It was really a combination of the tool threads with a bit of rust and that messed with the threads on the bar. Cleaned out the tool with the tap and use the die on the bar and it is smooth sailing. As a matter of fact, I received my collets today and the box of endmills from kpotter, I really like the 3/4 inch one and i am about to order a boring tool, larger face mills, some ballnose endmills , chamfer bits, a fly cutter, and I am sure to order an er32 collett set I am sure when I get sick of using collets.

Part #0001 nema 23 motor mount for ballscrews made from 1 inch cast acrylic (my order for 6061 has not yet arrived)

Attached Thumbnails

 

Looks good,,,good luck in your endeavours!

The only reason I have a 7/16-20 tap is to be able to finish the Chinese R8 collet threads. This is a very common problem, it seems.
On a related note, as pointed out by another poster, the toolbit clamping setscrews used on various inexpensive lathe toolholders seem to have a wide variety of defects and differences in characteristics. I did the same thing, but a bag of M10 x whatever length from McMaster, and every time I pick up a toolholder, get rid of whatever is in there and put real setcrews into the holes. Annoying, but at least there is an easy solution.
By the way, Metron9, cast acrylic might not have the "staying power" of an aluminum part when used as motor mount. Nice paperweight, though.

Then Aluminum it is. I have some questions on the new (old) bridgeport boring head since I have started the motor mounts this weekend, finally made some aluminum chips AND found out how sharp they can be when using a 5/8 drill bit that makes very long big chips that wrap around the bit. (small band aid on left index finger)

I will start a new thread for the boring head though.
Pictures of the motormount in 6061 as well.

There is an update on the drawbar however. When I initially put the bridgeport boring head in the spindle there was indeed about 1/4 inch the darn thing would not seat. So I measured the distance the threads had to go in the tool and it was about 0.700, Since I know the tool threads did not even go that deep I pulled the bar put the die on the threads 3/4 of the way up and got my grinding cutoff tool to take off .150 Rethreaded the edge and it works like it should. Perhaps one of the spacers on the bar was missing or the wrong size but all the other comments on cheap tools and rethreading is a good idea before messing up the threads on your drawbar.