Syscore- I did basically the same thing. I started out w they Shars 6" rotary table kit (came w chuck) then turned it into this (no brake though)
Don't worry about the path pilot part - that's easy.
I am looking at building my own 4th axis with a brake. It's purpose is accurate brass (spur) gear cutting. I have a very accurate worm/gear combination to drive it, but I also want it to work with on my 1100 (series 3) with PathPilot. I am thinking that if I simply buy the Leadshine drive and a Leadshine stepper from Tormach, maybe adjust something in the PathPilot (LinuxCNC) ini file to account for the different worm/gear ratio, that this should work fine. I will drive the brake using the I/O kit. I don't need all of the torque of the Leadshine stepper (I will use the 6" version), but this seems to be the easiest way to interface it with PathPilot. Any thoughts?
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Syscore- I did basically the same thing. I started out w they Shars 6" rotary table kit (came w chuck) then turned it into this (no brake though)
Don't worry about the path pilot part - that's easy.
See Roger Caffin's project at CNCzone
http://www.cnczone.com/forums/linear...gineering.html
He does an excellent analysis of why a worm gear isn't the right answer for a CNC rotary table (it's fine for an indexer). And then provides outstanding details on building a good one, comparable to those sold by Haas and others. It's a tougher job than just mating a stepper to a worm drive.
Here is the way I did mine. Started out life as a Vertex 6 inch Super Spacer. I have found that a brake is not needed. I'm able to adjust for 0 backlash and the motor is more than enough to hold position with a 90:1 reduction.
Here is the build thread
http://www.cnczone.com/forums/linear...onversion.html
I used a Grizzly rotary table as the basis for my 4th axis and built the direct drive adapter. The drive and step motor came from:
Stepper Motor |CNC Router | Laser Machine | 3D Printers For Sale Stepper Motor | Stepper Motor Driver | CNC Router | Laser Machine | 3D Printers For Sale
If I were to do it again I would use a smaller rotary as I have yet to need the 8 inch table size.
Robert
Here are some older photos of my home made 8" 4th axis, which works very well.
I have a 8" super spacer from Tormach. Not the most convenient tool to use at 180+lbs. That said it looks pretty straight forward to buy any decent super spacer or other type of 4th axis and add a drive motor. Thinking a design that keen did a few years ago was nice, along with many other crafty people around here. The first tool I made for my super spacer was a material stop that he shows in one of his videos. Very handy!
I like the pitched Y axis way covers in zetopan's pictures.
No thread is any good if it doesn't go off topic
I would like to keep my very heavy 4th axis on right side of table, with vice on left side. Opinions on whether this a good idea or not? Would it cause base casting to settle more over time and or other long term problems. I make mostly small parts and the vise on the left is more then enough envelope. Then all I have to do is keep it clean between uses .
No reason not to. I did by making a 4th axis relocation kit. In all fairness, I have a 6" rotary tho.
Wade
You have most likely noticed that I removed the right angle elbow on the oil filler since I use this only as an "A" 4th axis. I milled those holes in the hand wheel and the secondary timing belt pulley to reduce the rotational inertia by about 25%, which allows for significantly higher accelerations. The hand wheel is handy for setup when the power is off. With the 2:1 reduction the rotation is essentially unstoppable. I simply modified my Mach 3 settings to account for the 180:1 overall ratio and the acceleration settings. Some day I need to take some photos of my trunnion table and 5th axis (my only camera is dedicated for microscopy so it can't even be used for anything else).
Rather than start a new thread I thought I would bring this one back up. Now that I have servos on my 1100m I have 3 extra steppers/drives that I can use towards my 4th axis. I already have the "exact same" table that Tormach starts with https://www.ebay.com/itm/6-Precision...72.m2749.l2649. I have made 4th axis by "slapping" steppers on rotary tables for my other two conversion mills, so that is no big deal. Or so I thought.
When I was removing the drives during the servo upgrade I noticed the wiring that is pre-run for the 4th axis looks to be for bi-polar motors. All of the drives/motors I pulled out are 3 phase. I checked Tormach's website and sure enough the replacement motor for their 4th is bi polar. Is there a reason the 3 phase motor, say off the z axis would not be a good choice (compared to bi polar) for the rotary table conversion?
For reference: motor relocation idea Mandala Rose Works - 4th Axis Stepper Relocation Kit for Tormach 6 inch rotary table
older thread with technical info https://www.cnczone.com/forums/torma...c-tormach.html
-Jon
instagram @hermit.shed
Good question and Im in the same position. Im sure Tormach support would be able to tell you if that is possible.
I contacted support and made it clear that I was making my own table and asked if it was possible to use the x motor/drive or if I had to buy the configuration they sell for the table. A tech responded very quickly that they have not tried it but thought it could work. I am pretty pleased with Tormach and their support team so far. As long as it won't smoke the ecm I'm game to give it a try. Not my most urgent project so it may take a bit before I get to it.
-Jon
instagram @hermit.shed