Glueing scarf joints

[Larry Gallagher]

I'm hoping to tap the collective wisdom for experience and/or pointers to web resources.

I'm planning on making spindles for a project (an hourglass) out of two contrasting woods (maple & bloodwood, likely). They'll be on the order of 3/8", square cross-section. For visual aesthetics, I'd like to join them end-to-end with a scarf joint, cut at 45 degrees (if that actually qualifies as a scarf joint?). They'll be taking some light compression load as well as lateral load (figure people will pick it up by the spindles). My questions are:

1) Will a 45 degree cut suffice for gluing the joint without additional reinforcements?

2) Should I go for something like epoxy because of the quasi-end grain nature of the joint?

3) I'm considering reinforcing this with a thin dowel along the long axis (completely hidden).

I suspect my glue joint will hold up at least until I get it out of the shop, but may not survive much wear-and-tear. The interior dowel ought to hold, right?

TIA,

Larry

[Dave Jackson]

Larry , (1) Using just a scarf joint would work, but probably not for long. (2) I wouldn't rely on epoxy to solve the problem. (3) Adding a dowel would definately help.

You have options here. I scarf joint/dowel is the easiest thing, but probably not the best. If you think you have the skills and/or material to practice on, I'd suggest one of these joints. They are aranged from about the easiest, to more difficult:

1 half lap (maybe even pegged with another contrasing wood?)

1. slot mortise and tenon
2. sliding dovetail (this might look real nice here)
3. finger joint

There are other ways also, but these should get good results. --dave

[Charles Spitzer]

i've always heard that a scarf joint should be something like 5:1 or 6:1 to be effective. that's far from 45 degrees.

[bridger]

45 degrees is 1:1

if you're going to scarf them and want any strength, consider a scarf the full length (or close to it) of the spindle. it'll look very cool, be a lot easier to clamp and be about as strong as solid wood.

[Lawrence Wasserman]

Regular yellow glue combined with the dowel should be good for this application. IMO no way will the 45d butt joint be strong enough by itself.

[Lew Hodgett]

Anything less than about 8:1 can hardly be called a scarf.

Forget a 45 degree cut, it won't work.

HTH

Lew

[Andy Dingley]

Not a hope. Stick a dowel in there.

You could also make it like a pool cue butt. Those are parallel laminations, not scarfs (so no end grain problems) but because it's a tapered spindle, you get the same visual effect.

[Lawrence Gallagher]

Thanks to everybody who replied to my questions. In the end I did dowel this joint, and (knock on wood) so far so good.

I'm posting a picture of the finished project on a.b.p.w

Thanks again!

-Larry