Rostock Smooth Steel Rods

So my friend and I are both building Rostock 3D printers with the traxxas rod ends and carbon fiber tube. Most of my parts have been purchased and right now I am helping my friend find parts for his as well as find smooth steel rod for both of us.

Johan recommends purchasing these smooth steel rods:
[www.vxb.com]

My friends in my RepRap user group at my school recommend these:
Mcmaster Hardened Tight-Tolerance Metric Rods—Precision Ground Finish
Part number: 3821T14
[www.mcmaster.com]


The rods that Johan recommends are considerable cheaper and we would be able to save money buying a set for two printers at once. Are the rods that Johan recommends equal in quality to the McMaster counterparts?

I don't know how they compare but the cheap VXB ones work great and will last for years.

Additional note: McMasterCarr will often have cheaper nonmetric parts. I found 3/8" and 1/2" rods that are beefier than the 8mm for $15 for the same length. Of course, I can't source linear bearings of these sizes for anywhere near the $5 that VXB has for the LM8UU.

The cheapest 3/8 linear bearings I have found are from mcmaster and they are $22.14 a piece part #60595k12, So I guess the money saved on inch rods isnt really worth it unless you use brass bushings.

You could go with plastic linear bearings for $5. If you are willing to throw some efficiency away, you can use these. I have used these style bearings on my 2'x2'x1' envelope hobby mill for 5 years. There is little sign of wear. The gantry is 400 lbs and supported by 4 of the 1-1/2" ones. (My motivation to use them was not price. I didn't want to be required to keep my rails clean. I can throw a pile of saw dust on to a rail and the bearings won't hardly notice. They also make very little noise when compared to the ball version. However, my router doesn't allow me to appreciate the distinction.)

Nicholas.seward do you have any type of wiper on those bearings or do the grooves in the plastic bearing itself wick away the dust and debris? Do you need to apply any oil to the rods? Also could you use them for rotary motion as well as linear like the ultimaker brass bushings work?

I don't use a wiper. You need the rails to stay dry so lubricant will actual make matters worse. Depending on the load and the rotational speed you might get some chatter from the fins. (I don't think they are rated for rotation.) They are cheap enough that you could buy some and test. (I like to have two to play off of each other to compensate for any wiggle that they have.)

I use oil hardened smooth rods for my Rostock with no issues at all. I also use the cheapest LM8UU bearings that I can buy from China. I haven't had any issues with these bearings either. I do oil my rods occasionally to keep them smooth and rust free. The smooth rods I used are here, [www.mscdirect.com] and they are only $6 for 3'. I did use the traxxis rod ends, but I just used cheap steel rods and cut them to length, [www.mscdirect.com]. I have had no issues with these rods either and at $4 each you can't get any cheaper. Best of luck!

-Ben