Several of the chests I’ve used to inform this demonstration have been put together with treenails (trenails/trunnels/pegs etc.) I’ve used pegs for drawbored mortice and tenon joints quite a lot. A dowel plate is traditional for pounding them to shape and I’ve had some success with this method. It’s noisy work and sometimes I don’t get the straightest pegs but it does have one structural advantage – the pegs follow the grain of the timber.
Last summer I visited the Viking Centre near Ribe in Denmark. I was delighted to see them using an identical method but for much larger pegs. Their living history exhibits draw on a substantial body of research and I’m assuming that there is evidence that this is historically accurate. I’d welcome your corrections if I’m wrong.
However I rarely use the plate anymore. For this task I’ve chosen the “workmanship of certainty” over “the workmanship of risk”1. Partly because it gives more consistent results, partly because it’s a lot quieter but mostly because I get to use a really great machine!

Boring the holes at an angle draws the scarf together. So they say.
In the interests of full disclosure: some of the treenails used in this chest will be pounded out by hand in a thoroughly medieval fashion but most of them won’t be…