pegging scarf joints

[hayton1960]

I had a look in the archive but didnt find out about specifically how scarf joints are pinned

EG if you have a stop splayed undersquinted and wedged scarf (fig 11 page 49 of Jack Sobon's book Historic American Timber Joinery) How or at what stage are the pegs put in? Wedges first? Pre-tension and pin? Some sort of offsetting as in drawboring mortice and tennons? Would it help to put a wedge either end of the peg (like a windsor chair leg joint) to keep the 2 halves squeezed together, as in fig 22, page 51 of same book? What advice does anyone please have ??? Cheers Jonathan

PS, I will have to do 4 scarf joints as the timber suppliers here cannot supply 5x5x14 foot but I can get 5x5x8 foot; 2 plates, 2 sills.

[Raphael]

  What I did with the one in my addition was lock it together with just the wedges until I had the complete frame up, then I retightened the wedges, drilled and pegged.  Most of the illustrations I've seen have the pegs angled and driven from oposite sides.
  Draw bore isn't really needed in an end to end timber join since timbers don't shrink much in length, and the amount of shrinkage over length of a scarf joint should be negligible.

[hayton1960]

Thanks for your reply Raphael

Am I right in thinking that the wedges put some tension in the joint and the pegs help to retain it, and also to keep the 2 halves together and in line and stop them twisting etc??
Also do you think the stop splayed example I mentioned would be too excessive for a floor sill? Would a simpler scarf suffice for that purpose? Is it that the 2 or 4 pegs are arranged like when you do skew nailing or dovetailed nailing so they wont pop out as easy?
Many thanks, Jonthan ;D

[Raphael]

Am I right in thinking that the wedges put some tension in the joint and the pegs help to retain it, and also to keep the 2 halves together and in line and stop them twisting etc??

  That's the basic idea, more resistance to lateral forces than twisting.  undersquinting helps prevent twisting more than the pegs will.

Also do you think the stop splayed example I mentioned would be too excessive for a floor sill? Would a simpler scarf suffice for that purpose?

  Probably, especially if you've got a poured concrete or other solid perimeter foundation.  My sills use a simple half lap with bridled tennons.

Is it that the 2 or 4 pegs are arranged like when you do skew nailing or dovetailed nailing so they wont pop out as easy?

  Yup, that's the generally idea.  I'll have to take another scarf joint picture, I have five in the gallery but none post pegging.  In my case I used 3 pegs as the fourth would have wound up crowding a knee brace.