What taper to put on drawbore pegs?

[Eric The Viking]

I'm being a pain about this, I know...

I've got reasonably straight 8mm dowel and drill. Does the team think it's enough to just attack the end of the pegs with a pencil sharpener for a bit of a bevel, or is there a more scientific method I need to employ?

This is pine garden furniture incidentally, not a Louis XV monster staircase.



E.

 

[AndyT]

I think a bit of a sharpen will be just fine.

 

[Saint Simon]

Making sure the dowels have a nice straight grain, pencil sharpener on the dowels, heavy use of draw bore pins and not having drilled the offset holes in the tenons too far over seems to work for me (most times).
Simon
.

 

[Jacob]

Longer the better. So if your peg is 2" over length then gently taper the whole 2".
I think a pencil sharpened end would be too steep and you wouldn't get such a neat pull up.

 

[Racers]

Hi, Eric

http://video.pbs.org/video/2172740515

Thought you watched these :wink:

Pete

 

[Eric The Viking]

Thanks everyone - I think I've got it now!

Pete: yes I did watch, but my brain is the size of a small walnut these days.

Will undercut the tenon shoulders accordingly (very slightly!).

I think the mistake I've made is to use quite fat tenons (1" thick). I'm not sure if it'll work, but I will also make sure they're a slightly loose fit in the mortices before pinning, and try to go right through the leg (was originally going to make the back blind).

Apart from test fitting, do drawbore pins serve another function? I can get the alignment from the centre point of the
lip+spur drill, I think...

 

[Racers]

Hi, Eric

Belt and braces these days with modern glues.

Lip and spur drill will mark the tenons a treat.

Pete

 

[Jacob]

Thanks everyone - I think I've got it now!

Pete: yes I did watch, but my brain is the size of a small walnut these days.

Will undercut the tenon shoulders accordingly (very slightly!).

I think the mistake I've made is to use quite fat tenons (1" thick). I'm not sure if it'll work, but I will also make sure they're a slightly loose fit in the mortices before pinning, and try to go right through the leg (was originally going to make the back blind).

Apart from test fitting, do drawbore pins serve another function? I can get the alignment from the centre point of the
lip+spur drill, I think...

The pins act in place of clamps i.e. will pull the pieces together. That's the whole point, except they also pull them into alignment. If you can clamp anyway just do that instead and drill straight through - it's a lot easier!
Or you can use sharpened pegs in place of the pins and do it in one go.
Draw boring is in place of clamping esp for difficult shapes such as newel post to stringer. But it also helps to secure the joint as the peg gets crimped a bit and can't work its way out - which (surprisingly) they can do - it's to do with alternating expansion/contraction and a ratchet effect. Often seen on old window frames where the pegs can come right out under their own steam - over a long period of neglect.

 

[Jacob]

In fact here's a couple of snaps. Old window frame with dowels escaping under their own steam. They were found like this, not been pushed out or anything. These were square split dowels hammered into round holes in the trad way. The result is a taper - by the time they are through to the other side they have been squashed more round. I've seen this quite often.
My only explanation is as above - ratchet effect following seasonal humidity/expansion/contraction, perhaps with help from frost.

 

[Eric The Viking]

Thanks Jacob.

I'd seen old frames with the pegs sticking out a bit (say 1/4") in the past. I'd assumed it was just slight shrinkage. I'd never seen that before!

So I _will_ be applying glue, too!

 

[bugbear]

I'd seen old frames with the pegs sticking out a bit (say 1/4") in the past. I'd assumed it was just slight shrinkage.

Yeah - pegs are long grain, and normally set in the short grain of the workpiece, so it's good old grain direction clash.
BugBear

 

[Phil Pascoe]

I once renovated some box frame windows and found that all the pegs were actually twigs - which of course had dried out, and were half the size they should have been.

 

[Eric The Viking]

Thinking on it, are those pictures the outer corner of a casement - the opening side? I assume if it's been allowed to bang at all after the paint failed, the joint will have loosened up mechanically anyway.

 

[Eric The Viking]

I thought you might like to see the outcome:

The green stuff hides a multitude of sins (and shakes!). Anyway, the drawboring was easier than expected, although I'll do larger offsets next time: 1/16" was a bit too gentle and one or two tenons didn't pull quite tight. Still it's only rough and I used plenty of glue so it'll be fine.
The pegs look OK:

And the bottom slats are just pinned at the front with 6mm commercially-made dowels. I thought it gave a nice effect. I've no idea how long it'll last, but the slats (and planks on the top shelf) are easy to replace if they go before the rails do.

Thanks for the advice, everyone.

E.
(off to find some proper, traditional wood preservative for the next garden project!)

 

[longinthetooth]

In fact here's a couple of snaps. Old window frame with dowels escaping under their own steam. They were found like this, not been pushed out or anything. These were square split dowels hammered into round holes in the trad way. The result is a taper - by the time they are through to the other side they have been squashed more round. I've seen this quite often.
My only explanation is as above - ratchet effect following seasonal humidity/expansion/contraction, perhaps with help from frost.

Very lucid. (That's a compliment. You don't, of course, have to receive it graciously.)

 

[Jacob]

.....

Very lucid. (That's a compliment. You don't, of course, have to receive it graciously.)

Well foock off then, smart alec!

 

[longinthetooth]

I can't do what you suggest at all. It's just not in my culture to do that. Also I'm listening to some music, so if you could just pipe down a bit ...

 

[Eric The Viking]

Gentlemen, please!

You're upsetting my tomatoes...

 

[Sawyer]

George Ellis, writing in the early C20th. recommends a metal peg to pull the joints up, which is then knocked out and replaced with a wooden one. A long coach bolt of the right diameter, but heavily tapered on a grinder for about 3" should do the trick.