In this video I'm going to demonstrate some ways of removing rounded allen
head bolts. There are lots of variables when doing jobs like this but I'll cover
the techniques that I use regularly as they might prove useful. There are quite
a few different types of bolts that use an allen key or a hex key to undo them.
That is a counter sunk one, you then get button head,
and then a popular one is the cap head.
or the socket head. There are some basic things that you need to
do before you even attempt to remove a bolt using an allen key. The first thing
we need to do is clean out the head because there is a chance that there is some dirt
in there so it's good idea to get something like a small screwdriver and
just clean out the head before you even attempt to remove it using the allen key.
This is a massive problem with some countersunk bolts that we use at work
because they are in the floor and the dirt actually gets compacted in there so you do
have to ensure you give them a really good clean-out before you even attempt
to undo them. You always need to ensure that you use a good quality allen key.
This is a very cheap one, you often get these in packs with furniture and to
be honest they are not much good for anything other than assembling furniture.
So these really are like a disposable type of allen key I would not use them
for anything serious. An important thing is to get the correct type of allen key.
That is a metric bolt and that is a metric allen key and you'll see that
that fits in there perfectly. If you remove that and you try using an
imperial allen key that is the closest size to a 5 mm and you can see that
that is very loose. If you try to undo a bolt using that you will round it off
for sure. So you need to ensure that you get the correct type of allen key. If
you have Hex Plus bits like this there are definitely worth using because
there is much less chance of rounding the head off the bolt. For most of the
techniques in this video you are going to need a decent pair of safety glasses.
One thing that works very well is to shock the bolt you'd be surprised how
many tight bolts can be loosened simply by shocking them using a punch
and a hammer. Once you've shocked it there's every chance that that will
loosen the bolt. Another thing you can do is apply some heat to it or if possible
apply some heat to the surrounding area. Obviously this is not always possible
but if it is this can really loosen the bond. You never actually know if that has
been thread locked in if it has it will make it very difficult to remove it. If
you apply some heat to that there's every chance that it will loosen the
thread locker. Obviously you have to be careful when you do this you do not want
to be breathing in any of the fumes. If you're using burning gear and you get
that red-hot it is important to let it cool down before you try to undo it or
there's a chance that you will shear it off. See that now that's had a bit of
heat on it that is very easy to remove. You can also try some spray penetrant
if you spray that on there's a good chance that will loosen the
bond between the bolt and the surrounding material.
Some bolts are easier than others to remove for example socket head bolts like
these are normally very easy to remove unless of course they are counter board I
will cover that later on in the video. But if you ever get one of these thats
rounded off it's usually pretty easy to get out if you put the allen key in
there, then take a decent pair of mole grips, I've put the allen key in and that will
prevent the hole from being crushed because what happens is when you tighten
these up it tends to crush the head. So we need to get the mole grips on there nice
and tight once we've done that we can then undo the bolt.
You do have to be careful with some of these because you may think that they are
loose and there's every chance that you can actually snap the bolt. So with small
diameter bolts like that, it's a good idea to loosen it off, once it's loose
just back it off a bit and just ensure that it is completely loose
before you go any further. If you move it slightly and it tightens up spray it with
some spray penetrant move it back a bit and just keep moving it backwards
and forwards until it is completely free. You can remove counter sunk bolts by
chasing them out using the cold chisel and a hammer. It's critical that you
wear safety glasses when doing this. To do this you just need to hold the chisel
at an angle and then give it a good smack ensuring that the chisel bites
into the bolt. You also need to ensure that you knock it round in an
anti-clockwise direction to loosen it.
Obviously once you have chased that round a couple of times you can then get the pair
of mole grips on that, and we can simply remove the rest of it using the mole grips.
By far the easiest method is to weld on a nut. When you do this you do need to use
a nut that is plain you do not want to use a galvanized nut or a nut that has
been zinc plated.
Another option that you can use in some circumstances is to
use a left-handed drill bit. These actually work in reverse and there is a
chance that that will bite in there and actually extract the screw as it
bites. So I'm going to put that in the drill I'm going to ensure that we're
in reverse so we are drilling backwards and then I'm going to proceed
to drill this bolt. There is every chance that once it starts to bite it
actually extracts the screw. Sometimes this works sometimes it doesn't.
In this example the socket set bolt is counterbored and the head is stripped.
I'm going to drill the head off from the bolt. It has been shocked and you can
clearly see that the head is rounded you need to get a drill bit that is as close
as possible to the same size as the bolt head. I'm now drilling it off, this bolt is
stainless steel and so it is important not to let it work harden.
I'm now using some drilling fluid to keep the bit cool.
Once the head is removed we can lift the cap up to expose the bolt.
You will need a decent pair of mole grips or vise grip pliers. I'm getting the
grips as tight as possible on the bolt and I'm moving the bolt in both
directions.
The threads in this assembly are obviously damaged so you do not want
to apply too much force or the bolt will shear which is why I'm moving it in both
directions until it becomes free.
Once it's free we can remove the bolt obviously the hole will be re tapped
before it is used again. You can also try to use a screw extractor these are
useful in some circumstances but really if you are struggling getting it
out this should be the last resort. If you break this screw extractor in there
you a major problem trying to get that out. To drill out a bolt like this it
is very difficult because they are hard. We're going to use a cobalt drill bit if
that won't actually touch it you would have to use a solid carbide bit but they
are very expensive and very difficult to use. Obviously it's critical that you wear
safety glasses when you do this.
I'm now going to take the screw extractor I'm just going to tap it in
there gently. Ideally you'd use a tap wrench on the end of there, unfortunately mine
are both at work. So I'm just going to use an adjustable spanner and
I'm going to press in on this and then going to try and undo it in an
anti-clockwise direction.
As you can see that is extracting the bolt.
So they will work in some situations but they will not work in every single situation
especially if the bolt is rusted in. For small diameter bolts you could use a
GrabIt Pro these are made by Trend. Firstly we use that end to burnish
the bolt and then we use that end to extract it. These have got to be used in reverse.
So I'm now going to flip that over I'm going to apply some downward
pressure ensuring the drill is in reverse.
As you can see that has extracted the bolt. On small diameter bolts like this
you can sometimes use a center punch. This one is actually spring-loaded and
that is very useful in confined spaces where you can't hit the end with a
hammer. So this has actually been thread locked in there and that was
done yesterday it's actually been tightened so much that it's actually
rounded off the inside of the bolt.
So what we need to do with this to starts off with is to centre punch it
and you're better off doing that straight up like so, that will give us an
indentation in the bolt head.
So now we've got an indentation in there and I'm
going to turn the centre punch on an angle so that we can knock that around
in an anti-clockwise direction.
I did use quite a lot of thread locker on that
and it does look like the threadlocker is very tough stuff but we'll just give
that a few more goes,
and finally that is actually moving round we've actually
broken the bond between the thread locker and the bolt.
Once we've got that proud of the surface we can then grip that with the mole grips.
That's some of the techniques that you can use to remove rounded allen head bolts.
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