Astrokev

Meanwhile, back on the observatory build.... ? Have a free day today, but just realised the England game is on this afternoon and not this evening as I thought. I best crack on while I can!

Great progress James. And good idea to label the rods/blocks. There will almost certainly be minor variations and trying to figure out which goes where without labelling beforehand could be a real headache. I label stuff also - you can see some of my labelling on the wheel beams before they were lifted onto the roof to indicate which is which and orientation, and also numbered the wheels/holes they were matched to ?

Absolutely!

Another day that turned out with only limited time on the observatory build. And there was me thinking I'd have the whole day to myself ? . Well, the non-build time was to visit family, and to play taxi for my daughter who can't drive yet while her ankle heals, so I guess I shouldn't get too selfish - it's nice to help others ? . So the time I did have was spent finishing off laying the V track. Bit fiddly getting the short extension pieces adequately lined up with the longer lengths already partly fixed but eventually got them in a position where I was reasonably happy and inserted all coach screws to all four sections. A very small lip on the join between sections needed a bit of filing, but the wheels now cross the join with hardly a hiccup. One thing I've noticed now that I can roll the roof frame along the entire length of the obsy is that the south-eastern wheel lifts slightly part way along the track. After much rolling, pondering and head-scratching I've decided to leave it as it is. With 6 wheels I think it's impossible to get all 6 to be in full contact at all times. The reality is that at any one time there's likely to be only 3-4 wheels in good contact with the track. Once the rest of the roof is built there will be a lot more weight which may improve contact as the wood bends slightly under the weight. So, I'll keep eye on this. As it is, the frame rolls really easily along the whole length; in fact I can roll the frame with my little finger. I'm sure it won't be this easy once it's fully loaded but this is a good sign. Before packing up I cut out the EPDM over the warm room ventilation holes in case I forgot later on, and temporarily fitted the soffit vents to hopefully stop creepies setting up home in my nice dark and warm roof space ? . No time to start cutting the north and south beams to replace the temporary ones currently serving to hold the frame together. A job for tomorrow....

Great stuff, another build to follow ? . Good luck Alex. It's pleasing to hear that myself and James have been able to inspire you to take the plunge! One advantage of us being a little ahead of you is that you can hopefully learn from our mistakes (well mine anyway - I'm sure James won't be making many of those ?). I concur with James' point above. My build followed similar lines in that the outer floor joists are a few centimetres wider than the wall studding which gives an edge to support the flooring. I poured over my SketchUp design for more hours than I can remember during the design stage and tried to visualise actually building the thing - where I would add bracing, attach brackets, insert screws etc etc. I found this really helped identify problems and solutions before I went anywhere near real timber. I'll be following your build with great interest. Post loads of pics! Kev

Yeah, it was a great feeling when I'd finished the concrete work. Too much like hard work! Much more at home with cutting up bits of wood ?

Agree there. Quality of their timber can be horrendous. I was after 3m lengths. Some of it was so twisted it would hardly fit in the rack. Ended up in Jewson and picked up 3.6m lengths that were pretty much dead straight.

Thanks guys - dry track it is! Well, after spending half the day trying to find the size timber that I needed, I eventually managed to actually do some building. Wickes was hopeless for the longer lengths I wanted for the apex and north and south cross beams, so had to do some driving around. Eventually found what I needed but didn't get home until early afternoon, and then with lunch etc etc, where did the day go? Today's update - I made a "jig" to help me ensure the two tracks would be parallel. Unsurprisingly, it took longer to design and make the jig than it did to align the tracks and screw them down. For the moment I've only put one screw in each end, just in case I need to adjust. The acid test is to make the outer frame of the roof and actually check that it runs square. Once the track was fixed, the wheel beams were put on the track and joined with temporary cross beams. One end was screwed to the wheel beam, the other was just clamped to the beam to allow me to adjust if necessary. Few images below of the alignment jig at the south end of the track, and at the northernmost point above the warm room. It was then I realised that I needed to cut and add the extra metre of track needed to complete the entire track, so I could check the wheel alignment along the entire distance it will need to move. D'oh. I packed up before screwing the extra track extension, so this is where I'll pick-up tomorrow. I have to say though - the roof frame moves so sweetly with the slightest touch - it's completely satisfying! Even my son was impressed! Hoping to make more progress tomorrow.

Indeed! Thanks. My friendly plumbers been and gone. Time for some observatory action ? . What could possibly go wrong ?

Thanks Ray ? One less thing to do then!

A random question to all the FH Brundle users out there - should I grease or lubricate the track at all, or leave it dry? The wheels roll smoothly as it is but wondered if lubrication would improve performance further or help prevent the track oxidising over time? Thanks.

More playgroup fun with my grandson today so not much time working on the observatory. Did manage to complete the second wheel beam this evening though, which I was pleased to finish. Also started to measure-up and align the V-track on the walls but light was fading by this time so this will have to wait until tomorrow (after I've had a visit from my local plumber to have another look at my broken showers ? ). I've realised I would benefit from making a jig to get the spacing of the 2 tracks accurate across the width of the obsy. As most of the width is fresh air, simple measurement using a tape is tricky and prone to error I think. I'll be much happier, and it will probably be easier in the long run, making up a solid jig. So here's an exciting picture of two wheel beams ready to be raised to the roof ?

Think I'll stick to my drill and chisel. I'm lethal enough with that as it is without any further encouragement ?

In my experience you always need more cement and ballast than you think!

Crikey, d'you need a licence for one of those? ?

?. Never heard of one of those but sounds a serious bit of kit!

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!

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.

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!

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 ?

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 ?

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!

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 ?

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.

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