Rotary Axis

Don Baer

Moderator
Staff member
As I dive further into this abyss I am looking at buying a rotary axis for the CNC as the next major upgrade. I can see that in doing the submarine hulls and other projects it might be a desirable addition. I am also thinking that when not in use on the CNC I might want to use it on a future Laser engraver (another future add). So in doing my research I am looking at something like this https://www.amazon.com/Milling-Rota...eywords=cnc+rotary+axis&qid=1593735734&sr=8-6..
So what thinkith the collective.
 

Darren Wright

Administrator
Staff member
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Location
Kansas City, Missouri
First thing I notice is the 3 jaw chuck. It's fine for stuff that starts round or triangle, but harder to chuck up square stock. The other is that it's pretty small overall. I ordered one of the little tail stocks off ebay like that, and it's pretty much a linear rail support with the threaded piece added. You probably could mount them up on something to give you more swing and used a flange on the headstock end to screw onto your work piece to chuck it up easier. It could be made to work, just depends on what you want to do.
 

Leo Voisine

Member
Messages
3,996
Location
East Freeetown, Massachusetts
42 stepper - WOAH - do they seriously mean NEMA 42? WOW that is HUGE.

I have a NEMA 34 on mine but have only used it a couple of times. Seemed to be more than adequate.

I didn't see how to insert a video.

One thing I will mention is, and I know I will get a lot of pushback but, there IS a difference between a rotary and an indexer.

Now, on commercial rotary / indexer there is most likely a brake. Haas, Tsudakoma and others have brakes. I have not seen any in the hobby world with a brake. I think mostly because the hobby world for the most part uses axis swapping, so the cutter is directly above the rotary axis centerline all of the time.

Mine is a bit different. I have a more commercial sort of a setup.
I had an additional "A" axis drive installed so my machine is truly a 4 axis machine. I CAN drive all 4 axis's independantly. So the result is, I can do machining off the rotary axis centerline. The issue with the brake is that any forces on the rotary are only held in place by the rotary drive mechanism. That mechanism is really NOT all that robust. Even in a $450,000 Maier 12 axis machine it is highly recommended to engage the brake when milling off the rotational axis. These hobby machines we have certainly cannot be trusted for that sort of machining. I do NOT have a brake on mine. I DO have some thoughts on how to make and integrate a brake. I am thinking a band brake fired with a Mcode. Mach 3 and by BOB can manage that. I am thinking of using an air powered Bimba cylinder. I already have a few Bimba air cylinders. My 3 jaw chuck is 10" with room for a band brake. I am sure that will fill MY needs.
 
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