If so I'd be interested to hear what mainspring you used, and if you had to increase the barrel size. I'm currently completing one for a family whose horologist father started one 20 years ago, but never completed it. Having worked my way through various issues I now find that the mainspring that came with it, and appears to be new, won't allow a full 8 day wind on the fusee. I had a longer spring which will give a full wind, but being slightly thinner its power is not enough to keep it going reliably. Measuring the barrel ID, the arbor OD, and applying the formula to calculate the mainspring length, gives me a length which is even shorter than that of the spring I already know to be wrong. I've also found this comment on a forum, John Wilding Elegant Scroll Skeleton Clock | Model Engineer All this is leading me to the conclusion that a mistake has been made and, given the cost of fusee springs, I'm reluctant to start experimenting. My current thoughts are that I'll need a thicker, and longer spring, which will necessitate making a new, and bigger, barrel. This I can do, but if anyone has come up against this, and can give me some advice I'm happy to hear it ! Cheers, and thanks, Ralph. N.Z.