Tuesday, April 26, 2011

Hunting Hardware for the Prusa Mendel

Like with the printed plastic parts my original intent was to try as best I could to acquire the materials locally instead of relying on the Internet to deliver the pieces to my house. As with the printed parts, initial efforts proved frustrating and in the interest of getting on with it, I wound up on the Internet anyway.

My parts list, as shown in the parts document that accompanied the assembly instructions and printed parts.

It wasn't a complete failure. First I started at what is the closest thing we have to a mom-and-pop hardware store of ye olde days, True Value Hardware. There I got zip ties, 5/16" nuts and washers, plus a handful of #8-32 nuts and washers, and one M8 x 50 Hex Hobbed Bolt and nut. I'd asked her for two nuts but didn't realize she'd given me just one, so I'll have to go back. I could have gotten the 5/16" threaded rod there, but they wanted something like $21 for one, 6' rod. Umm, no thank you. McMasters had them listed for less than $5 ea.

Total spent at True Value: $17.50

What it would have cost online: $23.75 before shipping

Lowe's was my next stop, and there I got threaded rod, and the fender washers.

Total spent at Lowe's: $19.16

What it would have cost online: $31.91

So far, so good. But those were the easy parts. Nobody up to that point knew what drill rod was, and nobody had any. The guy at Lowe's did give me two important tips, though. He was concerned that I wouldn't be able to thread a nut on to the 6' length of 5/16" threaded rod I had him cut in half, because, he said, the cut messes up the threading where it's cut. To avoid that problem he suggested threading nuts on the rod on either side of the cut and then wind them off to smooth out the thread. Fantastic idea. Second, he told me there was a fastener store in town called Fastenal, and they might have the other parts I was looking for.

Fastenal had some of the parts, and ordered some more which should arrive Friday, but some parts are still missing. From Fastenal I finally got the drill rod (well, 2 of the 3 pieces I need), M4x10mm bolts, #4-40 x 1” cap bolt, #4-40 washer, and #4-40 hex nut.

Total spent at Fastenal: $50.77

What it would have cost online: $21.84

Ouch. So, the score for this round is: $87.43 for the home team, $77.50 for the away team.

Online is probably only beating local by the amount of shipping, or less, but as I get to some of the parts they had to order special for me, the price differential increases. For the metric bits listed under the Wade's Extruder section of the build materials, I will definitely have to go to McMasters if I want to keep the cost down. The brass bushings were the hardest to locate nearby. I got a couple leads from Fastenal, but it'll just be easier to get them with the other screws and nuts I need for the extruder.

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