Dont matter what i do every 3 months or so my core gets slack on the rales till the point I have to reprint a new core I’m in a humid area and I’m using a 1.5 spindle water-cooled 9 lbs can it be the weight of the spindle causing this? I was thinking of printing in PETG any advice?
What type of tubing are you using? Are the bearings not creating a dent on the gantry tubes?
First, how tight are you adjusting the core? It need only be just enough that the bearings contact the tube. If it is tighter, the plastic will bend to make it only just touch, but you will lose future accommodation.
Even with a heavy spindle, there should be room for adjustment…
I suppose that is another question. Are you adjusting the core tension? 
the two bearings at the bottom should allow adjustment with bolt tension. There should be a little loosening as the bearing bolts settle into the printed plastic, but you should be able to tighten the bolts holding the two bearings at the bottom to adjust the tension on the X rails.
im useing 23.6mm tubeing and yes it leaves some marks
, the first couple months it works perfect but after that it gets lose
hey thanks for the feedback and yes the first couple of months it works great i do all the adjustments nothing to tight or lose just right but then it changes
It really should not. The bearings should not allow the core to wiggle, but there ought not be any otessure on the tubing more than cutting forces. More pressure rhan that will force the core print to deform.
So youre saying that you’ve entirely run out of adjustment pissibility with these bolts?
After a couple of months, mine got a bit loose, and I had to adjust these by about a half a turn, maybe a bit less. They havent needed adjusting since (and my LR3 core was one of the first, as it was printed as a part of the beta test group.)
yes so basically when i printed the core I use the bottom 2 bolts to make sure it was firm (not to tight) on the rails its worked great then after some months I also had to do a slight turn now it seems it ran out of adjustments so I have to print another one but I’m not sure if its the PLA causing the issue as where my machine is it is quite humid and warm paired with the heavy spindle I’m thinking to try PETG 90% infill and see how it goes
90% infill should not be needed. Could you provide some pictures of your core and rails
im really not sure if these can work I printed a template in blue to show how the core has changed it’s dimensions over time
I‘d really try again to snug up the screws in the back of the bottom. There is a lot of room for tightening it up.
That does look like you have squeezed the adjustment quite a lot and the deformity at the top of rhe core looks like a lot.
At this point, PETg looks like an option, but more than 60% infill is often problematic.
I’d still say to be careful not to overtighten the adjustments, just touching is the goal.
PETg is less rigid than PLA, but prints with good dimensional stability, and has better heat tolerance.
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when i tighten it ,it stops the bearings from spinning
thanks for the advice running a PETG core will update after its finished
Hmm, then it should not wiggle. Mysterious. 
No, because the adjustment groove is crushed against the moving part of the bearings. The allowable adjustment is depleted.
Humidity should not cause this. Heat and pressure can cause creep like this.
PETg with increased heat tolerance may mitigate this.
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