Van'S Aircraft Bolt Size Chart

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VAN'S AIRCRAFT, INC.
Pivot Bolt Installation
areas where clear visibility is important, as the process will
When the bolt is rotated for final torque the chart values must
usually result in some degree of optical distortion.
be modified. When applying torque to a bolt be sure to have a
Pivot bolts are bolts serving as axes of rotation for other parts,
washer under the bolt head and lubricate the bolt shank. Add to
such as attachment of cable clevises to rudder control horns
Canopy Protection and Ventilation
the overall torque value the torque required to overcome the
and rudder cable links. These parts must rotate freely about the
Practice drilling holes in scrap pieces until you are familiar and
If the aircraft is tied down outdoors and subject to weather
friction associated with turning the shank of the bolt within the
pivot bolt. When installing, lubricate pivot bolt with wheel
confident with the process. It is important to remember that heat
elements for any length of time, then the use of an aircraft
assembly.
bearing grease and tighten only enough to prevent slop in the
from the machining and drilling processes may change the
canopy cover is highly recommended. The cover will protect
system. The bolt should still turn by hand when properly
acrylic characteristics some to allow some of the approved
canopies and windows from abrasive dust, dirt, and sand kicked
When tightening fasteners with self-locking nuts the chart
tightened and safetied. Do not use standard torque on these
products to affect the material. This is an important reason to
up by wind or prop wash. Before purchasing, verify that the
values must be modified. Due to the friction of the locking
fasteners! This does not apply to rod end bearing attach bolts
cut slowly and avoid overheating the acrylic material.
canopy cover is NOT waterproof as the trapped moisture and
device noticeable torque is required just to turn the nut onto the
because in that case the bearing is the pivot or axis of rotation
heat from the sun can be deleterious. Acrylic subjected to this
threads and does nothing to actually tighten the parts together
and its attaching bolt does not rotate.
Use of a step-drill (Unibit) or reamer is recommended for hole
treatment over a period of time may turn slightly milky and
and stretch the bolt (clamp load). This is called friction drag (or
enlargement.
eventually crazes.
prevailing) torque. The friction drag torque must be determined
and then added to the standard torque from the table. Run the
CAUTION: Do not use a regular twist drill as they have tips that
Keep your canopy ventilated or covered when your aircraft is
nut down to where it nearly contacts the washer or bearing
tend to fracture the acrylic. Using a regular twist or plexi drill to
parked in the hot sun. Cabin temperatures can easily reach
surface and check the friction drag torque required to turn the
enlarge a pre-drilled hole is not recommended and will almost
150-200 degrees F even on a mild day. The acrylic can
guarantee to crack a canopy.
generally take these temperature conditions multiple times
nut. (At least one thread should protrude from the nut). Add the
without any apparent adverse effect. It is the cumulative affect
friction drag torque to the standard torque. This sum is referred
Fiberglass Bonding, Cracks, Etc.
that will cause shortened service life of your canopy. The use of
to as the final (or total) torque, which should register on the
Be certain to use ONLY epoxy resins. Do not use the more
a Van's Aircraft Canopy Cover will significantly reduce the
indicator or setting for a snap-over type torque wrench.
common polyester or vinyl ester resins. They are not
internal temperatures inside your aircraft to just a few degrees
compatible with Plexiglas and cause crazing that will ruin the
above outside ambient temperatures. Additionally it will also
As an example illustrating the importance of determining the
canopy. We have had excellent luck with West Systems Epoxy
protect your expensive avionics from heat and your
friction drag torque consider new AN3 bolts and MS21042-3 all
products, available from boat yards and mail order houses.
upholstery/seat belt harnesses from harmful UV rays.
metal lock nuts. Testing showed the friction drag torque at 14
in-lbs. The standard torque for this nut/bolt combination is
Cracks… Seriously avoid jeopardizing or cracking the canopy
In winter conditions, ensure that the cabin and canopy is
20-25 in-lbs. Let's say we choose 20 in-lbs. This results in a
at all costs. If the worst does occur and you develop a crack,
warmed adequately prior to flight if possible. A heat lamp or
final torque setting on our wrench of 14 plus 20 or 34 in-lbs.
they may sometimes be fixed using a solvent adhesive such as
small, low output ceramic space heater can raise the cabin
Though we exceeded the 25 in-lb value listed in the table by
Plasti-Fix or Weld-On 3. Stop-drilling the crack is typically
temperature to warm the acrylic, keeping it free from ice or
using a final torque of 34 in-lbs we are still well within the
required to keep it from running.
snow. It will also be less prone to cracking.
capability of the nut. (Incidentally this nut must meet a
CAUTION: Do not use Polyester resin of any type, as it will
5V NUT AND BOLT TORQUES
maximum torque test value of 60 in-lbs per the military standard
cause crazing.
spec sheet.) Now what if we completely ignore the friction drag
The importance of correct torque application cannot be
torque and set our wrench to just 20 in-lbs? Recall that it
Cleaning And Use Of Liquids
overemphasized. Under-torque can result in unnecessary wear
requires about 14 in-lbs (friction drag torque) just to turn the nut.
For general cleaning use dishwashing liquid and water followed
of nuts and bolts, as well as the parts they secure. Over-torque
We subtract 14 from 20 and arrive at only 6 in-lbs of
by a clear water rinse. To prevent water spots, blow dry with
can cause failure of a bolt or nut from over - stressing the
torque(torque being the measurement of friction, not tension)
compressed air or wipe dry with soft cotton flannel. Plexus,
threaded areas. Uneven or additional loads that are applied to
applied to induce preload (clamp load) in the bolt. Not a
Sprayaway #848 Industrial Plastic Cleaner, or All Clear can also
the assembly may result in wear or premature failure. The
satisfactory result.
be used for day to day cleaning. Grease, oil, tape residue, etc.
following are a few simple, but important procedures, that
may best be removed with mineral spirits, refined kerosene,
should be followed to ensure that correct torque is applied.
(Portions of this information has been adapted from AC 43.13-1B Section 7-40.)
white gasoline, naphtha, or isopropyl alcohol. Wash approved
solvents off of canopy with dishwashing liquid and water. It is
Be sure that the torque applied is for the size of the bolt
best to avoid using products that are not specifically formulated
shank not the wrench size.
for acrylics on your canopy such as Rain-X or furniture polish.
Use the standard torque table provided as a guide for tightening
CAUTION: Do not use Loctite, aromatic solvents, acetone,
nuts, bolts and screws whenever specific torque values are not
Bolt Size-
Standard Nuts
benzene, ethyl acetate, carbon tetrachloride, lighter fluid,
provided in the builders manual. These values are for clean and
AN Bolt Size
Threads Per Inch
AN310, AN315, AN365
lacquer thinners, gasoline, toluene, window sprays,
dry threads. Note that on the smaller bolts the torque is quite
concentrated alcohols, keytones, scouring compounds, or
low and is in inch pounds. Do not try and use a foot pound
INCH POUNDS
FOOT POUNDS
ammonia products on or around acrylic or Lexan canopy
torque wrench on these bolts. Use a torque wrench calibrated in
AN3
#10-32
20-25
1.6-2.0
materials.
inch pounds. The propeller manufacturer and the engine
AN4
1/4-28
50-70
4.2-5.8
manufacturer have specific torque requirements for their
CAUTION: Do not allow electrical tape or auto fuel to come into
equipment. Consult the appropriate manual for that information.
AN5
5/16-24
100-140
8.3-11.6
contact with Lexan as it will also cause crazing. This is a
Apply a smooth even pull when applying torque pressure. When
AN6
3/8-24
160-190
13.3-15.8
particular issue to beware of when refueling the RV-12.
using the 1/4 in. drive snap-over type torque wrench we
AN7
7/16-20
450-500
37.5-41.7
recommend practicing with it off the aircraft first until you get the
Scratch Removal
feel of the snap-over since it can be rather light depending on
AN8
1/2-20
480-690
40.0-57.5
Small scratches can be buffed out with Meguiar's Mirror Glaze
the size of the fastener.
AN9
9/16-18
800-1000
66.6-83.3
#17. For deep scratch removal, use Scratch Off , Micro Mesh,
AN10
5/8-18
1100-1500
91.6-125.0
or 3M Window Repair kits. Avoid removing scratches in critical
Apply the torque to the nut and not the bolt whenever possible.
This will reduce rotation of the bolt in the hole and reduce wear.
05-10
RV-12
4
10/01/12
PAGE
PAGE
REVISION:
REVISION:
DATE:
DATE:

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