the pic that burntorange posted pretty much is the tits, just make a pattern then trace it on a block of aluminum of the thickness you'll need and drill out the holes and cut it out with a band saw or hack saw. smooth it with a table sander or hand files. you'll need to buy 3 1/4" x 20's the length you need. i also made one out of 2 pieces of 3/16" steel plate and a 1/2" tube of the length you need. make a pattern for the 2 plates, finish the on a bench grinder or hand file. drill the holes and weld them to the tube. use the bolts that attach the filter to bolt it to the valve body and use 3 1/4" x20 shorter bolts and nylocs to bolt the filter on.
