Mortiser Bushing help Woodtek 924-020

[lee cox]

I bought a used Woodtek Mortiser floor model 924-020. I was given 2 bushings a 5/8" and 3/4". The 3/4" has a threaded brass insert. The 5/8" bushing has no insert just a hole. So my question is how are the bushing suppose to be setup on the Woodtek? Do you use a set screw to lock the bushing to the chisel and then put the bushing in the machine and use a set screw in the machine to lock the bushing in? Should I drill out the brass insert and use a long set screw in the machine go through the bushing hole to clamp against the chisel? I am not sure how the bushing should be setup. If the 5/8" bushing is missing the brass insert can I fix it or do I need to replace it? Where do I buy replacement bushings.

Any ideas?