Quick question concerning the required length of coach bolts... I'm
going to build a deck using 100mm support posts with 47mm joist
connected with coach bolts. Question is should I use 150mm coach bolts
or longer? Is the 3mm left over ample to tighten the coach bolt?

Sorry if it seems obvious to some just never used coach bolts before.

On 6 Sep 2005 14:57:22 -0700, "leighton_castle@hotmail.com"
 wrote:


>Quick question concerning the required length of coach bolts... I'm
>going to build a deck using 100mm support posts with 47mm joist
>connected with coach bolts. Question is should I use 150mm coach bolts
>or longer? Is the 3mm left over ample to tighten the coach bolt?
>

By the time you add a washer under the nut there'll be a bit less bolt
available :-)

Are the post & joist dimensions you quote actual or nominal?

I would rather have a bit of bolt protruding from the nut.

-- 
Frank Erskine

The dimensions are off the order form so nominal... I was thinking the
same thing about the protruding bolt

The message 
from "leighton_castle@hotmail.com" 
contains these words:


> Quick question concerning the required length of coach bolts... I'm
> going to build a deck using 100mm support posts with 47mm joist
> connected with coach bolts. Question is should I use 150mm coach bolts
> or longer? Is the 3mm left over ample to tighten the coach bolt?

> Sorry if it seems obvious to some just never used coach bolts before.


Even without a washer (you are using washers?) 3 mm seems a little
inadequate. 

What you need to avoid is an unthreaded shaft length in excess of the
thickness to be clamped but if the numbers don't add up you can get
coach bolts that have a fully threaded shaft. I would have it that these
are technically screws rather than bolts but don't blame me if the
vendor doesn't appreciate the difference.

-- 
Roger the Bodger

Roger  wrote:

> The message 
> from "leighton_castle@hotmail.com" 
> contains these words:
> 
>> Quick question concerning the required length of coach bolts... I'm
>> going to build a deck using 100mm support posts with 47mm joist
>> connected with coach bolts. Question is should I use 150mm coach bolts
>> or longer? Is the 3mm left over ample to tighten the coach bolt?
> 
>> Sorry if it seems obvious to some just never used coach bolts before.
> 
> Even without a washer (you are using washers?) 3 mm seems a little
> inadequate. 


However, you can recess the coach bolts into the wood, and even plug on
top of them with cut out circles when you've finished.
Just leave enough room for the appropriate socket for the nut to go over it.

leighton_castle@hotmail.com wrote:

> Quick question concerning the required length of coach bolts... I'm
> going to build a deck using 100mm support posts with 47mm joist
> connected with coach bolts. Question is should I use 150mm coach bolts
> or longer? Is the 3mm left over ample to tighten the coach bolt?


Counterbore the post to a depth of 1/2". If you want to be able
to dismantle this structure easily, grease (or dip in Waxoyl)
the bolts before fitting - they tend to rust in solid.