# Forum Home Renovation Fences & Screens  Fixing hardwood fence rails to steel fence posts

## KSG

What is best method of fixing 75 x 38 hardwood fence rails to 65 x 65 steel fence posts (not sure of thickness of these)?  Is it best to use screws (8g or 10g hot dipped galvanised coach screw?) or bolts which go completely through the post? 
If using screws do you need to pre-drill the post or would they just self drill?  
Thanks in advance 
KSG

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## cyclic

Gal bolts and nuts are always going to be best.

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## KSG

Thought so.  How much better are they than the screws as mainly seen screws being used?

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## sol381

Or self tapping roofing screws..Pre drill the hole and countersink the head.

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## KSG

Yes I have seen this before Sol. What is longevity of self-tapping roofing screws v bolts?

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## Bros

Bolts are the best but you have to fit anti compression spacers.

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## Marc

It all depends from the look you want. A 65x65 post will look better with the railing butting between post. You can achieve this with L angle bracket with the long side upwards so to conceal the angles. I fix the brackets using  this threaded insert in the SHS but I do so only because I have the pneumatic gun to fix the nuts to the post easily. The gun that can fit stainless nuts is not cheap. You can however fit the angles using 8 mm bolts through both angles and the post.  
65 - 38=  27 27/2= 13.5mm 
Providing your slats are not thicker than 12 mm  you are good. You don't want the slat to be proud of the post. If that is the case, fit the angles and the rail further back. 
If you are concerned about the railing being fixed only from below (you don't have to since the slats with stabilise them), you can use angles that hold the railing from behind, but that will be seen. 
A railing that goes behind the post and bolts against it would probably be the worse look, but if you don't mind it, and if you don't want to bother with inserts, a through bolt will work.
A self tapping screw will work providing your SHS has a decent thickness wall.

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## sol381

> Yes I have seen this before Sol. What is longevity of self-tapping roofing screws v bolts?

  
Im sure longer than the crappy rails and palings fencing material is made from.

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## KSG

What is decent thicknesses of SHS for using self tapping screws?

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## Marc

It depends from the screw used. 
You want at least 2 to 3 threads to engage the steel.
So it depends from the diameter, and the pitch. 
On a post that has 3mm walls you should be good, but fence post usually are 2.4.
That is why inserts are so much better.

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## Bros

Over 20 yrs ago I made some gates out of 1.6mm RHS and I used steel galv screws to attach pickets to it and they are almost as good as when I built it but these are pickets not rails.

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## Marc

Yes, palings on there own are light. A fence railing will be heavy adding the weight of all the palings, so must be fixed properly. Of course there are other factors to consider not just how thick the post. You must consider the spacing of the said posts, hardwood is heavy. The screws size, the bolt size, the thickness of the brackets if used etc.

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## cyclic

> Thought so.  How much better are they than the screws as mainly seen screws being used?

  I have no idea of the sheer strength of a 10 mm bolt as opposed to 2x12 gauge roof screws. 
Personally, I like to over engineer things, so bolts are my preferred method, although Bros idea of crush tubes is a bit of overkill. 
Over time, the timber may rust the screws/bolt, so a thicker bolt will last longer than thinner screws. 
And I believe you will find roof screws are zinc sealed not gal.

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## phild01

> And I believe you will find roof screws are zinc sealed not gal.

   :Confused:  What is zinc sealed, have only ever used gal ones?

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## cyclic

> What is zinc sealed, have only ever used gal ones?

  In the early days of roof screws, they were called zincaseal screws. 
Basically a thin zinc coat. 
I just had a look online and some call them gal, so no real difference I guess considering gal is zinc. 
Some screws online look to be hot dipped whereas some look to be coated.

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## KSG

> In the early days of roof screws, they were called zincaseal screws. 
> Basically a thin zinc coat. 
> I just had a look online and some call them gal, so no real difference I guess considering gal is zinc. 
> Some screws online look to be hot dipped whereas some look to be coated.

  The ones I have seen show as galvanised finish but are Climaseal coated

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## r3nov8or

Snapped this fence today

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## Whitey66

> Snapped this fence today

  No wonder it snapped, it hasn't been built properly  :Tongue:

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## KSG

> Snapped this fence today

  I like the look of that, it's quite tidy.  What have they used across the top of the palings?

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## Whitey66

It looks like colorbond fence capping.

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## phild01

More chance of sag with those single span rails.

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## Whitey66

That angle should go the full height of the rail and have 2 or 3 screws to secure the rail better. Support from the bottom by the way of a solid plinth and the fact that all the palings are joined together should prevent sagging.

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## Marc

Agree with a support in the center of the bottom rail. 
Larger bracket against the post not necessary, it only takes vertical load and one two or three screws make no difference to that.

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## r3nov8or

The whole photo (finally resized it small enough)

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## Whitey66

4 rails, makes sense now.

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## Whitey66

> Agree with a support in the center of the bottom rail. 
> Larger bracket against the post not necessary, it only takes vertical load and one two or three screws make no difference to that.

   I disagree regarding only one screw necessary, if it was a steel post and steel rail fence would you think it was ok to just weld half?
This is more for a 2 rail fence, not a 4 rail with plinth like r3nov8or posted which is almost overbuilt imho.
All those rails would make it very easy to climb over, I hope there's not a pool on the other side  :2thumbsup:

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## r3nov8or

It's a newish commercial estate. I'm on the ALDI side  :Smilie:

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## Marc

> I disagree regarding only one screw necessary, if it was a steel post and steel rail fence would you think it was ok to just weld half?
> This is more for a 2 rail fence, not a 4 rail with plinth like r3nov8or posted which is almost overbuilt imho.
> All those rails would make it very easy to climb over, I hope there's not a pool on the other side

  Considering the OP has gone walkabout ... this is just academic. 
Welding half and having one screw on the side and one on the bottom have no relation. Half of what? Anyway, I was referring to the screw that pulls the timber against the vertical side of the steel bracket. There is 4 of them so one per rail is plenty. 
However in the case of the Op with just two rails, I would use U shaped brackets welded against the steel post if I have the chance to galvanise the lot after welding. If not, purposely made bracket to screw against the post but not from the back of the post, rather in between them. An angle placed vertical with the bottom end bent horizontal (cut out a little square) to take vertical load 
As for the original question of screws to be used vs bolts, it is not possible to answer properly without knowing how the rails go and what sort of bracket if any.  
Half questions get half answer ... or at best a few guesses  :Smilie:

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## r3nov8or

> 4 rails, makes sense now.

  And a double plinth. It's a very high fence, over 2 metres I'd say. Just not much there for context of it's size

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## KSG

> Considering the OP has gone walkabout ... this is just academic. 
> Welding half and having one screw on the side and one on the bottom have no relation. Half of what? Anyway, I was referring to the screw that pulls the timber against the vertical side of the steel bracket. There is 4 of them so one per rail is plenty. 
> However in the case of the Op with just two rails, I would use U shaped brackets welded against the steel post if I have the chance to galvanise the lot after welding. If not, purposely made bracket to screw against the post but not from the back of the post, rather in between them. An angle placed vertical with the bottom end bent horizontal (cut out a little square) to take vertical load 
> As for the original question of screws to be used vs bolts, it is not possible to answer properly without knowing how the rails go and what sort of bracket if any.  
> Half questions get half answer ... or at best a few guesses

  Not gone walkabout just busy besides I felt my question was answered and the post has become more about the fence r3nov8or posted a pic of.  I quite liked the look of that one but alas that won't be my fence.

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## jbig

Hi fellas, first time user. would this system work with pine rails? would it work with 50x50 SHS? Got to replace a boundary fence between two old houses, less than 2000mm, so every mm counts for access. This system will cut back on fence thickness. Could anyone suggest a supplier of similar posts in sydney? Thanks for the input.

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