I am posting some unsolicited observations about sourcing parts for a MilkRap build (or any "xxxxxRap" for that matter. I will also post links to parts I self sourced if anyone is interested. Perhaps my experience will save someone some time, money or headaches.



I am a cheapskate by nature - something that fuels my DIY spirit - so I have spent countless hours looking for the cheapest way to build a 3D printer. In fact, when I was designing the MilkRap, lowest possible cost was one of my two major design goals - the other was easiest/fastest possible build.



As a result of my time spent scouring the web for the cheapest components I came to the conclusion that buying direct from places like ebay or a Chinese website like AliExpress.com can perhaps save you a few bucks but they come with potentially higher "prices" in other areas: Delivery time, quality, completeness, correctness and accountability.



Delivery times for some Chinese websites (even things on ebay coming from china) can be up to a month or more depending on where you are located.



Quality: I am an expert on this as I have purchased the same component from many different factories in china. What I can tell you is this; if there are 100 factories in china that all make product "X", they will all use different levels of quality components in the manufacture. So like a box of chocolates, you never know what your gonna get.



Completeness: I recently bought a set of Nema 17 stepper motors (used) on ebay for cheaper than a new set would havfe cost from a reputable supplier who I had purchased from before. When the motors came they were six prong outlet when my printer needed four. Not a huge deal, but it would take some soldering to fix. Also, they did not come pre-wired. I would have to buy a double ended plug for each motor to get them to work (actually two sets for each motor to convert them from 6 prong to 4 prong.) The set I could have purchased from the reputable supplier was about 30% more expensive, but came correct, new, and pre-wired. I originally thought I wouldn't mind soldering the connections, but when I was done I wish I bought the more expensive ones.



Correctness: A different time, for a different project I purchased an AC to DC power converter from AliExpress. The description on the website clearly stated that it could be used with either a 220V input or a 120V input, so I bought it. For my application, I specifically needed a power converter that can be used for either input voltage depending on what was available wherever I was. However when I plugged it in to a 220V outlet the huge spark and smell of burnt electronics told me instantly that the product had been mislabeled on the website and was not actually build to handle 220V input.



Accountability: American companies (for the most part) have all figured out that accountability (i.e. customer support) is a huge part of getting return business and favorable reviews. China on the other hand, has not. Trying to explain a problem to a foreign company is hard enough, then you try to get a refund - Yikes!



So, in brief, if I had to do it again I would stick to American suppliers with good reputations (check the web for company reviews). I have had a very good experience with the folks at Makerfarm.com. This is not to say other companies wont give you just as good of an experience, its just that I have really only delt with Makerfarm. They should have everything you need, more or less. If you need custom raw materials like PTFE tube or steel round bars, McMaster Carr and Grainger are the place to go. They have really good pricing, no minimum order quantity for most products, and one time I ordered from them in the morning and it was delivered that afternoon (How did they do that !?!?) Both of those companies are a makers best friend - they carry everything under the sun.



Partial MilkRap self sourced BOM.



Black rectangular milk crate 24 quart $7 + $12 shipping

https://www.milkcratesdirect.com



Mk2 j-head hot end $49

http://www.ebay.com/itm/New-RepRap-3D-Printer-MK2-J-Head-Hot-End-Makerbot-Prusa-Mendel-/290768331825?pt=LH_DefaultDomain_0&hash=item43b324a431



Printer board rev d. $87

http://www.ebay.com/itm/New-version-Printrboard-for-Reprap-Prusa-Mendel-3D-printer-improves-upon-Gen6-/281101127668?pt=LH_DefaultDomain_0&hash=item4172eecff4



Mk1 heat bed $19

http://www.ebay.com/itm/1pcs-RepRap-3D-Printer-PCB-Heatbed-MK1-heated-heat-bed-For-Prusa-Mendel-/290908896216



Nema 17 used motors $52 for 5

http://www.ebay.com/itm/5-Nema-17-Minebea-Stepper-Motors-Mill-Robot-RepRap-Makerbot-Prusa-3D-Printer-/171030142212?pt=LH_DefaultDomain_0&hash=item27d230dd04



Minimalist direct drive extruder $0.0

http://www.thingiverse.com/thing:15718



Lm8uu linear ball bearings $5.25 for 10

http://www.ebay.com/itm/10pcs-LM8UU-8mm-Linear-Ball-Bearing-Bush-Bushing-FREE-SHIPPING-/121096649695?hash=item1c31ec3bdf&vxp=mtr



Mk7 drive gear $12.5

http://store.makerslide.com/index.php?main_page=product_info&products_id=95



Atx 500w power supply $20

http://www.ebay.com/itm/Hercules-500W-120mm-Fan-Silent-ATX-Power-Supply-w-20-24pin-SATA-Serial-ATA-NEW-/260937035816



Steel rods came from McMaster Carr online



PTFE tubes for Bowden extruder came from McMaster Carr or Grainger, I cant remember.



Glass plate for top of heat bed came from Lowes (I found you do not need to use borosilicate glass, soda lime window glass has worked just fine for me)







