Tool to indicate where a drilled hole will exit?
 

Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side. In case I
haven't described that very well, you would have someone hold one half
of the tool at the point where you intend to drill, then you go round
the other side with the other part of the tool and move it around until
it indicates, by light or sound, the point where the drill is going to
exit. Anyone know what I'm talking about? Thanks

peter wrote:
Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side. In case I
haven't described that very well, you would have someone hold one half
of the tool at the point where you intend to drill, then you go round
the other side with the other part of the tool and move it around until
it indicates, by light or sound, the point where the drill is going to
exit. Anyone know what I'm talking about? Thanks

Magnet and compass?

--
Dave S
(The return email address is a dummy)

"peter" wrote in message
ups.com...
Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side. In case I
haven't described that very well, you would have someone hold one half
of the tool at the point where you intend to drill, then you go round
the other side with the other part of the tool and move it around until
it indicates, by light or sound, the point where the drill is going to
exit. Anyone know what I'm talking about? Thanks


Look in screwfix:
thruwall detector 15433
40 quid

mrcheerful

peter wrote:
Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side. In case I
haven't described that very well, you would have someone hold one half
of the tool at the point where you intend to drill, then you go round
the other side with the other part of the tool and move it around until
it indicates, by light or sound, the point where the drill is going to
exit. Anyone know what I'm talking about? Thanks

screwfix sell a thruwall locator
p/n 15433-76, page 499
sorry don't know how to munge their URLs

Thanks all, the Screwfix one is exactly what I had in mind, I did look
there but didn't use the right search terms.
Does anyone have any experience with these, in particular how accurate
an indication it would give through a GRP boat hull?

peter wrote:
Thanks all, the Screwfix one is exactly what I had in mind, I did look
there but didn't use the right search terms.
Does anyone have any experience with these, in particular how accurate
an indication it would give through a GRP boat hull?


I wasn't meaning to be flippant when I suggested a magnet and a compass,
this should be all you need for a GRP boat hull and you've probably got
them both in the house somewhere. However, I can understand the desire
to buy a new gadget and this is a good excuse :-)

--
Dave S
(The return email address is a dummy)

"peter" wrote in message
oups.com...
Thanks all, the Screwfix one is exactly what I had in mind, I did look
there but didn't use the right search terms.
Does anyone have any experience with these, in particular how accurate
an indication it would give through a GRP boat hull?


I had a fight to locate it in the screwfix catalogue or the website !!

I haven't used one, but I expect the accuracy gets better as the material
gets thinner, so it should be great on GRP.
Some hulls transmit light so you might be able to see a good spotlight on
the other side, particularly at night.

mrcheerful

"mrcheerful ." wrote in message
k...

"peter" wrote in message
oups.com...
Thanks all, the Screwfix one is exactly what I had in mind, I did look
there but didn't use the right search terms.
Does anyone have any experience with these, in particular how accurate
an indication it would give through a GRP boat hull?


I had a fight to locate it in the screwfix catalogue or the website !!

I haven't used one, but I expect the accuracy gets better as the material
gets thinner, so it should be great on GRP.
Some hulls transmit light so you might be able to see a good spotlight on
the other side, particularly at night.

Yep! ... My wife was horrified when she opened a small
cubby hole in the boat and discerned the sun through
the hull! Unless the pigment is black, the resin should
be quite translucent.

--

Brian

Brian Sharrock wrote:

Yep! ... My wife was horrified when she opened a small
cubby hole in the boat and discerned the sun through
the hull! Unless the pigment is black, the resin should
be quite translucent.

yes, that's fine for the topsides, but below the waterline (where you
tend to drill holes for water intakes!) sunlight is not going to
penetrate the antifouling. Also, the lay-up is heavier nearer the keel.

On 7 Jan 2005 04:06:57 -0800, "peter" wrote:

an indication it would give through a GRP boat hull?

White LED torch
--
Smert' spamionam

Brian Sharrock wrote:
Some hulls transmit light so you might be able to see a good spotlight on
the other side, particularly at night.

Yep! ... My wife was horrified when she opened a small cubby hole in
the boat and discerned the sun through the hull! Unless the pigment is
black, the resin should be quite translucent.

You might get away with a laser pointer, then, or even a little white
LED torch.


--
Ian White
Abingdon, England

"peter" wrote in message
ups.com...
Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side. In case I
haven't described that very well, you would have someone hold one half
of the tool at the point where you intend to drill, then you go round
the other side with the other part of the tool and move it around until
it indicates, by light or sound, the point where the drill is going to
exit. Anyone know what I'm talking about? Thanks

Yes, the Thruwall Locator does exactly that, £37.95 from Mills
(www.millsltd.com) part no C00-7951.

You use Blu-tak to stick the transmitter to the point where you intend to
drill and move the locator up and down and sideways on the other side to
pin-point where the drill will come out. Of course you'll still need a cable
and pipe detector to make sure there's no surpises in store before you
drill.

"peter" wrote in message
ups.com...
Maybe I dreamed this, but I'm sure I remember seeing advertised a
gadget in two parts which you could place either side of a surface to
show you where a drilled hole will exit on the blind side.


Put a 1/8th drill bit in a drill ... drill hole through material .... go to
other side ... where drill is sticking through is where the hole will exit
:-)

Rick Hughes wrote:

Put a 1/8th drill bit in a drill ... drill hole through material ....
go to
other side ... where drill is sticking through is where the hole will
exit
:-)

And if the drill is sticking through a fuel line you just wrap some
tape around it and drill somewhere else I suppose.

"peter" wrote in message
ups.com...
Rick Hughes wrote:

Put a 1/8th drill bit in a drill ... drill hole through material ....
go to
other side ... where drill is sticking through is where the hole will
exit
:-)

And if the drill is sticking through a fuel line you just wrap some
tape around it and drill somewhere else I suppose.


No the lighted match you use to look for thr hole will take care of that