Rusty
Postmaster
Reged: 08/06/03
Posts: 15841
Loc: Brooker, FL
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Actually, there's no reason the casters would have to be forged (McMC "C"s - 2000# WL) - the "D"s would be plenty, and about the same price as Grainger's.
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N11GPS Fastar
TOA-130S
MK66 Std
Vintage C5
Megrez II 80mm ED Triplet APO
SolarMax 40
NJP Temma II
Sirius EQ-G
ST8XE/CFW-8 (LRGBHa)/AO-7/DF-2/STV/ST237a/350D (Unmodded)/Mallincam Color Hyper Plus/DSI III Color
Two not-spoiled Golden Retrievers - Maggie and Casey
Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering. - Arthur C. Clarke
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John Fitzgerald
In Focus
Reged: 01/04/04
Posts: 1029
Loc: AR
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The first ones (wheels) he was looking at have very wide apart mounting holes. The ones I got are pretty much the same wheels with a narrower side to side bolt spacing that will bolt perfectly to three 2-bys laminated together to make a beam. I used 3-2x12's.
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?
Observing since 1966
Messier Cert #898
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blatterjr
sage
Reged: 08/13/07
Posts: 254
Loc: Saint Petersburg Florida
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Here is a detail we used for a rolloff roof (non-observatory, but applicable none-the-less).
It incorporates a 4" wheel sandwiched to reduce the profile. It eliminates lateral forces by having the steel angle "sleeve" into the caster trough. There is flashing to the left side to reduce water intrusion as well.
Two layers of nylon brush strip reduce insects if they can get through the 1/16" steel angle gap. A routed piece of trim is used to conceal the exterior flashing. Ultimately, the trusses are set directly on the top plate.
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Robert
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Meade 12-LX200-ACF
BINO: Nikon AEX 10x50 6.5°
DSLR: Nikon D70+CCPro2
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Saint Petersburg Florida
27°47'22.92"N , 82°43'09.48"W
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WidowMaker
professor emeritus
Reged: 12/29/07
Posts: 656
Loc: Frankfort, Ky
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Good Morning, yall.
Its raining horribly with severe thunder and lightning. 
My poor baby is standing out there all alone in the pounding rain all by herself...but she is still standing! 
Thanks for all the help, and the drawing, Robert. Your drawing has the wheel riding along the flat side on the angle iron, right? The plans I have and I think the others here, have used the pyramid side up and rested their v-groove wheel on the point of the upside down 'V'.
The local guy here that sells 1/8 and the 3/8 wondered about sitting anything on the upside down V of angle iron, especially a roof that potentially weighs a ton or more.
Thats what got me interested in what thickness of angle iron I should be looking for.
Thats also what keeps the wife and I wondereing about possibly just using a castor wheel rated to hold 800lbs or more.
Quote:
I used 3/16" thick x 1.5 x 1.5 inch angle. Some use 1/8". 3/8" thick is too heavy and thick to easily drill for screws. The 3/16 inch thick seemed about right for my heavy roof.
Thank you, John. And since youre obs is almost the same length as mine, I would have to think your choice in thickness for angle iron would work for me too.
Quote:
The ones I got are pretty much the same wheels with a narrower side to side bolt spacing that will bolt perfectly to three 2-bys laminated together to make a beam. I used 3-2x12's.
So you kind of made an axle-box as well to hold the wheel in, right? The plans call for that box, which looks kinda like Robert's drawing up there. Great minds, eh?
Im gonna see if anyone has that 3/16" angle iron.
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Sleep is the Cousin of Death
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John Fitzgerald
In Focus
Reged: 01/04/04
Posts: 1029
Loc: AR
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Your example above is not riding on inverted angle, so more potential friction is involved, and there is no access to the lube inserts for the wheels. I went down that road, and by experimentation I found that IMO, the wheels on inverted angle are the best route.
I looked into brush strip. It's at least $5.00 a foot. it would have cost me over $160 just for brushes that would wear out or deteriorate in a couple of years. Not worth it IMO.
Not to throw water on your ideas, but I just completed an observatory, and so far avoided most of the pitfalls that others have encountered, including a person who helped me with some of the construction.
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?
Observing since 1966
Messier Cert #898
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csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 25568
Loc: montana
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Quote:
The local guy here that sells 1/8 and the 3/8 wondered about sitting anything on the upside down V of angle iron, especially a roof that potentially weighs a ton or more.
That's why I suggested contacting Scott Horstman; he has built some mighty big observatories, using this system.
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
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WidowMaker
professor emeritus
Reged: 12/29/07
Posts: 656
Loc: Frankfort, Ky
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Thanks, Carol & John. Diane is going to ask Scott when she hears from him and let me know what he says.
I just assume (you know what happens when you assume) that the 3/16" John uses would be fine for me.
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Sleep is the Cousin of Death
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Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2823
Loc: Bolton, MA
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I measured mine (Scott/BYO built it): it is the 3/16" Angle Iron...
Believe me; it is MORE than strong enough to hold your roof... and the friction is nice and low due to the small surface area of contact (versus casters on flat surface anyway).
clear enough skies
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Dave
Ustream
YLive
XT10i, RTP, CGE, TMB80SS, SN8
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
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John Fitzgerald
In Focus
Reged: 01/04/04
Posts: 1029
Loc: AR
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Scott told me that he usually uses 1/8", but I went with 3/16 anyway, not so flimsy so easier to haul hanging over a trailer.
BTW, the wheels were the first significant item I bought for the observatory. I had them before groundbreaking. They sat in my garage for about three months. The obs was designed around the wheels from the slab up.
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?
Observing since 1966
Messier Cert #898
Edited by John Fitzgerald (06/03/08 12:48 PM)
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Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 830
Loc: Northern Illinois
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What kind of roofing are you going with, shingles / steel?
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Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
8" f4.9 Orion piggy backed
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
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blatterjr
sage
Reged: 08/13/07
Posts: 254
Loc: Saint Petersburg Florida
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No worries... just food for thought. The example was done with a sealed bearing wheel, no need to lube. It held 740# per wheel using polyurethane... at just over 4 tons it was easy to displace.
Additionally, we had to meet lateral wind loading which the V-groove couldn't accomplish... Florida, go figure.
We used door bottoms instead of brush strip. It cost about $0.60 per foot (and was nicely modular at 36")
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Robert
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Meade 12-LX200-ACF
BINO: Nikon AEX 10x50 6.5°
DSLR: Nikon D70+CCPro2
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Saint Petersburg Florida
27°47'22.92"N , 82°43'09.48"W
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WidowMaker
professor emeritus
Reged: 12/29/07
Posts: 656
Loc: Frankfort, Ky
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Carl, Ive heard stay away from shingles as they absorb heat or something like that, so I'll probaly go with steel sheeting. Whatever is the lightest kind I guess.
I placed a call to the company that made my pier and the lady said she seen the paperwork on it and thought it was done but I guess they forgot to call me back.
She also said they would reccommend the 3/16" since thats what she thought they usedon Dean's, but shed have to check.
Still raining here. Were under a tornado watch until 7:00 p.m. with strong wind and rain expected all night.
*Sigh...
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Sleep is the Cousin of Death
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Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 1881
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White steel roofing would be best, if you can use it and if it is available.
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Steve Durham
www.margesmonograms.com
(Marge made me do it)
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John Fitzgerald
In Focus
Reged: 01/04/04
Posts: 1029
Loc: AR
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Shingles and decking are HEAVY.
I used Galvalume roofing on purlins on mine. 242 pounds for all the sheeting, 12 pieces 9'5-1/2 x 38" wide less screws and trim. I am guessing the screws and trim weigh about 35 pounds or so, so it is well under 300 pounds.
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?
Observing since 1966
Messier Cert #898
Edited by John Fitzgerald (06/03/08 06:48 PM)
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Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 830
Loc: Northern Illinois
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Quote:
White steel roofing would be best, if you can use it and if it is available.
Thats what I used on my OB. I put a single layer of Astro-Foil 3.5" under the steel, and I vented that gap. I installed a temp probe in the gap to keep track of the temps. Last Aug 10 @ 14:00 LT. the temp in the gap was 103°, The outside air temp was 85° and the temp inside the OB was 81°. I have noticed that as soon as the Sun sets, The roof temp drops to ambient, Must be from the lack of thermal mass.  A bonus to using steel is that it is also lighter to move.
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Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
8" f4.9 Orion piggy backed
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
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DeanS
sage
Reged: 07/12/05
Posts: 406
Loc: Nicholasville, Kentucky
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Looking real good so far Michael. I wish I was around to help but someone needs to attend the Texas Star Party 
I posted some images under the star party section, TSP thread, if you are interested. hotter than the dickens here right now.
cya
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8" LX200gps
AP1200GTO Mach1GTO
FS-60C Tak E160 C9.25
SXV-H9 ST2000XM STV
Meade 12" Lightbridge
Moonlite Focusers
www.doghouseastronomy.com
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Rusty
Postmaster
Reged: 08/06/03
Posts: 15841
Loc: Brooker, FL
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Whenever I get moved and can have an observatory, I'm considering aluminum sandwich roof panels, like I have on my house addition here. Very, very strong, and when the interlocking panels are assembled, the roof is essentially one piece, insulated, and finished both sides. The roof on the addition is rated at 150mph winds, but then again it's anchored to CB walls.
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N11GPS Fastar
TOA-130S
MK66 Std
Vintage C5
Megrez II 80mm ED Triplet APO
SolarMax 40
NJP Temma II
Sirius EQ-G
ST8XE/CFW-8 (LRGBHa)/AO-7/DF-2/STV/ST237a/350D (Unmodded)/Mallincam Color Hyper Plus/DSI III Color
Two not-spoiled Golden Retrievers - Maggie and Casey
Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering. - Arthur C. Clarke
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csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 25568
Loc: montana
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Carl: How did you attach the "astrofoil" to the roof? Staple it over the roof supports?
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
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WidowMaker
professor emeritus
Reged: 12/29/07
Posts: 656
Loc: Frankfort, Ky
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Good morning, yall.
Thanks for all the suggestions. Hiya, Dean! Hope youre having a great time at the TSP.
I think Im going with the 3/16" iron angle and the castors from grainger. These specifically.
Im 214" on each side that needs the angle iron but keep noticing in different pics that not everyone runs their angle iron all the way from the very start of the wall to the very end.
Some look like they start from the South wall about a foot in or so, then run all the way to the end.
I guess it depends on where I start my first castor?
The lady I spoke with said the angle iron comes in 20' lengths and I guess I need about 70-72 feet total, so I was just trying to figure out the cuts I need for both sides.
Too early to think straight right now. Im still on my first cup of coffee. 
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Sleep is the Cousin of Death
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csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 25568
Loc: montana
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Quote:
Some look like they start from the South wall about a foot in or so, then run all the way to the end.
Mine run full-length of the building, right to the end of the support forms.
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
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