M10 Sleeve Bolts on Aerial T & K brackets - How tight?

[braychurchmouse]

Confession time...after a LONG delay I'm finally actually getting our new aerial up with T & K brackets and using M10 (16mm hole) Shield Anchor Bolts (see previous thread ...//www.diynot.com/forums/viewtopic.php?p=821141#821141).

Rather than resurrect the old thread can I ask the specific question about the M10 bolts I did finally decide to use. (Rawlbolt M10 which need a 16mm dia hole drilling in the brick. http://www.tlc-direct.co.uk/Products/FXRBM10.html ).

I've successfully drilled the holes (thank goodness for SDS drills!) and inserted the bolts with the T & K brackets in place. I have tightened up the bolts sufficiently to hold the brackets fairly firmly. It is clear though that I could tighten them up a lot further with a spanner, but I'm concerned that because of the way the bolts work I could expand them too far and split the brick. The bricks are reasonably good quality facing bricks. I saw somewhere that there is a recommended pressure using a torque spanner, but just wondered whether you have any tips for a DIYer without a torque spanner.

Incidentally I paid about £1.60 EACH for the ones from TLC, but I see screwfix are doing similar for £2.08 for a pack of FIVE !!!

Anyway I promise to update the board on the success or difficulties when I finally get this thing up! Hopefully in time for the Olympics.

 

[RF Lighting]

You need to do the bolts as tight as you can. Unless you are near to the edge, there should be no issue with splitting the brickwork.

The problem with sheild achors is if the aerial gets blown in the wind, the wedge at the back of the anchor will get pulled towards the face of the brick. It will result in the bolt being loose, but the sheild and wedge will still be in nice and tight.

I personally tend to use chemical fixings for this sort of thing.

 

[ColJack]

unless you have 4 ft long spanners, or have the physique of a greek god, then it's doubtfull you will split a brick doing the bolts as tight as you can by hand.. unles they are particularly bad bricks

 

[braychurchmouse]

Thanks folks, as always extremely fast and helpful advice... I'll give them a firm turn with a 6 inch long spanner.

I guess I ought to start a new thread but I was also wondering whether people ever put a lightning conductor dicharge wire to earth on these tall aerials (3 meter aerial on the end wall of a bungalow)....and for that matter also any need to connect the aerial pole to an earth point. I read somewhere (I think on Satcure.com) that log periodic aerials work best in proximity with an earth plane...but wasnt quite sure what that meant.[/b]

 

[conny]

No wish to upset you but I am under the impression that you shouldn't drill chimney stacks for danger or loosening the brickwork. Recommendation is that you use straps that go right round the stack and tighten these with a special threaded sleeve like a karabina.

 

[holmslaw]

..

 

[braychurchmouse]

Thanks again for the responses...don't worry conny, its firmly on the side wall of the house not the chimney, which was removed some time ago....but good advice nevertheless for those with chimneys.

Its amazing how I notice all the aerials now as I drive around and see the most amazing things, aerials toppling over at all angles, old VHF TV aerials with half the rods missing (circa 1960?) and sat dishes perched high up on poles on roofs when they could be easily installed lower down with perfect line of site to the satellite.