The FAL Files  

Go Back   The FAL Files > Weapons Discussion > Gunsmithing & Build It Yourself

Notices

Reply
 
Thread Tools Display Modes
Old December 29, 2012, 22:31   #1
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Barrel torque--updated

Ok so installed the barrel into the reciever tonight and it handtimes to about 11:10. I torqued it over to 12 by hand.

Now im an auto tech and pretty brute but this didnt feel like alot of force to get it there......but its by no means loose or easy haha. I just assumed it would have felt tougher the way you guys talk about yours in gigantor vises and huge breaker bars. Ill stick a torque wrench on it tomorrow as well.

ok so checked torque tonight and very unhappy......40ftlbs!! So if i get a larger breeching washer and kick it back to 10:30 ish with the breeching washer then the torque should go up considerably correct?
Is this going to change headspacing at all?

Last edited by tywest; January 02, 2013 at 21:09.
tywest is offline   Reply With Quote
Old December 30, 2012, 01:29   #2
FUUN063
Registered
 
FALaholic #: 35576
Join Date: Apr 2008
Location: Converse, Indiana
Posts: 6,580
That's probably because it hand times to 11:10 in your words. Some people feel this is fine and others, probably the ones talking about how long a cheater baar they used, like them to time at about 10:45 or so. Not a problem.


Leland
FUUN063 is online now   Reply With Quote
Old December 30, 2012, 06:22   #3
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Im to used to torquing head bolts haha or lug nuts

Thanks for the peace of mind leland
tywest is offline   Reply With Quote
Old December 30, 2012, 09:14   #4
gunnutt
Registered
 
FALaholic #: 14732
Join Date: Jun 2004
Posts: 152
You turned it by hand to 12? To me that says, I took my hand and twisted the barrel on without any tools to 12 O'Clock. If that is the case you have a problem. I suggest a washer if that is the case.
gunnutt is offline   Reply With Quote
Old December 30, 2012, 12:22   #5
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
No, used a 1/2 1.5 ft ratchet with barrel fixed in a vise
tywest is offline   Reply With Quote
Old December 30, 2012, 12:27   #6
def90
Registered
Bronze Contributor
 
FALaholic #: 50609
Join Date: Nov 2009
Location: The Peoples' Republic of Boulder, Colorado
Posts: 12,247
http://www.falfiles.com/forums/showthread.php?t=195562
__________________
There is no theory of evolution, just a list of creatures Chuck Norris allows to live.
def90 is offline   Reply With Quote
Old December 30, 2012, 14:43   #7
LaConservationist
Registered
 
LaConservationist's Avatar
 
FALaholic #: 42319
Join Date: Feb 2009
Location: South Louisiana Bayous!
Posts: 7,060
I usually try for 110 to 125 MAX ft/lbs......and yes I use a Full size 1/2" Drive Torque Wrench....(Snap-On if that matters)

LaC
__________________
In MEMORY of Roger "DUNKRD" Dunkelbarger September 13, 1943 - May 09, 2010

"Any one who thinks he can be happy
and prosperous by letting
the Government take care of him,
better take a closer look at the American Indian."

- Henry Ford
LaConservationist is offline   Reply With Quote
Old December 30, 2012, 14:56   #8
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Ill swing my torque wrench home monday and check the current torque. Im cool with it now just overly paranoid in everything i do, double and triple checking.
tywest is offline   Reply With Quote
Old December 30, 2012, 16:00   #9
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by tywest View Post
Im cool with it now just overly paranoid in everything i do, double and triple checking.
This is all to the good.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old December 30, 2012, 21:20   #10
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
If you have 60 ft-lbs or more it will be good to go. I have one that's probably 50-60 lbs and it has held up just fine. The worse thing it can do is back out of time it's not going to fly off.
__________________
I'm just here to feed the alligators.

Last edited by garyd1961; December 31, 2012 at 12:48.
garyd1961 is offline   Reply With Quote
Old December 30, 2012, 21:57   #11
gunplumber
Arrogant Bastard
Gold Contributor
 
gunplumber's Avatar
 
FALaholic #: 96
Join Date: Jul 2000
Location: Surprise, AZ
Posts: 24,586
My elbow clicks at 100 ft pounds. And again at 120. It's most annoying.

I doubt anything as low as 80 would be a problem.

60 - I dunno - feels too light to me, but I have no evidence it is a problem.
__________________
T. Mark Graham, Master Gunsmith
Arizona Response Systems, LLC
gunplumber is offline   Reply With Quote
Old December 31, 2012, 12:45   #12
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
I've been using torque wrenches regularly for the last 15-20 years and I'm just estimating the torque on the barrel. I tried three different washers and decided to just let it ride and see what happens. That was about three years ago and maybe a 1000 rounds with no problem.
__________________
I'm just here to feed the alligators.
garyd1961 is offline   Reply With Quote
Old December 31, 2012, 17:56   #13
GMB74
Member
Bronze Contributor
 
FALaholic #: 7987
Join Date: Nov 2002
Location: Vermont
Posts: 346
I, too have an extensive background in auto repair. If the barrel were a lugnut, would you be happy with how tight it is? If so, you are good to go. If not, get a thin shim to put in there to increase the torque. As the other members stated, something in the 80-125 ft lbs range is good. If it's tight, it's right!
GMB74 is online now   Reply With Quote
Old December 31, 2012, 22:13   #14
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
I have tightened more lugnuts than most people. I have never seen or heard of a wheel coming loose from not being torqued enough. I have seen them come loose from not being torqued at all.
__________________
I'm just here to feed the alligators.

Last edited by garyd1961; December 31, 2012 at 23:13.
garyd1961 is offline   Reply With Quote
Old December 31, 2012, 22:38   #15
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by garyd1961 View Post
I have tightened more lugnuts than most people. I have never seen or heard of a wheel coming loose from not being torqued enouugh. I have seen them come loose from not being torqued at all.
I have seen lug nuts tightened so much that a cross-type lug wrench was twisted into a pretzel by the owner, while trying to break the nuts loose.

First hand.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old December 31, 2012, 23:02   #16
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
I have broken a Craftsman 1/2 inch drive breaker bar on them. I also have wrung a quite few studs off because the lugs were cross threaded.
I do recomend tightening the lugs to the proper torqe. But if the correct torqe is 100 ft-lbs I had rather have 75 than 150. Over torquing damages the threads and is more dangerous than under torqing.
__________________
I'm just here to feed the alligators.
garyd1961 is offline   Reply With Quote
Old December 31, 2012, 23:11   #17
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by garyd1961 View Post
I have broken a Craftsman 1/2 inch drive breaker bar on them. I also have wrung a quite few studs off because the lugs were cross threaded.
I do recomend tightening the lugs to the proper torqe. But if the correct torqe is 100 ft-lbs I had rather have 75 than 150. Over torquing damages the threads and is more dangerous than under torqing.
Because of the above, I have started requesting that the tech just bump the lugs down with the impact, and let ME come and final tighten when the vehicle is back on the ground. That way I KNOW I can get 'em off. I'm sure that makes me a PITA for some techs, but tough shit.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 01, 2013, 08:10   #18
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Quote:
Originally Posted by shlomo View Post
Because of the above, I have started requesting that the tech just bump the lugs down with the impact, and let ME come and final tighten when the vehicle is back on the ground. That way I KNOW I can get 'em off. I'm sure that makes me a PITA for some techs, but tough shit.
Im willing to accomodate just about anything personally, they are paying my bills. My impact torques to right at 98ftlbs on setting 2 and i double check it twice a day but if someone needs something else for peice of mind then so be it.
tywest is offline   Reply With Quote
Old January 01, 2013, 12:20   #19
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
I always use torque sticks on the inpact wrench. They will set the torque pretty close. It's still a good idea to go behind and use a torqe wrench but I seldom did on account of management didn't want to waiste the time. At one place I use to work they made you use a torque stick then a torque wrench then another tech had to use a torque whench then you had to go into the parking lot and do a figure 8 and torque them again.
__________________
I'm just here to feed the alligators.
garyd1961 is offline   Reply With Quote
Old January 01, 2013, 13:09   #20
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by garyd1961 View Post
I always use torque sticks on the inpact wrench. They will set the torque pretty close. It's still a good idea to go behind and use a torqe wrench but I seldom did on account of management didn't want to waiste the time. At one place I use to work they made you use a torque stick then a torque wrench then another tech had to use a torque whench then you had to go into the parking lot and do a figure 8 and torque them again.
I never thought of this as being that involved.

There's gotta be a pretty wide gap between where they stay on when ya want 'em to, and where they come off when ya want 'em to.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 01, 2013, 13:34   #21
yovinny
Registered
Bronze Contributor
 
yovinny's Avatar
 
FALaholic #: 7679
Join Date: Oct 2002
Location: NY transplant to central Illinois, Now in Kentucky
Posts: 5,697
AHHHHH,,,
Watch a few bench rest guys switch barrels with a barrel block in a 4" Chinese vise bolted to a tailgate and a 12" long 1/2" ratchet and you'll be cured of any 'adequate' barrel torque fears.
yovinny is online now   Reply With Quote
Old January 01, 2013, 16:46   #22
TideWater 41009
Registered
 
FALaholic #: 1789
Join Date: Dec 2000
Location: Minneapolis, MN, USA
Posts: 1,345
Years ago someone quoted part of a British repair manual that said to torque the barrels between 140 and 190 ft/lbs as I recall.

Anything less than 140 is too little IMHO.
TideWater 41009 is offline   Reply With Quote
Old January 01, 2013, 17:18   #23
gunplumber
Arrogant Bastard
Gold Contributor
 
gunplumber's Avatar
 
FALaholic #: 96
Join Date: Jul 2000
Location: Surprise, AZ
Posts: 24,586
Are you sure you're remembering correctly? I have all the REME files since the 50s, and IIRC, 120 was a minimum with no upper limit listed.
__________________
T. Mark Graham, Master Gunsmith
Arizona Response Systems, LLC
gunplumber is offline   Reply With Quote
Old January 01, 2013, 17:41   #24
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by yovinny View Post
AHHHHH,,,
Watch a few bench rest guys switch barrels with a barrel block in a 4" Chinese vise bolted to a tailgate and a 12" long 1/2" ratchet and you'll be cured of any 'adequate' barrel torque fears.
Like to see them jokers get thru a bayonet course with a rig like that.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 01, 2013, 23:19   #25
TideWater 41009
Registered
 
FALaholic #: 1789
Join Date: Dec 2000
Location: Minneapolis, MN, USA
Posts: 1,345
Quote:
Originally Posted by gunplumber View Post
Are you sure you're remembering correctly? I have all the REME files since the 50s, and IIRC, 120 was a minimum with no upper limit listed.
That could be, but it seems to me there was a lower and upper limit with the specs indicated in my post above. The manual might have been Australian rather than British. Some time ago there was a very avid collector from there or New Zealand that used to post a lot of L1A1 pictures and technical data, and I think it was he who provided the data.
TideWater 41009 is offline   Reply With Quote
Old January 02, 2013, 05:29   #26
FUUN063
Registered
 
FALaholic #: 35576
Join Date: Apr 2008
Location: Converse, Indiana
Posts: 6,580
I have posted this before from my Canadian Manual:





Leland
FUUN063 is online now   Reply With Quote
Old January 02, 2013, 07:23   #27
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
I seem to wanna ask whether 140 psi of hydraulic pressure on the gauge is the same thing as 140 foot-lbs of torque, and if there something in the literature that says so.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 02, 2013, 16:12   #28
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Quote:
Originally Posted by shlomo View Post
I seem to wanna ask whether 140 psi of hydraulic pressure on the gauge is the same thing as 140 foot-lbs of torque, and if there something in the literature that says so.
140psi of hydraulic pressure is in no way comparable or convertable to ft/lbs....that i know of

Id like to see the measurements of the tool or a picture of the tool to get an idea of estimated pressure......even if we only knew the line diameter we could probably get an idea


ok im really taking the torque wrench home today and checking
tywest is offline   Reply With Quote
Old January 02, 2013, 16:18   #29
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Quote:
Originally Posted by FUUN063 View Post
I have posted this before from my Canadian Manual:





Leland
leland........can you interpret haha, i seriously imagine it wouldnt take alot of FT/lbs to create 140psi in a cylinder...but then we dont know what this contraption looks like

according to one spreadsheet 2800 psi=55ft/lbs......that aint right for this though

Last edited by tywest; January 02, 2013 at 16:45.
tywest is offline   Reply With Quote
Old January 03, 2013, 07:51   #30
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
so I added .005 to my .056 breeching washer and it handtimed to 10:20-10:30.......so would I need about a .060 #8 washer to bring the torque up or a tad less?

guess ill order a #8 and thin if needed

Last edited by tywest; January 03, 2013 at 08:44.
tywest is offline   Reply With Quote
Old January 03, 2013, 09:18   #31
FUUN063
Registered
 
FALaholic #: 35576
Join Date: Apr 2008
Location: Converse, Indiana
Posts: 6,580
Here's the device pictured with this text:





And, it sounds like you got it about right. Just get it tight. Done.


Leland
FUUN063 is online now   Reply With Quote
Old January 03, 2013, 09:26   #32
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by FUUN063 View Post
Here's the device pictured with this text:





And, it sounds like you got it about right. Just get it tight. Done.


Leland
God, there are so many force variables in that system, both hydraulically and mechanically, there's no telling HOW much foot/poundage you are delivering to the barrel torque.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 03, 2013, 09:29   #33
gunplumber
Arrogant Bastard
Gold Contributor
 
gunplumber's Avatar
 
FALaholic #: 96
Join Date: Jul 2000
Location: Surprise, AZ
Posts: 24,586
how does 100 psi convert to ft pounds or newton meters
__________________
T. Mark Graham, Master Gunsmith
Arizona Response Systems, LLC
gunplumber is offline   Reply With Quote
Old January 03, 2013, 09:31   #34
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by gunplumber View Post
how does 100 psi convert to ft pounds or newton meters
Verrrry carefully, is my guess.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 03, 2013, 09:45   #35
Deltaten
Registered
 
Deltaten's Avatar
 
FALaholic #: 124
Join Date: Jul 2000
Location: aboard on the N. Chessie
Posts: 8,597
Jeezus! Rube Goldberg is creamin' his (dead) jeans
What a confuxtulation of 'quipment!!!!!!!?!?!?!
__________________
All or Nothing!
Senator McCarthy was right! and as always......FYB!
Deltaten is online now   Reply With Quote
Old January 03, 2013, 10:26   #36
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Quote:
Originally Posted by gunplumber View Post
how does 100 psi convert to ft pounds or newton meters
psi (pressure) doesnt convert to ft/lbs (torque) directly. with this picture we can only get an idea.......using lots an lots of math and a similar hydraulic cylinder and length of stock mounted to receiver wrench.
tywest is offline   Reply With Quote
Old January 03, 2013, 10:31   #37
gunplumber
Arrogant Bastard
Gold Contributor
 
gunplumber's Avatar
 
FALaholic #: 96
Join Date: Jul 2000
Location: Surprise, AZ
Posts: 24,586
Looks like Tidewater was pretty close. I dug out the Aussie spec - they use a similar contraption. But have a note that the acceptable range is 269 to 375 psi which corresponds to 120-181 ft pounds. I guess the shorter Aussie wrench requires more psi than the longer Canadian for the same torque.
__________________
T. Mark Graham, Master Gunsmith
Arizona Response Systems, LLC
gunplumber is offline   Reply With Quote
Old January 03, 2013, 10:40   #38
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Quote:
Originally Posted by gunplumber View Post
In other words, the post is irrelevant to the discussion?
I think it was intended as a historical/technical footnote.


That said, one of the things I've wondered about for years is what the effect is on the ACTUAL torque on the fitting, when using an extension plate, such as the typical FAL action wrench you see with a wrench lug hole a couple inches away from the real axis of torque.

I'm starting with a presumption that the torque wrench is calibrated at the center of the ratchet, and that extending the length of the lever will alter the actual torque delivered at the fitting from the reading set on the thimble of the tool.

But not being a mechanical engineer, I don't really know how to analyze this or calculate the effect. Anybody got an insight?
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 03, 2013, 11:31   #39
29sedan
Registered
 
FALaholic #: 62946
Join Date: Mar 2011
Location: Bend, Oregon
Posts: 124
Quote:
Originally Posted by shlomo View Post
God, there are so many force variables in that system, both hydraulically and mechanically, there's no telling HOW much foot/poundage you are delivering to the barrel torque.
Looking at the drawing, one would have to make some assumptions, not having the tool drawing and specs on hand. It appears to my eyes the arm (lever) with the hole in it rotates at the barrel to receiver axis, which would be a basic device just like a standard torque wrench is designed. In other words the length of the lever determines the torque value. If the center point of the lever were not at the center of rotation then that would change the torque value and one would need to use some kind of a multiplier value. One of my assumptions is in regards to the hole in the lever. It seems to have a clearance built in so that the lever can only go so far. Maybe this was their safety feature to keep from over torquing the barrel? Clear as mud?
__________________
29sedan
29sedan is offline   Reply With Quote
Old January 03, 2013, 12:07   #40
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
so like GP said

the longer lever arm reduce needed pressure for torque
and
would correspond to a shorter lever with more pressure needed for same torque

so then aussie/canadian/brit or whatever would still be the same? and so then theres a fairly standard torque spec across the board no bones about it---thats what im looking for.....i dont think id feel good about anything under 80ft/lbs but if spec is a bit more....your already there tightening it so why not keep going (unless your already at 12 with less.....some would be ok with that)........i cant honestly be satisfied with hand timed slightly past 11 and 40ft/lbs to 12.....thats asking for issues

Last edited by tywest; January 03, 2013 at 12:16.
tywest is offline   Reply With Quote
Old January 03, 2013, 17:24   #41
garyd1961
Registered
 
FALaholic #: 39373
Join Date: Nov 2008
Location: NC
Posts: 4,029
Quote:
Originally Posted by shlomo View Post
I think it was intended as a historical/technical footnote.


That said, one of the things I've wondered about for years is what the effect is on the ACTUAL torque on the fitting, when using an extension plate, such as the typical FAL action wrench you see with a wrench lug hole a couple inches away from the real axis of torque.

I'm starting with a presumption that the torque wrench is calibrated at the center of the ratchet, and that extending the length of the lever will alter the actual torque delivered at the fitting from the reading set on the thimble of the tool.

But not being a mechanical engineer, I don't really know how to analyze this or calculate the effect. Anybody got an insight?
I always wondered the same thing.
I don't know a formular to get the exact torque but I bet these guys torquing to 140 or more are going way over the specs. Maybe someone can make a two inch extention for the ratchet end of a torque wrench, torque a few bolts then check the torque without it.
__________________
I'm just here to feed the alligators.

Last edited by garyd1961; January 03, 2013 at 17:32.
garyd1961 is offline   Reply With Quote
Old January 03, 2013, 21:17   #42
kotengu
Registered
 
FALaholic #: 1594
Join Date: Nov 2000
Location: Baxter, TN, USA
Posts: 7,960
Quote:
Originally Posted by shlomo View Post
I think it was intended as a historical/technical footnote.


That said, one of the things I've wondered about for years is what the effect is on the ACTUAL torque on the fitting, when using an extension plate, such as the typical FAL action wrench you see with a wrench lug hole a couple inches away from the real axis of torque.

I'm starting with a presumption that the torque wrench is calibrated at the center of the ratchet, and that extending the length of the lever will alter the actual torque delivered at the fitting from the reading set on the thimble of the tool.

But not being a mechanical engineer, I don't really know how to analyze this or calculate the effect. Anybody got an insight?
You are correct, sir - the offset multiplies the torque, so you are actually applying more torque than what is shown on the dial (or whatever your torque wrench shows). In general - just take the offset in inches, add twelve, and divide that sum by twelve to get the torque multiplier (assuming you're using a ft-lb torque wrench).

For example - if the center of your receiver/barrel were 2" away from the center of your torque wrench ratchet hole, the torque seen at the receiver/barrel joint would be (2+12)/12=1.1667 times more than shown on the torque wrench. If your torque wrench were set at 100 ft-lbs, you would actually be applying 116.7 ft-lbs to the joint.

Torque is a funny measurement though, which is why you usually see such a wide tolerance in torque specs. No one would ever say "torque that to 116.7 ft-lbs", because it would be about impossible to do with that much precision, and meaningless even if you could.
__________________
"The way is in training." - Miyamoto Musashi
kotengu is online now   Reply With Quote
Old January 03, 2013, 21:55   #43
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
Thankee, Matt. I knew somebody would come along and rescue me.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Old January 03, 2013, 22:23   #44
kotengu
Registered
 
FALaholic #: 1594
Join Date: Nov 2000
Location: Baxter, TN, USA
Posts: 7,960
Anytime, sir - I'm with you on the lugnuts, for the record. I've had more morons at tire shops overtorque lug nuts and cross-thread studs than I care to count.

On the FAL barrels, I think enough has been said already. Too much torque deforms things more than you want them deformed. Not enough torque will probably run just fine, but might come unscrewed just enough to malfunction when you're butt-stroking and bayonetting.

If I had to choose I'd rather take a slightly off torque spec instead of a hand-filed barrel shoulder or not very uniform breaching shim.
__________________
"The way is in training." - Miyamoto Musashi
kotengu is online now   Reply With Quote
Old January 03, 2013, 23:07   #45
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Quote:
Originally Posted by kotengu View Post
Anytime, sir - I'm with you on the lugnuts, for the record. I've had more morons at tire shops overtorque lug nuts and cross-thread studs than I care to count.

On the FAL barrels, I think enough has been said already. Too much torque deforms things more than you want them deformed. Not enough torque will probably run just fine, but might come unscrewed just enough to malfunction when you're butt-stroking and bayonetting.

If I had to choose I'd rather take a slightly off torque spec instead of a hand-filed barrel shoulder or not very uniform breaching shim.
I hear yah but what is slightly off?

So in your opinion 40 is ok just might come loose im gonna get a bit more on it haha. Im sure youd agree as well.

As far as the applied pressure from leland's pic.......140psi exerted on that leverage arm is quite a bit of pressure, with my 1/2 impact 90 psi of pressure will torque a lugnut to 85-110 ft/lbs and it to is applying pressure to a small area albeit through a straight vane drive and such but the principle is that a drive area of about 2 sq inches can torque that much so this tool at 140 psi has (IMHO) got to be over 100ft/lbs of force exerted at the axis of the receiver.

The air tool torques to 85-110 with a bypass at 90psi......that tool doesnt look to have one, looks like you can very accurately apply controlled pressure incrementally and hold it static.
tywest is offline   Reply With Quote
Old January 04, 2013, 02:47   #46
Potshot
Registered
 
FALaholic #: 6398
Join Date: May 2002
Location: xxx
Posts: 1,418
Let's be clear, what we're really after is two things:

1. Correct preload of the bolted joint
2. Alignment of the damn sights (i.e. timing)

Torque is not necessarily the indicator of preload. For example if one used differing assembly lubes, one can see a great difference in the relationship of applied torque to fastener load. I'm talking difference between correctly assembled to stripped threads at the same torque.

When torquing an FAL barrel one would want to get the maximum preload with the minimum torque (i.e. assembly lube that yields the lowest coefficient of friction). Load is a function of elongation of the fastener, which is governed by 'timing' of the barrel.

Due to my activities in my professional life, the best stuff I've run across for a situation like torquing FAL barrels (or Garands for that matter) is Cop-A-Slip.

If one knew the diameter of the hydraulic piston and the length of the lever arm of the Rube Canuckaberg contraption, torque vs. hydraulic pressure would be pretty easy to figure. Interesting device though. I've become enamored with use of one of the laser thingys for doing AK's. Wished I had one for my last FAL build.....and the Garand...
__________________
Remember, remember! When you vote in November, The gun bans, treason and plot;
I know of no reason Why the gun banning treason should ever be forgot.
Potshot is offline   Reply With Quote
Old January 04, 2013, 03:14   #47
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Forgive me Potshot but

What your saying exactly is? I know what your talking about with preload from bearing assemblies i replace at work.....but for me thats drag loading on rotation not a nonrotating assembly like an assembled barreled receiver. I was assuming while resding your post that since preload is a rotational resistance measurement for the most part that the torque value IS the preload since youd have no other way to measure it or fastener stretch independantly.

So i guess what im getting at is.........what do you mean by maximum preload with minimum torque? Are you simply talking about the difference between torquing a dry to a lubed fastener? In my line of work torque measurement are on dry fasteners.
tywest is offline   Reply With Quote
Old January 04, 2013, 06:36   #48
kotengu
Registered
 
FALaholic #: 1594
Join Date: Nov 2000
Location: Baxter, TN, USA
Posts: 7,960
Quote:
Originally Posted by tywest View Post
I hear yah but what is slightly off?

So in your opinion 40 is ok just might come loose im gonna get a bit more on it haha. Im sure youd agree as well.
Depends - if it's just a fun gun I'd probably shoot it and see what happens. At a worst case your zero will wander as the barrel (and front sight) wiggles around, or the piston will bind and the rifle won't cycle. You can always rebarrel with a shim later.

If you do, make sure to shoot some groups with the 40ft-lb torque, and then again with the 120 ft-lb torque. There's been a lot of discussion and speculation about the affect of barrel torque on accuracy, and I'd be curious to see your results.
__________________
"The way is in training." - Miyamoto Musashi
kotengu is online now   Reply With Quote
Old January 04, 2013, 07:38   #49
tywest
Registered
 
FALaholic #: 66761
Join Date: Jul 2012
Location: West, GA
Posts: 2,432
Well id be happy to oblige haha
tywest is offline   Reply With Quote
Old January 04, 2013, 08:56   #50
shlomo
Registered
 
FALaholic #: 12779
Join Date: Dec 2003
Location: elsewhere
Posts: 16,451
I love this place.
__________________
"Neither you nor any other person can grant rights. That, along with resurrecting the dead are powers reserved to GOD alone."--HBR
shlomo is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 12:56.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
©1998-2018 The FAL Files