Help with lathe tutorials

[DocsMachine]

I've finally had a chance to sit down with my Logan lathe conversion and start working through the tutorials. I had a great deal of difficulty this last weekend until i realized the manual I'd downloaded and printed out, from back near the first release of the Acorn board, was badly out of date. (The cover sheet said CNC11, version 3-point-something.)

I downloaded and printed out the latest version, and this afternoon tried the first tutorial again. I've followed the instructions exactly, word-for-word, verbatim, and keep coming up with this:



That's basically exactly right, except the arc is of course concave rather than convex. And I can't for the life of me figure out why.

It actually cut well, with everything operating and tracing as it apparently should, which I was happy about.



(That's a wax table candle, only about 7/8" OD, used as a test bar in case something decided to crash- again.)

The lathe computer is not hooked up to the internet, so posting a report and/or screenshots are kind of a pain. (Hence the photo of the screen.) What do I need to look at? What am I doing wrong? Again, I typed in the first tutorial, word-for-word, and checked several times for even so much as a misplaced decimal.

Doc.

[cncsnw]

Change the arc direction from CW to CCW (or vice versa).

Even if your tools are in front, you program as if the tool approached from the back (first quadrant, with X+ away from you).

[DocsMachine]

Spot-on, sir! I did in fact think I needed to swap that from the tutorial- I was afraid I'd crash something since the instructions assume a turret and 'rear' tools. Classic overthinking...

Anyway, the graph finally appeared to be pretty much spot on (at least, that's how it looked to my clearly-not-all-that-educated eyes )...



So I gave it a shot with a chunk of scrap acrylic rod- hopefully a little more forgiving than aluminum if there's a crash.



Feed was a little aggressive for the plastic, but it worked.



Wound up with a small chip due to the aggressive feed, but the radius seems spot-on and the OD size is spot-on.



Looks good so far, on to the next tutorial!

Doc.

[DocsMachine]

Oh, and I finally got to see the CSS working properly- the spindle speed ramped as it made the profiling passes.

Finally getting somewhere with this thing.

Doc.