BORESCOPES - More than meets the eye - Part 2

This 3 part series is reprinted with the kind
permission of
Safe & Vault Technology
Magazine
3003 Live Oak Street
Dallas, Texas 75204
(214) 827-SAFE (7233)
FAX (214) 827-1810
http://www.savta.org/
and the author Ken Doyle, owner
Advanced Safe & Vault
Engineering
http://www.advancedsafe.com
Ok, boys and girls, this month I'll be
talking about illumination,
light
sources, and flexible borescopes(also
known as fiberscopes); and their uses,
importance, features, advantages and
disadvantages.
light. Daylight is what we use to "normally" view things. If you're like me,
and have limited color perception (a lot
of men do), you go around everyday
misjudging colors viewed under a variety of artificial lights. The more naturallooking the light, the better you can disIllumination
tinguish gradations in color, hue, conGood illumination plays a key role in trast and texture.
the sucessful use of borescopes.Very
Colors definitely look different when
little illumination may be required to observed with different kinds of light.
look into the interior of a lock case This is why quality camcordersand prothrough a small, shallow, accurately fes-sional video systems usually have
placedhole that hasbeendrilled into the some sort of white balance system to
front of a safe door. Illumination
compensate for dif-ferences in color
becomesmuch more critical when we temperature.
are unfamiliar with the lock or containWhen looking at structures on the
er, or if the causeof the lockout involves inside of a container, through a small
remotely placed locks or relockers. hole, we needall the help we can get to
Another situation where it would be identify compon-ents. Remember, we
advantageousto havelots of light would only get to use one of our senseswhen
be if you were dealing with internal looking through a borescope.The strucmalfunctions of an unknown nature in tures on the inside can be painted,made
large containersor vaults.
of different materials, and will certainThe more "high quality" light, the bet- ly be difficult to seeeven under the best
ter, in these situations. A good quality, of circumstances.Any augmentationto
high-output lightsource and lightguide our senseof sight might make the difis- desirable. I use "high quality" to ference between a smooth, profitable
describelight that is the closestto day- opening and the proverbial "opening
from hell."
Light sources
Tungsten-halogenand quartz-halogen
light sourceswith output rangesof 30 to
150 watts are readily available from a
variety of sources.New, they range in
price from $200-$600. The most common are the ISO-watt halogen variety,
but I've seen them with outputs up to
300 watts. The difference between
quartz and tungsten is mainly one of
color temperature. Tungsten-halogen
tends to produce a much whiter light.
Whiter light provides better illumination and more accuratecolors.
The lamps that are used in both these
types of units are similar to those used
in movie projectors.They are very fragile and expensive.Touching the tube of
the lamp with your hand (resulting in
the deposit of debris and body oils) c;:an
reduce its useful life. Handle lamps by
the ends when installing or replacing
them. Clean lamp fixtures gently and
regularly to remove corrosion and other
deposits.Always keep a sparelamp on
hand.
,.
The intensity of the transmitted light
Julv 2000
PaQe21
in these light sourcesis controlled by
one of two different ways.The first is by
use of a simple rheostat (usually used
with quartz-halogen lamps), and the
second (used predom-inantly for tungsten-halogen) uses a mechanical iris
system similar to that which controls
incoming light to the human eye or to a
video camera'sCCD via the lens assembly. A rheostat changesthe color temperatureof the light throughoutits range
of intensity.An iris doesn't. Lamp life is
also greatly increasedwhen usedin conjunction with the iris type mechanisms,
because the heat up and cool down
cycles that occur with rheostatsdrastically effect filament life. Both types
require a fan to keep the interior of the
light source cool. If they are of good
quality, they also provide some sort of
thermal and circuit overload protection.
A very common quartz-halogenlight
source (made by Chiu Technical
Industries)is sold under a variety of different brand names.I've seenthe price
for this unit vary as much as $200.00,
dependingon whosebrand namewas on
its case. High-output light sources are
also available for resalein the used and
military surplus market, in good to
excellent and even new condition,
priced at 30-60 percentoff their original
cost. Thereis, however,a lot of junk out
there, so the classic marketplace rules
will apply.
end of the light
guide is attachedto I
a port usual-ly
located in the front
panel of the lightsource. The other
end
is
then
attached to the
lightguide
input
port of the scope
head. It is a flexible tube of varying
diameters, with
fiber-optic material
inside.
Light guides are
commonly avail- .
-
--.-:E...
CROSSSEctION Of' fLUUL6
Safec&Vault
FIBUOPTIC 'KOBE
obvious from talking to many techs at
trade shows and in classes, that the
value of this type of borescopeis not
fully appreciated.I think this is because
they are very expen-sive (when purchasednew) and also becausethe technology is not exactly commonplacein
our industry. It's hard to justify purchasingequipmentthat you don't understandand don't appreciate.
I fIrst learnedto appreciatethis when I
found I was able to utilize existing
openingsin depository safesinstead of
drilling. Scoping change key holes
through mounting holes, drop slots or
rotary hoppersbecamea routine way of
opening these containers without
drilling and repairing. I've also been
able to read and decodekeys that were
accidentally dropped into drop slots,
and easily fit a new key for an obsolete
keylock. No drilling! This is a good
thing, isn't it?
I chargethe samefor these openings,
as I do for the more back-breakingvariety. I don't feel like I haveto appologize
for not working up a sweat. I'm using
available technology that I have invested in. The customerbenefits by getting
the same res-ult with much less mess
and disruption to their routine, and also
gets a container that is returned to service much faster.
Flexible Scopes
Later on, I startedfinding lots of uses
Flexible probe
for
flexible scopesthat wouldn't have
borescopes may
occurred
to me until I had this technolobe one of the least
gy
in
my
bag of tricks.
understood pieces
Shops
in
Europe (especiallytho~ that
of equipment in
do
a
lot
of
work on high security conour industry. It's
able in lengths of 6-8 feet, three different diameters (6-13 rom), and two different types.The first type usesa a large
glass fiberoptic bundle. The secondis a
tube filled with a special liquid that has
fiberotic properties. (See Illustration.)
The liquid type carries light more efficiently, is less prone to yellowing over
time, and is less susceptibleto damage
(from being over-stressedor steppedon)
that would inhibit its light carrying ability. They are more expensive,but in my
opinion they are worth the extra cost.
At either end of the light guide are terminators that allow firm attachmentto
the lightsource and scope,respectively.
Adapters are sometimes required on
either end to connect the light guide to
dif-ferent brands of light sources and
scopes.The most common type of conLight guides
A fiberoptic light guide (some-times nector used in the industry is "ACMI."
called a light cable) is usedto carry the Adaptors are usually provided (either as
light from the sourceto the scope.One part of a kit or as an optional accessory)
by the various
light-source, lightguide and scope
I manufacturers, to
adapt their equipment to other
maker's
equipment.
Page22
~~
or lessis not uncommon.With the inclusion of tip articulation, you can seethat
this can be very useful in a lot of situations.
tainers)use this technology all the time.
They have learned that buying and
maintaining the proper equip-mentto do
thejob is essential,and that the costsare
defrayed the sameas they are with any
other equipmentpurchase.They bite the
bullet, purchasethe neededequipment
and reap the benefits of its use. The
prices for openings that they perform
reflect the investment in tools, equipment, training and skills aquisition and
(hopefully) profit as well as actualhours
spent on .the job. That is the way it
should be.
Now that we have a greaterapp-reciation of the value of flex-ible scopes,
let's discusswhat they are and how they
work. Flexible probeborescopescontain
speciallenseson either end of a bundle
of tiny optical fibers which relay the
image from the tip of the probe back to
the eyepiece.
Depending on the diameter of the
probe and the thickness of the fibers,
there may be several hun-dred fibers
packed into the shaft. Each fiber carrys
a different seg-mentof the image.
The "pixelized" resolution of flexible
scopesdependson the quantity, quality
and diameterof the fibers that are used.
Some of these scopes,from the better
brands, can approach the resolu-tion
found in rigid scopesthat useglassrelay
lens systems.
As with the rigid borescopes,in addition to the fibers that convey the image,
there are additional fiberoptics that
carry the light from the light source to
the probe tip. Thesefiber optic bundles
are also what allow a certain degreeof
flexibility to the shaft.
How much flexibility is inherent in
the probe?The actualbendradius varies
dependingon the type of construction,
sheathingmaterial, brand, and price of
the scope.Two to 6 inches bend radius
Articulation
Flexible scopesmay also contain a set
of lever controls in the head which are
connectedto thin cablesthat run within
the length of the probe. These cables
connectto and control movementof the
tip so that you can easily guide the
scopepast obstructionsand also so that
it is possibleto view objects to the side
and even to the rear without incorporating a prism or mirror to change the
direction of view.
This is called an articulating tip (see
photo). Four way articu-Iation (very
desirable)allows movementof the tip in
four directions (up, down, right and
left).
With the addition Qf an assortmentof
guide tubes,flexible scopescan be used
in much the same manner as rigid
borescopes and also in ways rigid
scopescouldn't possibly be used.Guide
tubes are nothing more that thin-walled
tubing with an inner diameter slightly
larger than the outer diameter of the
probe. With the proper bending equipment, they can be bent smoothly into
any needed shape to facilitate guiding
the probe to the target and then holding
it there. These can be made up in
advanceor fashionedon-site to whatever shapeis required.
Although much more resistantto damage than rigid borescopes,extreme or
repeatedflexion of the probe (especially beyond the recommended bend
July 2000
Page23
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Page24
-
Safe& Vault
radius)
can
typesdescribed
result in broken
above,
frefibers. These
I quent-ly come
broken fibers
up for sale on
do not relay
the milit-ary
that particular
surplus market.
segmentof the
Brand
name
image.
This
flexibles
shows up as
including
very tiny black
Olympus,
dots in the
Schott, Wolf
viewed image
andLennoxare
View of a CKH through a flexible borescope with less than 15% broken fibers
available at less
(See photo).
. than half their
With
proper.
care, main-tenoriginal cost.
ance, and storage, these scopes can These scopesusually come on the surprovide years of useful and profplus market due to facility closures,puritable service.
chasing errors, excess stock and
changesin military specific-ations.The
Used and surplus flexibles
largest user of these types of scopesis
Although the small defects,men- the U.S. Air Force. They are routinely
tioned earlier, may be cause for usedfor disassembly-freeinspectionsof
replacementof borescopesusedfor aircraft air framt?,~,power plants and
critical medical and mechan-ical other critical systems.
inspection purposes,a few broken
A lot of these scopes have a probe
fibers here and there are not too diameter of half an inch or more.
significant when viewing the interi- Obviously, drilling a 5/S-inch hole in a
or of a safeor lock. Medical scopes TL-30X6 is going to be more work than
which have lost the ability to be is desired. Try to locate used scopes
sucessfully sterilized (due to dam- with small probe diameters (less than
age to the outer sheath), but still 5/l6-inch) to minimize the neccessity
retain their optical and mechanical for drilting larger holes in tough materiattributes,are an alternative source als. Guesswhat! Quality flexibles with
of barg-ain flexible scopes.
probe diameters of less than 5/16-inch
This is why usedborescopesthat tend to be the most expensive.
are no longer suitable for use in
If you had to aquire a brand new one
these fields make an excellent from a regular dealer, you'd pay
choice for the lock-smith or between six and ten thou-sanddollars.
safetechon a budget.Theseflawed The surplus Olympus I purchased
but perfectly serv-iceable scopes recently was only $695.00.
are routinely sold for only a small
In part 3 of this article series,I will be
fraction of their original cost. On talking about accessories,adjuncts and
the other hand, unrepairablefocus- video systemsthat are used in conjuncing difficult-ies, an excessivenum- tion with both rigid and flexible scopes.
ber of broken fibers (>15 percent), These optional items are designed to
or an excessiveamount of yellow- overcomecertain physical problemsand
ing (due to fiber age), may be a limitations that are encounteredin the
very good reason to pass on what field when using any scopesystem,and
otherwise looks like a "bargain" also to maximize operator comfort.
scope. These repairs may out- Othersenableremote viewing or modiweigh any cost advanatagein buy- fy and enhancethe image quality. .
ing "used". It may not be possible
to repair certain types of damageat
About the Author: Ken Doyle lives in San
all. The problem is what is Francisco, California. He is an establishedwriter
for S&V1:
.
repairable,and what isn't?
Brand new flexible scopesof the
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