Very Very Expensive

I never imagined it can be that much.

McMaster is usually not the cheapest for things like that. What do you need it for?

I had no idea they existed. But the idea of having to hook up an air compressor just to run the machine…nope, that’s not for me.

For some reason I find it humorous…, the ad states “they glide smoothly and silently without wearing over time.”
Yet, they also carry “Replacement Bearings”…,

Screenshot (6)


Actually, I’m looking for the item in the attached image, for a project I’m working on.

I believe the prices in the McMaster Carr catalogue are there for use when preparing your cost plus bid for the US DoD


This is the part number I’m looking for 21550-161002. Any recommendations before I order it and pay 160 Euro for it?

What’s the requirement?

These would appear to be lubricant (and therefore contaminant) free, assuming the air supply is also clean and oil-free but there are various grades of linear rail with pretty low sliding friction (zero preload HiWin for example) with very long and well understood wearout lifetimes.


Hey the cost of fun keeps going up and up and up.


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