Building a Prusa

[Arthur Howell]

I am with Unallocated Space in Central Maryland, and I met a few of you at SkyDogCon this past year. 

I am getting ready to place my order with McMaster Carr and am wondering if someone would go over my shopping list I have just created and make sure that I have the parts exactly right. 

If any of the parts are incorrect please let me know what it is, which part number is preferable, and any other insight would be greatly appreciated.

93827A219	Ultra-Coated Grade 8 Steel Hex Nut 5/16"-18 Thread Size, 1/2" Width, 17/64" Height, packs of 100
96765A145	Black-Oxide 18-8 Stainless Steel Flat Washer 5/16" Screw Size, 3/4" OD, .04"-.06" Thick, packs of 100
92140A116	Black-Oxide Steel Large-Diameter Flat Washer 5/16" Screw Size, 1-1/4" OD, .11"-.14" Thick, packs of 10
93635A116	Metric 316 Stainless Steel Hex Head Cap Screw M4 Size, 20 mm Length, .7 mm Pitch, Fully Threaded, packs of 50
90685A039	Metric Black Finish Class 10 Steel Hex Nut M4 Screw Size, .7mm Pitch, 7mm W, 3.2mm H, packs of 100
98269A430	DIN 125 Black-Oxide 18-8 SS Flat Washer M4 Screw Size, 9mm OD, .70mm-.90mm Thick, packs of 100
93635A008	Metric 316 Stainless Steel Hex Head Cap Screw M3 Size, 10 mm Length, .5 mm Pitch, Fully Threaded, packs of 50
93635A020	Metric 316 Stainless Steel Hex Head Cap Screw M3 Size, 25 mm Length, .5 mm Pitch, Fully Threaded, packs of 25
91287A028	Metric 18-8 SS Hex Head Cap Screw M3 Size, 40mm Length, .5 mm Pitch, Fully Threaded, packs of 50
98269A420	DIN 125 Black-Oxide 18-8 SS Flat Washer M3 Screw Size, 7mm OD, .45mm-.55mm Thick, packs of 100
98676A100	Metric Black-Oxide 18-8 SS Hex Nut M3 Size, .5mm Pitch, 5.5mm Width, 2.4mm Height, packs of 100
5972K222	Metric Steel Ball Bearing Double Sealed Bearing NO. 608 for 8mm Shaft Dia
94210A055	ASTM A193 Grade B7 Alloy Steel Threaded Rod 5/16"-18 Thread, 3' L, Black-Oxide Finish

Some of the parts that I am having trouble tracking down part numbers to:

The Smooth Rods/Percision Rods: 8mmx420mm, 8mmx406mm, 8mmx330mm, Also these seem to only come in set sizes. Do you get a machine shop to cut to exact measurements or do you cut them yourselves? I have the same problem with the threaded rods.

I haven't found the belts in the right measurements: 840mm x 5mm and 900 mm x 5mm

225mm x 225 mm print top plate and 140mm x 225mm print bottom plate: how thick should the plate be?

I also seem to remember a "controller" box that you guys were using that was separate from the top of the machine that most people seem to use. Do you guys have a diagram for that box somewhere?

Any help would be greatly appreciated. 

I have also considered LocTite on some of the joints to make sure they don't come apart. Is this recommended or is this overkill?

I know we covered a lot of tips and tricks using the irc channel, but I feel like it would be better documented in an e-mail chain. So if anyone would like to throw in their 2cents about what I can do to make my life easier, that would be awesome as well. 

[Arthur Howell]

Also: Is there any benifit to buying everything from McMaster Carr or for $70 I could just get this:  http://ultimachine.com/content/prusa-mendel-hardware-kit-metric 

[Ben Eishen]

I'll take a stab at this real quick, I'm sure others will have something to add. You look to have all the faseners accounted for except for fender washers. Fender washers are used to sandwich a bearing for a makeshift idler pulley. Keep in mind this is black oxide coated, grade 8 hardware, The best of the best.

Smooth rod (drill rod) is sold in fixed lengths and cut and ground to the right size. Keep in mind that some times the shipment of drill rod will be bent and have to be tossed out. This is why it is a good idea getting it pre cut from a reprap parts vendor. This will ensure that you have a straight piece.

Top plates can be anywhere from wood to aluminum. My personal bot has a platform made out of 1/4 plywood, others have 8mm aluminum I beleive. Thickness isnt a real concern here, its weight and rigidity.

Belts are bought by the length. Somewhere we have a part # for them.

Ramps board enclosures (electronics enclose): These can be printed or sonny designed a custom laser cut acrylic case that sits on his venom.

Loctite would be overkill and messy. Every once and a while you'll get a bolt come loose, but the plastic almost acts like a lock washer when tightened.
--
Ben S. Eishen
773.234.7436 | b...@eishen.com
9160 Hwy. 64, Suite 12-302, Lakeland, TN 38002

[Ben Eishen]

Side note: Your BOM might not match the build-offs BOM and cause some grief and frustration. Best bet would see if Sonny has any more available seats for the build-off.

--
Ben S. Eishen
773.234.7436 | b...@eishen.com
9160 Hwy. 64, Suite 12-302, Lakeland, TN 38002

[Arthur Howell]

I wanted too, I just wouldn't be able to pick it up for some time. 

I've placed all the orders today and found a decent kit. It matches the Prusa Mendel kit exactly for parts. If it all works out, our wiki will include all of the updated information. 

[Sonny Mounicou]

Arthur,

I had given one of the members from your space that BOM.  I referenced both the official prusa BOM as well as my own BOM that I used for my second prusa.  Most of those parts you can get local from fastenal.  There are certain items like the hot end, electronics, and motors which can't be found locally.  If you want to send me the list of items from all of your orders, I'll be happy to look it over and tell you if anything is missing.

--Sonny

[Arthur Howell]

Hardware Kit:

http://www.a2aprinter.com/index.php?route=product/product&path=18&product_id=47 

Stepper Motors:

http://www.a2aprinter.com/index.php?route=product/product&path=33&product_id=51 

RAMPS DIY Kit:

http://ultimachine.com/content/ramps-diy-kit-complete 

Heated Bed:

http://ultimachine.com/content/prusa-pcb-heated-bed 

Plasruder .35mm hybrid for 1.75mm filament

http://www.makergear.com/products/plastruder 

Hobbed Bolt:

http://www.lulzbot.com/en/7-hobbed-bolts.html 

As best and I can tell; I'll still need to pick up a couple of things.

The glass plate

2 pullys

a bunch of zip ties

a power supply for the RAMPS DIY kit (I don't think it included one)

In regards to the external controller box, was that just an acrylic box that you put all of the RAMPS kit inside with the power supply and used a wiring harness to connect everything to? Also where did the wiring harness come from? Pictures or a link would be helpful.

[Ben Eishen]

You don't need the hobbed bolt if using the plastruder. The hobbed bolt is for wade and wade variant extruders.

--
Ben S. Eishen
773.234.7436 | b...@eishen.com
9160 Hwy. 64, Suite 12-302, Lakeland, TN 38002

[Arthur Howell]

Well i'm glad its only $12 bucks lost.. I'll just have to build another one!