pegging roof rafters

I have attached a 10x22 shed style room to the rear gable end of my barn. The rafters are 4x6 @24" o/c. I have cut step lap rafter seats on both the wall plate and the upper girt that suports the upper end of the rafter. The rafters are locked in and fit quite nicely. I need to fasten down the rafters to the plate and girt. I purchased 8" TimberLok hex drive screws, but I would like to use a more traditional method of fastening, ie, white oak pegs. I am not sure how to do this. Is the peg hole drilled on an angle and is the top of the peg square to help lock it in? Any help would be appreciated. Thanks, John...

John: If you haven't already you should download Jack Sobon's History American Timber Joinery, A Graphic Guide from the TFG website, or purchase the new book of these articles. Especially part 5 Roof Joinery Excluding Trusses. It has several examples of what you are looking for, such as drawing #9 on page 4. It shows a step lap rafter seat and tail with a peg hole perpendicular to the roof plane. Good luck with your project. Jim

Hi John,
As for your question it sounds like the Historic Joinery series suggested by Jim would be a good place to start.

My question for you is how you cut the joints for the upper ends of the rafters. Did you cut step lap rafter seats in the top of both the lower wall plate and the upper girt? What is the roof pitch of the shed? I've always wondered what the best/proper joint is to use at the top of a shed roof.

Thanks,
Chip

Hi all:
Just a small additional note from my storage of historical notes. I have observed a dovetail type of attachment at the upper end of the rafter at the seating point on the girt. I know this is a little more work but it will hold the rafter from any movement out of its seating, and all that was used was one blacksmith made square nail to keep it in place. I believe the use of one oak peg will do the job as well as the nail, but I always revert back to what the old tyme framers used, and they did use dovetailled work in many instances where the attachments just couldn't move, NH

Hello Chip, I cut step lap rafter seats at both wall plate and top girt. The shed roof has a 4 on 12 pitch. I looked at the picture from Jack's article and it appears that the hole in the rafter is square. If the hole is square, how deep?, is the peg octagon with a square head?, and how long? Any do's or don'ts? Good to hear from you, John...

Hi John,
Well, I looked at the drawings in the Historic Joinery. Every relevant example shows that the peg hole is round in both the plate and the rafter.

The pictures of the assembled joints show the peg flush with the top rafter surface and square in shape.

The text accompanying the figures says "a squarish pin through the tail secures it". Figure 10 also mentions a squarish pin.

The answer is in the Historic Joinery Wall and Brace Joinery article. Figures 12, 13, and 14 clearly show a square pin and round holes used for lapped brace joints.

Because the braces and the rafters are a type of lap joint they have the potential to work loose. The corners of the slightly oversize square pins will "bite" into the wood of both pieces to help hold the two parts together.
Chip