Ulster style screen tube sizes

[John P]

For a very long time I've been intending to make an Ulster style folding screen and have already been given a lot of advice.  However I'm still a bit vague about the various tube sizes used for the main bottom tube and also the swivel tubes around which the main tube rotates.

From some old instructions which apparently accompanied a windscreen kit it looks as though the main tube should be 7/8” diameter brass and from the photos I've seen this has a fairly thin wall thickness which I was just guessing was probably 16 SWG.

What's confusing me however is that on e-bay someone is selling what he describes as the “Wingnut Clamps” which are the headed sections that fit inside the swivel tubes.  These have a shank diameter of 1/2” and head diameter of 5/8”.

Does this mean the the bottom tube really needs to be 7/8” OD and 1/8” wall?  If so presumably the swivel tubes would be 5/8” OD and 1/2” ID.

Any input would be much appreciated.

John.

[Robert Leigh]

Willie MacKenzie  http://austinrepro.com/specialised-products/  can supply what you need although he only lists complete screen assemblies. He may be prepared to supply just the components you want. The tube and fittings are the same type on a Chummy windscreen, so find a local one and ask to check dimensions. If you are local to me come and look at mine.

[Charles P]

The “wing nut clamps” don’t have to be the exact same OD at their “fat end” as the swivel tubes. It doesn’t much matter if they are 5/8 at their largest and the swivel tubes are 3/4, it all still works and the clamping action on the screen is the same. It matters more that the wing nut clamp is a good sliding fit in the bore of the swivel tube.

Charles

[Chris KC]

As Charles says, I think they are a fairly slack fit in the tubes.