80/20 linear bearings

[Ursine]

Anybody tried these? Looks like they might work nicely.
http://www.8020.net/PDF/Fractional%20Section%209.pdf

Dave

[ger21]

The general consensus is that they won't work well for cnc. Too much play and too easy to bind. A lot of people ask about them, but I've never seen anyone use them.

[Ursine]

Darn...seemed too good to be true.

[ranman]

Originally Posted by ger21 The general consensus is that they won't work well for cnc. Too much play and too easy to bind. A lot of people ask about them, but I've never seen anyone use them.

That's kinda what I thought when looking at them too.
Even though I think the play could be adjusted out some, I am not sure that enough could be completley removed for good accuracy when working with alum or steel.

Then you do have to wonder about the binding too (even though I had not thought about that.)

But if anyone has made them work w/ accuracy w/o binding, I'd like to hear about it too.

[Edh]

Hi All,

First post here – but long time CNC fan. I built a small machine a few years ago – it didn’t work too well, but I learned a lot. I’m now ready to build a new one.

I just spoke with an engineer at 80/20 and at my local 80/20 distributor - they both agreed that their bearings should work if I am not looking for super high tolerances – which I’m not. I mainly just want to cut out wood & foam for projects.

My next step is to send a sketch of what I want to the engineer, he’ll spec out the parts needed and price it. As long as this isn’t too expensive, I’ll probably build a small (~30x20x6) table in this fashion and see how it goes. I’ll post my findings.

If anyone has any suggestions, please jump in.

Thanks!
-Ed

[pen25]

I am thinking the unibearings would be allot better. as you can take two peices of say 1515 and put in another say 8" 1515 inbetween using the unibearings this would allow the whole binding issues and allow you to tighten it up.

[mxtras]

Hello all -

I am new here, but not to the hobby or the industry.

YES - I have used these for two designs - both were manually positioned motion platforms with less than 5 pounds. The arrangements were extremely simple (single 80X80 beams) and the requirements were extremely minimal and they failed to satisfy me or my customer. I will likely never use them again. They DO bind - unless they are left extremely loose. They don't slide all that great, either. At first, I figured it was something I had done incorrectly, but after a couple attempts by first myself, then a collegue, then the customer to come up with a happy medium, we gave up in agreement that they were just not worth the results we were getting.

Personally - I would NOT recommend them for a machine. I will use something like Redi-Rails (www.pacific-bearing.com), which are the cheapest guiding I have found (?). I would likely even use cam followers on Cold Rolled before I used these things again. Sorry, 80/20. I will continue to buy your other products - just not these things.

Scott

[CRFultz]

The flange bearings will not work for motion applications that require accurate postioning. In order to take out the slop you have to use the included blue u-shape shims....this also will make the bearing have more friction...delrin against anodizied aluminum. Far better and cheaper to go with rails or shafts.
The 1020 series bearing will cost you close to 50 bucks.
I use them all the time but only for manually moving fixtures into place and then locking them down with the brake kit.
If you are set on using them I have some I'll sell ya ...cheaper then what you could buy em' for...I have a few dozen laying around..

[Edh]

Good input, thanks for the warnings.

Maybe I'll just use 80/20 for the frame and find another rail bearing system to attach.

Thanks,
-Ed

[jerryrigge]

Currently using these linear bearings on my y axis. Only carries about 10 pounds (the plasma torch). After spraying with silicon spray mine slides and zips around OK. Nothing like a precision bearing but I do think these are servicable for some applications. Also...mine are from T Slots so they might actually work better.

jr

[marchantdice]

For a full range of profile extrusion visit; http://www.marchantdice.com/linear/retrosystem.pdf
Send your enquiries to admin@marchantdice.com

[Dan Mauch]

I actually tried those linear bearing on a small router that I was building. As mentioned in these posts there was binding when I tried to decrease the clearance.
Definetly not useable for cnc.

Dan Mauch

Originally Posted by ranman That's kinda what I thought when looking at them too. Even though I think the play could be adjusted out some, I am not sure that enough could be completley removed for good accuracy when working with alum or steel. Then you do have to wonder about the binding too (even though I had not thought about that.) But if anyone has made them work w/ accuracy w/o binding, I'd like to hear about it too.