After multi-year hiatus, I’m planning on getting back to getting my Maslow up and running. I’m leaning toward using unistrut for the top bar.
Unistrut isn’t to be found in the common box hardware stores here in New Zealand, but they do have a distributor found at https://unistrut.co.nz.
In the catalogue I see a bunch of options. What part number are people using? Slotted right? P1000T?
Thanks in advance!
That is what I bought for mine (not yet assembled) and is commonly available in stores near me (USA).
Incidentally, I called to get a price on the P1000T and it was going to be $40 per meter here in NZ. I’m now considering building a box beam for the top bar instead 
Yikes! I can get 10 feet for less than $20.
Here in the US “Superstrut” id the 1-5/8" Square tubular style ( which is what my frame is made from) . the “Unistrut” is half thickness i believe, and will have too much flex / twist in it.
Superstrut is just the Thomas and Betts brand for channel. Unistrut channel is made by Unistrut. Both come in 13/16” and 1-5/8” deep (among some other sizes). I definitely agree, for a top bar without a lot of other support the 13/16” would probably flex more than desired.
check with plumbing and electrical supply houses, it’s very commonly used for
holding pipes and conduit in commercial buildings.
In the US it isn’t in most hardware stores, but is in the big box home centers.
David Lang