this is a through bolt and it's extremely useful when you fasten into
any masonry surface especially concrete you've probably seen these
stick out of the ground at some point and they are very useful through bolts
like this work of expansion so it's essential that you drill the correct
size hole then if you look just the end you should see that it says m12
so that means that we have to use an m12 drill for drilling our hole so we're going
to fasten this piece of wood to a concrete garage base just to demonstrate
how to use the thru bolts you can actually use these for fixing a ledger
to a solid brick wall or to a stone wall and they have thousands of uses these
bolts are very common and they use quite a lot in industry and they can be used
for fixing machines down or fixing barriers down as long as you've got a
nice piece of concrete to fix into obviously before you drill into the
concrete you need to check to make sure there's nothing buried in the concrete
one thing you can do with these is use them for close to the edge fixing so you
can use them at the edge of a piece of concrete because the actual end bit
expands there if you try to use them at the end they're just going to break the
actual concrete the most important thing when you're using two bolts is to drill
a holel the correct diameter and the correct depth a lot of people just will
do large will depth which isn't deep enough because what may happen is you
may have come along and think about I don't want that bolting down there
anymore so you come along and you remove it so you end up with a stud sticking
out of the ground so that means you've ever got a going at an angle grinder and
cut it off or you've got to chisel it out so the best option is to drill the
all the full length of the thru bolts plus about an inch and then if you do
come along at a later date and realise you don't want it there anymore all you
have to do is undo it take off what it is holding and knock it down with a hammer
and that will go below the surface of the concrete and that way you are guaranteed
that nobody's ever going to trip over it so I've got me drill bit which is an m12
and I'm just going to mark on the drill I'll deep I need to go so we're going to
drill it about that depth so I would know about the
piece of wood where we want it and I've got me SDS drill and this drill bit is a
little bit long for this but it doesn't really matter it will still work so now
we're just going to drill a hole into the concrete
so you can see that we drilled that hole deep enough so now we'll just need to
remove the concrete dust
so I also need to do is align the workpiece off the hole that we just made
put the thru bolt in and tap it down
then once you've got it down so far all you need to do is tighten it up using a spanner and that
is now perfectly tight I can even hit it and it's not going to go anywhere so that's how you use a
true bolt for fixing to concrete but if you decide a few months down the line
you don't actually want it there anymore all you need to do is undo it take the
nut off take your piece off and all you need to do is hammer that down nobody is ever
going to trip over that and why you can do is knock it down below the surface
and then just fill it in with a bit of concrete repair mortar and nobody will
ever know that the hole is even there