The picture above shows
a 6”x 6”, a 6”x 9”, and
a 9”x 9” wall bracket.
There are two opposing views as to which bracket should go at the top. The K is obviously the more robust bracket and the received wisdom is that this should go at the bottom because, being further down, the wall is stronger there. However the top bracket is probably under the most stress (certainly if the wind is blowing the pole away from the wall) and so some think the K should go there instead ! Basically one has to work out the relative importance of the two factors for the particular install being undertaken. For an install at the peak of a gable I would put the K at the bottom, whereas on a strong flat top wall I`d put the K at the top.
Basically it`s six of one,
and half a dozen of the other,
But, if in doubt,
put the K at the bottom !
In the left hand picture we have a 6”x 6” and 8”x 8”(mitre) chimney bracket, and
the right hand picture shows the contents of a “Lashing Kit”. The latter includes
5m of pre-
The picture illustrates the difference in construction standard between a pressed
Chimney bracket and a welded type. Perhaps even more striking is the amount of rust
on the “Pre-
Note the “failed” steel pole.
Also see “Wall or Chimney Bracket ?”
For aerial poles up to 3ft supporting small or medium size antennas we recommend and stock the 6”x 6” bracket (see picture). It is important to stress that a 6” welded bracket won`t “fail”, it`s the masonry which will go first, because a 6” bracket only spreads the load across the corners of two bricks, see picture on the left.
For other installations using poles up to 8ft and aerials up to the size of a DY14 we sell the 8” mitre bracket. If an XB16 is fitted with an 8” mitre we`d go up to a 6ft pole. An 8” mitre usually covers three bricks and to a greater “depth”, see picture below left. The mitre bracket should also be used if your brickwork is in poor condition.
Unless the aerial is small poles of 10ft (or over) usually require a pair of brackets.
An 8 inch mitre chimney bracket in use.
Note the fact that the loads imposed by the installation are spread over three courses
of bricks and to a greater depth than the simpler types of chimney bracket, compare
to 6” bracket install. This really is a fantastic product, note the pre-
Pair of Heavy Duty Chimney
Brackets. These are exceptionally strong but must be used as a pair with a separate lashing wire each. These brackets come with 2” V bolts as the standard 1.5” size will not fit. Note that the pole can be mounted either side.
The crucial difference between a wall bracket and a chimney bracket is that the former
is screwed to the wall whereas the latter is lashed to it, in fact they are sometimes
referred to as lashing brackets. It is vital that this difference is appreciated
because the main reason that anything bolted to a wall has any strength is the bulk
of the brickwork above (and around) that to which it is actually screwed. Unless
a chimney is of large proportions it is unlikely that there will be sufficient bulk/weight
in it for a screwed fixing to be adequate. The answer is to use a lashing wire to
tightly hold the bracket onto the corner of the chimney. For the same reason mentioned
above, there should be a few courses of brick left above the installation. J-
Shared chimney ? What to tell an awkward neighbour……
It must be stressed that T & Ks are used to gain more stand off, not because they`re stronger than a pair of smaller brackets, particularly if the latter are of the welded variety. So long as the pole`s V bolts will fit the bracket there is no reason why two standard wall brackets (or low profile brackets) cannot be used for a long pole and/or large aerial. Quite apart from anything else a pair of smaller brackets will have eight wall anchors and four V bolts to secure the pole, as against only five anchors and two V bolts for a standard pair of T&Ks. Remember : more wall anchors = a stronger install (the wall anchors usually fail before the bracket) and this is particularly important when the forces are towards/away from the wall. Alternatively use sleeve anchors.
“T”s and “K”s are available separately and 2 x “K”s are obviously a bit stronger than a T&K, though it must be admitted there are relatively few installations where this would be of consequence, after all, the pole would generally fail before the bracket anyway ! However, each “K” does take three wall anchors (in fact “K”s generally have a fourth hole just at the point the two base plates are welded together) whereas each “T” only takes two. This can be significant if there are loads of voids in the brickwork and some of the wall anchors won`t tighten…… Alternatively, if using a “T” with a long pole and/or large aerial, consideration should be given to drilling additional holes (they won`t rust if the bracket is galvanised) in the bracket`s baseplate to allow the use of additional anchors.
But do you really need T & K brackets, when cranked / Supercranked poles are available ? !
The simple answer is that it`s bad practice and it shouldn`t be done unless there is absolutely no alternative. A bracket mounted on a wall (with the appropriate pole to clear any overhang) is far stronger than just attaching it to a fascia or bargeboard. Furthermore screwing brackets to wooden boarding greatly increases the chances
of rot setting in and makes it more awkward to repaint them as well. Finally, many people will eventually have UPVC replacement fascias fitted, and then the bracket will need moving anyway.
I don`t even want to think about anyone actually screwing an aerial to a UPVC fascia.........
Brackets including :
Shown above left are a pair of 12”and 24” T & K wall brackets, 18” and Heavy Duty 36” are also available. Like all the brackets we stock they are welded and “Hot Dipped” galvanised.
It is good practice to follow these recommendations, in addition they must
be followed to qualify for the lifetime warranty on our brackets.
A 3ft pole can utilise a 6” welded wall bracket (6 x 6” or 6 x 9”) for any size aerial.
A 6ft pole can be used with a 6” welded wall bracket for any aerial up to a Yagi18 though a 9x9 is preferable. As always, one must make sure the wall anchors are tight. For larger aerials we would use a 9”x 9” wall bracket especially in exposed locations. Since cranked poles put a bit more strain on the bracket it may be advisable to go for a 9”x 9” bracket with a crank, and definitely so if fitting a Supercrank pole.
An 8” mitre chimney bracket should be suitable for all of our antennas on a 6ft pole.
An 8ft or 10ft pole should be suitable for use with a 9 x 9” wall bracket on any aerial, apart from an XB16 / XB22, provided the wall anchors are tight. I would probably advise the use of two brackets (or T & Ks) with an XB16 / XB22, particularly in exposed locations
An 8” mitre chimney bracket would be suitable for a small aerial (e.g. our DM log periodic) but anything larger should use a pair of chimney brackets. These would usually (but not necessarily) be the H/D type spaced at about 12”, or more for an XB16 / XB22 antenna.
I would be wary of fitting a pole of 10ft (particularly with a large aerial) on a small chimney with any size of brackets.
For chimney mounting a pair of lash kits and two brackets should be used. The latter would usually, but not necessarily, be the H/D type. The spacing should be at least 20” (or 30” for a large aerial) for a 16ft pole and I would be even more wary fitting it on a small chimney ! It should be pointed out that it is very rare to have to fit a 16ft pole on a chimney.
If mounting an aerial on a chimney which is being used, or ever likely to be used, I`d recommend a cranked pole to try and get the aerial as far away from any smoke and/or fumes. The smoke won`t affect the signal, but it isn`t good for the aerial so I`d also place the aerial on the upwind side (of the prevailing winds, usually from the S or SW) if at all possible. Bear in mind that a smaller end mounted aerial (like a Log Periodic) can sometimes be mounted below the height of the chimney pots.
Close Up of lash wire terminations
On the left is a “pre-
When it`s called a wall bracket, that`s for a reason. They`re not meant for chimneys. That would be a, what do they call it ? Ahh yes, a chimney bracket....... (pictures courtesy of Vision)
Some installers fit “Self Supporting Brackets” (sometimes called “Bang Bangs”) which do not utilise a lashing wire. They have two “L“ shaped pieces of metal which are hammered into the mortar between the bricks, hence the term “Bang Bangs”. Unless access problems are severe (and two are utilised to increase the support) most riggers know they`re a bodge because the strength of the install depends on the mortar around just two bricks at the corner of the stack.
We are more than willing to give advice to those actually purchasing from us. Could those only seeking information please just find the answer somewhere on this site, or ring an aerial installer local to them, or call the reception advice phone numbers.
Subjects on this page are listed in the following order :
We stock clamps to attach poles to each other, the most basic is the 2" x 1" or a 2" x 2". The latter type will clamp parallel or perpendicular but the smaller one only perpendicularly. If two poles of any length are to be clamped in parallel it is normal practice to use two clamps, also see aerial clamps / cradles and pole couplers.
An aerial obviously requires a clamp to attach it to the pole and the vast majority of aerials come with a clamp, all the aerials we sell certainly do. Most aerial clamps will accept pole diameters up to 2”, and again all of ours will do so.
In addition cradles move the antenna away from the pole which, for a centre mounted aerial, is particularly important when vertically polarised.
Tilting clamps allow for elevation of the end of the aerial to help achieve the most accurate alignment but more importantly (the possibility of) reducing interference. All our aerials come with tilting clamps except the Log36. The manufacturer`s of the latter maintain that one is not
required for Log Periodic type aerials, though I`d certainly disagree if using one on a boat or caravan.....
The aerial on the above is aligned onto Cow Hill transmitter which is high up on a hill (would that be why it`s called Cow Hill....) next to Fort William which is down in the valley. It must be said that it is rare to require a clamp to tilt this far !
Incidentally I don`t like the install, it`s on a fascia and it`s a Contract aerial. Contract aerials don`t come with tilting clamps, so did the installer buy the clamp separately ? Why not just buy a decent aerial, with a tilting clamp, in the first place ? ! ?
This Multi Angle Bracket has got to be just about the most versatile ever. The plate clamps to a pole (between 1" and 1.5" diameter) onto which can be attached anything from a CCTV camera to a tube (up to 2" diameter) using an additional clamp, see below. Note : this product is not meant to join big poles together or mount large aerials in exposed locations, it`s to attach, well just about anything of relatively low wind loading, and at an angle if required.
On the left we have the basic multi angle bracket, on the right its versatility is demonstrated here with a simple clamp bolted to it.
If you`ve found this site informative and, hopefully, interesting as well,
The tilting bracket is specialised for, well, tilting. This product is very handy when you need to point your pole anything other than parallel with the wall (or whatever). This bracket is not intended for heavy duty applications (indeed it will only accept a 1 inch pole), but having said that it`s actually rather stronger than it looks !
The bracket will allow +/-
Note that there is an alternative to this bracket, an L Section loft kit, but insert
the short of the L section into the side of the supplied two way bracket (see picture
on the link). You can now rotate the pole to any angle +/-
T & K brackets are designed to increase stand off but what about when less stand off is required ? ! ? For those applications use the Low Profile Bracket. These brackets accept poles up to 2 inches in diameter and the stand off is approximately 1.5 inches. They are supplied with a sledge and bolts so you don`t need to separately order a pair of V bolts. You would generally use them in pairs unless it`s a small aerial on a short (3ft or less) pole. Because the stand off is so small the brackets are actually very strong despite only being 1.5mm pressed steel (“Pre galv”).
Note that these brackets don`t allow any adjustment of the poles stand off so should only be used on a flat surface. (Link)
Low profile brackets look very neat and if standoff is required this can be achieved by using a cranked pole.
A 2”x 2” clamp is shown above left clamping two 2" poles in parallel (though it`ll actually clamp any 2 poles between 1" to 2"). Note that two are usually required to join two poles together in parallel. The clamp will also clamp perpendicularly, though only a 1.25” to a 2” in that plane.
The 2”x 1” clamp (above right) is holding a 2 inch pole perpendicularly to a 1 inch. It will also clamp 2 x 1" or 2 x 1.25” poles together, but it will only clamp perpendicularly, not parallel.
Think about it, the latter is capable of clamping something as small as one inch to something as big as three and a half inches. Obviously it will only clamp parallel ( ! ) and you`d generally use as a pair. Like they say on the cereal packets the pictures are serving suggestions, the clamps can be used in any number of ways, for instance with or without the centre nuts. Also, if clamping to a square section member, 2 saddles interlaced and “back to back” provide a flat surface, though if using the M10 bar the holes may need drilling/filing out to enable the saddles to remain perpendicular to the studding.
Next we have two clamp kits. The 3.5 x 3.5 version clamps two poles from 1” up to 3.5”.
Ever wondered what the neatest strongest way is to install a pole on a wooden post ? You haven`t ? Well there`s one born every minute, so they tell me, but for the rest of you, the answer is to use some 2.0” saddles and some studding, preferably stainless studding (like this). You`d usually use two sets of saddles and get a very strong but also very neat installation. The picture on the right is a 2” pole bolted to a 4x4 fence post.
All very neat I`m sure you`ll agree, but what happens if you can`t (or don`t want to) drill into the post ? Well, purely by fluke, but very fortuitously, it just so happens that Low Profile Brackets fit perfectly round a 4x4 fence post as the picture on the right proves ! Use two (or two pairs for a stronger install), one each side of the post. When I set up the install for the pic I used our stainless threaded bar and fixing pack (though that does require the holes drilling or filing out slightly) but any bolts will do. The mounts bend slightly as the nuts are screwed up but that isn`t significant for the strength of the install. Also see the 3.5in U bolt (below)
The next category up (in terms of strength) is the welded bracket. These are significantly stronger than the pressed variety and are welded together out of steel angle/bar of typical thickness 3.0 to 5.5mm. Welded brackets are available in either painted or galvanised finish. Although there is no difference strength wise between them the difference in finish is chalk and cheese. A painted bracket can start rusting almost straight away and will often show significant surface rust within a few years. It must be admitted that it`d usually take decades for rust to significantly weaken a painted welded bracket, but it will do so eventually !
Pole clamps and couplers incl :
Weather station installations (Poles & Masts page)
Avians on your aerial (Poles & Masts page)
Guy wire supported poles (dedicated page)
Also see :
Do you really want that
on the front of your house ? ! ?
It isn`t uncommon to see rusting steel brackets fitted on the apex of rendered walls
with huge rust stains stretching out beneath them.... All for the sake of a bit of
decent galvanising. The latter is just what you get on a galvanised welded bracket
and these are the only type we sell. None of your thin finish "Pre-
20 years plus without a trace of rust staining. In fact we`ve got an experiment running where we`ve actually tried to file off the galvanising finish (on a section of bracket) and left it outside in the rain.
It hasn`t rusted at all in nine years !
I really wonder how anyone, no matter how big a bodger they are, could possibly contemplate using a painted bracket. They must be tighter than a camel`s arse in a sandstorm.......
It must be admitted that in most locations and/or for most jobs galvanising is primarily about appearance, but, as the picture on the right shows, it can also be about the long term strength of the install……
Obviously the spacing of any pair of brackets determines the strength of the installation and this varies according to the size of the aerial, the length of the pole and the likely winds to be encountered. For small aerials in sheltered locations I`d separate the brackets by at least 1” for every foot of pole, but for large aerials in exposed areas I`d at least double it to 2” per foot of pole. Satellite dishes may require 3”, 4” or even 5” separation per foot of pole, depending on the size and likely winds.
A 6 x 9 bracket : the first dimension in a bracket size is relevant according to the length of the pole which the bracket is expected to support. A longer pole will generate more leverage on the bracket (and the wall.....) and therefore a bigger bracket should be used. The second dimension is the length to the end of the bracket and it is this which determines the stand off of the bracket (minus 4” though ! see above).
There are basically three main variants of the standard type brackets used on many
smaller installation jobs, that is to say the 6"x 6" bracket (wall or chimney mount).
The cheapest of the three is the pressed steel bracket. It is galvanised but it is
of the “Pre-
Brackets are classified according to their size (from the top pole clamp to the bottom
one) and their stand-
But always remember you don`t have to use a huge bracket if you can use a cranked pole !
When installing a wall bracket always leave 2 to 4 courses of bricks above the install*, and try to make it 4 to 6 courses if installing the aerial on a gable.
* Depending on the size of the aerial and the length of the pole, and whether you`re using a Black and Decker or an SDS hammer drill to drill the holes......
When deciding how strong to make your install remember that the weight of the aerial/satellite/weather station is almost irrelevant, it`s the wind loading that counts !
Remember, if you`ve got a big aerial on a long pole and it`s accessible, if particularly high winds are forecast it is sometimes possible to temporarily lower the install for the duration of the storm.
They could call it the “Rod Hull Rule”.
It`s pity he didn`t fall on that bleedin` bird isn`t it ?
Or perhaps he did ?
Is that a tautology ?
There could be some Health & Safety Bollocks ruling* about trying to fit your own aerial, so consider this sentence to be a concession to that.
Results of pulling out (albeit at a slight angle) one of our 50mm M8 wall anchors using a tow rope attached to a car !
The method used to fix a bracket to the wall is actually a subject of some debate.
Should one use wall anchors of the classic type, the shield anchor (often known as Rawlbolts), or heavy duty versions of the plastic wall plug and screw variety (often referred to as Rawlplugs) ? There are arguments on both sides. Shield anchor type fixings can undoubtedly exert more grip on the brickwork, they will take a much bigger load than the screw /plug anchor, but there is a far greater risk of splitting the masonry if you tighten the fixing too far. Furthermore if one uses an M8 shield anchor fixing the hole in the masonry must be 14mm. And that is a pretty big hole, plus most people don`t have a 14mm masonry drill bit or, in many cases a drill big enough to use it. Lastly, there are arguments that shield anchors (particularly large ones) shouldn`t really be used with in bricks, for one thing the edge of the hole shouldn`t be within 50mm of the edge of the brick. One answer is to use a smaller shield anchor, but even an M6 type still requires a 12mm hole and an M6 fixing really does look a bit small for a wall bracket (you`d have to use a large washer on it ! ) though it`s stronger * than it looks.
Virtually all aerial installers actually use M8 wall screws and M10 wall plugs in either 50mm or 75mm lengths, the latter are most often used in rendered walls. The SWL on a well fitted 50mm screw/plug combination is about 45Kg, though the maximum load would be around double this. A 75mm screw and plug combination would usually have a higher SWL than the 50mm but only if there is no void in the brickwork. If, when drilling the hole, you feel the drill bit has hit a void deeper within the brick (newer bricks are more likely to have voids than older types) then our advice is to fit the shorter fixing so the plug expands into solid masonry, or use “Universal” wall plugs. I`ve used the latter and am very impressed with them, They may be a bit more expensive than conventional type wall plugs but I only buy them now. The critical point with wall plug type fixings is that the anchor must be a tight fit in the masonry and be capable of taking a decent level of torque when tightening up. Shield anchor type fixings are more forgiving in that they can expand further to compensate for a hole which may be a little too big or masonry which may be a little soft. If you do find yourself in the position where any wall fixing won`t tighten up, try removing the screw, hammering some wood slivers (e.g. matchsticks) into the hole to pack it out then replace the screw. If it still doesn`t tighten up sufficiently hammer more wood into the screw hole and repeat the process until the screw will tighten up OK. At one time packing (just) wood in the hole was actually how it was done. Alternatively try a “Universal wall plug ! Remember, sufficient tightening torque is the name of the game, and providing enough can be applied to a wall plug type fixing it is highly doubtful that it would ever fail. Finally, always remember to ensure that any wall anchor is screwed into the brick, not the mortar. We once pulled a 12” K off the wall * * (which was screwed on with our M8 wall screws / M10 plugs) with a tow rope attached to a car, it pulled some of the brick out with it ! (see picture below right). Admittedly the force was almost parallel to wall, but that`s still relevant as a practical test of wall anchor performance.
There is one last type of wall anchor, the sleeve anchor. This is basically a shield anchor with a long thin shield ! They`re cheaper than shield anchors but, according to Rawl very nearly as strong (approx 300Kg SWL), for our purposes any difference is academic because the pole would have failed long before the (correctly installed) sleeve anchors. Sleeve anchors are more forgiving then wall plugs if the hole is a little too big, they`re not as forgiving as shield anchors but on the other hand they`re also less likely to crack the brick and can be installed a little closer to the edge of the brick (35mm ? ). These attributes mean shield anchors are recommended for blockwork. Technically resin anchors are the best choice for soft type blockwork but they`re expensive, difficult to get hold of and awkward to use. I`d just use sleeve anchors…..
Last, but by no means least, an M8 sleeve anchor only needs a 10mm hole !
NOTE : on sleeve anchors, unlike most other types of anchor, the sleeve is supposed to screw up to the nut, i.e. pass through the fixture.
Just one last thing, a slight downside of sleeve anchors is that if you accidentally put the anchor in the wrong place (or no longer need it) you can`t easily remove it ! You`ve got 2 options, the first is getting the angle grinder out. The second may not work but is worth a try. You remove the nut and the fixture. You carefully tap the bolt into the sleeve so the end is no longer wedging the anchor open, to have a chance of doing this you must obviously have originally drilled the hole somewhat deeper than the anchor. I would suggest the latter is a good habit to get into, apart from possibly assisting in anchor removal is also means there will be room for any masonry debris as the fixing is initially tapped into the hole (alternatively use one of those “blowers” for that). If the hole is drilled deep enough, you can, as a further option, just tap the whole anchor into the hole and leave it ! Anyway, assuming you would rather remove it, you then get a big pair of mole grips and squeeze the section of sleeve which is proud of the masonry against the bolt, and try and pull them out together (without the wedging action of the bolt). It sometimes works…….. If any reader uses any other method of removing redundant sleeve anchors please get in touch !
* * There`s a story behind this, are you interested ?
I thought you would be.
We used a 12” K as a galvanised (obviously) attachment point to chain our ladders up. We soon kicked the idea in the head but kept walking into the bleedin` thing. However, removing it was a bit difficult because we`d welded the wall screw heads to the bracket, it was supposed to be theft proof remember.
If I`d have known how much damage using the tow rope would do I`d have fetched my soddin` angle grinder from home……
The big advantage of these 3.5” U bolts is the fact our 3.5” sledges fit them. Note that the 3.5” U Bolts are supplied without sledges, the latter being available as an extra if required. Using the sledges the 3.5in U Bolts can be used in may ways, including, and we`re asked for this quiet often, attaching a pole to a box section / square section. Below are some pics showing the maximum dimension of box section that the 3.5” U bolt / sledges will fit. It will be noted that a 1.25in pole can be bolted to a 3x3 post, also see “pole on a post” (above)
All measured internal diameter.
Note, all our V bolts come with washers.
If replacing a pole even the tightest aerial installer would use new V bolts, mainly because it`s far easier to just hacksaw off the old Vs rather than try and undo the nuts on rusty ones.
If you have to use V bolts larger than 1.5” make sure you check they will fit the bracket. Some brackets, esp 6" types, only accept 1.5" Vs. You may have to drill an extra hole yourself, or get the file out !
When using V bolts I would tend to tighten the bottom one more than the top one because if you crush the wall * of the pole you will significantly weaken it just at the point where it`s under most strain. In our tests all the poles (unsurprisingly) failed at this point. The bottom V bolt can be done up as much as you like to ensure the pole doesn`t twist in the wind. Sufficiently tightening the bottom clamp is particularly important if using an end mounted aerial (though we don`t actually recommend end mounting aerials for outside use, not large aerials anyway) or a cranked pole, and especially a Supercrank pole.
Also see use of saddles.
* Crushing an 18G (1.2mm) pole is rather more likely than with the thicker 16G (1.6mm) or 14G (2.0mm) versions which we sell.
The Vs would usually start rusting between 2 and 5 years after installation dependent on the local conditions. It must be admitted it`d take about 5X that length of time for a V bolt to rust sufficiently to significantly affect its strength but removing the nuts would be problematic rather sooner than that ! The latter is particularly important when installing weather stations of the type which need regular maintenance……. The reason the Vs are the first thing to rust is because virtually all V bolts are (only) zinc plated. It`s not possible to hot dip galvanise a thread, for obvious reasons*. The only way round this is are stainless V bolts, they don`t rust but are obviously significantly more expensive !
* OK, for those it isn`t obvious to, the threads would fill with galvanising and the nut wouldn`t screw up. You can get round this using oversize nuts but how complicated do you want to make it ? Anyway, stainless are superior to (even) galvanised.
It should be noted that the first thing to start rusting on a decent quality install (an alloy [or hot dipped galvanised] pole and a galvanised bracket) would be the V bolts.
The great majority of aerial installers just bolt the pole straight to the bracket like in the top of the two pictures on the right. This is absolutely fine for most installations but if you have a large aerial in an exposed location then the use of saddles with the V bolts gives a stronger install. This is because the saddle grips the pole better, and, as a side benefit, means the V bolts don`t have to be done up quite as tightly (to ensure the pole doesn`t slip round). As stated above excessive tightening of the V bolts, particularly the top one, should be avoided if possible because it weakens the pole.
Installs which would benefit most from the use of saddles are those likely to be subject to twisting forces, that is to say larger aerials on cranked poles or large end mounted aerials on any pole.
We sell three combinations of V bolt and saddle, two at 2 inches (internal diameter) and one at 2.5 inches. It is perfectly acceptable to use a 2.0in V bolt / saddle combination with a 1.25in or 1.5in pole. However, it must be noted that the plated 2.0in V bolt is not long enough to accommodate a 2in pole + saddle + bracket, though it is fine for poles up to 1.5in. The stainless 2.0in V is a bit longer and can be used with a 2.0in pole and saddle, as can the 2.5in V.
Ordinary plain nuts don`t usually come loose (if the correct torque is used) because of the friction between the nut and bolt, and indeed the fixture itself, but it`s not unknown for loosening to occur particularly if the joint is subject to vibration. This is where locking nuts, most commonly Nylocs, come in. Nyloc nuts are a type of self locking nut which utilises a ring of nylon (unsurprisingly…) to grip the threads of the bolt, the big advantage being that they don`t work loose. The aero industry tends to use a lot of Nyloc type fastenings mainly because an unsecured wing (or two) does not tend to encourage passenger confidence. On the other hand it must be said that very few aerial installers use Nylocs (even on specialist jobs) partly because they cost more but mainly because they take much longer to put on, you can`t spin the nut down the thread, it has to be wound down the whole way with a spanner. The other disadvantage of Nyloc nuts is they`re thicker than the equivalent plain nut, e.g. an M10 plain nut is about 8mm high whereas an M10 Nyloc is around 10mm. This can be significant if short of thread on the bolt. For example if our 2in stainless Vs are used with 2in saddles and a 2in pole Nylocs are only suitable if the washers are omitted. Obviously a Nyloc nut can still be used (if the thread doesn`t reach the nylon insert) but it would defeat the object because there wouldn`t be any locking function !
Nylocs can also be used on bolts which can`t be fully tightened up because movement is still required, e.g. hinge type mechanisms.
Most of our clamps are available with either plain nuts or Nylocs.
Nyloc nuts :
for when you really don`t
want that fastening
to come undone…..
The best method of joining two poles (although they must both have a 2" diameter) is the 2" Pole Coupler, shown right. Apart from looking a lot neater than two 2" x 2" clamps, it had also has the advantage that you don`t "lose" the height of the pole that is required for the overlap between the two aforementioned clamps. It is sufficiently strong that the pole would fail before the coupler.
Note ! We do not normally advise joining two 10ft x 16G poles together. If making up a longer mast we recommend coupling our 10ft x 2” (16G/1.6mm) to our 8ft “satellite pole” (which is 14G/2mm) using a thicker pole at the bottom and the thinner pole at the top. Think Eiffel Tower (stronger at the bottom......). [Link]
* SWL (i.e. the force required to pull it straight out of the wall)
Or, put another way, gravity plus height is a bad combination, don`t fall off the ladder.
If in any doubt about this scientific fact, don`t do the job.
See basic ladder safety.......