We bought a bunch of Newman rollers the older blue type with a square bar.
the frames are great except they have a plastic spacer inserted into the ends of the square tube.
These plastic spacer / inserts do a real poor job handling anything more than 25 ft/lbs of torque on the bolts without cold flowing and allowing the square bar to crush under the load of the bolt.
we can get the bolts to about 30 ft/lbs before the square tube begins to crush under the load of the bolt. Additionally the plastic will cold flow ( deform under the load) and be of little help holding the roller against the mesh tension and further colapsing the square tube.
To solve this issue we pulled the plastic insert and replaced it with a 1 5/16 inch length of 3/4 diameter EMT electrical conduit.
http://www.lowes.com/pd_72713-1792-101550_0__?productId=3129553&Ntt=3%2F4+emt+conduit&pl=1¤tURL=%3FNtt%3D3%252F4%2Bemt%2Bconduit&facetInfo=Cut the tube to a little over 1 5/6 in long and grind the ends square. Simply insert into the EMt spacer as shown in the pic below.
This mod will allow the bolts to torque to at least 45 ft/lbs a value sufficient to hold resistance against the pull of the mesh set at 45 Nm.
The cost of a 10 foot piece of EMT tube is way less than $5.00 and has proved quite successful as a spacer and load bearing element.
mooseman