Sliding gate track, one side or both???

[anthony]

Hi

Have I made a little mistake?!

I am building my roll off roof obsy and am expecting today sliding gate track and wheels from fhbrundle.

The obsy will be around 4m x 3m.

As I am reading around this I have noted advice to just have the track on one side to avoid issues such as binding in the short or long term as the wood that holds the tracks may change dimension or position.

So sliding gate track on one side or both?

What have people noted in practice?

Cheers

 

Anthony

[AstroKeith]

I would say definitely both sides, but mount the rollers so they can 'float' a little in the required direction (tangental to the track). The metal track should be fixed to the timber with slotted holes so if the timber warps the track can stay straight.

Timber will change dimension only across the grain, so in general a building won't change size. It might warp, causing distortion, but bracing would help

[saac]

Both sides on mine (been up close to 10 years now) - never had any issue whatsoever with binding, tbh think that is a bit of a red herring. 

I'm having a wee giggle because I actually have 3 rails - my roof is octagonal so I have a middle rail in addition to two on the outside  

Jim 

 

Edited July 19 by saac

[anthony]

Cheers guys 👍

[saac]

I seem to recall when I did mine I placed the rails onto the supporting timbers, lined up by eye and them left them without screwing them down. I then ran the roof over the rails to allow the rails to take up the alignment required.  Once I was happy the rails were then screwed down.  If you feel like doing this , move the roof slowly and maybe have somebody helping as another pair of eyes watching the track of the roof.  It's also a good idea to have a slight incline on the rails to allow water to shed off the rails away from the observatory; a shim at one end of each rail made from a few washers would do. 

Jim  

[anthony]

That is a good idea re the slight cant to the rails. I’m planning on a decent overhang to minimise water getting to where it should but there is an inevitability to that happening I think, particularly on the west side where the prevailing weather comes from.

My approach is that as I complete each stage I pause and have a good think about all the would be gremlins lurking below the horizon. The ones that I don’t know that I don’t know about 😀

[old_eyes]

Mine has F H Brundle track and rollers on both sides. Yes the wooden rails have moved (twisted), but not enough to cause problems. In four years, not a single case of binding, jamming or derailing. If the rails continue to distort I can reposition the track slightly to compensate, or if it gets really bad I have already decided to replace the wooden rails with recycled plastic lumber which is dimensionally stable