Dan's Rostock Max

[dbarrans]

OK, so I didn't take many pictures during the build, so this isn't a build log, but it's just to talk about a few things I've done to mine to make it mine, in no particular order.

I've had this thing running since the end of January after taking my time building it after getting the kit on New Year's Eve. Haven't made a lot of useful stuff yet, but I did print a belt tensioner for a friend's Printrbot LC+ that he and I put together in October.

- dan

[dbarrans]

Ever heard of shipwright's disease?

Well, I noticed a belt was a bit frayed, so I ordered some new belts from SDP/SI. I noticed the new 20 tooth pulleys at SeeMeCNC and figured I'd change out the pulleys at the same time so the belts won't fray so fast next time. I've been toying with some kind of tensioner arrangement so I pulled off the top to work on the upper idler assemblies. Had to pull out the endstop wiring to do that. While I have the top off I dropped a few more t-slot nuts on both sides of the rails for another thing I'm working on.

Now I'm standing here next to my workbench looking at a half-disassembled printer, wondering what I've done. There are some things I want to print.

- dan

[dbarrans]

Here's a picture of a new 20-tooth pulley next to a 15-tooth pulley.

The old pulley has half-round valleys between the peaks like I'd expect, but the new one has flat-bottom valleys, flat-top peaks, and flat sides on the teeth. Doesn't seem quite like it fits the belt profile, but it claims to be GT2. The pulleys are from RepRapDiscount, apparently, from the URL on the pulleys.

- dan

[dbarrans]

Here's another picture showing the half-round valleys on the old pulley.

- dan

[dbarrans]

These things come with some seriously small setscrews and an Allen wrench (about 1.5mm). Don't drop one; you'll never find it again.

- dan

[dbarrans]

When you put on the top plate and idler assemblies, some clamps on the rails will keep the top from dropping all the way down and damaging something.

- dan

[dbarrans]

I found an easy way to install the belts today that I haven't seen here before. The idea is to cut a strip of plastic from packaging and use it as a ramp to guide the belt through the slot in the carriage.

1) Cut a strip of flat plastic narrow enough to fit in the slot in the rail.
2) Push the strip into the belt slot far enough to stick out above the carriage.
3) Grab the top end of the plastic. You'll need to use a toothpick or something else sharp enough to get behind it.
4) Thread the belt between the plastic strip and the back of the carriage.
5) Hold the belt and strip together with your thumb and finger, pushing them both down a bit to open up enough space in the slot for the belt to fit through.
6) Push the belt and strip through the slot enough so you can grab the belt from the front.

Using this technique, it took me maybe 20 seconds to get the belt through the slot.

- dan

[dbarrans]

A week or two ago, I saw these mirror brackets at a local hardware store. Hmmm. I can use those. So I got six of them.

- dan

[dbarrans]

I figured if I drill a hole in the end, and cut off the other end, it will hold a hex-head bolt and keep it from turning.

- dan

[dbarrans]

Combined with some other bits, here's what I ended up with last night for a belt tensioner.

- dan

[Eaglezsoar]

Good job on the tensioner, that had to be fun to drill through the rod.
I did something very similar except I used small eyebolts that the top rod slid through.
Many ways of doing things. Your build is looking good, I'm looking forward to watching
your progress. Thanks for posting the pictures.

[dbarrans]

Like I said at the start of this thread, I've already built it, and started printing stuff at the end of January. I'm not particularly satisfied with the print quality, and I know I need to fine tune the arms and U-joints, but I'm putting that off in hopes I'll be motivated to go magnetic instead to avoid that particular pain.

I've still got more stuff to post about things I ran into while building it, and more stuff I'm planning on doing to it, and I'll be doing that in between getting it up and running again with new belts.

- dan

[jesse]

Very nice belt tensioner, I was curious what those upper holes could be used for.

[dbarrans]

I used 1/2" aluminum rod for the top of the tensioner. Yeah, I was wondering how I was going to drill the holes until I found the right tool for it. This did the trick.

- dan

[dbarrans]

So, this is what I ended up with. I drilled the holes in the crosspiece far enough out to let me put a nutdriver on the nuts, so the vertical bits had a bit of an angle once the screw through the idler was tight. I added fender washers to keep these parts vertical, and to spread out the load to avoid crushing the wood when I tightened the screws.

This arrangement lets me fine tune the idler angle to keep the belt centered.

- dan

[cambo3d]

looks good, I tried to do this too but i couldn't get the holes in the top rod drilled accurately, so went another path.

[dbarrans]

Side view.

- dan

[dbarrans]

That drill guide made all the difference. And it was an excuse to get another tool.

- dan

[dbarrans]

A while back I realized I wanted to swap my doors to put the LCD in front between the X and Y columns. I didn't want to take the printer base apart to do that, so I thought about it for a while. When I saw someone had mounted the RAMBo to an interior partition, that was my motivation. I attacked the upper door hinge tabs with a mortising chisel, got the doors out, then chopped off the bottom tabs. Then I moved the RAMBo and left the doors off until I got some piano hinge. Then I left them off even longer.

I finally decided to switch to the Repetier firmware this weekend, but I had to get the door mounted first so I could mount the LCD somewhere. A couple days ago I finally got around to mounting the front door with a piece of piano hinge.

- dan

[dbarrans]

I should add that the chisel didn't leave the cleanest cut, but I was able to clean it up better after the door was out. Here's the door after I got it out. The second one I did looked better, because I had some practice by then.

- dan

[dbarrans]

The new hinge lets me open the door wider too.

- dan

[cambo3d]

That drill guide made all the differrence. And it was an excuse to get another tool.

- dan

where did get your drill guide? I tried to make one out of wood and it wasn't working. for me anyway.
i need to add to my collection of tools also.

[dbarrans]

I got the drill guide from Woodcraft, but you can get them online too. http://v-drillguide.com/

- dan

[dbarrans]

Here's how I attached the power wiring to my Onyx. I used 12 gauge stranded wire, split up the strands into several groups, and soldered each group through a separate hole in the Onyx pads for a better connection. The only alternative I saw was to fan them out flat and solder them all to the bottom of the pad, but that seemed like it'd be less secure, and a worse connection because solder has higher resistance than copper.

How did you attach yours?

- dan

[dbarrans]

The aluminum plate was screwed on right on top of the Onyx, so I put a layer of polyamide tape on the bottom of the plate to keep from shorting out the Onyx. I soaked two pieces of 8" wide tape in water for a few hours, then slid them onto the plate, let them dry, and trimmed the edges. You can barely see the butt joint between the pieces a couple inches to the right of the hole at the closest edge of the plate.

- dan