[NIC 77]

Hi Everyone,

I'm going to be building a new CNC machine. The last machine I built used V groove bearings and IVT guides. This time I'm looking at linear rails with bearing blocks. I have zero practical experience with these guides.

The machine will be used mostly for cutting aluminum. I have a large powerful spindle that should provide me with ample torque at appropriate cutting speeds.

I've got a good deal on some Bosch Rexroth linear guides, size 25, with carriages P/N R165329423, standard accuracy class N. I believe they're part of their ball rail system of products.

I've heard lots of talk about NSK, Hiwin, TSK, rails, but not much about Bosch Rexroth. Are these rails comparable in quality and suitable for my purposes? What do you all think?

I'll have a look at them and may buy them tomorrow afternoon, so please be forthcoming with your opinions, time is a factor here.

Thanks in advance for your opinion.

[ger21]

Yes, the Bosch should be comparable to the other brands. I think that they are more common in Europe than over here, which is why you don't here much about them.

[jfong]

I bought a 15mm rexroth linear rail on eBay. Seems to work as well as the THK and NSK rails I have used in the past. If the price is right, don't see why they wouldn't work. 25mm are bigger than what is normally found on eBay. I see mostly size 15 and 20mm. 25mm should handle quite a bit of load. Make sure you get atleast 2 bearing blocks per rail.

[thegolfer]

Bosch Rexroth is a German company, quality is not a problem.

25mm guides will probably be able to handle a moving load of around 15 to 20 kN so unless you're building a 2000 kg machine you should be fine

[Galane]

I'm using a Star Linear ball screw linear actuator for the Z axis drive on a lathe. It was made in 1997 and still moves like new. Rexroth bought Star Linear then Bosch bought or merged with Rexroth - which still produces actuators with the same dimensions as many of the old Star models.

[NIC 77]

Thank you to everyone who posed here. Yes, I bought the rails and carriages. The carriages seem very robust and solid. I had a look at some size 20 carriages and they are much smaller than the 25's. I went with the size 25's. I put one carriage on a rail and immediately I could feel the quality. Tight fit, smooth movement. I hope they work. Right now I'm figuring out what to do for ballscrews. This will be my 2nd machine. The first one I built was rack and pinion and used V groove bearings.

I was a little bit concerned about imitation parts. I did some searches and found a picture comparing the packaging of genuine made in Germany carriages to imitation carriages made in China. Almost identical with a few give always. I don't know if this is a prevalent problem, but when I inspected the rails and carriages it was clear to me that I got the real deal and the quality seems superb. I won't know more until I try to put my machine together, which is still in the design phase, although I have committed to using these rails and carriages.

[loka]

ball guides can get damaged rather easily with hard chips jamming into the track. Protection and proper lube maintenance will go a long way to have designed product life.

Bosch, INA, SKF, scheeberger are all good european brands equivalent to Japanese brands.