Weekend Rails

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Of eave beams and wind tunnels

6th September 2015

I set myself an objective this week, and I'm sad to say I failed: but not by much. Come to think of it, what happened to 'Management by Objectives' which I seem to recall was in vogue as a principle (that word again) of company control years ago. Did it fall by the wayside as greater employee protection measures migrated in from Brussels?

The target was, in fact to get the cladding material on order, and though the order for the roof-lights (triple glazed panels that replace a proportion of solid sheets in the roof) did get placed, the Sales Office of Tata Steel Building products, having seen the schedule of my cladding requirements twice before, this time took it seriously enough to do more than simply add up the total area and instead came up with a query that means I ought to go through all the sheets and double check that my lengths are correct. I might have rushed it through and got the order placed, but as it was 2pm on Friday, Tata closes at 4 for Poets day and Andrew had the afternoon off and was keen to go get something done, I defered it until Monday.

You must forgive me if I keep harking on, but between now and when the contractors come in and start turning this 'thing' into a real shed, there is still a lot to do. A top horizontal purlin row is required across each end and this is out of range for the forklift. Similarly, the roof purlins on the end roof trusses need me to fit little extension brackets to provide a better support for the top ends of the sheets. The brackets etc I have, but wings I do not, and the cherry-picker, though promised, has still not materialised. With 2-3 weeks lead time on the cladding (well actually the roof light manufacturer said 'oh, we'll manufacture them next Thursday') and a strong desire on both our parts to progress the build, that leaves much to do, and I haven't even mentioned the eave beams.

When the old eave beams come down, the new eave beams and 'adaptor brackets' should be ready to go straight back up, but although the bracket parts are good to go, the eave beams themselves are simply formed sections of galvanised sheet, and require holes drilling to mount them. This is not a task I relish at 6metres above ground and I would like to think my CAD drawing of the shed frame was good enough to manufacture them on the ground, but civil engineering is nowhere a precise as mechanical. In fact, I'm kicking myself for not have manufactured my new brackets with slotted holes which would have been so much simpler, but they are what they are.

Driving back after a night out on Thursday, it occurred to me that if I could temporarily mount the brackets at the bottom of the columns, and placed the eave beams on top of them, this would give me a close enough replication of how it will be at the top of the columns, (you see, I can think in 3D). So on Friday, while Andrew started on removing all the remaining brake blocks on 14 901, I clamped two of my eave beam brackets to two of my purlin brackets and then attempted to clamp an eave beam to the former.

This was not a resounding success. The multiplicity of G clamps, the 'give' in the purlin brackets and the wind tunnel effect caused by the breeze funnelled between the concrete walls of the shed and the VBA, acting on the relatively large surface area of a 6 metre eave beam – well, let's just say that I could not succeed in getting an eave beam to balance on the quaking column bracket long enough to get a G cramp tight enough to stop the whole caboodle crashing back to the ground.

Andrew suggested that a simpler answer is to lower one of the existing eave beams, which are drilled to suit the original brackets, add a pair of my brackets and hence, a ready-made template to back mark the new beams. But the eave beams are still 6metres of the ground. Well, not all are now. One is now at ground level and whilst I don't suppose my Health and Safety advisor would have been overly impressed with our methodology, it was completed without incident. These old eave beams incidentally are 6×3inch channel, 6mm wall thickness and with loads of tabs on, giving a total weight of something like 20kg per metre if our calcs are correct.

IMG 0698 blog

So on Saturday we were down again, but although Andrew did progress more on the 14's brake blocks, in particular cleaning the pins and inspecting them to make sure there is no excessive play, for the most part he was doing something for me on a different front, and although we were both anxious to progress the shed and the '14, there is only so much we can do at one time.

Today Andrew and Steph were returning grandson after his fortnight with us, so leaving me to my own devices for an afternoon at Diddley. For starters I made up the sealing joint for the top of 14 901's new fuel header tank. The tank comes from the manufacturer with a self-adhesive foam one, but while that may be fine for a static tank, somehow it might not be so effective with a tank that doesn't stay still. Besides, I used the tank for another purpose last Christmas and the self-adhesive foam strip got lost, so a proper 3mm cork joint was made up, the float switch o-ring fitted, the top of the tank lid tapped 1/4 inch BSP for a breather and with the painted brackets in place, it is all ready to take its place in the loco, as soon as the old one has been drained and removed.

IMG 0699 blog

I decided to crack on with the eave beams. After all, I told Tata at the medical last week that I did partake in moderate exercise, so staggering around with 6m eave beams ought to fit the description. After carefully wedging the template beam slightly past horizontal, I was successful in placing the beams on the brackets, back marking and drilling them.

Round about beam four, that wind tunnel effect caught me. The eave beam sailed round and clipped the template beam, which toppled over, graving my ankle for good measure. Since the template beam is heavy enough for me to regard it as outside the realm of moderate exercise on my own, (and one of the blocks we'd sat it on had broken) I decided there had to be another way. I measured the holes I had drilled so far, which were reasonably consistent, and made up a marking out jig which enabled me to complete the rest of the exercise.

IMG 0701 blog

When I got back this evening though, I checked my drawing, and back-marked from an actual beam or not, I reckon they're all 3-4mm out of position. So, we might be up there drilling fresh holes after all. Oh, Goodee.

As Andrew is aiming to take all his allotted leave entitlement before he leaves Porterbrook, it works out that he can settle down to a 4 day week by taking one day per each remaining. This week's is Wednesday, so I am anticipating some additional time down at Diddley, weather permitting that is. Oh, for a roof! Which reminds me, must speak to the man at Tata first thing tomorrow.

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