@dougfir3 wrote:
Shapeoko 3XL/Dewalt
Another circles vs ovals situation.
When I mill a pocket for say, a .375 bolt, the pocket ends up .370 in the x and .365 in the y direction.
When I mill a 1" pocket the X width is approx .997 and the Y is .992.
It is consistently wider in the X and narrower in the Y.
My spindle runout is negligible, about 5/10000, if that.
When I use a drill toolpath, i.e., just plunge the cutter straight down, with a .247 endmill, I get a circle with a .247 diameter.
I’ve run the circle,diamond,square test and the circle should be 2.25 and it comes out as 2.245 but it is round. Round because it’s an outside profile and not a pocket?
On that test as well, the diagonals of the square come out exactly the same.
The smaller square’s od was 2.50 and I measured 2.50.
So my outside profiles, especially the squares are good.I’ve read dozens of posts/articles/tips I could find, including the wiki.
I squared the extrusion ends prior to assembly.
The machine is square corner to corner.
The Y rails are parallel to each other and square to the X rail.
The v-pulleys are tight, the belts are tight. I use an arbitrary tension of approximately 4 pounds for each of the belts.
There is no wiggle/movement at all in the Z structure.I know how to calibrate my steps per mm and I have adjusted the X/Y steps per mm such that the machine moves exactly as far as it should. If I jog it (x) mm it jogs exactly that distance, both X and Y directions. My ratio is set at X=40.14 and Y= 40.070.
I the tried resetting the ratios back to x=40.000 and y=40.000 but the result did not change, the pocket was oval by approx 5 thou.
I’ve also tried milling the pockets using a climb cut as well as a conventional cut, no change.
I get that it’s a hobby machine and I’m probably OCD but if any of you technical gurus have something else I could track down I would like to hear it.
Or, if this is as good as it gets, then so be it.Thanks.
Posts: 3
Participants: 2
