I mentioned this in another thread, so I thought I'd show a few pics of a lathe steady I built recently. It's made primarily of 1/2" BB ply, except the base, which is jarrah. The "ring" is two layers of 1/2 ply glued and pinned together, and the "arms" are a single layer. I painted the ring bexause I originally cut the slots for the two lower arms at the wrong angle, and had to fill the slots and re-cut them correctly. I also filled any countersunk screw holes. The paint hides the patches.
The base is made of some leftover jarrah I had. I figure if it's good enough for piers and heavy piling, it'll hold up for my needs. To mount the ring on the base, I cut long slots in the bottom of the ring with the mortiser, then glued and screwed the base into the slot from above and below. It's not going anywhere. I originally thought the plywood arms would be too flexible, but so far they've proven to be plenty stiff. The ring is also very rigid.
The wheels, bearings and axles were purchased on eBay. I read somewhere recommending the use of softer wheels (78a to 80a, with lower numbers being softer). These are 78a wheels and they do have a little "give" to them, which I believe is a good thing.
The upper left-hand arm and wheel do block the beam of the laser (but not the bar holding the laser), so I think I'll cut another slot at the 9 o'clock position for that arm and move it there when I'm getting down to the last bit of finishing the inside.
Here are a few pics and a sketch:
And a sketch showing more clearly how the base is inserted into a slot in the ring, although I didn't bother rounding the corners of the ring as shown in the sketch:
So far, with a single use, the steady seems to be doing what it's supposed to be doing. Now if I could only get the lathe back in business. (Parts have been ordered.)