Where to splurge on my Prusa i3 build?

I'm self-sourcing a Prusa i3 and am actually under budget at the moment, so I'm considering where it might be good to spend a bit more.

I'm looking at rods right now and thinking I'll go with the nicer McMaster hardened rods (http://www.mcmaster.com/#6112k15/=ruke5w) instead of the eBay tool steel I had planned.
For threaded, I'm looking at some cheap ones I found here: [www.zoro.com] but I wonder if it would be worth it to spend more. Also, is zinc plated OK for those?

I'm thinking of spending more on the smooth rods because I already bought my LM8UUs from Misumi and it seems like cheaper rods might be a mismatch for the nicer bearings.

Aside from that, I'm getting a hot-ends.com J-head and, theoretically, new 2A steppers from Massdrop. Is there anywhere else it might be a good idea to spend more?

Thanks!

Splurge an all-metal hotend. There are some really good ones around (like E3D). The upgraded rods are a good idea.

Go for an electronics package that'll allow you to put an additional hotend on at some point. You'll end up wanting a dual extruder before too long.

Hardened chrome rods are the best. They will last a long time (almost indefinitely) Other rods may work but will need replacing from time to time.

[www.amazon.com]

I agree on getting a good hotend as well like the E3D

Quote
3dkarma

Go for an electronics package that'll allow you to put an additional hotend on at some point. You'll end up wanting a dual extruder before too long.

Can you clarify what you mean by this? Do you mean something better than a ramps 1.4 kit?

Ah thanks, I hadn't looked at those Amazon rods in a while. Cheaper to go with these longer ones

[amzn.com]

But is it any harder to cut chrome? Assuming I find an angle grinder.

I've been advised repeatedly to stick with a real J-head since this is my first printer, although I like the idea of future proofing with all metal. Thoughts?

I'm afraid I've already ordered cheapo RAMPS. We'll see how it goes.

Best way to cut them it with a chop saw. If you don't have one, find a local welding shop and ask nicely, they may cut them free or a small fee. I have several so was not an issue for me.

I like Misumi's rods, the ends are clean and never scrape things as they enter and leave the rod during installation/maintenance. Not one is bent/warped/not straight in any manner I can tell. I've never seen more beautiful rods. My ebay rods however..
My personal example of splurging on electronics is the Megatronics V3, with enough for both dual Z-axis steppers and triple extruder steppers.

---

Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

tmorris,

Do you use an abrasive disk or a steel cutting blade on the chop saw?

I would splurge on the frame and linear motion components. You can't can't go wrong with misumi's bearings and their hardened rods. I would also use their belts and pulleys too. Their Aramid reinforced S2M belts are relatively inexpensive, and they stretch very little. The upgrade will probably cost you $15-20 over Chinese parts.

The Zoro tools link showed an M10x1.5mm threaded rod... Is this what you're planning to use? There's really no need to upgrade to an acme or trapezoidal leadscrew but, you'll probably want to go with an M5 or M6 rod. The threaded rod will be inherently bent and not always concentric. The thinner and more flexible threaded rod will be less likely to overpower your z-axis smooth rods and affect print quality. I would use the M6 x 1.0mm because it makes for easier math when determining layer heights, but I would also be inclined to upgrate the smooth rods to 10mm so you don't see any banding or artifacts in your prints. If you have a Fastenal nearby, they sell a nice oil-finished M6x1mm threaded rod in a 1M length for around $4.00.

You can't beat the j-head from hotends.com, but your filament drive system is another great place to spend a little (tiny) bit more cash to ensure accuracy. Buy a quality filament drive gear or hobbed bolt. I have used some hobbed bolts that are non-concentric and result in an uneven feed. They have kind of cam effect, and their eccentric shape will drive you crazy when you're trying to finely calibrate your extruder for thin-walled prints. Makerbot has a nice drive gear, and Airwolf3D sells a very well made hobbed bolt. Upgrading to either one shouldn't add more than $5 to your build.

If you still have a surplus, go for a nice 12V regulated power supply. Something like this $70 450w Meanwell (here) will supply more than enough power for a large heatbed with 2 extruders, and should last forever. The 350w version is also a good choice, and can be had for around $50.

I see that you've already ordered a cheapo ramps setup. Don't sweat it. Cheap electronics will not be a limiting factor if the rest of your machine is precise and well tuned, but they are more likely to fail and are generally built from less robust components. If something does go up in smoke, use that as your opportunity to upgrade.

Great feedback and great education on Z-axis and filament drive-- thanks so much.

This does validate some of the choices I've made. I've since opted to go with chromed bearing steel rods from Misumi. I think it's worth an extra $17 to not have to cut them myself. Those, along with my Misumi bearings and pulleys/belts (ordered during their $150 promo in March) seems like they'll make a pretty smooth XY.

That M10 rod was actually for the Y frame, I'm getting M5 for the Z-axis screws.

My other recent change (not yet ordered) is the E3D hot end. I initially got a lot of advice toward the J-Head because this is my first printer, but everything I've read and watched about the E3D sounds very encouraging and it seems like it will last me longer.

Thanks again.