FYI Drillrod is a crappy linear bearing surface…likewise, 10 for $10 linear bearings on ebay.
My delta printer is protesting what I put it through last weekend. I’m looking at having to replace the linear rods and bearings that, despite lubrication, are squeaking noisily.
The problem is: The cheapass tool-steel drillrod that was $3.50 from McMasterCarr and the cheapass Chinese LM6UU bearings that are $10 for 20 (10, plus another 10 shipped when I complained about the first ones) are a sub optimal solution. They lasted about 6 months.
And purchasing the RIGHT stuff is down right pricey! 2’ of hardened Stainless is $40 (so $120 for my needs), and quality linear bearings can be $17 a piece and up. ($102…or more than two Franklins to 'solve the problem and never think about it again)
Rods need to be 18" or longer, I can cut to the right length and turn the ends to mate within the existing envelope. Bonus points if they’re mated with bearings! (a la takeouts from surplus printers. Double Triple bonus points if they’re all the same. )
I’d get pre-cut, hardened, chromed rods. Ever since I got the correct stuff from that #First150 deal, I don’t think I’ll ever use stainless or drill rod ever again. I can’t even dent/mar them with set screws.
@Mike_Miller depends. You need a stiff lathe with hard, sharp carbide inserts and a lot of patience. Else the tool will just slide on the surface and slowly go dull (or suddenly grab and snap)
@Mike_Miller I’ve got a lathe and carbide tools too, I’m no expert but I’ve had plenty of time on a lathe. I can tell you that I would just buy them pre-cut. It’s very difficult and probably the most dangerous thing I’ve tried to cut. When they say hard, they aren’t screwing around.
@Mike_Miller Guys. I have heard this conversation before. I have been designing and building industrial automation for 39 years. Drill rod will never work with then linear ball bushings. You can use drill rod only with plastic bushings. You can cut hardened shafts to length by annealing the area that you want to cut with a torch . Heat it up till its past purple . Then you can machine it easily
Annealing works great, that was the only way i was able to machine ball screws on my flimsy lathe. Of course, you get a soft surface on the ends of whatever you’re machining.
But honestly, just get them pre-cut. Here’s where i just ordered from: http://aliexpress.com/item/-/1092438345.html - they’ll cut you whatever length you need, and from what i’ve heard so far, the quality of the rods isn’t too shabby either.
@Thomas_Sanladerer usually having a half inch of the end of the shaft soft is not an issue. But you are absolutely correct, I buy all my shafts cut to length, you can even buy them tapped or threaded
Another local guy (smarter than I) reminded me that the goal is to get to the next printer. I’ve got a pile of second-string linear bearings…I’m thinking I’ll remove the drillrod, sand down the highpoints, lube and replace the linear bearings…and concentrate on getting the other printer in service.
This isn’t a wasted conversation…it’s important to note that drill-rod isn’t a good idea, and if I jump from Quadrap (gantries on skate bearings or PTFE) to Ingentis (movement on 8 and 12mm linear rods), I’ll obtain the right stuff the first time.
Back when we were using drill rod which wore down we’d just rotate the rods so that the grooves were no longer aligned with the balls. Just a 45degree rotation and you’re back in business. Drill rod is bad, but it works well enough in some cases - work with what you have.
You can usually cut high strength chromed rods with an angle grinder with a cutting blade, it gets hot while you start cutting, just go slow. I am finding cheap 12mm chromed linear rods on Alibaba. although they don’t say if it’s high carbon steel, check out: http://ntl-bearing.en.alibaba.com/product/1270394737-212219230/Cylinder_linear_shaft_WCS12.html as an example (sorry never used these guys… but they offer rods made for linear bearings)
I’m not thrilled by chromed rods because I’ve had the chrome flake off and screw up the bearings I was using. However, that may have been because it was cheap.
Unplated case-hardened rod is also a viable option - i you keep it well-greased, since that’s usually not stainless steel. I’ve once used proper linear, hardened rod for a Sells Mendel (a complete waste for that machine, btw) and they started getting rusty spots pretty quickly.
If you just want hardened bearing grade steel - then misumi will do a 8mm dia by 400mm long for 9.50 each. Stainless is not that great except for the non rusting feature.