Right, dinner is over so now on to some test cuts.
I was interested to see how fast I could generate some circles. I wrote a perl script
shortly after I got my Shapeoko 1 that generates arrays of holes (something that I make quite often) but the S1 wasn't rigid enough to be faster than my drill press and the holes never turned out very round.
I was curious to see what the S3 would do. I have to admit up front that I'm pretty happy with the results. But there were a few entertaining things that happened getting there.
On my S1 I had a small vise mounted at the end of the travel. It stayed there unless I needed to mill something a bit long. It is bolted to a piece of MDF and has holes on 6" centers to attach it to the table. It also had two dowels to locate it so all I had to do was place it and bolt it down.
I'm not ready to drill dowel holes in my S3 table yet, so I cut the dowels off. Then I bolted the vise to the table and indicated it square.
I was getting ready to start making some holes when I noticed a problem. See if you can find it.
Yup, the vise handle interfered with the carriage plate. That's not going to work. But luckily all I had to do was move it over to the next set of t-slots and square it up again. Then there was plenty of clearance for the handle and the bit could still reach the whole work area.
I wanted to try various feed rates to see if it made any difference in hole quality. I used a 1/4" two flute router bit and made a program to generate a 1/2" hole. The milling took two passes - one to rough and one to finish. I ran them at feed rates starting at 40 ipm and increasing by 5 ipm up to 70 ipm in hard maple.
After I had all the holes finished I measured them. They were all around 0.495" in diameter with no appreciable difference in roundness or quality. The last hole at 70 ipm took 13 seconds to do both passes.
I was hoping to be able to mill 50 holes in under 12 minutes and 13 seconds per hole is right in that ball park. So I set up one of my loading block blanks, generated the g-code at 70 ipm and let her rip!
12 minutes and 2 seconds later I had 50 1/2" holes milled in maple. Now we're talking!
The next test will be to do the same work but use a 3/8" diameter router bit so the holes get generated in one pass.
I have to say that I am pretty darned happy with the rigidity and accuracy of my upgraded S3 so far. The only thing I might work on still is the stiffness of the Z carriage plate.
But I'm sure I'll come up with more to modify soon. And there is that SuperPID coming. And I need to make a control box one of these days...