Linear slides vs linear guides

[mindoverflow]

Hi,

What are the application differences between linear slides (bearing and shaft) and linear guides (profile guide way and appropriate bearing), looking at the prices we would say the second is better by far, but how?

Any precision difference, load, smoothness .....

I'm trying to build a lathe I'm yet at early stages of the design as shown. I found a price difference of 5-7 times between the two types. Any advice is welcome.

[jboggs]

As is so often the response here: Why not buy one? Are there some special requirements? What are you cutting?
I doubt if you can build one at home that will be as good as one you can buy. I 'm sure the machinists on this forum will have more information, but most of the lathes I've been around have machined ways rather than linear bearings of any type. You need absolute rigidity, very high precision.

As far as your bearing selection, the catalogs and websites will pretty well describe their products' capabilities. You have to determine what capabilities you need.

You will have to dig down further than just the price. You will have to read the technical sections.

[PinkertonD]

Depending on the size of the lathe (watch parts or car parts) you are intending, more friction is better than less friction so a flat, sliding, metal-to-metal way and saddle are much better. Anything with ball bearings is going to run into problems fairly quickly. The rapidly vibrating dynamic loads of cutting metal will very quickly embed the balls into the ways making tiny dents. Never a good plan.

As JB, correctly surmises, buying a lathe is a lot more practical. Check some of the Machinist newsgroups for used oldies but goodies. You will learn a lot about the workings of a lathe by rebuilding an old one.