Used to make slab leveling jig for my router.

Very smooth. Rail appears to be case hardened, not through hardened, but I could be wrong about this. Very little play on bearings. I cut to size and used to increase rigidity on a 3018 CNC.

I got this to make a flush cutting jig for my hand router. I was able to cover a cutting board 18"x20" and level both sides in less then 20 minuets. This made the best jig I could ask for it slids very smooth in both directions. I was able to level both sides that I used to take hours tring to level by hand sanding. The Sbr-16 bearing blocks work perfect but they are a little tricky getting them to slide on the rail the first time. I hand 2 that just did not want to go on and I hit them on and some bearings poped out. I was able to snap them back in place and aline the block again on the rails. Its a learing experience for me making this jig with these rails but no regrets. I even ordered me 4 spare bearing blocks. to make more jigs to run on these rails.

Easy to set up and use. Customer service was totally awesome when I had a question about the product… quick response and very helpful.