Everything came together for the first real use of the forth axis mandrel for ring carving. It’s nice when the plan comes together and everything works as intended. There was of course far more than just making the mandrel. There is the CAD design stage and the CAM (Desk Proto) for generating the G-code for the 4th axis. Then running the G-code on the micro-mill. I use LinuxCNC and I had to write my own metric post processor for Desk Proto. Not all that hard, actually. I made a USC (inch) version too. One tiny code change.
The first picture is the carved ring blank on the mandrel. I can accommodate a wide range of wax sizes. There will be much more experimentation and determination of the correct wax width for a project. This example worked fine.
The second photo is after the wax master model was hand finished and at this point is ready for casting. Sprue’s were added the ring put into a flask and the investment added. This post is not about the lost wax process. However, I thought it was interesting to show the wax carving and the final result the mandrel helps create.
The last picture is the finished Sterling silver ring shown on my hand (size 11). It really looks great. I will be doing a lot more wax carving on the 4th axis of the Taig micro-mill.
I was self taught in brazing and soldering metals long before I became certified By Harris Industries (Now called the Harris Products Group) about 35 years ago. Nothing has changed about the processes in all that time. It is a skill that can easily be developed and improves with use or practice. Most skilled hobbyist can quickly master the basic technique.
What is required is an understanding of the science and what is going on in the heating process. I have always needed to know the why of any process before I could truly master the how. Silver brazing is a process a machine can be set up to do perfectly every time on an assembly line; but not until all the variable factors are preset and under control. A human operator in a mixed environment must understand all the variables and observe and modify the process “on the fly” to make a perfect assembly.
I am not going to explain the process here in the blog. Just Google Silver Brazing and you will find all the how-to you will ever need. If you are close to Ohio you can still go to the Harris factory and take a two day course. My course was for making piping joints but the process is still the same for model train parts.
Correct heat and the correct tools for keeping that heat under control is critical. Also the prep work is the key to successful joints. Playing with the big flame seems intimidating but with practice it just becomes a comfortable step in the process.
Every trade from jewelry makers to pipe fitters has mastered the processes of brazing and soldering. For model builders it ought to just be another skill in a big bag of tricks. It is a fun… Continue reading