4th Axis Yet ?

[curmudgeon]

Has anyone added a rotary to the Rockcliff yet?
I'm currently building a CNC lathe for turning duck call barrels. Now that I'm into that project I'm thinking it sure would be nice to do it all on the same machine and with the same CAD/CAM and NC (Mach3 Mill). I have figured out how to use offsets and jigs, just wondering now if having the 4th axis would make my Model "A" an all purpose machine. Anyone have some examples of the process for drawing a profile for the rotary axis ? A simple spindle would be a great example. Is that considered 3D ?

Any help would be much appreciated.

More projects than I can say grace over !!

RE

[Boort]

curmudgeon

Earlier this year one of the guys on the Vectric Forum posted details on how to build a 4th axis rotary indexer for under $100. He has given out where to buy the gearbox parts he used and a couple of others have built them and had good looking carvings from them.
Here is a link to the forum topic (you don't need to own a Vectric product to sign up and read or post):
http://www.vectric.com/forum/viewtop...t=7173&start=0

Regards,
BoorT

[curmudgeon]

WOW !
That's an outstanding thread, thank you so much!
I already own Vectric Vcarve Pro and see where the latest version has direct support for wrapping. Between the indexer described in the post and the software support, even I might be able to get er done. Sure would be nice to buid the entire duck call on the same machine. Maybe put my logo on the barrel at the same time...try that with a lathe !

[Boort]

Curmudgeon,

It should be easy enough for you to do. I have seen guys who setup thier routers with jigs so that they can build 3-4 parts at a time, swap out the jig base for the Rotary 4th axis and cut the bodies. Good luck and be sure to post pics when you get one done!

BoorT

[curmudgeon]

About to pull the trigger but need to confirm it will fit under my Z axis and that I can wire the 6 wire stepper to the Rocklifff board as a 4 wire (I think I can). I only need about an inch of free Z for the tool path, and I could probably extend the router out a few inches to get the clearence I need.

[Boort]

Curmudgeon

You might want to talk to sfsubcutter, In Feb he was working on some plans that were designed for our routers. His post is over here:
http://www.rockcliffmachine.com/foru...ight=materials

I don't know if he has the bill of materials or plans finished yet, but the renderings of his design appear to take in to account getting really good envelope usage from the Model A.

BoorT

[sfsubcutter]

Hey there!

I hit a small speed bump in my build recently as my working room got overtaken. I'm back on the build though and should have some designs up within a month or so. I'm still working on getting my own model A working in the basic sense.

I'll be sure to keep in touch here as well as in my thread BoorT linked too.

As for the stepper BoorT posted a link to earlier - I like the idea of the head and tail stock to make piece as sturdy as it would be on a lathe. My plans account for the piece to be held by a 4-jaw chuck on one end only. Having seen that link, I might just look at adding plans to my list for a tailstock addition.

SFSub

[Boort]

SFSub,

It should not be hard to make a mount by cutting another set of your head stock mounts and flipping the structure around. Since we are not spinning the workpiece quickly (like a lathe) the tail stock can probably be as simple as a 1/2" bolt ground down to a point, held in place by a T-nut in the mount.

BoorT

[curmudgeon]

My hang up point right now is software. Vcarve has a wrapper gadget, but it's almost useless and to draw a profile on a cylinder in Vcarve requires the use of the fluting tool, and is very very complicated. Mach3 has a turn tab in Lazy Cam, but you still need to have a drawing to start with. If I have to upgrade to $2K CAD software to use the 4th axis on the router, or a proper cnc lathe, I'm not sure I will. Still looking. More when I have it.

[Boort]

Curmudgeon
I poked around in my bookmarks and found the following post talking about how to program a Sherline CNC lathe.

This was for turning some wooden "bobbles" or maybe spinning tops The author includes pics of the CNC output in both walnut and birch. He describes his tool chain as follows:

" Gcode for roughing was hand written. The finishing path was traced from your sketch in Coreldraw, exported as dxf to CamBam, which converted it to gcode in the XY plane (CamBam doesn't "do" lathes); then a simple search and replace to change all Ys to Zs in text editor. Finally, a bit more hand editing such that finish cuts are always with the tool moving into the workpiece. Very circuitous, but it's what I have and doesn't take nearly as long as it may sound. "

The good news is that these tools are low cost and easily downloaded, the bad news is that you will need to learn a bit of gcode to make it happen. Heinz Reimer discusses this in more detail and provides example gcode and cambam files to see how it was done at each stage.

Here is the full thread :
http://www.cnczone.com/forums/showthread.php?t=72513

Regards,
BoorT

[curmudgeon]

BoorT

Once again you have been a big help!
I have made some progress with importing a DFX of a "curve" vector from Vectric to LazyCam (comes with Mach3). LazyCam has a turn operations tab, and that seems to recognize the imported vector as a profile in XY coordinates ? I don't find much help on the turn functions of LazyCam, and for some reason my copy is a demo so I can't output any g-code to see what it will look like a a tool path, so I'm still unsure what I will have. Waiting on a email from Artsoft regarding the license for LazyCam. IF this works, I think I have the software side figured out for using a lathe. I'll just have to muster up some gumption and go finish the Sherline conversion.

[Boort]

Curmudgeon

I'm glad that that link was helpful. You might also want to check out the cad2lathe program it appears to be a low cost lathe DXF 2 gcode transform. They have videos and manuals that describe the process as well as a demo of the software.
http://www.cad2gcode.com/lathe/
It looks like he also has a 4th axis program in the works. Bob Adams, the guy who wrote the software, is also aware of the Rockcliff machines (Judging by his link to the main site from his web page).

Regards,
BoorT

[curmudgeon]

I don't get to Colorado very often so lunch is not an option. Still, you've been a huge help and I'd like to find a way to say thanks.

Do you Duck Hunt by any chance ?

[Boort]

Curmudgeon,

I'm glad that I can help. Unfortunately, I have not been duck hunting yet. My brother and his friends go every year but so far I'm not hitting clays reliably enough at the range to head into the field.

Regards,
BoorT

[curmudgeon]

Originally Posted by Boort

Curmudgeon,

I'm glad that I can help. Unfortunately, I have not been duck hunting yet. My brother and his friends go every year but so far I'm not hitting clays reliably enough at the range to head into the field.

Regards,
BoorT

You need to start duck hunting, then you'll start hitting those clays!

[curmudgeon]

I made some progress last night fussing with the cad2gcode utility. It's a bit weak, not at all intuitive and has no documentation, but once I found a youtube video someone made of how to actually use it, I was able to go from a DFX to lathe g-code pretty quickly. It's a shame the developer has put so little into explaining how to use it. Lots of help on how to draw the DFX before you convert it, but then he just skips to the part where you run the gcode to test it. Weird. It comes with 30 free trial conversions, I used up 12 before I got a single one to work just trying to figure out what to do.
Just a single display with all the buttons on it, and no clue what to do with them.

If I can figure out how to correctly draw the profile in TurboCad so it converts to usable gcode, I think Ill pony up the $35 and then focus on building up a CNC lathe.
More when I have it.

[curmudgeon]

http://www.mpja.com/prodinfo.asp?number=16237+MS
I had ordered this gearbox/stepper before I found out about needing the high dollar software to draw correctly for a true forth axis. Now I'm back full circle and have decided not to build a 4th axis, or to CNC retrofit the Sherline for lathe work, but to build a rotary axis for the Model A, that's more of a spindle than an true axis. So I started fussing with this gearbox and I'm ready to power it up and see what it can do. I have it ready to mount, and I have a 5/8 expanding mandrel on it. All my barrels have a 5/8 bore and that's all I ever use to hold a piece of stock to turn it. I plan to draw and cut 2d profiles, and to just turn the stock to get a round product. Sort of like how they turn pool cues on a router.
Here is what I have so far. I will need to figure out how to wire it, and to power it, but it's esentialy going to be a spindle, not an axis so it doesn't need any gcode, except to possibly turn it on and off.

[curmudgeon]

Got it wired as Bipolar half.
Got it running as a "A"
Got it swapped out with the Spindle output in Mach3. Very cool how that works.
Got it running with Mcodes (off/on and speed control)

Just need to mount it and try it out.