I am about to have the builders fix some brackets to a 10mm square steel
post.

They are proposing to drill all the way through and have nut and bolt.

Fine for the intermediate posts but it might be neater for the end posts
to drill and tap and then just use a bolt.

So how straightforward is it to drill and tap a hole for say an M8 bolt?

Something to buy, something to hire, or something to avoid?

Cheers

Dave R

On 04/03/2013 16:29, David.WE.Roberts wrote:
I am about to have the builders fix some brackets to a 10mm square steel
post.

They are proposing to drill all the way through and have nut and bolt.

Fine for the intermediate posts but it might be neater for the end posts
to drill and tap and then just use a bolt.

So how straightforward is it to drill and tap a hole for say an M8 bolt?

Something to buy, something to hire, or something to avoid?

Cheers

Dave R

Is the post solid, or a square tube? Either way, an 8mm hole in a 10mm
post doesn't leave much meat either side!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills wrote:

Is the post solid, or a square tube? Either way, an 8mm hole in a 10mm
post doesn't leave much meat either side!

Caveat of "unless it's a decent thickness tube wall."

However, rivnuts are the thing the OP wants.

--
Scott

Where are we going and why am I in this handbasket?

On 04/03/2013 16:39, Roger Mills wrote:
On 04/03/2013 16:29, David.WE.Roberts wrote:
I am about to have the builders fix some brackets to a 10mm square steel
post.

They are proposing to drill all the way through and have nut and bolt.

Fine for the intermediate posts but it might be neater for the end posts
to drill and tap and then just use a bolt.

So how straightforward is it to drill and tap a hole for say an M8 bolt?

Something to buy, something to hire, or something to avoid?

Cheers

Dave R

Is the post solid, or a square tube? Either way, an 8mm hole in a 10mm
post doesn't leave much meat either side!

I guess it isn't *really* a 10 mm square post?

I'd normally agree with you about tapping for neatness at the ends,
subject to having enough meat. But a dome headed bolt (carriage bolt)
with the dome on the outside should be reasonably inconspicuous. What
loads does the bracket see? If seeing fluctuating loads (e.g. wind
loads) there is something to be said for the through-bolt because that
gives you a better load path.

On 04/03/2013 17:23, Scott M wrote:
Roger Mills wrote:

Is the post solid, or a square tube? Either way, an 8mm hole in a 10mm
post doesn't leave much meat either side!

Caveat of "unless it's a decent thickness tube wall."

Not really. Even if it's solid, there's not much each side of the hole.

However, rivnuts are the thing the OP wants.


They are if it's a tube. Don't think they'd work if it's solid. That's
why I asked. And I don't think you'd get an M8 rivnut in a 10mm wide
tube - you'd have to use a smaller bolt.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 04/03/2013 16:29, David.WE.Roberts wrote:
I am about to have the builders fix some brackets to a 10mm square steel
post.

They are proposing to drill all the way through and have nut and bolt.

Fine for the intermediate posts but it might be neater for the end posts
to drill and tap and then just use a bolt.

So how straightforward is it to drill and tap a hole for say an M8 bolt?

Something to buy, something to hire, or something to avoid?

Cheers

Dave R


Drilling and tapping for a 8mm bolt?, never usually done, but to drill
and tap for an 8mm hex head screw, that's better.
You would need the correct tapping drill and 2 8mm taps, one starter or
taper, and the other a 3rd or finish tap.

But as others have said, bolt through would be my option, but not using
an 8mm bolt through a 10mm square bar.

Can you not use wider steel as in 12mm or 16mm is better.

If you think about it a post which is 10mm square is not really
substantial enough for a post. 10mm = 3/8 inch approx. 8mm = 5/16 inch
approx

Roger Mills wrote:
On 04/03/2013 17:23, Scott M wrote:
Roger Mills wrote:

Is the post solid, or a square tube? Either way, an 8mm hole in a 10mm
post doesn't leave much meat either side!

Caveat of "unless it's a decent thickness tube wall."

Not really. Even if it's solid, there's not much each side of the hole.

Mea culpa. Didn't read the 10mm tube size. 8mm too much in any way shape
of form for that size of tube.

Scott

On Mon, 04 Mar 2013 21:02:16 +0000, Scott M wrote:

Roger Mills wrote:
On 04/03/2013 17:23, Scott M wrote:
Roger Mills wrote:

Is the post solid, or a square tube? Either way, an 8mm hole in a
10mm post doesn't leave much meat either side!

Caveat of "unless it's a decent thickness tube wall."

Not really. Even if it's solid, there's not much each side of the hole.

Mea culpa. Didn't read the 10mm tube size. 8mm too much in any way shape
of form for that size of tube.

Scott

Gah!
I blame the keyboard!!
There is a '0' missing there.

4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.

So thanks for the responses and let's try again :-(

Uck off big brackets to hold 2 * 5 timbers to support some plastic for a
car port.

I also expect to hang a pair of hinges off one of the posts, so the same
applies - through bolts or tapping for hex head bolt/screw (what is the
difference?).

Possibly different answer for the brackets and the hinges.

Cheers

Dave R

"David.WE.Roberts" wrote in message
...
On Mon, 04 Mar 2013 21:02:16 +0000, Scott M wrote:

Roger Mills wrote:
On 04/03/2013 17:23, Scott M wrote:
Roger Mills wrote:

Is the post solid, or a square tube? Either way, an 8mm hole in a
10mm post doesn't leave much meat either side!

Caveat of "unless it's a decent thickness tube wall."

Not really. Even if it's solid, there's not much each side of the hole.

Mea culpa. Didn't read the 10mm tube size. 8mm too much in any way shape
of form for that size of tube.

Scott

Gah!
I blame the keyboard!!
There is a '0' missing there.

4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.

So thanks for the responses and let's try again :-(

Uck off big brackets to hold 2 * 5 timbers to support some plastic for a
car port.

I also expect to hang a pair of hinges off one of the posts, so the
same applies - through bolts or tapping for hex head bolt/screw

The difference is basically the appearance and effort.

I personally prefer to weld the brackets onto the square steel post.

How viable tapping the post is depends on how thick the steel is.

(what is the difference?).

Hex head allows you to use a proper socket spanner on it.

Possibly different answer for the brackets and the hinges.

On Monday, March 4, 2013 11:19:59 PM UTC, Rod Speed wrote:
"David.WE.Roberts" wrote in message

...

On Mon, 04 Mar 2013 21:02:16 +0000, Scott M wrote:



Roger Mills wrote:

On 04/03/2013 17:23, Scott M wrote:

Roger Mills wrote:



Is the post solid, or a square tube? Either way, an 8mm hole in a

10mm post doesn't leave much meat either side!



Caveat of "unless it's a decent thickness tube wall."



Not really. Even if it's solid, there's not much each side of the hole.



Mea culpa. Didn't read the 10mm tube size. 8mm too much in any way shape

of form for that size of tube.



Scott



Gah!

I blame the keyboard!!

There is a '0' missing there.



4"/100mm square hollow powder coated steel post.

As others have noted a 10mm steel post isn't that substantial and putting

an M8 bolt through it would leave it very insubstantial.



So thanks for the responses and let's try again :-(



Uck off big brackets to hold 2 * 5 timbers to support some plastic for a

car port.



I also expect to hang a pair of hinges off one of the posts, so the

same applies - through bolts or tapping for hex head bolt/screw



The difference is basically the appearance and effort.



I personally prefer to weld the brackets onto the square steel post.



How viable tapping the post is depends on how thick the steel is.



(what is the difference?).



Hex head allows you to use a proper socket spanner on it.



Possibly different answer for the brackets and the hinges.

Personally I find tapping a real p.i.t.a. even when I can use a drill press (turning the chuck by hand naturally) to hold the tap vertical. If you have no experience of it then bolt through. At least then the load will be taken by two walls of the post rather than just one. If a heavy vertical load is being applied then the tapped hole will be less able to withstand twisting motion than a through bolt,

Just my tuppence worth

On Mar 4, 4:29*pm, "David.WE.Roberts" wrote:
I am about to have the builders fix some brackets to a 10mm square steel
post.

They are proposing to drill all the way through and have nut and bolt.

Fine for the intermediate posts but it might be neater for the end posts
to drill and tap and then just use a bolt.

So how straightforward is it to drill and tap a hole for say an M8 bolt?

Something to buy, something to hire, or something to avoid?

Cheers

Dave R

There are things available like a bog pop rivet but they are threaded
on the inside for just this purpose.

Or weld the fixing on.

On 04/03/2013 22:51, David.WE.Roberts wrote:

4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.

I would drill an 8 mm hole on one side and a bigger hole the other for a
length of steel tubing to make a spacer.
If you don't you may compress the tube and mangle the powder coating.

David.WE.Roberts wrote:

So thanks for the responses and let's try again :-(

snip

I go back to the advice of rivnuts! :-)

Also, if you want to bolt through, how about drilling through at 8mm and
then opening out the 'other' side to 20-odd mm to let you put the nut
inside the post with clearance for the 13mm socket[1]. The 20mm ish hole
can then be capped off with some form of cap/gromit.

Scott

[1] Assumes a 13mm socket will fit through. Adjust according to taste
and socket set.

On 04/03/2013 22:51, David.WE.Roberts wrote:


4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.


In case case, I agree with the person who suggested Rivnuts - see
http://www.rivet-nut.com/Rivnut_Fasteners.asp

They will give a firmer fixing than simply tapping a thread in the wall
of the tube.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Tue, 05 Mar 2013 19:58:15 +0000, Roger Mills wrote:

On 04/03/2013 22:51, David.WE.Roberts wrote:


4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.


In case case, I agree with the person who suggested Rivnuts - see
http://www.rivet-nut.com/Rivnut_Fasteners.asp

They will give a firmer fixing than simply tapping a thread in the wall
of the tube.

If the tube is, say, 2mm thick, then an M8 thread will give 1.6 threads and
that might not be enough to withstand the tension plus other loading.
--
Peter.
The gods will stay away
whilst religions hold sway

In message , PeterC
writes
On Tue, 05 Mar 2013 19:58:15 +0000, Roger Mills wrote:

On 04/03/2013 22:51, David.WE.Roberts wrote:


4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.


In case case, I agree with the person who suggested Rivnuts - see
http://www.rivet-nut.com/Rivnut_Fasteners.asp

They will give a firmer fixing than simply tapping a thread in the wall
of the tube.

If the tube is, say, 2mm thick, then an M8 thread will give 1.6 threads and
that might not be enough to withstand the tension plus other loading.

Takes 3 threads to give full strength or so we apprentices were told.

--
Tim Lamb

On Wed, 06 Mar 2013 07:39:14 +0000, PeterC wrote:

On Tue, 05 Mar 2013 19:58:15 +0000, Roger Mills wrote:

On 04/03/2013 22:51, David.WE.Roberts wrote:


4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and
putting an M8 bolt through it would leave it very insubstantial.


In case case, I agree with the person who suggested Rivnuts - see
http://www.rivet-nut.com/Rivnut_Fasteners.asp

They will give a firmer fixing than simply tapping a thread in the wall
of the tube.

If the tube is, say, 2mm thick, then an M8 thread will give 1.6 threads
and that might not be enough to withstand the tension plus other
loading.

Pretty sure it is more than 2mm thick - having picked the damn things up.

However advice upstream about the general difficulty has confirmed that we
bolt through.

Bought the bolts yesterday - although I didn't think I would have so much
trouble finding M10 140mm bolts.
Screwfix only do up to 120mm.

Mainly using 150mm M10 and will trim the end afterwards.

Cheers

Dave R

On Wed, 6 Mar 2013 07:56:08 +0000, Tim Lamb wrote:

In message , PeterC
writes
On Tue, 05 Mar 2013 19:58:15 +0000, Roger Mills wrote:

On 04/03/2013 22:51, David.WE.Roberts wrote:


4"/100mm square hollow powder coated steel post.
As others have noted a 10mm steel post isn't that substantial and putting
an M8 bolt through it would leave it very insubstantial.


In case case, I agree with the person who suggested Rivnuts - see
http://www.rivet-nut.com/Rivnut_Fasteners.asp

They will give a firmer fixing than simply tapping a thread in the wall
of the tube.

If the tube is, say, 2mm thick, then an M8 thread will give 1.6 threads and
that might not be enough to withstand the tension plus other loading.

Takes 3 threads to give full strength or so we apprentices were told.

Might depend on the quality of the material, so steel would be OK at that.
I've always tried for 1,125 diameters (as I was told) if possible,
especially for high torqe applications.
--
Peter.
The gods will stay away
whilst religions hold sway

On 05/03/2013 09:16, fred wrote:
On Monday, March 4, 2013 11:19:59 PM UTC, Rod Speed wrote:
"David.WE.Roberts" wrote in message

...

On Mon, 04 Mar 2013 21:02:16 +0000, Scott M wrote:



Roger Mills wrote:

On 04/03/2013 17:23, Scott M wrote:

Roger Mills wrote:



Is the post solid, or a square tube? Either way, an 8mm hole in a

10mm post doesn't leave much meat either side!



Caveat of "unless it's a decent thickness tube wall."



Not really. Even if it's solid, there's not much each side of the hole.



Mea culpa. Didn't read the 10mm tube size. 8mm too much in any way shape

of form for that size of tube.



Scott



Gah!

I blame the keyboard!!

There is a '0' missing there.



4"/100mm square hollow powder coated steel post.

As others have noted a 10mm steel post isn't that substantial and putting

an M8 bolt through it would leave it very insubstantial.



So thanks for the responses and let's try again :-(



Uck off big brackets to hold 2 * 5 timbers to support some plastic for a

car port.



I also expect to hang a pair of hinges off one of the posts, so the

same applies - through bolts or tapping for hex head bolt/screw



The difference is basically the appearance and effort.



I personally prefer to weld the brackets onto the square steel post.



How viable tapping the post is depends on how thick the steel is.



(what is the difference?).



Hex head allows you to use a proper socket spanner on it.



Possibly different answer for the brackets and the hinges.

Personally I find tapping a real p.i.t.a. even when I can use a drill press (turning the chuck by hand naturally) to hold the tap vertical. If you have no experience of it then bolt through. At least then the load will be taken by two walls of the post rather than just one. If a heavy vertical load is being applied then the tapped hole will be less able to withstand twisting motion than a through bolt,

Just my tuppence worth


Tapping has its place (use Trefolex!) but certainly agree that through
bolts is the way to go here. Rivnuts are great for fitting stuff inside
cars and vans where there is no way to get to the other side, but not
very substantial.

On 6 Mar 2013 08:02:38 GMT, "David.WE.Roberts"
wrote:


Bought the bolts yesterday - although I didn't think I would have so much
trouble finding M10 140mm bolts.
Screwfix only do up to 120mm.

So where did you get them from?

TIA

On Fri, 08 Mar 2013 11:49:24 +0000, Fred wrote:

On 6 Mar 2013 08:02:38 GMT, "David.WE.Roberts"
wrote:


Bought the bolts yesterday - although I didn't think I would have so
much trouble finding M10 140mm bolts.
Screwfix only do up to 120mm.

So where did you get them from?

TIA

http://www.suffolkfasteners.com/

Wonderful old fashioned firm with lots and lots of interesting nuts,
bolts, hinges etc. and not that expensive either.

They only had 4 * M10 140mm, but plenty of 130mm and 150mm.

I made up the numbers with the 150mm and will cut them back when my tuit
becomes round.

Also impulse bought some galvanised hinges for the gate I am eventually
going to make.

Cheers

Dave R