I am building a small 6 ft by 6ft trailer out of a scrapped mobile deer stand. Originally the spindles were welded at the very rear of the stand to give it a 3 point stability but the pipe they were welded to was nearly rotted off so I decided to move them forward and make a small utility trailer out of it by moving the axle forward, plus I wanted to lower the bed a little so I needed to make a drop center axle.
To do this I flipped my tilt top table over to utilize the beam as a welding fixture. I added a couple of scrap drop offs from my fork carriage project to lay the axle tube on then clamped the spindles to the table with bare wheels mounted on them to hold them square
this is what the fixture looked like and how the drop center axle turned out.