little model out of a couple of Post-It notes and tried it...

:lol:

That is exactly what I did yesterday!

Cheers

Karl

Great minds, Karl, think alike! :lol: - Rob