Tracking - ROR

[malc-c]

Guys, Need some advice before I order some Aluminum U channel for the guide rails for the Roll off roof section of my observatory that I'm currently building.

I've purchased the wheels from Screwfix (rubber tyre fixed 50mm) which are 17.6mm wide. There are two common standard width of square U channel 3/4" and 1" outside width. I'm planning on using the 1" wide tracking, but wondered if this would offer too much freedom (just under 1/2") or would this freedom be ideal to allow for any tracking issues such as binding if the channel was too close a tolerance ?

[Gina]

I don't think those wheels would go in 3/4" channel. Thats about 19mm OUTSIDE and if the metal thickness is 2mm, this would give 15mm inside. Even if it were only 1mm thickness (not strong enough) that would still be 17mm inside measurement.

1" outside = 25.4mm less 2 x 2mm walls gives 21.4mm - that would be fine IMO OR... 3mm walls would give 19.4mm

EDIT... I was looking for ali channel - where are you planning to get it?

[malc-c]

Thanks for that - I think all that sun has fried my brains, you are so right with the conversions... 1" it will be then.

I've just googled and came up with Aluminium Channel | Aluminium Warehouse

2 x 4000mm length of 1" x 1/2" with 1/8th thickness - and 1 x 2000mm length of the same = £22.13 (not sure if that is ex vat or what the delivery charge will be as I need to register)

[malc-c]

LOL - I didn't think to check the address

Contact Us Address:

Welham Green

Hatfield

Hertfordshire

AL9 7HF

Tel: 0800 520 0729

Fax: 01707 274655

They are just up the road from me (well 20 mile round trip which is cheaper than their £14 delivery charge !)

[Astrokev]

Thanks for that - I think all that sun has fried my brains, you are so right with the conversions... 1" it will be then.

I've just googled and came up with Aluminium Channel | Aluminium Warehouse

2 x 4000mm length of 1" x 1/2" with 1/8th thickness - and 1 x 2000mm length of the same = £22.13 (not sure if that is ex vat or what the delivery charge will be as I need to register)

That sounds like excellent value.

[Merlin66]

I took the cheap way out. I use the same castors on a 2" x 2" beam with a 50mm side plate in 6mm marine ply. KISS

[malc-c]

On further investigation, I went with Buy Metal | Online Metal Supplies | Aluminium | Brass | Stainless Steel - the cost was a little more, but this was for 2 x 4.8m lengths so less joins as I would have to of had 5 x 2m lengths from the other place to get it in the car - which would of cost more from the place in Hatfield.

[Gina]

Thanks for that - I think all that sun has fried my brains, you are so right with the conversions... 1" it will be then.

I've just googled and came up with Aluminium Channel | Aluminium Warehouse

2 x 4000mm length of 1" x 1/2" with 1/8th thickness - and 1 x 2000mm length of the same = £22.13 (not sure if that is ex vat or what the delivery charge will be as I need to register)

I've bought aluminium tube from them for my weather station mast and a couple of other things. Yes the delivery charge is rather high but so was the tube (some 5m lengths and some 2.5m) though cheaper than anyone else.

EDIT... Just checked the price for a channel to suit my wheels (30mm wide X 80mm diameter) and it's not that expensive. Wish I'd checked before - I think my brain is addled too! - I paid £44 for some mild steel angle for that purpose. The ali channel comes to just over £50 including the delivery cost. It would be absolutely ideal! I know their ali is good - the tubes have brrn outside for some time now and no sign of corrosion 1.5" and eighth in wall thickness = 1.25" inside = 31.75mm. Just enough clearance