[starCNC]

I want to know if thomson SSU PBO 20 rails sag without using shaft support

[the4thseal]

looks like you have low profile supprts, i would use them. Nice rails
TC

[jwatkins]

You bet they will. Question is, how much? There's a formula for figuring it out which I don't remember, but the quickest thing would be to simulate the weight that will be riding on those bearings and measure the deflection. Also, since you've got the bearing style with an open side, it would be pretty easy to add some support along the length.

[BigDaddyG]

Yes they will! Not only will deflection be a problem, but the harmonics will come into play when you get the thing working, I assume your doing a router thing, when stuff gets spinning and cutting the harmonics will be a BIG problem. Plan on putting supports under the rail, preferably along the entire rail. Good Luck.
Glen

[Bloy2004]

Did you snag these on ebay? Looks like they already have a support plane/strip. ....just got to mount!

[starCNC]

I got them off ebay, they do come with shaft support. i was just wondering if it will be ok to not use them. Now i'm planning to sit them on top of 80/20 tslot