Rosettes for M3 nuts that make spring-loaded leveling easier. A lot easier. I even reach in and give them a quick tweak while the first layer is printing.
I made these a few months ago and forgot to post them. Aside from the rosettes, my leveling method is darn close to haqnmaq's recent Thing: http://www.thingiverse.com/thing:6558
The rosettes are useful anywhere, of course, but I made them specifically for leveling the build platform on my cupcake.
â€¢ Three screws instead of four (with four screws one nut always seems to end up loose)
â€¢ Conical springs (I kept bottoming out on one side. Conical springs can collapse almost flat) and M3 thin nuts to keep the platform from getting too tall.
â€¢ Flathead screws to avoid collisions with the extruder nozzle.
I ordered my conical springs from McMaster. They're very nice, just the right size, and strong....but $14.73!? For three springs?!?! Later I realized that I was surrounded by conical compression springs: anything that takes AA batteries will have a double set of them just the right size, so raid your junk drawer.
Make two M3NutRosette2.stl and one M3NutRosette1.stl. M3NutRosette1 will work for all three. Rosette2 is bigger and easier to adjust, but it hits my x-stage on the right side, so I have to use the smaller one there. Thread a M3 nut on a M3 screw and use that to center and level the nut in the bottom of the rosette.
To cement everything in place I used liquefied ABS (test extrusions and scrap parts dissolved in ABS--I added enough ABS to make it just a little thicker than Elmer's Glue) applied with a syringe. A brush works, too.
â€¢ FWIW, I found that I could speed up the evaporation of the acetone by dunking the assembly in isopropyl alcohol for a second.
â€¢ The liquid ABS makes them look pretty, too, and that's nice.
I only used three screws--two on the left of the build platform, and one the center of the right side.
â€¢ Pro: all the nuts stay tight and are unlikely to rattle off. I tried four first, but found myself getting everything level only to find that one of the nuts was now loose. I'd get that tight and then have to readjust everything.
â€¢ Con: leveling at three points isn't as intuitive as leveling at four points. Keep in mind that when you lower one of the left side corners it will raise the opposite corner as the platform pivots on the center right screw.
I chose to place the single screw on the right side because there's no window there, so it's harder to reach.
I got an aluminum build plate from MakerGear and driled my own holes using a M3 90Â° countersink bit http://www.mcmaster.com/#28145A71 An original Makerbot aluminum plate will work fine, too.
Combine your HBP PCB and your aluminum plate, insert your M3s, add thin nuts and tighten into place. I used thin nuts because I didn't want my platform getting too tall.
I reamed out the holes in the wooden base of the build platform a little bit so that the screws have a little play. You don't want the screws catching on the edge of the holes while you're adjusting, and you want a some room for thermal expansion. The springs will keep things stable.
The final assembly should be: plate, pcb, nut, conical spring (narrow side up), an optional large OD washer, wooden base, and rosette (flat side up).
I found that when I leveled my platform cold it would bow in the middle once it got to temperature, so I might recommend that you lightly screw on the rosettes, grab a handful of nickles for the swear jar, heat up your platform, and then do your leveling. Of course I wouldn't recommend that you do that because you'll probably get a little burned. And of course no one will think you're a wuss if you don't do hot-leveling, so don't let that worry you.