Selfsufficientish.com

Arrggghhhh!!! I have lost my rag totally building our tunnel. It is a very good make and myself and partner are very experience DIY'ers. I am an engineer and spend my workdays putting stuff together so I don't understand why this project is being such a cowbag..
Basically, it is a well known make of tunnel, 20 x 15 feet and we are trying to assemble the hoops, sounds easy we thought but you have to screw them together with "self tapping screws" which do absolutely nothing when you try. Next, we bought two brand new metal bits and the metal hoops were so hard, we spent twenty mins on one hole and broke both bits trying.... We have given up now and other half has gone to B and Q to buy duct tape instead. No way should it be so stupidly difficult.... are we missing some vital hoop building tip here???? Never again...

Haven't ordered mine yet but i so want to get one that comes with a person to build it for me

I'd like to help,and maybe able to, but not sure which bits you're having probs with. Can you do a picture? What make is this tunnel?
Best Wishes.

the trick with the self tapping screws (there is a knack to it) start them slowly and gently.... really take it easy then, when you are through the first mm or 2 increase the pressure.

I bought and erected a 12 x 15 first tunnels polytunnel 2 years ago and yes it was a cowbag... till I figured it out.... OH was cursing and blinding as he couldn't manage

If it's a 'First Tunnels' one as Annpan has guessed, I'd suggest hand screwing.

We found it to be far better than trying to use the rechargable screwdriver. I litterally started the screws by hand for the first few turns & then used a hand driver to tighten.

Good luck!

MW

What material are the hoops made from SC? From what you say (20 mins on one hole despite brand new bits) they’re stainless steel and require drilling before fastening together. If this is the case the metal is work hardening as the drill bit generates heat. If so, once hardened, self tappers will really struggle to cut their way through. (Sorry if I’m barking up the wrong tree here..)
If the hoops are stainless, drill speeds need to be kept as slow as possible and cooled whilst cutting. I’d try repeated squirts of WD 40 or even white spirits during drilling and have a couple of new drill bits to hand.
Hope this helps

Good luck with it and keep us all posted

I sympathise with you.
We bought and built a First Tunnel one last year and a few swear words were said during the build.
Good luck!

I spent a month over mine. I just do a section at a time, then come back and re jiggle some sections. I find that it is better for the blood pressure

My experience was similar to dustydave's. Might only have been three weeks but it seemed a lot longer. Certainly (as, to be fair, the instruction book emphasised) more than a simple Sunday afternoon job).

I found the self-tapping screws did work well with my cordless drill but agree with Annpan that you have to start very slowly. For the first few, I used a metal punch and hammer to make a dent in the metal; by later on in the project, I had built the confidence to start without that. At a very slow speed (pressing the trigger very gently) the screw would begin to bite and then I would start going faster, in pulses and continuing to push in hard.

It wasn't nearly as easy as I hoped but don't lose heart. The result should be a pretty decent polytunnel and, a few months later, I'm very glad of mine.

Wulf

Self-tapping screws are not the same as self-drilling screws. With self-tapping screws it's best to drill a small pilot hole first.

I agree my tunnel is from First Tunnels and we drilled pilot holes for each self tapping screw using a tiny drill bit just big enough for the screw to bite into. I found our biggest problem was making sure everything was square to everything else. Lots of swear words muttered but with the help of some friend we got it up in 4 days.

Sarah x

Did one of these the other day. Pilot holes do help - but you need a decent metal bit mounted quite far back in the drill head to lessen the chance of it snapping. Use a bit of masking tape to stop the bit from slipping at the start, turn hammer setting OFF (if you have a hammer drill), keep revs LOW, and put a squirt of WD40 on now and again.

And remember, you only need to do this ONCE!

Erm, I think you're all missing the point of these screw/ joint thingys (as you can tell I'm good at technical terms ) - Y

You don't need to screw through the inner piece, the screw creates enough tension to fix it rigid just pushing up to it.

That's what it said to do in the instrucitons that came with our First Tunnels polytunnel and thus far it has stood up to 90+mph without a murmur.

I think spamchops is having some trouble getting them to bite.