Hah! Take that Jeff!
I ordered my magnets yesterday. A 1/2″ and a 3/4″.
Took a trip to Fry’s today to pick up a set of Dupont crimpers so I don’t have to dig through the junk box to find spare cables to cut up for the ends.
It moves!!!
Oh, check the album in the first post. Updating pictures and whatnot there.
I haz magnets!
That looks great, Barry!
What are you using for the tray? Looks like masonite. Is it stiff enough for the size of your table?
Great job!
Temporarily it’s masonite. It actually doesn’t bow down too far. I was hoping I’d be able to get some glass at Lowes, but they don’t have any long enough. I might go for two pieces and just put some packing tape over the joint. It will be covered with sand anyway. 1/4" acrylic might work too. They have pieces that size.
Got it making patterns in the soda. Ended up glueing the magnet to the top of the center piece even with the frame cut to flush the hardboard. I think a smaller bearing will work better. This one wobbles too much. That or use glass.
What is the rating on the magnet you used? I think Ryan used an N45 and I’m using an N52. My first magnets were N35 - too weak, and there was a lot jumping and skipping. Since you special ordered your magnets, I’m sure they’re plenty strong.
I don’t think glass would be much improvement over the smooth masonite.
How did you glue the magnet? The main caveat here is don’t use hot glue - heat destroys magnets.
What size is the ball?
Congrats on getting your first patterns!
It’s an N45, bearing is 1". Superglue for the win! Don’t think hot glue would get hot enough to really hurt the magnet. At least not one this size.
Maybe not. My google-fu says that hot glue is 100F hotter than the temp that destroys magnets, but you’re right, it might not transfer enough heat to such a large magnet. Superglue was the better choice, I think.
1 inch! You could chase Indiana Jones out of a temple with that thing! I’ll be interested to hear what your experience is with a 1/2" ball. I tried both a 5/8 and 5/16 before settling on 1/2.
Yea, it is a bit big. That’s all I had in my junk drawer. Pretty sure they’re bearings out of a bulldozer. Rescued a dozen of them from a dumpster when I worked at Ft. Knox gold mine.
The guy who plated the balls and hid them in the dumpster was probably very disappointed that his retirement took a hike before he could cash them in… Oh wait, you said the magnet worked. 
Yea, they weren’t heavy enough to be chrome plated gold. I wonder if you can chrome plate gold…
Ok, update! If you have a Menards close by, I’ve found a quick way to get a 5/8ths diameter bearing. They carry those little bearing blocks you see at the post office counters for the heavy stuff to roll over. I wouldn’t use one of these for that though. The ball sits on a delrin doughnut, so it’s not going to work very well for very long.
The 1/2" ball I’m using is actually slingshot ammo. You might find a local store - maybe sporting goods? - that carry them. Of course, you’ll get enough for dozens of tables.
I got mine at amazon:
I got my 1/2" ones on Amazon as well. Since it’s ammo instead of precision bearings it’s a heck of a lot cheaper, though you do end up with 50-100 of them, but they roll just fine. 
Heh, didn’t think of slingshot ammo!
The 5/8ths bearing works much better! Posted up a new video in the gallery.
Dang I just looked through the album, that thing is huge!!! I am trying to pretty mine up right now, I made a wrong cut and my top glass was 1/4" low and I want to get it a little closer to the edges. Is your better half going to let you bring it inside or it a table for the mancave…manbarn, barncave?