GoodBadUgly said:
I store mine horizontally in a simple way- just hanging over two nails through the holes on each end of the rails. The nail are at upward angle and I push the tracks flush to the wall. Haven’t seen any bowing issues (yet)... should I be careful about that issue especially on the longer 2700mm rail?
Yes.
If you have a known-good straight edge with a high-enough accuracy class you would be able to measure this. With a supports distance int he 2600+ range for a 2x200 mm aluminum alloy profile, you will see a self-weight bend of about 0,1 mm/0.004" in the center.
That is NOT an issue short-term during use as it is well into the elastic range for aluminum alloys. However long-term the bend can become permanent and create a new, bent, "no-stress-shape" for the material.
Every metal alloy has a certain range of "plasticity" where if there is a long-term stress the material will "accept" the new shape before it reaches a point where the crystalline structure is able to prevent further bending. This is a non-issue for a structural element (the support will not bend beyond this plastic threshold) but is a big issue for measuring instruments which rails kinda are as far as accuracy requirements go.
In general, the only 100% correct way to store the rail is vertically or -fully- horizontally with a low surface friction - i.e.upside down or on slippery "casters" so the anti-slip mats cannot create a bending force.
That said, there are limits into how much this is a practical problem.
I would say the 1400 rails are "on the edge" of where it is safe to hang them just by the holes. The 1900 ones will probably be still fine but with the 2400+ rails I would be careful and the 5000 one is an absolute no-go.
A 1400 rail supported only on edges get self-bent only around 0,006 mm i.w. about (2650/1350)^4 = about 15-times less than a 2700 rail does. What is more important is that the same low bending as for the 1400 one applies for the 2700 rail if supported at 25% and 75 % length. Critical is the maximum distance between the supports not the actual rail length.
Note:
Unless you can guarantee supports being exactly in one line horizontally (hint: you cannot *) using more supports DOES NOT help.
The self-weight-bending gets approximately (2^4=) 16-times worse for each multiplication of this distance by 2.
*)
Well, you kinda can, using equal-force springs to hang the rails. But that is very much impractical and for the 2400-3000 length rails more than two supports are an overkill anyway. Place the supports at the 25/75 locations and should be fine.
