I have an old barn (early 1900's) I have just moved to my property. It is timber frame type and needs some repairs and the addition of a rear wall. I am not new to woodworking and I have been studying how the other walls are made. I have some material from another pulled down barn that I intend to use for the repairs. My question is regarding general fit. On well dried oak do you need interference fits on the joints before pegging and do I drill the peg hole slightly off center to pull the joints together firmer. On my joint I can drill both pieces together or drill one part, mark the center on the other piece, and drill off center and then assemble and drive in the pin. Ideally I should be able to put the pin in shear. Which of the two methods is typically used for repairs. This is my first attempt at peg and beam joints so any wisdom or nifty tricks on the subject would be appreicated.

I'm not sure what you mean by "interference fits" on the joints. We were taught that the new piece and the old piece should fit exactly together with no gaps first. Then bore one set of holes in one piece while they are apart, usually the piece with the mortise. Next, put the joint together and run the drill in the hole and poke the tip into the other piece and use this location for the beginning of the off-set for your draw bore hole. After, assemble your joint and put the tapered peg in and it will pull the joint together for you very snuggly.

Others may say you don't have to offset the peg hole if both pieces of the stock are truly dry, but it wouldn't hurt if you are careful and do not over do the offset hole location.



Each type of repair, based on location of the timber being repaired, may require different types of repair joints. Understanding the load being placed on the timber and the repair joint is important when picking the repair joint to use.

Good luck with your project, and keep asking questions.

Barnmover, what you have described is called "Draw boring", as Jim indicated. Just remember to offset the hole in the correct direction. This is important.
Also, there are several ways to go about pegs. Most people use Oak, but some other hardwoods will work. You can purchase turned pegs, or you can make them yourself. I never thought I would make them myself until someone showed me how easy it is. You do need to make a shaving horse(Jim has plans he shared with me). Then you need a draw knife(which I bought from Jim too) and a froe. You simply split an green oak chunk with a froe into square sticks, then shave them on the horse with the draw knife. Once you have your split squares, you can make tapered pegs on the horse at about 60 seconds a piece. Just keep the split squares wet, like in a tub of water, until you shave them. Keeping them wet makes them easier to shave.
Do you know how to post pictures on the internet? It is very helpful to post pictures when asking for advice on a specific repair. If you are new to posting pics, PM (private message) me and I can help.

Politically incorrect way to remember drawboring heard at a workshop: "To the shoulder will hold 'er".

Thanks for information on drawboring. I will likely need it when I want to peg the joints. I am still in the information gathering stage of my repairs and trying to select sound timber of a correct size to make the repairs. I will likely need some recommendations when I am farther along. I think I have a good rear wall design based off the front wall. The rear wall needs to attach to (4) 8" timbers with partly rotten ends. I will post drawings and pictures for a sanity check before even picking up a saw. I have found that a few extra sets of experienced eyes is the next best thing to experience.