wobblycogs

Yes, that sounds about right (it was a few years ago now that I built that though). You could certainly get away with less timber. The legs only need to be 150mm if your joints are good and tight and you'll probably only climb one end of the tower as well so you could leave out all but the top and bottom rung on one end. This is construction timber though so it's not that expensive and if you don't glue things most of it can be re-used (I've just built a router table from some of mine).

Thanks, glad you liked it. I'll consider bumping up the difficulty level.

Glad you like it. Personally I prefer the design in the attached photo. I came up with idea a few years ago. It's two pieces of dowel rod with metal clips attached using eye hooks. I forget what the clips were sold for, I think it might have been to hold papers together or something like that. Any small metal clips would do.I would have used this design again but it wouldn't work on a map that wants to roll itself back up all the time.

I don't know where this vice comes from as it was a gift but it's clearly a knock off of an older design. The iron that came out of the casting as I drilled seemed pretty poor quality but it's held up so far.

Cheers, I've had a few people say they have a vice with this problem.

What a great idea. The only thing I'd add is that you need to tell the kids not to try and swing off it!