Print heads for the Makery Mendel

Tonight, I was on assignment for Brandon and the Makery Mendel again, this time drilling some really really tiny holes.

These acorn nuts will be used as print heads to extrude the molten plastic on the almost-done Makery Mendel 3D printer. I started the process by holding the piece of allthread (Which has a shallow hole in the end) in the lathe chuck and threading a nut onto the end.  I know that generally a bolt thread isn’t true enough to rely on for machining, but in this case, I want the operations all true to the bolt, as that’s how it’s going to be held in use.

Next, I faced off the rounded end of the nut, being careful not to get too deep (which is what happened on the rightmost unit). I then used a tiny drill bit in the tailstock chuck to ever-so-gently drill the hole.  On the 0.3mm unit, you can see where the drill bit had a slight bend in it, and wanted to drag around the part instead of start drilling in the center.  I was able to change the orientation of the bit in the chuck to correct this.

Finally, I cut a bit of an angle on the side of the nut, making it more conical than round.  Sort of like a cut-off funnel.  Hopefully it works well. One of the nuts turned out to be plated (which, sadly, is one of the sizes I didn’t make a duplicate for)

Stepping Up…

Tonight, I did some prep work on a new EasyDriver (on breadboard) that I ordered for an upcoming project. I mounted a 4-pin Molex Floppy connector for the motor output, and pin-headers reversed for breadboard mounting.

I also milled the gear off of a scrap stepper motor and built a coupler to a fancy leadscrew I had laying around. The leadscrew in question (pictured foreground) is about 9″ long, has 5 starts (5 parallel sets of threads) and has a twist-rate of 1 inch per turn (one TPI).  The screw is further teflon-coated and uses a (probably Delrin) plastic nut.

Brandon questions if “that wimpy stepper” can drive such an aggressive leadscrew, but I don’t think it’ll be a problem.  If it does become a problem, building a new coupler (or finding a motor that has the same shaft size) shouldn’t be hard.

Printer Parts – Heater Tube

Jason notes that I forgot to post a photo of the other Mendel parts I’ve been building for the MakeryMendel.  Below are photos of a stainless steel heater tube (the one that I didn’t ruin by welding a drillbit to the inside) as well as the “order form” that Brandon sent me. His drawings aren’t anything fancy, but we seem to have gotten the job done.  For scale, the bushing in the photo is 1″ OAL, and the threaded rod heater is 1.5″ OAL.  The picture with the fire is a prototype plaster bushing that we were testing.  It’d probably work, but we dried it a bit too fast and it developed a nasty crack.

BrandonSpec (Medium) Plaster Heater

HTC TouchPro as Wireless Webcam

I’ve started to accumulate quite a heap of old smartphones, and would really like them to either get useful or get gone. It was my initial intent to “simply” hook one up as a networked webcam, and have it serve images via HTTP, not unlike the units sold by everyone from Axis to Panasonic.  Sadly, however, this proved more complicated than I’d imagined.

After quite a bit of procrastination and some help from the guys down at the Makery, I found a package called WebCamera Plus, which only partly fit the bill.  Half of this packages’ functionality requires a client installed on a PC, where the actual web serving happens.  Without that “server” PC, the best it can do is FTP photos out on a timed basis.

Adding insult to injury, about the time I was ready to bite the bullet and spend the $20 on this thing, the company sorta disappeared.  On the upside, the company’s website did resurface a few weeks later, with the software now priced at $9.99.  The decision had already been made, however, to go in a different direction.