Building a 16hp longtail I'm just going to use bushings
At both ends. I don't think I did a good job sealing the last longtail
I built I just sandwich the seals between two bushings.

What's another way?

Stack the seals on the outside of the bushings, not on the inside... stack 4 going out in out out and 2 in the top going out... The object is to keep grease around the bushings...

I did that but holding the in what I did was take a flang bushing
And sandwich them together on both ends should I have made a housing.

yes

You have a pic

Search harder.... There is a wealth of info on this site and this topic has been discussed many times... larger pipe welded over the end of the shaft housing

Ya but what holds your seals in ?

some form of cap, you can thread the outside of the housing to accept a cap to hold it all in, with a hole for the shaft... I guess you could tack on a washer at the end but if you gotta replace it know youll have to buzz off them tacks and reweld a cap on when youre done

I would think you would damage your seal pushing it past the threads

don;t push your seals past/over the threads turn them or screw them on like a nut.less chance of doing damage to them.

Just take some electrical tape and cover the threads.... slide on seals.... remove tape...