Gina's Observatory

[malc-c]

As you know I've been agonising over what method of tracking to use, and I keep coming back to using wood. I don't see any problems at all.

The only issue that came up was the wheels may wear a rut in the soft wood. Great if it does, better tracking I think.

I will probably use rubber wheels which would also make the running, if on wood, a lot quieter than poly on aluminium.

Tony,

I used 50mm rubber wheels from Screwfix (£8.99 for 4) Rubber Tyres Fixed 50mm Pack of 4 | Screwfix.com

They run smooth, both in the channel and on the wood on the other side, and are quite in operation. Recommended

[Gina]

I got a new Machine Mart catalogue through the post a couple of days ago, they do a good range of wheels if you a looking for some.

Thank you but I already have the wheels. Nylon 80mm diameter x 30mm tread width.

EDIT... but see my next reply............

[Gina]

As you know I've been agonising over what method of tracking to use, and I keep coming back to using wood. I don't see any problems at all.

The only issue that came up was the wheels may wear a rut in the soft wood. Great if it does, better tracking I think.

I will probably use rubber wheels which would also make the running, if on wood, a lot quieter than poly on aluminium.

Yes, that's a good point. I've been wondering about buying some rubber tyred wheels instead of the plain nylon ones. The 8 nylon ones only cost a few quid - cheap and cheerful but I'm having second thoughts. The wheels will be protected from harmful UV rays so I can't see any problem with rubber tyres. And as you say, smooth and quiet

For hard wheels, 80mm is rather small. Larger, rubber tyred wheels would run quite happily on wood I think and with a rather heavy roof, would seem better generally.

[Freff]

Tony,

I used 50mm rubber wheels from Screwfix (£8.99 for 4) Rubber Tyres Fixed 50mm Pack of 4 | Screwfix.com

They run smooth, both in the channel and on the wood on the other side, and are quite in operation. Recommended

Hi Malcolm, I just seen the same ones a bit cheaper from MachineMart at £34.40 for 16.

I'm going to run mine on wood. I'd need about 45' of aluminium for my obsy. I don't see the need to go to all that expense.

[Gina]

I just used rubber castors from screwfix (50mm wheel - grey colour) and ran them on wood. There is a thin strip along the outside of each runner to keep the roof-roll straight. I did use planed timber for these parts, which is a little more expensive than the sawn that I used for the rest of the construction. The roof has been in use for two years now and shows no sign of wear.

Interesting I would have thought 50mm wheels were a bit small for the load involved. OTOH, how many a side did you use?

Gina,

I ordered two lengths (4.8m ea) from Click metal - here's copy of the costings I paid

2 x Aluminium Channel

1" x 1/2" x 1/8" (AC1001)

Length - 4800mm

GBP 19.81 + GBP 3.96 VAT (20%)

-----------------------------------------------------------

Shipping

Standard Post - Mainland UK

GBP 9.45 + GBP 1.89 VAT (20%)

-----------------------------------------------------------

Order Value = GBP 49.07

VAT = GBP 9.81

Total = GBP 58.88

(GBP = British Pounds)

Buy Metal | Online Metal Supplies | Aluminium | Brass | Stainless Steel

I ended up using just one for the roof as the tracing accepts the screwfix rubber wheels with just enough clearance, but due to the tolerances of trying to get all the wheels within this clearance. Also having joints in the rails can cause issues with wheels jumping out of the track (unless you opt for wider channel with more freedom). I would suggest you use just one length to guide the wheels and then use timber as a guide on the other side.

Thanks for the link Malcolm A much better bet than Aluminium Warehouse as they cut stuff to the length you want, so no joins The cost for 2 angle pieces to suit my present design works out at £54 (54 UK pounds). OR one piece of channel (like you use) works out at just over 40.

OTOH I'm seriously thinking of just using wood and rubber tyred wheels. I think the tolerances will be easier to accommodate.

[Freff]

For hard wheels, 80mm is rather small. Larger, rubber tyred wheels would run quite happily on wood I think and with a rather heavy roof, would seem better generally.

Hi Gina. I will be going for the 50mm rubber castors I think. A quick calculation should see 16 of these castors taking the weight. The roof will be quite large at 14'x 8' with a frame of 3"x 2" supporting 5 sheets of 11mm OBS skinned with thin felt, and steel profile atop.

I need to contact my brother to see how much the steel profile weigth before a final decision.

[Gina]

So now I'm searching for wheels again.

Hi Gina. I will be going for the 50mm rubber castors I think. A quick calculation should see 16 of these castors taking the weight. The roof will be quite large at 14'x 8' with a frame of 3"x 2" supporting 5 sheets of 11mm OBS skinned with thin felt, and steel profile atop.

I need to contact my brother to see how much the steel profile weigth before a final decision.

There seems to be two ways to go - many small wheels or fewer larger wheels. I tend to favour the latter. Less work and slacker tolerances (as befits an otherwise wooden construction).

eg, At the extreme, 4 of these (2 each side) :- http://www.screwfix.com/p/rubber-wheels-160mm-diameter/18206#

Maybe a bit too extreme

[Earl]

Dont go Rubber it perishes and does not deal with the weather as well go hard Nylon imo. Mine just run between timber and then on a angle iron track.

[malc-c]

Hi Gina. I will be going for the 50mm rubber castors I think. A quick calculation should see 16 of these castors taking the weight. The roof will be quite large at 14'x 8' with a frame of 3"x 2" supporting 5 sheets of 11mm OBS skinned with thin felt, and steel profile atop.

I need to contact my brother to see how much the steel profile weigth before a final decision.

I used 10 (5 on each side) on an 8' x 8' roof section. I'm guessing that having 8 wheels on each side with a span of 14' that should support the weight OK. My only concern is that moving that weight by hand might give you a hernia

[Freff]

I worked out 8 x wheels should support 11cwt. That will be sufficient for my roof.

I intend to use either a manual pulley system or a small 12v winch to move the roof.

[Gina]

I don't like the idea of running 2" (50mm) wheels on sawn timber, which I have on order. I'm thinking something like 4" (100mm) would be suitable. Maybe something like this :- 4" fixed castors / truck/trolley wheels (pair) TE338 | eBay

For easier alignment I could dispense with the bracket and mount between two pieces of wood as in my present design.

OTOH there seems to be a difference of opinion on rubber tyres regarding durability. I suppose I could just stick with my 80mm nylon wheels and see how well they run on the wood surface. It wouldn't be too difficult to change them later for larger and/or rubber tyred ones.

[Freff]

I don't like the idea of running 2" (50mm) wheels on sawn timber, which I have on order. I'm thinking something like 4" (100mm) would be suitable. Maybe something like this :- 4" fixed castors / truck/trolley wheels (pair) TE338 | eBay

But there seems to be a difference of opinion on rubber tyres regarding durability.

I suppose I could just stick with my 80mm nylon wheels and see how well they run on the wood surface. It wouldn't be too difficult to change them later for larger and/or rubber tyred ones.

Gina what are your concerns with 50mm wheels.

[Gina]

Gina what are your concerns with 50mm wheels.

That they won't deal with the unevenness of the timber as well as larger ones, particularly on sawn timber. OK, I have the shiplap still to order so I could add a couple of planed and pressure treated lengths to that.

[Freff]

If you have ordered normal studding it will probably be Easiedge C16 which has the corners removed and almost as smooth as planed (PSE).

All to do with H&S and the poor chippies getting splinters.

[Gina]

If you have ordered normal studding it will probably be Easiedge C16 which has the corners removed and almost as smooth as planed (PSE).

All to do with H&S and the poor chippies getting splinters.

AFAIK it's just sawn with sharp corners. I might well sand it down a bit and smooth the corners since it'll be exposed and could give me splinters I would think.

[Gina]

I've now found some 100mm rubber tyred wheels on Amazon which are the same width and axle size as my nylon wheels so would make a virtually direct replacement (just have the holes a bit higher in the side members). They also have needle roller bearings so lower friction. Cheap too - just over £16 for 8 including delivery. With the effective tyre being thicker than the "tyre" of the nylon wheels, I can use a higher guide rail and make for better tracking.

https://www.amazon.co.uk/100mm-Black-Rubber-Castor-Wheel/dp/B002SPMGHA/ref=sr_1_4?s=diy&ie=UTF8&qid=1315465218&sr=1-4

Same but with plastic centre and plain bearing at just over £9 for 8.

https://www.amazon.co.uk/100mm-Black-Rubber-Plastic-Centre/dp/B002SPMGKW/ref=sr_1_6?s=diy&ie=UTF8&qid=1315465218&sr=1-6

I think the pressed steel centred ones would be the best bet. Unless anyone has any detrimental comments about the needle roller bearings etc. (I shall be running it on smooth stainless steel bolts).

[Gina]

I have heard from the timber yard - timber delivery scheduled for 8am Monday morning

[yesyes]

Nice. So it will be worth keeping an eye on the webcam again soon... ;-)

[Gina]

Nice. So it will be worth keeping an eye on the webcam again soon... ;-)

Yes, pretty much as soon as we get some decent weather after delivery Monday I may be able to get one or two of the corner posts up before then as I already have some second hand timber for those. I let you know.

[Freff]

I've now found some 100mm rubber tyred wheels on Amazon which are the same width and axle size as my nylon wheels so would make a virtually direct replacement (just have the holes a bit higher in the side members). They also have needle roller bearings so lower friction. Cheap too - just over £16 for 8 including delivery. With the effective tyre being thicker than the "tyre" of the nylon wheels, I can use a higher guide rail and make for better tracking.

https://www.amazon.co.uk/100mm-Black-Rubber-Castor-Wheel/dp/B002SPMGHA/ref=sr_1_4?s=diy&ie=UTF8&qid=1315465218&sr=1-4

Same but with plastic centre and plain bearing at just over £9 for 8.

https://www.amazon.co.uk/100mm-Black-Rubber-Plastic-Centre/dp/B002SPMGKW/ref=sr_1_6?s=diy&ie=UTF8&qid=1315465218&sr=1-6

I think the pressed steel centred ones would be the best bet. Unless anyone has any detrimental comments about the needle roller bearings etc. (I shall be running it on smooth stainless steel bolts).

Good find Gina. These were the type I was looking for when I was contemplating mortising them into the roof plate. I gave up on that idea because I was using 3"x 2" and a mortise in that would probably weaken it.

[Gina]

Ordered them plus a couple of spares for good measure

Also heard from B&Q who gave me the phone number of their suppliers. Phoned them and delivery is booked for Monday. So things are progressing

[yesyes]

So big delivery day on Monday then...

[Freff]

Come Tuesday you'll have the windows in.

[Gina]

Well, you never know. I might make up the obsy door complete with window I don't think the warm room window will be done until a lot later on.

Been looking at the corner posts this afternoon. Well, actually one corner post and one running track support - on the south side. I've got them clamped in approximate place ATM. Not sure if it will be practical to bolt them to the floor beams at this stage or whether to wait until I have a couple of wall frames made up. I'll see how it goes.

[Gina]

Well I have the SW post bolted onto the beam with two M10 x 180mm Coach bolts. This takes the weight of the south side roll off runner at the west end.