Lots of Questions!

[evamvid]

Hey All,

I have lots of questions about building a Morgan in the USA.

What length of belts do I need? I couldn’t seem to find that in the BOM?
Closed or Open Loop?

I can’t get metric coach/lag screws in the US. The smallest size I can get is 1/4 inch, which is 6.35mm. Will that size work? Where on the printer are these used? Is it somewhere where I could drill a hole and use a machine screw and a nut?

Do the pipe diameters need to exact? I can get the metric pipes here, but it’s more expensive, and is driving the price way up. Can I give or take a few mm on the diameters, and modify the scad files in some way to fit the pipes I use?

I remember when the Morgan came out there was a bit of sag on the arms. is that still a problem? Is there a fix for that?

Is there somewhere I can get the drill bit leadscrews from over here? Have you considered rack and pinion on that axis?
Even better, is the threadless ball screw (like on Robert Kuhlmann’s fork) compatible with the original Morgan?

Has anyone considered printed bevel gears instead of the worm gears that Ryan Altair used?

Thanks!
evamvid

[Quentin Harley]

So many questions!

The screws are used to attach the ABS toolhead to the PLA arms inside the drop shaped holes. Use any convenient replacement.

Check the forums of some of your fellow American’s efforts. The pipe available to you are close enough, and can be made to work with only a slight amount of reaming.

Sag is not a problem since the “armlevel” branch of my Morgan Marlin. Get it from Github. Corrected in the firmware for perfectly level prints, even if you had severe sag (which was improved vastly with the new PSI arms)

Rather use ACME lead screw, since it should be cheap and easy to get where you are. Look for something with a nut about the same size or slightly smaller than an M8 nut. The nuts can be slightly loose, since the anti backlash spring takes care of any play.

Please feel free to do your own thing with the gears. Let us know how it works out. I use belts and ropes because it has limited hysteresis.

Hope it helps…
Quentin

[evamvid]

Thanks a lot.

About the leadscrews, the only place I can get the acme screws is McMaster -Carr. They’re kind of expensive. But, the nuts are the deal breaker. It’s close to $40 per nut (I don’t know if you’re familiar with USD; you can get about 100 M8 nuts for $5). I didn’t realize it was meant for a nut with around M8; I’ll probably just end up using regular old threaded rod for the z-axis.

Also, for the coach screws, how big is the hole, and is there room for a nut on the bottom?

Thanks!

[evamvid]

How big should the plywood be? And what is the radius of the semicircle you cut out of it?

[evamvid]

For the copper tubing, are the diameters given ID or OD?

Blaze_1: I’ve picked up on that a little bit, just looking at all the different build pics on this site. I’ll definitely keep what you said in mind. At the same time, thanks for the dimension. I’m nervous in general about setting off without a predefined plan, so that really helps me out.

[evamvid]

And what about the ported/non-ported pipe adapters? Are those a potentially printable part?

[evamvid]

Also, if I went with belts for the drive, do you think I could make a full loop by hot-gluing the non-toothed side together?

[evamvid]

Thanks!

How exact are the dimensions you have to use for mounting the pipes etc.?
Are there any? Or do you just have to make sure that they are stressed against each other?

[evamvid]

I keep seeing references to 6805 bearings; but they’re not in the actual pdf BOM. I see a printed part labeled 6805 bearing adapter, though. How many 6805s do I need?

Also, there is Kapton tape in the BOM, and it says it’s used for assembly. Where is the tape used on the printer? Is it just used in the toolhead assembly?

[sam_s]

You should take a closer look at the Assembly instructions, it can really fill in some of the gaps. That’s what I did and everything clicked. For example, the lengths of pipes (and which ones should be used for ported ends) and link to exploded diagram can be found there.

The copper tubing is 1/2″ and 3/4″ (inner dimension). Very common in the US.

The PVC pipe is 1″ inner diameter Schedule 40, plain end.

You need two 6805 bearings. I also found it odd that this wasn’t in the BOM. Also, heed the F608 bearing suggestions.

I’m believe the 6mm Kapton tape is needed to tape in the thermistor if you use a J-Head.

For mounting the hotend holder, I just used some long M3 screws. Tolerances were plenty tight so they just held. Try not to overtighten if you go this route.

I would really recommend following the suggestion of two 0.9 and two 1.8 degree motors. The 0.9 motors I purchased from Sparkfun were only a few dollars more (yes, and shipping…) than the high quality 1.8 motors I usually buy.

[evamvid]

Also, where is the exploded view of the driveshaft assembly. I know I saw it somewhere earlier, but now I can’t find it.

PS Thanks for taking the time to answer my incessant questions 🙂

[evamvid]

Also, the BOM says I need two 0.9 degree and 2 1.8 degree steppers. Since the cheapest way for me to get the steppers is in sets of 5, it’ll be much cheaper for me to get all of one kind or all of another. If they all need to be one kind, which kind is better?

Thanks!

[Quentin Harley]

I will check the BOM again. Thanks for the heads up.

[evamvid]

WAHOO!

I just found out that the local hardware store sells loose Metric hardware!
(Unfortunately no metric pipes though)

No I don’t have to buy them in bulk from McMaster. This might cut my build costs anywhere from $30 to $100, depending on if they stock some of the less common hardware (like the fender washers).

JACKPOT!

[hoff70]

You can search through my posts and find some info. I’m in the US as well so I’ve been through the metric/SAE and Z leadscrew stuff.

Don’t sweat the coach screws just find something that works. I believe I used 3mm.

Good luck!

Threadless ballscrew looks promising but not tested yet:

All good things

[Blaze_1]

I’m getting close to finishing my build, and the one word of advice I have is to focus more on how the machine works, and less on the exact specifications in the BOM.

Case in point. I wasted a month trying to figure out how to source the same parts you’re asking about. I ended up using #4 x 3/8 pan head philips screws in place of the small coach screws to hold down the motor mounts and the z axis brackets and #4 x 1 1/2″ flathead wood screws for the toolhead. GT2-20T puleys and open belts for the drive wheels.

I also used 1/2″ and 3/4″ copper pipe for the drive shafts. Little bit of filing on the printed parts and some reaming on the copper pipes and it all fits snug like a baby. Doesn’t seem to be a need for any SAE-sized printed parts.

I also got a lot of ideas from reading about building other RepRap models. The Morgan has several parts that are common to many other models. It took a while, but it finally clicked just how modular the Morgan is. Awesome machine, i’m sure you’ll enjoy building it as much as everyone else here seems to be.

[Blaze_1]

I went with 1/2″ plywood. All pipes are OD because the need to fit the arms and wheels.

I’m also using small binder clips to hold the belts. I mean freaking tiny.

The Pipe adapters are a printable part. As far as the wood, I couldn’t tell you the radius, I just used some linear measurements based on the the dxf file. Didn’t feel like finding a compass large enough.

[Quentin Harley]

You could use NPS 1 pipe. SCH 30 will be a bit loose, and SCH 40 will be a very tight fit. You could sand the adaptors slightly for a snug fit.

It is the ID that is important here…

Great news on the availability of the metric hardware!

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