Saturday, February 13, 2010

Pricing the Mini Mendel

I will be going ahead with both my Mini (M3) Mendel, and my M4 Mendel in parallel. So I figured I would do some US costing for a Mini Mendel vs it's M4 big brother. Just a reminder the M3 Mendel is not in development, and I am doing this more out of curiosity than trying to get a fuctioning printer out of it.

Threaded Rod:

Cheapest place I have found for M6 threaded rod is a local fastener company that sells it for $3 for a 1 meter stick (zinc coated). That would mean I need 6 sticks of rod if I cut them in this pattern. $18 plus sells tax

1 4x244
1 270,230,257,230
1 270,230,320,84,82
1 244,244,183,183,102
1 320,102,102,102,84,84,84,82
1 82,82,82

Smooth Rod:

Considering we are using bearings the rod doesn't have to be quite as good as bushing rod. I will be going with They sell a 36 inch (914cm) long 6mm smooth rod for $2.70. That's 1/10 the cost of the vxb linear motion rod which runs $25 for 30 inches. at 36 inches I will need 2 bars. About $6 dollars plus shipping

1 224,224,272,
1 275,275,272


Local supplier usually beats, but without the shipping costs associated with them. Luckily I have a good bit of M3 nuts, washers, and socket caps left over from my Makerbot, but I plan on costing out all the M3 so I can have a good idea of the real cost of this project. I don't use nylocks, I use lock tight instead because I am very forgetfull, and always end up stripping them. Costs without Nylocs would be $54 dollars.

m3x12 100 $5.41
m3x20 100 $5.93
m3x30 100 $8.42
m3nut 200 $4.32
m3washer 400 $7.44
m5mudwasher 17 $2.55
m6nut 200 $9.38
m6washer 200 $6.94


NEMA 14 motors are hard to find. The only NEMA 14 motor that I could find online was at for $15 dollars each. They are only 1250 g/cm, which is a little lower than the suggested 1400 g/cq torque suggested for the Mendel m4. Has anyone seen a high torque NEMA 14 stepper in the US? If I can't get a good prospect that doesn't break the bank, I might have to go with the lower torque ones. Also I plan on going with a Makerbot gear motor for the extruder, just because that's what I know.

Bearings: I usually use because I usually can't beat their price. I came up with 4 sets of vxb 623 for $60 and 1 set of 20 vxb 626 for $25 for a total of $85 dollars worth of bearings (ouch)

RP parts

I am averaging 20-30 hours a week of print time at this point, and should have my m4 Mendel printed by next Friday. Good thing is I will be able to print ALL the parts for the m3 Mendel in 1 week! That will be a fun change of pace.

Total cost of m3 Mendel for me will be Stud $18, Rod $6, Fasteners $54, Lasercut (Don't know where I am getting my lasercut parts yet, but assuming $30 for all the LC parts), Electroncis $175 (makerbot), belts form mcmasters for $20, bearings $85 and motors $100

$500 for a fully functioning slightly larger than Makerbot scaled, belt driven RepRap is not that bad. Considering it will only take $300 out of pocket for me I think this is doable.

Any suggestions on cutting the cost?


  1. it took me way to long to figure out why it was on a good idea on where to store the material used for printing.

  2. Lasercut parts can be made at ponoko. Why using lasercut if it is cheaper to reprap them?

  3. Some components of all repraps are made of what is called "thick sheet". It can be acrylic, mdf, or even plywood. If you search "m4 mendel reprap" you will see the data sheets that show you the BOM.

  4. Yea, found out that was an underestmate. looks like $70 for the cutting with me providing the acrylic. EEKK!


    The parts sheet

  6. I built mine with a build platform the size of the original mendel, and only needed 5 1-meter threaded rods. I didn't build the spool part, though. I also needed a third smooth rod because of the size increase.

    You listed 40 623 bearings. I barely managed to put mine together with 42, should have used about 5 more. Found a better deal from

  7. Oh, I also saved on the thick sheet by not laser-cutting. I bought a sheet of acrylic and used my dremel and a stencil to cut a close-enough version of the froglet. With the flex shaft and a plastic-cutting disk, it was shockingly easy.

    For a build stage, I bought an 8"x8"x1/4" sheet of aluminum that just needed mounting holes drilled and polyimide applied (turns out, I really should mill the surface flat, too), but I'll probably swap it out for MDF or some other insulating material (any suggestions?) to carry a pcb heated platform similar