Lathe controller

[rsba1]

Does anyone have any opinion on the Autoturn digital lathe controller from Putnam Engineering? I have an older 12" Grizzly lathe that would seem to be a candidate for this system. I would have to get motors and drivers from somewhere. Thanks.

Bob

[rich_vandenberg]

Bob,

I have worked with the AutoTurn during the development process. I have no financial interest in what they do at Putnam but do recommend it as a great solution for CNC'ing your lathe. I use the equipment with my mini-lathe and a 10K South Bend machine.

The AutoTurn performs as advertised. Putnam can supply or recommend a power supply and motors. Your lathe sounds large and will probably require their large driver box. They also have designs for stepper motor mounting brackets for various lathes. I worked on some of those designs.

Get in touch with them. The engineer, owner, Charles is very helpful.

Rich Vanden Berg

[rsba1]

Rich, thanks for the reply. After watching the "Utube" video, I'm a little concerned about the number of passes required to complete the job. It seems like there would be some premature wear of the bed ways and brass nuts for the lead screw. It might not be an issue at all but that's what struck me while watching the video.

Bob

[teqdruid]

Bob-

The cut depth of each pass the AutoTurn makes is controlled entirely by the machinist operating the device. If your lathe can handle it, you can certainly set a deeper depth of cut and thus reduce the number of passes you make. There are a few things to keep in mind, however:

- When turning a radius, the larger your cut depth, the less round your radius will be. You'll notice in the video that it's a circular approximation, not an actual radius pattern. The solution to this is to use a very small depth of cut in the first few passes, then increase the cut depth, since the accuracy of the radius depends less on the cut depth with each cut. (In an exponential manner.) A routine to do this automatically is in the works, and will be present in a software update available to all users at some point in the future.

- When using a higher cut depth, you may have to pay more attention. If you are nearing the limits of your system (spindle horsepower, carriage power, ect.) to make sure you don't get a tool jam. Therefore, you must take care in selecting your cut depth.

- Given the additional care needed, and the cut-repeat feature on the AutoTurn, it's easier to set a low depth of cut, tell the AutoTurn to repeat that cut a bunch of times, then relax for a few minutes. Yes, it's a bit lazy. Yes, it increases wear on your lathe. This is precisely how the video was filmed, however.


Anyway- you can use the AutoTurn however you like using your machinist's judgment to determine the proper cut parameters (and tune the parameters while making the part.)


You might take a look through the user manual on the site to get a feel for general operation and cut parameters. It provides a good deal of usage information.


~John Demme
PELLC Developer

[rsba1]

John, thanks for your reply and input. I will do a little more research on this product as well as reading the manual as you advise. The main use for this would probably be threading; which should not be much of a wear issue.

Bob