The constructive idea of the future case implies the sheets fitting with a threaded joint in the end surface. To realize this idea and make the device look nicely, it’s necessary to machine the end surface impeccably, for example with a milling machine. Unfortunately I don’t have a milling machine, that’s why I had to invent another technology…
We need an angle grinder with cleanup and emery disks, two steel angle bars and some clamps. The essence of the technology is simple. Fix the processed sheets between angle bars and erase all protruding elements with the angle grinder. The angle bars serve as a guide and don’t allow the angle grinder cut deeper than necessary. The process is illustrated in the photos below.
Grip exactly by the shifting gage mark. (For those who don’t know – shifting gage is bench tool resembling a trammel and allowing to mark the work pieces. It has a sharp pobedit end which makes distinct marks by scratching the work piece in necessary place.)
Perform rough deseaming with a standard cleanup disk. Don’t forget about protective spectacles.
Make final processing with an emery disk. It’s funny but the best is a disk with the roughest abrasive… with 1.5-2 mm grains!!!
At final stage of flattening, process with the whole surface of disk. Give a rest to the angle grinder; otherwise it will burn out. If its casing has heated up to 50°C the inside temperature is nearly 120°C… bear this in mind.
The result is almost ideal; I was surprised… And the work didn’t take much time. The first photo illustrates surface irregularities of 3-4 mm. I machined this edge for 20-30 minutes at most. In other words, we “mill” all edges of the case in two hours.
