Tony--
Bolt the lock plates to your solid 4mm plates, providing they are completely flat lock plates using the appropriately shouldered bolts, with the appropriate holes drilled in the 4mm plates for attachment from existing holes in the lock plates.........then load and pack tightly in the crucible....you don't want them to move....at all....use caution......PLUS, the 4mm plates will act as heat sinks and collect the heat and increase the heat/temperature -(larger mass)- "that is maintained" for the lock plates throughout the process and stability as you quench, and the colors will also be improved as a result........
Most actions should be assembled when loaded in the crucible with special fixtures (that you make) bolted in place to make one solid firm unit, which retains heat better as a larger solid mass (less the internals of course), therefore cannot move and the colors are enhanced as a result ......the single mass unit retains heat much better than single small pieces by themselves.......problems occur if the parts are not properly secured in this fashion.....
Mike:
Thank you sir....your work is outstanding and speaks well of your talent and attention to detail.....
I started doing my own CCH about 25 years ago and I am always learning......like you.....it takes a lot of effort and practice runs with test pieces every time you change formula's....but it is fun......and rewarding......
Best,
