View Full Version here: : RoR wheel size
06-02-2012, 09:54 AM
Just wanting to get some concensus on what size wheels / castors
for a RoR 3x3.6 . I was originally going to go with v-groove till I got the price :eyepop: just too much . I can get plain 50mm steel castors from local hardware
for a couple dollars each so I am rethinking to go that way and just running
them on angle iron or Al .
06-02-2012, 11:33 AM
I just have about 6 castors on each side running in channel steel. Just get reasonably strong ones and use lots of them.
06-02-2012, 05:37 PM
Thanks Terry , how do you find it tracks in the channel ? I know about adding a guide wheel to keep it straight which is what I had thought of doing.
06-02-2012, 09:50 PM
It works quite well. I also have a guide wheel on the outside of each track. If I deliberately push on one side I can make it jam but as long as I push evenly it runs well.
06-02-2012, 09:53 PM
Best RoR I've seen uses grooved castors running on a track made from upturned angle iron.
06-02-2012, 11:17 PM
I know David except the castors are $45 each ! thats what I had planned until I got the price - x12 I dont think so
07-02-2012, 07:15 AM
The roof I'm thinking of is pretty large and heavy and there's not 12 castors on it.
07-02-2012, 10:23 AM
How big is it and how many castors a side were you planing ? I figure I need at least 5 a side for 3.6m
Was the $45 quote from Richmond?
If not, it might be worth giving them a call.
I have 3 on each size, v-groove cast iron castors on upturned angle iron. Rolls very smoothly. There are some pics here (http://deepspaceplace.com/observatory.php)
07-02-2012, 11:22 AM
Yes James it was from Richmond unfortunatly compared to plain steel castors at $2.50 each its a big difference . I guess 3 would work but I would feel happier with more.
07-02-2012, 01:57 PM
I'm guessing that it's my ROR that David is talking about so I'll throw in my choices and reasons.
When I built it, I used standard Bunnings 4" wheels and they ran on a rail. They didn't have bearings in them. The roof is 4 x 5 metres and made of steel with Zincalume roofing so yes, it's heavy.
I originally only put 4 wheels a side in but soon found that this was not enough. I added another 4 a side and it was OK but still sluggish and over time, prone to the wheels becoming a little eccentric and hard to get going.
I re-engineered the roof to run on vertical steel bar rails using castors with bearings. These are relatively small, about 50-60mm OD I guess. I set them in 50x50mm square steel box section with a spring-loaded axle - so that only the bottom 15mm or so actually show below the rail in which they sit. These now run smoothly on their steel flat bar rail. I have 8 a side.
This might be an important point to consider if you plan to add an electric opener later on - in most cases it's mounted on one side or the other (not in the center of the roof).
BTW I also started off with the bunnings $2.50 special and ended up replacing them.
07-02-2012, 08:04 PM
I may look at some better quality castors than the bunnings ones. Its a shame the v-grooves are so expensive but others have managed quite well
with out them . Building the thing will be the easy part, but sourcing all the little bits is a pain - and dont get me started on the door thats my next thing to tackle .
07-02-2012, 11:38 PM
I learn't a lesson with my current DIY project, try not to buy stuff from Bunnings if possible source from specialist places unless discounted heavily.
I bought some threaded rod from Bunnings 10mm x 1m cost $approx $8.00. Sound cheap. I went to Coventry Fasteners and bought a higher quality zinc rod for $3.80. Go figure :(
There are some specialist castor places may actually be cheaper, I know they have a much greater range.
08-02-2012, 08:49 AM
Thanks Malcolm I have been spending a lot of time shopping around so far. :)
08-02-2012, 11:46 AM
The observatory I was actually thinking of belongs to Chris (hotspur) up at Blackbutt - sorry Peter. He's posted some photographs of the internals of his observatory before on IIS, so it may be worth a search of the archives.
He bought his from a "Castor Shop" in Brisbane.
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