Scaffold pole strength.

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I want a "gantry" in the garage from which I can hang a chain block as an engine hoist. Small section RSJ would be ideal, but they seem to be eye-wateringly expensive. A bit of lateral thinking later and I came up with the idea of using two scaffold poles clamped together at each end.

I fed the measurements (ten foot span, two inch dia, 4mm wall, 180KG load) into a couple of web deflection calculators and got the rather eye opening result of nineteen inches of deflection for one pole (presumably half that for two parallel poles). This can't be right, can it?

I'm just imagining my 90KG body weight stood in the middle of a 10' pole, and I wouldn't expect much, if any, movement at all.

So, are scaffold poles a bit limp-wristed or are the "calculators" wrong?

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Looks like I'm back to plan A - an RSJ. Thanks for the replies chaps.

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Collectingbrass said:

Engine hoists are only £100 to £150, so to be harsh for a moment what does a home built gantry get you that a designed, tested & warranted engine hoist doesn't?

What it gets me is lifting capacity that's hidden in the roof of the garage rather than a huge collection of (99.9% of the time) scrap iron that I'd have to store in the garage and which I would be guaranteed to bark my shins on every time I went in there!

Collectingbrass said:

Stuff about welding and CofGs

I take your point about welding galvanised stuff and adequate support, but I wasn't intending to do any welding and the support is already sorted. I was just surprised that thick wall tubing was so flexible. However, I suppose in its primary use that flexibility is not an issue as it can be braced. My proposed use would have precluded bracing due to the welding issues and/or the cost of the necessary additional material, putting it within a gnat's of the cost of an RSJ. Yes, I'm from Yorkshire and hence a tightwad careful with cash.

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finishing touch said:

I am toying with this quandary at the moment.
It's looking more and more like the engine & gearbox Is going to need removal from my Seven.

Paul G

I'm in the same boat. My seven's gearbox is in dire need of a rebuild. So the engine/box needs to come out. When I've had the engine out on previous occasions I've been doing work on it, so could remove the head in situ and then lift the bottom end out by hand. Now I'm a bit older I'm not sure my back will thank me for doing that and, anyway, I don't need/want to split the engine this time.

I'm going to arrange for the gantry to extend over the top of the workbench so that, with the help of a trolley arrangement on the RSJ, I can lift the engine from the car, move it sideways and lower it onto the bench.

Collectingbrass said:

As an East Yorkshire (1) tightwad myself I would at this point be thinking long and hard about how often I really would use the gantry and whether treating Ebay, Gumtree et al as a hire shop (buy it, use it, sell it) might not be the better idea, especially if really it is a one off for a restoration project...

(1) We're like normal Tykes, but shillings and white five pound notes are still legal tender as we have so many still on hand...

Trouble is, I'm an inveterate tinkerer, so engine removal is a fairly frequent occurrence. I've hired engine cranes before and find that they have as many limitations as advantages.

Paul S