While waiting to get delivery of a 1.5 mm FC3 end mill to mill the slots in the port face of the Trojan, I decided to continue with my version of a QCTP (Quick Change Tool Post). I have been looking at various ready-made items, but found them too expensive for my liking and after finding the drawing(s) at the Ishimura site I knew I had found what I was looking for.
The only difference is that I had to modify the size to better fit my SIEG C3 machine. when that was done I started to hack out the main block an old cast iron iron

Some finishing off made it more looking like a what was a tool post to be.

The locking sleeve came next out of a piece of 40 mm BMS.

And the two put together it looks as follows.

The came a centercolumn to be the center and the clamp to secure the whole thing to the lathe top slide. Some arms and at a test setup it looks like this - sorry for no pics in between).

At this stage the whole project ran into a standstill until just recently. I badly wanted the QCTP functionality and a desire to finish something off - well partly that is - made me have a go at it again.
A 12 mm dia silver steel plunger was made to suitable length to act as locking piston and an arm of suitable design was attached to the sleeve and finally a lick of paint giving the same test setup the following look.

As can be seen there is a first tool holder as well!

a typical standard one.

I made a batch of 12 basic parts to become new tool holders. A few of the other types made so far are:
The boring bar holder

The threading tool holder Mike Cox type but with a dove tail instead of a mounting bar.

This is a flip-up variant which looks like below when flipped up

... and finally one of the standard types to be. Only drilling and threading left to do.
The QCTP works very well and locks the holders firmly and repeatably as intended. More holder of other types will show up every now and then.
BR
/Peter