Now things are getting serious with the vise project:
This is the first prototype base. I got a bit more time to work on it this weekend while Lauren has been out traveling, so I was able to finish the entire part last night. This is the first time that I've been able to use a few of my roughing end mills and you can see the marks they leave with their serrated edges on the interior of the part. This is mostly due to a last-minute change from my original CAM setup - the 21mm insert end mill was a little too large, and the vise was set too far back, so the final program exceeded the Tormach's Y axis limit.
There were also a few other hiccups:
The vise has a few thin-walled sections that aren't very rigid, and the way I had the work set up didn't support them very well:
As you can see, there's a bit of overhang there.
(Side note: You can see my perhaps-overly-clever, not-very-rigid workstop setup where I abused the crap out of a cheap dial indicator and a magnetic base. The Edge Tech vise stop that I got sticks out over the portion of the fixed jaw that's attached to the vise, so when I have the jaws on the outside I can't use it. Rather sad, that; but I was able to work around it with this setup, and the results were fine. I'm considering machining another holder for the stops, though - or maybe I'll just get longer bolts, and mount it with the outside jaw...)
The final pass on both sides of the part is a light chamfer to break the burrs on the machined edges and help give a nice, finished appearance. Unfortunately, my 1/4in chamfer mill was just a little too large to do the final pass on the mounting slots:
I'll be buying a smaller, long-reach chamfer mill to finish these types of parts.
This was also the largest part that I've made so far, and to get it done efficiently I made use of Fusion360's High Speed Machining toolpaths. These try to keep the cutter uniformly engaged with the workpiece, and when you're clearing out a pocket that means going in circles. The result is a pretty interesting pattern, at least until you face mill the bottom of the vise off.
Doing this part taught me a lot about what my machine can and cannot do, and now I know that I definitely need a pair of soft jaws to support long work like this. Cutting the back side and the vibration it induced left the finish in a bad shape, so if I'm going to be making more of these I need to solve that problem. Finishing is another concern, so I've been doing a lot of research on inexpensive methods. Tomorrow I should be receiving a package of plastic tumbling media for the vibratory tumbler that I received last week. I'm hoping that I can use it to put a satin finish on this piece, and finish with some walnut shells to put a final polish on it.