I’m considering getting a rotary attachment.
While I believe one with a chuck would be better overall I’m looking to engrave wooden dowels and/or wood rolling pins. I’m wondering if one with rollers instead of a chuck would be better since area I can engrave won’t be limited by the jaws?
Also, is there a product that uses a spar drive and a tail stock?
Your thoughts?
I think there are several rotaries, including the Sculpfun RA Pro Max, that can be both. You can also tilt the chuck.
There are pro’s and con’s for each type. Really depends on what you are doing. I have both types and use them where applicable.
Con for a roller, is that you have to limit you acceleration and rotational speeds. If not it tends to slip. This isn’t so bad as you are generally doing some type of scan operation so the actual rotary doesn’t really need to rotate more than the interval step.
Pro is that it doesn’t need to know the diameter as the drive wheels drive the surface, not driven from the center like a chuck type.
Pro for the chuck is that you can easily do vectors with it. I don’t do vectors on my wheeled rotary because it tends to slip, even when slowed down.
Con for a chuck type is that things get bigger, you may not be able to chuck it up.
Make sense?
I just looked at that, this is what I meant about a spar drive, it goes into the headstock
Yes it does, with a lot good information. Thanks.
Now I see the need for both 
Got it. Unfortunately, the chucks do not have a hollow center in the hobby laser class. A machine shop rotary would likely be too big, not to mention interfacing it.
Those look like they have a taper (R8?) and even if you shortened the shaft, the taper would prevent a good flat grip by the chuck jaws. You would get a better grip on the wood instead. You would have no need for the spar because there is no turning torque resistance on the wood dowel.
You might simulate the spar by using a butterfly bit with most of the shaft whacked off.
I have plenty of M2 spar drives. The difference is an R8 has a taper of around 3.5" per ft where as an M2 has a taper of around 0.6" per foot.
I use to have a spar drives that fit into a 4-jaw chuck, I have to look for it, I think I might have given it away.
McMaster-Carr has end mill tapers with an R8 taper, but I’m sure they’ll slip when holding a wood dowel
My chuck has plastic jaws, and I suspect the rest do as well. You will not be able to clamp like you do with metal jaws. I still think you will not need a spar. The 3-jaw chucks are self-centering.
The jaws don’t do much work, so little bitty 3D-printed ones suffice for the Ortur YRC-1 I hacked into my CO₂:
It has a tiny tailstock benefiting from a larger cup center:
(That’s an aluminum rod for sizing; I know bare alumInum shrugs off an ordinary CO₂ laser. 
)
I wasn’t willing to spring for a PiGrip, but Black Friday was a good excuse for a smaller rotary …
I have a PiBurn rotary, it’s great, but very expensive.
Now you are bragging! 
Checked your web page. This is a really great idea. I had never considered anything but roller tailstocks. Thanks for sharing!
I have access to a Bridgeport and last night I was thinking I could machine some smaller jaws out of metal. Then this morning, while working on my first cup of coffee, I read Mike’s post that the jaws on his chuck were plastic I thought 'Oh! I can 3D print a set. Now I see Ed confirmed that this would work!
I have live centers like that for my lathes, simple to make, Thanks!
I took a look at your website, you’ve been busy!
The picture of the skunk reminded me of something that happened to me. I was out in my backyard peering through a telescope and felt something brush against my legs that felt like a cat. I look down and there was that white band of fur. I stood there frozen and luckily it just walked away. (Sigh Of Relief)
I got a better idea, rubber grommets.
This is a set of cole jaws for a wood lathe which I don’t use since I made myself a vacuum chuck.
Usually R8 tapers use a thread rod to hold it in place. If this is the case with rotary attachments I might be able to make one for the laser.
Maybe you can adapt this for your needs
I recall someone posted a wood self-locking chuck …
Here it is:
If you want something stronger you can use a NEMA23 and an external driver.
The forum has everything. 
Don’t you hate it when someone steals your idea before you get a chance to think it up!
I made a 4 jaw longworth many years ago. I gave it away when I made a vacuum chuck.
I like the Cheap & Easy Roller Rotary, something to think about! Thanks!
