Astrokev's ROR - The Build

[JamesF]

I was tempted by a C11 for sale near here recently, and there's still a 12" Meade SCT not far away too.  I have promised myself no further telescope purchases until the obsy is weathertight though (at which point I probably won't be able to afford any more anyhow

James

[Dr_Ju_ju]

OTA - RORO, OTA - RORO  the devil is in the detail ??

Superb build BTW Kev

[smudgeball]

2 hours ago, Astrokev said:

In a bit of a dilemma.

Just picked up a nice shiny second hand C11 and Moonlite focusser. ?

So, do I do some more work on the observatory while the weather's nice, or play with the new toy ?

Kev we're on Page 9 ! Put the toy down and finish the build ?

 

Neil

[Astrokev]

Haha. 

Sorry Neil, I didn't realise I had to complete the build in under 10 pages. I must try harder ?.

I seem to recall Gina's build back in 2011 was over 45 pages ? so I have a bit to go yet ?.

 

[Astrokev]

Well I had to have a quick play with the C11 didn't I? And yes, it's lovely.

Then I squeezed in an hour on the obsy. Finished sticking down the EPDM over the beam which means I can now start work on the rolling roof!

Still a few bits to finish off on the warm room roof, but these can be done anytime - making holes in the EPDM on the beam facing the scope room to re-open the ventilation of the roof space; stick down the EPDM on the edges of the rails; fit battens at the rear and on the rail edges; trimming excess EPDM; fit guttering.

 

[Astrokev]

9 hours ago, JamesF said:

I was tempted by a C11 for sale near here recently, and there's still a 12" Meade SCT not far away too.  I have promised myself no further telescope purchases until the obsy is weathertight though (at which point I probably won't be able to afford any more anyhow

James

Yeah, from your profile I can see that you are clearly a bit short in the scope department ?

[JamesF]

8 minutes ago, Astrokev said:

Yeah, from your profile I can see that you are clearly a bit short in the scope department ?

I swear I have no idea where they've all come from.

James

[Astrokev]

6 minutes ago, JamesF said:

I swear I have no idea where they've all come from.

James

Collecting scopes is a competition between astronomers. The one who has the most when you die is the winner ?

[smudgeball]

11 hours ago, Astrokev said:

 

That's why I got someone else to build my obsy and put an EPDM roof on for me.

If I'd have done it there would be a massive bubble right in the middle of it !!

 

[Gina]

Surely not!!  It's not difficult to put EPDM onto a roof, just a matter of being careful and following the instructions.  Far easier than roofing felt.

[Astrokev]

Having done both I agree. The contact adhesive is a pain around the edges but getting the EPDM down and flat is fairly straight forward and easier than felt. 

[Gina]

I didn't use contact adhesive on my roof.  I was surprised how easy it was to use the EPDM rubber roofing.  I used clout nails to hold the edge down up under.

[Astrokev]

56 minutes ago, Gina said:

I didn't use contact adhesive on my roof.  I was surprised how easy it was to use the EPDM rubber roofing.  I used clout nails to hold the edge down up under.

That clearly works well and I guess I could've done similar. Rubber4roofs recommend using the adhesive though, so thought I'd follow their guidance to avoid risk of problems down the road - this roof is designed to outlast me and require zero maintenance!

I seem to have loads of useful large offcuts already (I may have added too much size contingency!) so need to think of creative ways of putting it to good use. I'll probably end up putting it with all the other "useful" bits n bobs that I've collected over the years ?

[Gina]

I don't think they had the contact adhesive when I bought my EPDM but no doubt other makes of contact adhesive would have done.

[Astrokev]

Your obsy's been up for several years now so clout nails clearly work just fine!

Just checked out guttering. I think the mini-guttering should work fine. The full scale stuff looks huge and seems over the top for my little obsy!

Edited June 16, 2018 by Astrokev

[RayD]

19 minutes ago, Astrokev said:

Your obsy's been up for several years now so clout nails clearly work just fine!

Just checked out guttering. I think the mini-guttering should work fine. The full scale stuff looks huge and seems over the top for my little obsy!

Mine is miniline Kev and it works a treat. It's only a small area to deal with so is ample as far as capacity goes. 

[Gina]

Yes, obsy roof is all fine and I used the mini guttering attached to the ROR with the down pipe running into a full size down pipe and spout, arranged so that when closed the water from the roof runs down into the 4" spout.  When the roof is open it shouldn't be raining ?  The guttering on the warm room roof is full size as it collects water off the warm room roof and half the ROR.

 

Edited June 16, 2018 by Gina

[Dave]

Looking good Kev. ?

 

[Astrokev]

Not much to show over the last few days but I've been busy re-designing the ROR, when time allows. This is to increase the clearance above the warm room dividing beam. 

Hoping to start more construction this week ?

[Astrokev]

Well, not a huge amount to show today but at least I've restarted construction, and significant in that I've finally started the rolling roof!

Spent the morning playing with my little grandson ?, then in the PM I searched through over 30 lengths of timber and finally managed to find 2 that were not twisted, bent, damaged or split, to use for the wheel beams. I love Wickes!

So didn't have much time to start sawing, but did manage to cut one hole for the first of the 6 V-wheels, 3 per side. Although not yet fixed to the beam, the pics below show the design I'm using. The last image is upside-down to show the wheel design for anyone unfamiliar with such things. I must say I like this wheel design, the weight of the beam and roof acting vertically on the fixings which feels very secure. My plan is to cut the 3 holes I need with a small amount of lateral play, and drill the bolt holes with similar lateral play (effectively short slots rather than round holes), to allow me to adjust the alignment as best I can before tightening the nuts on the bolts. Well, that's the theory, I suspect it won't go as smoothly as that!

With good weather forecast for tomorrow, hopefully I'll get a few more holes cut ? 

 

[Astrokev]

Why does everything always take 3 times as long as you expect? I did spend an age deciding what size screws, bolts etc I needed, and then visiting Toolstation, so that dragged things out a bit. In the end I opted for stainless coach screws for the track, since these will be exposed to the elements. It also took me a while to figure out the best way of cutting out the holes for the wheels. Could really have done with a router but had to make do with the cordless drill, rasp and chisel.

Anyway, managed to finish the East rolling rail. The track isn't screwed down yet; I'll do this when both rails are complete and I've aligned the tracks to ensure they're parallel and square to the north dividing beam. Recommendations from other builders say to spend time getting the alignment as good as possible, so intend to do just that ? 

Have to say that the rail rolls so easily and smoothly! I hope it's the same when it's taking the weight of the roof and EPDM!

In the first pic the rail is upside down!

Edited June 20, 2018 by Astrokev

[Gina]

My roof rolls with a push from one finger but I only have four wheels on mine so they always line up.

[Astrokev]

Yes I was originally going to have 4 as these would easily take the weight at 250kg capacity each. My worry was the risk of the wheel beam sagging slightly in the middle as the wheel separation is quite big, and I've chosen to have the rail beams oriented horizontally and not vertically. The middle wheel will be directly under the supports for the apex beam, removing the risk of deformation. Aligning 3 wheels on a side is more challenging though, as you say, since the beam (and I note the track also!) aren't perfectly straight.

[Astrokev]

Here's the redesigned roof (minus most of the joists to aid clarity). Wheels are crudely shown as red blocks. Probably looks pretty much the same as the last SketchUp drawing I posted but the apex has been raised slightly to increase clearance above the warm room dividing beam. I've decided to also add a length of steel strapping on either side of the apex beam to increase rigidity (not shown in the drawing). Also not shown is the side retaining mechanism to stop the roof lifting. This follows the wrap-around design used by a number of other builds and I guess is becoming the standard method of preventing your roof ending up in next-doors garden!

 

Edited June 20, 2018 by Astrokev

[JamesF]

I think six wheels is a good call given the length of the timber, Kev.  I'm sure it could be braced and built so it wouldn't sag noticeably, but actually having another wheel would probably still turn out to be cheaper and faster.

What you really need for cutting the holes of course is not a router, but a chain mortiser.  Imagine a vertically-mounted mini chainsaw combined with the mechanism of a pillar drill.  A very cool (and wickedly dangerous) bit of kit.

James