First build, had a few questions

I plan to build a GUS Simpson as my first build. I have access to a working printer, and everything else I'm doing on my own. Before I start ordering parts, I had a few questions.

First of all, stepper motors. I plan to use drivers that can handle 2.2A. I want to get good motors. I plan to get one 2A NEMA 17 for the extruder, and more normal ~1.2A 17's for the arms. Is this overkill? Would it make sense to use a 23 for the extruder? Do my steppers need heatsinks?

Secondly, the hotend. I'm not that familliar with hotends in general. What are the differences between them, and how compatible are different designs with different plastic parts? Are they as standard as NEMAs? And do I need a fan?

Third, the Simpson's printbed is basalt. I really don't want to deal with custom-cut stone, especially to this thing's tolerances. Would glass work? Aluminum?

Fourth: Is there some way to get the custom cut flat parts for GUS without paying for a service like Ponoko?

And finally: Is GUS changing fast enough that I should wait to plan my build (I'll start in February)?

Edited 1 time(s). Last edit at 12/17/2013 01:38AM by epicepee.

I'd steer clear of Nema 23's. You'll run into a lot of mounting issues and Nema 17's are more than capable of handling the load. As long as they're tuned properly, you shouldn't have much of a problem with overheating.

Be careful of the ratings on some of these drivers. Some "2 amp" drivers don't make it to 1.2A in the real world. Fans are always a good idea (as long as you don't have a heated bed...). They are cheap and don't pull much power.

I'd bet your local kitchen counter outfit would be more than happy to cut you a chunk of rock for the bed. A lot of other things will work. Rock looks cool.

You probably would get more GUS specific information in the area dedicated to these printers rather than in the general interest area. You might even find somebody who has a spare set of printed parts ...

Would rock cut by a kitchen counter outfit be precise enough to use as a printbed? And can DRV8825 StepSticks really handle the 2.2A they say they can (with cooling)?

There is a builders forum over here.

For GUS any NEMA17s will do. (Low torque requirement.)

I would just cut some wooden boards by hand. (The holes are 250mm from each other.) A 200mm round piece of glass would work well on top.

GUS is evolving. I suspect it won't evolve much by February.

I designed GUS for the UBIS hotend which doesn't need a fan. However, I have modified the mount to be compatible with the Kossel mount. So anything people mount to a Kossel will also mount to a GUS.

I've been told by my glass supplier that tempered glass will be good to 700f. That gives you plenty of overhead, and it will be the cheapest...

If you go over to the granite counter shop and watch what they are doing, it's pretty impressive. I'd bet that their stone surfaces are flatter than a lot of pieces of glass.