super easy measuring rod

rulers are nice, but when you want to tell the difference between 470mm and 469mm, there is no better way than with a stick that is 469mm long.

The reprap build instructions suggest you cut some sticks of precise lengths in order to verify that your threaded rod lengths are exact when the frame is all bolted together. That is a good idea, but it seemed like a little too much effort. What I did was to use the last threaded rod from the reprap build. Before I installed it, I put two nuts on with a washer in between. Now I can move the washer to whatever length I need to measure and I can stick it between two vertexes. It’s less steps, and it already uses parts that you have!

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completely unsorted reflections on building a clonedel

1) Last weekend I completed drilling out my clondel kit and started bolting things together. Here’s a list of things I realized.

2) Having precisely cut threaded rods is nice, but not necessary provided they are longer than spec.

3) Drilling out the metrix createspace clonedel kit is difficult verging on impossible to do exactly. The vertex pieces that require precision don’t have flat, 90 degree sides. Also, some of my pieces varied +- 3mm in thickness. That is a big problem when the piece is 15mm thick, and it’s off in the – direction. I had to do a fair bit of eyeballing on those undersized pieces or else the drill bit would have just ripped through one side. This kit is a lot better than nothing, but the first thing to print is definitely replacement pieces. I also think I have one of their earlier versions judging by the way my z motor brackets look, so potentially they have improved since the first few batches.

4) I scavenged some 8mm rod from two desktop printers. That gave me enough for the z and the y axis. To get the long rods needed for the x axis I think I will probably need 2 more printers to destroy. I’ve been toying with looking into the rods from ikea filing cabinets to see if they are even vaguely straight or consistent. I doubt it.

5) Looking at the printers made me wonder if dc motors could be used with opto-encoders for this project as a replacement for the steppers. I’m not sure what would be the best way to do it, but I’m considering making a “stepper driver board” out of an arduino to see if I can get it to behave as a drop in replacement.

6) It appears like the thin and thick sheet are unnecessary for a prusa. Well that’s nice.

7) I’m looking into using my xylotex 3 axis kit as the stepper interface for this prusa. I think that just means I need to put the mosfets, end stop pins, and thermistor circuits on a shield for my mega and I ought to be good to go.

Nema 17 on the left, Nema 23 (with 260 oz/in of torque) on the right
8) I’ve got 3 nema 23 260 oz/in steppers that would be delightfully overkill for this. I’m wondering if it is worth the trouble of building new brackets for everything. I know that torque does not necessarily equal speed, but I would like to see how fast those would print. I would try the extruder (possibly) and the x and y with those monsters. The z axis doesn’t need that kind of speed.

9) I ended up buying some 8mm linear ball bearings from ebay. 12 for $15 isn’t too bad considering they will last a lot longer than the pla.

10) Using the testing setup of repg from Ben Jackson I have been able to connect to a mega 1280 and a 328. I can’t do much else before it crashes, but at least its a start. Repsnapper seems to work flawlessly with the 1280, untested on the 328.

A Makerbot disaster struck!

I’m not sure what’s been going on with my makerbot, but I don’t like the way it has been progressing! All week long I have been having trouble with my extruder board. I’ve been talking with Matt at Makerbot and he has been super helpful, but we haven’t figured it out yet. It will give me the dreaded “toolhead 0 : not found” error, and once finally connected it will “get tired” mid print and stop heating.

Well… today it stopped heating the extruder tip while printing, then it snagged on the print, bent the brass tube, and the hot end snapped off of the mount with a little flourish!

broken makerbot hot end

I’m going to try to find the drawings for the plastic mount piece that broke. Thankfully that ought to be easy enough to make by hand. After that I have to say I’m at a loss as for what I can do to prevent this from happening again. This is why they call it DIY. I just wish sometimes it was more “doing”, and less “yourself”.

$10 DIY Makerbot filament spool

I can’t believe it took this long, but I finally had a bad filament tangle last week, and a few aborted prints because my old setup wasn’t working. I really needed to get my filament spooled so that it would nicely dispense, and not jam, tangle, or unspool.

I really love the way the official makerbot kit looks, and I bet it really works smoothly. I just don’t have $90 sitting around. I’ve already spent that on ABS, relays, arduinos, and prusa parts!

I went down to the old Home Depot and picked up a cheap ($8) extension cord spool and a few feet of nylon water tubing. My extruder hasn’t had any trouble with its grip, so this creation has the extruder just pull the filament off the spool. I drilled out the handle and carefully spooled the ABS on the spool. THAT took a while, but it’s way better than having to constantly babysit the machine.

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