The past few weeks I have been unable to make a blog post for some reason or another so here is an update on the tube. (spoiler: I finnished)
I finished off the final passes on the tube and realized that trying to use the ball endmill to add a radius to the flange tube interface was more trouble than it was worth. I was able to achieve a much better surface finish by using the regular wide angle turning insert which had a radius about half that of the radius I hoped to get on this feature. The great part about being both the designer and machinist is that I can change the design to make the machining easier.
Although I had tried to design for manufacture, the button inserts for radius turning are a lot more expensive than I had originally thought, so I reduced the fillet radius to allow my turning insert to naturally cut it. I determined that the improved finish would make up for the change in geometry in this feature, especially because of its very minor load case.
after finishing on the lathe, I created a drawing to help me input the coordinates of each hole. I then used hold down clamps to affix the tube to the mill bed and used the diagram to center drill each flange hole. I then drilled and chamfered each hole. I repeated this process on the other side of the tube with 3 slightly different holes in addition to the holes in the same locations on the other side. Notably I had to use 2 drill bits, placed in the holes of the first flange, and used parallels to generally align the holes from the bottom to the holes on the top.
Next I used an oversized drill bit and my fingers to chamfer the back side of each hole (which took an ungodly amount of time and pain). and with that done, the only remaining step with the tube is to polish its ends on our granite block before we seal it. I will not do this step now, as ruining this finish will be inevitable and I don’t want to polish the tube multiple times.
