Quick question for the group. When setting the torque on prop bolts (I
have bolts with nuts), if the hole for the cotter pin doesn't line up
with the castleated nut at the proper torque setting, is it better to go
tighter or looser to get the hole lined up. My gut instinct says
tighter, but....

Scott

Scott wrote:
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott
>
Try various thicknesses of washers. Jerry

--
"jerry wass" > wrote in message
. ..
> Scott wrote:
>> Quick question for the group. When setting the torque on prop bolts (I
>> have bolts with nuts), if the hole for the cotter pin doesn't line up
>> with the castleated nut at the proper torque setting, is it better to go
>> tighter or looser to get the hole lined up. My gut instinct says
>> tighter, but....
>>
>> Scott
>>
> Try various thicknesses of washers. Jerry

Also shuffle the nuts around. the threads do not all start in the same
place relative the slots in the
castlleations.

Scott

If you have a metal mini lathe, you can shave a little off the nuts to
get them to line up exactly with the cotter pin.
================================
SQ2000 canard http://www.abri.com/sq2000

Scott wrote:
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott

I heard somewhere (from a "knowledgeable source"; probably at the bar
somewhere) that it is acceptable to go to the next castellation to get the
hole lined up and to never loosen. One place to check is with the pros.
There is an engineering forum called www.eng-tips.com that has a forum on
fasteners where discussions of details about fasteners will give you a brand
new appreciation for these little thingies that we take for granted.

--
Stuart Fields
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478
(760) 408-9747 general and layout cell
(760) 608-1299 technical and advertising cell

www.vkss.com
www.experimentalhelo.com


"Scott" > wrote in message
.. .
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott
>

"Stuart & Kathryn Fields" > wrote in message
...
>I heard somewhere (from a "knowledgeable source"; probably at the bar
> somewhere) that it is acceptable to go to the next castellation to get the
> hole lined up and to never loosen. One place to check is with the pros.
> There is an engineering forum called www.eng-tips.com that has a forum on
> fasteners where discussions of details about fasteners will give you a
> brand
> new appreciation for these little thingies that we take for granted.
>
> --
> Stuart Fields
> Experimental Helo magazine
> P. O. Box 1585
> Inyokern, CA 93527


I'd stick with changing washers, bolts, or nuts to achieve the spec'd torque
value. Torque limits are defined for a reason.

KB

Why are you using castlelated nuts? Does the airframe or prop
manufactuer require their use?

Diamond aircraft uses fiberlock nuts on the DA-20 C1 which uses a wood
prop on the IO-240 engine.

My glider club uses fiberlock nuts on the Hoffman 4 bladed wood prop of
a PA-25 Pawnee 250 used for towing gliders.

Both these aircraft are type certificated, if fiberlock are good enough
for them.....

If you check the torque on a regular basis as all wood prop
manufactuers I know of require than you whill have no problems with
loose bolts.

Robert Mudd
Moriarty, NM
A&P I.A.



Scott wrote:
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott

pbc76049 wrote:

Hey, never thot of swappin nuts--thanx

"Kyle Boatright" > wrote

> I'd stick with changing washers, bolts, or nuts to achieve the spec'd
torque
> value. Torque limits are defined for a reason.

I am absolutely against absolute statements. <g>

I would have to say a little commons sense has to apply, here.

If the specified torque is 75 foot pounds, and it would line up if you went
to 76 foot pounds, go for it. Your torque wrench could be out of spec that
much, and it would still be legal.
--
Jim in NC

Scott wrote:
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott


>From chapter 7 of the AC 43.13-1B


"f. When installing a castle nut, start
alignment with the cotter pin hole at the minimum
recommended torque plus friction drag
torque.

NOTE: Do not exceed the maximum
torque plus the friction drag. If the
hole and nut castellation do not align,
change washer or nut and try again.
Exceeding the maximum recommended
torque is not recommended."

This is also what I remember from school.

Jesse M.
PP-ASEL
A&P

Scott wrote:
> Quick question for the group. When setting the torque on prop bolts (I
> have bolts with nuts), if the hole for the cotter pin doesn't line up
> with the castleated nut at the proper torque setting, is it better to go
> tighter or looser to get the hole lined up. My gut instinct says
> tighter, but....
>
> Scott
Use a pair of Belleville washers rated for about 2000 lb under each
bolt head, installed with their conacave sides facing each other. See
if you can get to the recently-deceased Vance Jaqua's web site, and see
his write-up on the Belleville use.

I have a metal prop on a tapered crank and as far as I know, there is no
requirement to check the torque periodically. The washer fix sounds
reasonable. Now, is there a limit of one washer or is two or three
acceptable?

Scott



wrote:
> Why are you using castlelated nuts? Does the airframe or prop
> manufactuer require their use?
>
> Diamond aircraft uses fiberlock nuts on the DA-20 C1 which uses a wood
> prop on the IO-240 engine.
>
> My glider club uses fiberlock nuts on the Hoffman 4 bladed wood prop of
> a PA-25 Pawnee 250 used for towing gliders.
>
> Both these aircraft are type certificated, if fiberlock are good enough
> for them.....
>
> If you check the torque on a regular basis as all wood prop
> manufactuers I know of require than you whill have no problems with
> loose bolts.
>
> Robert Mudd
> Moriarty, NM
> A&P I.A.
>
>
>
> Scott wrote:
>
>>Quick question for the group. When setting the torque on prop bolts (I
>>have bolts with nuts), if the hole for the cotter pin doesn't line up
>>with the castleated nut at the proper torque setting, is it better to go
>>tighter or looser to get the hole lined up. My gut instinct says
>>tighter, but....
>>
>>Scott
>
>

That is the answer I was looking for (a quote from AC 43.13)...I can't
find my copy. Now, can you define "friction drag" ? If I know what
that is, I'll have 'er whipped! Thanks!

Scott



Jester wrote:

> Scott wrote:
>
>>Quick question for the group. When setting the torque on prop bolts (I
>>have bolts with nuts), if the hole for the cotter pin doesn't line up
>>with the castleated nut at the proper torque setting, is it better to go
>>tighter or looser to get the hole lined up. My gut instinct says
>>tighter, but....
>>
>>Scott
>
>
>
>>From chapter 7 of the AC 43.13-1B
>
>
> "f. When installing a castle nut, start
> alignment with the cotter pin hole at the minimum
> recommended torque plus friction drag
> torque.
>
> NOTE: Do not exceed the maximum
> torque plus the friction drag. If the
> hole and nut castellation do not align,
> change washer or nut and try again.
> Exceeding the maximum recommended
> torque is not recommended."
>
> This is also what I remember from school.
>
> Jesse M.
> PP-ASEL
> A&P
>

Scott wrote:
> That is the answer I was looking for (a quote from AC 43.13)...I can't
> find my copy. Now, can you define "friction drag" ? If I know what
> that is, I'll have 'er whipped! Thanks!
>
> Scott

Friction drag is the drag exerted by the locking feature of the
nut, whether it's a nylon ring or a crimped metal collar. The amount of
torque required to turn the nut on the threads before any tension is
put on the bolt is added to the torque spec so that the proper tension
is achieved in the bolt (or stud). It can be critical especially with
all-metal locknuts; they are pretty tight on the threads.

Dan

Thanks! Got it! So I think there would be hardly any friction drag
with a castleated nut since there is no inherant locking mechanism built
into the nut...

Scott


wrote:

> Scott wrote:
>
>>That is the answer I was looking for (a quote from AC 43.13)...I can't
>>find my copy. Now, can you define "friction drag" ? If I know what
>>that is, I'll have 'er whipped! Thanks!
>>
>>Scott
>
>
> Friction drag is the drag exerted by the locking feature of the
> nut, whether it's a nylon ring or a crimped metal collar. The amount of
> torque required to turn the nut on the threads before any tension is
> put on the bolt is added to the torque spec so that the proper tension
> is achieved in the bolt (or stud). It can be critical especially with
> all-metal locknuts; they are pretty tight on the threads.
>
> Dan
>

"jerry wass" > wrote in message
.. .
> pbc76049 wrote:
>
> Hey, never thot of swappin nuts--thanx

My Pleasure... It's the simple stuff that makes life a joy.
Have a great say.....
Scott.