Thanks for the suggestion.
Maybe, is perhaps the answer.
Having done several bags, the possible problems might be:
a. To find a punch of the correct diameter.
b. The risk of the cut fibres fraying. That’s maybe not too much.
c. The challenge of getting and then supporting the bag (along with the block beneath the bag, onto which the punch will strike) at the right angle in order to get a good whack on the punch. Depending on where the owner wants to put the socket onto the bag, it can sometimes be a bit of a fiddle to line the bag up. My method, using the socket’s metal washer * as a template, a block of wood and clamps is sometimes a bit fiddly but, once set up, it does work. With the punch, I think you would need something like a fairly robust cobbler’s last (dad used to have one but I have no idea what happened to it) to put inside the bag. Then maybe a third hand to hold the lot in place, before you whack.
I have a variety of the simple ratchet clamps, which have come in handy. Once clamped, they are very efficient at holding things in place. Depending on where the socket needs to go, the larger bags can be quite deep (requiring longer armed clamps) and a bit of a fiddle if the socket needs to be on a curved portion of the bag. When the 30mm nut is tightened, the soft plastic of the socket does distort a bit, giving a good seal to the curve. But a nice flat part of the bag is best and easiest, obviously.
* I’ll be stuffed using the soldering iron method, should they ever make the washer plastic. I’d have to get a metal template made. That’s now got me thinking. If I got one made, I could make the outer area of the template wider, making clamping a bit easier.
