Rotary tool attachment for laser engraver

[Roger Lueck]

I'd appreciate some information regarding building a rotary tool attachment for a laser engraver. The rotary tool would be used with a woodturning lathe chuck system, hence my desire to build this tool rather than buy one with a 3 jaw chuck or one of the roller models.

I believe all the Morntech lasers use the same stepper motors (Kangda) and drivers (Leisai). Does anyone know the specific specs on the Kangda steppers or a know of another brand of stepper motor that is interchangeable with the steppers supplied from the factory?

[George Carlson]

Laser engravers are designed for a cutter with no tool pressure. The belts used in laser engravers will probably stretch too much to be able to hold the tool securely and precisely.

[Roger Lueck]

I believe I may not have been clear enough in my intended use of the rotary tool.

The intent is not to use the rotary tool with a wood lathe. The intent is to remove the "chuck and the turned article" from the wood lathe and install it on the laser engraver for engraving. Unless the "turned article" were extremely large and/or the article was "offset turned" the resistance should be minimal and a small stepper motor should be able to rotate the "turned article" for engraving with ease.

[Dan Hintz]

It's a crapshoot, Roger... wood lathe chucks are pretty hefty animals made mostly from steel. What you really want is an aluminum one for the weight factor, but I doubt you'll find many chucks made of aluminum. Still, I'd first try with a standard chuck and a heavy weight to see if the stepper motor skips steps... you may get lucky. A Talon chuck might be a good compromise between low weight and good gripping size. If you want accuracy, though, you'll probably want to step up to a 4-jaw metal lathe chuck, and those will not be lightweight, especially if you want any range to the gripping diameter.

I don't see much work being required, just use the standard in-line rotary device and swap out the endpiece for a chuck (may need to drill a hole for a grub screw or turn down a shaft, but it's a lot better than creating an entirely new one from scratch.

[Chuck Stone]

I would think about hitting Little Machine Shop and browsing the chucks for
the Taig lathes. Those are small, lightweight aluminum and fairly inexpensive.
But you'll need to find a way to attach it to your rotary.

As for the accuracy on those.. they ship you the jaws and then you run
the chuck and cut them yourself to make sure they run true. (not sure
how you'd do that .. on your wood lathe? that's another adapter!)

[Roger Lueck]

I apologize for the late response, I'd like to thank all of you for your input. The machining to make something fit or work isn't a problem for me. I will look into the chucks for the Taig lathes from the Little Machine Shop.

[matthew knott]

You would be amazed at how capable a little stepper motor is at turning a chuck, a laser rotary does not need to turn or accelerate fast, you would need to gear it either by a gearbox or toothed belt pulleys, normal ratio would be about 8:1 (motor 8 turns, chuck 1)
416516484_382.JPG
The above shows sort of the idea, we made one with a massive chuck 12 inches across, 2 hand lift, geared 10:1 and it turns just fine and its about 15 kg

[Kev Williams]

Stepper motors are strong little devils- When my first XT was a couple of years old, I engraved fireman instructions on the sides of three 21" wide x 7' tall stainless steel elevator walls. Not just the steel plate, but fully wired and assembled ready-to-install 4" thick walls. They weighed over 300 lbs, and the XT's table moves along the Y-axis, so all that weight was constantly moving as the machine was engraving. I had to fake the machine into thinking it wasn't an XT so the tool-up travel time was slower, but the Y stepper never faltered or skipped.

I'm pretty sure with the small increments that a rotary-Y axis moves in a laser that most stepper motors would handle turning a fairly heavy chuck...

[Mike Null]

I have the chuck shown below. It is a very strong lightweight unit that can handle rings as well as items several inches in diameter.

I use it on my Newing Hall machine but it could be easily rigged for use on a laser if you have that aptitude.

Newing_Hall.jpg

[David Somers]

Kev,

Just curious.....when you are dealing with a rotation device like yours, aren't the chucks normally in place with a Morse Taper? In your case you have what looks like a 3 jaw chuck with a morse taper on the tail side. And I have seen another one that used a Jacobs Chuck, which is nothing more than a drill chuck with a morse taper on the tail side. That would make changing the work hold portion of the rotating unit a breeze?

Locally, so far all I have run across for rotators is the paired wheel with O-rings that rotates the object with friction. It is a bit hard to judge since I know those are built differently than the chuck style rotators.

Dave

[Dan Hintz]

The need to remove the chuck is relatively rare, so a Morse Taper doesn't make much sense... a simple screw type is sufficient.

[Kev Williams]

For what it's worth-- My NH 3200 'orbiter' has a 5" 3-jaw chuck. I also have an 8" chuck I need on occasion for big seal molds. The big chuck has a big threaded hole, 1-1/8" or so, the 5" chuck has an adapter so it just slides onto a 1/2" (or so) shaft. When I need the 8" chuck, I just hold it with the 5"er. Yeah, it's pretty heavy, but it works!

So, I'm thinking, maybe Roger can just hold his lathe chuck with his laser's chuck?

[Greg Holt]

...................aren't the chucks normally in place with a Morse Taper?

They are occasionally, although some sort of screw mount is more common. However it is very common for the tail stock to have a morse taper.

The need to remove the chuck is relatively rare,

It is my experience to be the opposite.

For me at least, removing the chuck to fit another type of holding fixture is a regular occurrence.

I tend to engrave all sorts of objects in the rotary and a chuck is great for some and inadequate for others.

The best chuck mounting method in my opinion is one that lends itself to easily making up and quickly fitting a variety of work holding fixtures as required.

Greolt