Which method are you using to set the zero point for the rotary axis? That’s the tricky part, since being off by a fraction of a mm really stands out on indexed rotary jobs.
I’ve had one go at 4th-axis indexed milling. It’s tricky to find the centre, and I was still off by a tiny fraction in my attempt.
I had two 1/4 inch rods, one in the spindle and the other in the chuck, but I still had to “manually adjust” the calculated values to cut a cube from four sides. I roughed with a 1/8th bit.
What was your method for "dialling in " the centre?
FYI: I used f360, which wasn’t too tricky. Using previous set-up stock and duplicating setups for the other sides was relatively easy, contrary to my expectations, and meant that I limited the re-cutting of previously cut areas.
I had a long rod in the chuck when I installed the rotary on the waste board to have it point in the right direction parallel to the y axis.
I think there best way to center is to use a rod in the spindle and touch of with the masso probe cycle on the chuck. Yes, you can also put a rod in the chuck.
The rotary is attached and has to be only probed once, and the coordinates should be in the masso forever.
The live end is far more difficult to center. I have to readjust and check it every time I move it. I use the rod in the spindle and micro adjust the tailstock.
Yes, Fusion should be great for this too.
I am still curious about their pricing, do you have the free version, and is that limited or the subscription and how much is that per month?
It is restricted. The biggest restriction, for me, is the lack of rapids at rapid speed. They are throttled back to, I think, the last feed rate. It is a problem with large jobs that have fine detail spread over the job (e.g. rest machining).
@AndyP have you seen Tim Paterson’s GitHub project which restores rapids?
Fixes tool change restriction in Fusion for Personal Use. Also restores rapid moves the free version of Fusion limits to feed-rate moves. See section below.
Interesting. I remember researching this a while back and concluded from others attempts that it was too tricky. The f360 add-on you have identified above looks more promising, but it still claims to be experimental. I will give it a go. Thank you for the post
Finding true center of 4th axis is really simple and easy, I do mine with an indicator, sweep centerline with indicator to get close on your 1/4 rod, then to fine tune it, position 4th at A0. And indicate one side of centerline then raise up in z and rotate indicator to opposing side and then rotate A axis 180 deg and sweep that side. Split the diff in axis. Should be in within .0001 or .0002” from centerline. Thats how I have done it for over 30 years. But that is true center of rotation.
