X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost05.isp.att.net ([207.115.11.55] verified) by logan.com (CommuniGate Pro SMTP 5.4c2a) with ESMTP id 4838090 for flyrotary@lancaironline.net; Fri, 04 Feb 2011 09:53:37 -0500 Received-SPF: none receiver=logan.com; client-ip=207.115.11.55; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-85-106-221.mco.bellsouth.net[98.85.106.221]) by isp.att.net (frfwmhc05) with SMTP id <20110204145300H0500b61mie>; Fri, 4 Feb 2011 14:53:00 +0000 X-Originating-IP: [98.85.106.221] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Case bolts and torque readings Date: Fri, 4 Feb 2011 09:53:04 -0500 Message-ID: <2BA176BFC66944B585D8AFC42936640D@Desktop> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002E_01CBC451.519D75E0" X-Mailer: Microsoft Office Outlook 11 Thread-Index: AcvEMA1ADWwGfK8tTByTVJ0EuOEg7QASk6hw X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_002E_01CBC451.519D75E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit We visited the Fantasy of Flight museum a couple of weeks ago. You really can not see everything you want to see in just one day! Kermit Weeks has more airplanes than Carter has Little Liver Pills! (an age test!) Bill B _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com Sent: Friday, February 04, 2011 12:54 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Case bolts and torque readings In a message dated 2/3/2011 6:00:48 P.M. Eastern Standard Time, Lehanover@aol.com writes: Lynn, Forgive me if I am a little dense but after your explanation and all the mention of torque readings based on "Dry Threads" then your statement to use "Antiseize" which method produces the most accurate and repeatable torque readings ??............In my hunt for bolts of the correct thread length for the "Dynaocal" mounts to bolt to my "Mistral" backplate to my engine mount I obtained a lot of info regarding bolt torque from the "ARP" (well known fastener company)........Their torque procedure recommendation includes the use of their own brand of thread lubricant............... Kelly Troyer "DYKE DELTA JD2" (Eventually) Well, any method of installation that is consistent bolt to bolt and hole to hole can then produce repeatable torque readings within some acceptable range. All dry holes in one range, or all motor oiled holes or many builders like STP because it clings to stuff so well. So, there is a big range in tension developed between say 25 pounds of torque on a bolt with clean dry threads in a clean dry hole (Vapor degreased) and another bolt lubricated with nearly any kind of oil or, oil like product. Then all of the oil like products will produce a very much narrower band of tension outcomes. I like Nickel anti-seize, but nearly anything works. So if the bolt is torqued up and you find some below torque, back each out in sequence one full turn to allow some lube to migrate onto the threads and torque up in one continuous motion. If you have to stop the motion before the wrench clicks, then back up one full turn and try again. If it was not a single motion from the last torque step to the wrench click, then the bolt has not been torqued and shame on you. Torque is called out to control some other factor. In this case how much pressure is on the stack, and that controls beam stiffness and some torsional stiffness. In very highly stressed bolts in tension, the bolt is torqued into a tensile stress above the maximum load expected. SPS (Standard Pressed Steel) makes all kinds of bolts. The great tension bolts have a dimple on both ends. You stick a special dial indicator jig on these bolts and you torque the bolt until it has stretched a specific amount, like .007" for rod bolts. It is best to have a spare set of SPS bolts that you use just during resizing you rods. The clown who runs that machine generally torques rod bolts to 35 pounds for everything. You want you rods resized with bolts close to 50 pounds and stretched to .007" That is if you actually want round big ends. (Higher HP and lower oil temps). The torque callouts for most bolts have nothing to do with the bolts at all. It is to prevent your ham fisted brother in-law from jacking the threads out of an aluminum casting. So bolts in aluminum for most applications can be made of crap. Since not into their working range, there is no way to keep them from backing out without some positive locking system. Not Locktite as it will glue the bolt in tight and require much heat to kill it before removal, lest the threads come out with the bolt. Or, Locktite just under the bolt head and washer. Or drill the bolt head for safety wire. The aircraft bolts with thin heads and very short thread runs, are shear bolts. Always used in double shear to avoid a bending load, and very lightly torqued as they are poor in tension. They have a hole through the threads for a safety pin or split cotter to keep the half height castle nut from falling off. Went to Kermit Weeks Fantasy of Flight museum today. Went on all of the tours. Well worth a side trip up I-4 while at Sun&Fun. Lynn E. Hanover ------=_NextPart_000_002E_01CBC451.519D75E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

We visited the Fantasy of Flight = museum a couple of weeks ago.  You really can not see everything you want to = see in just one day!  Kermit Weeks has more airplanes than Carter has = Little Liver Pills!  (an age test!)

 

Bill B

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com
Sent: Friday, February = 04, 2011 12:54 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Case bolts and torque readings

 

In a message dated 2/3/2011 = 6:00:48 P.M. Eastern Standard Time, Lehanover@aol.com = writes:

Lynn,

   Forgive me if I = am a little dense but after your explanation and all the mention of  = torque

readings based on "Dry = Threads" then your statement to use "Antiseize" which = method

produces the most accurate and repeatable torque readings ??............In my hunt for bolts =

of the correct thread length = for the "Dynaocal" mounts to bolt to my "Mistral" backplate = to

my engine mount I obtained a lot = of info regarding bolt torque from the "ARP" (well known =

fastener company)........Their = torque procedure recommendation includes the use of their =

own brand of thread lubricant...............

 

=

 Kelly Troyer
"DYKE = DELTA JD2" = (Eventually)

 

=

Well, any method of installation = that is consistent bolt to bolt and hole to hole can then produce repeatable = torque readings within some acceptable range. All dry holes in one range, or = all motor oiled holes or many builders like STP because it clings to stuff so = well. So, there is a big range in tension developed between say 25 pounds of = torque on a bolt with clean dry threads in a clean dry hole (Vapor degreased) and = another bolt lubricated with nearly any kind of oil or, oil like product. =

 

=

Then all of the oil like products = will produce a very much narrower band of tension outcomes. I like Nickel anti-seize, but nearly anything works. So if the bolt is torqued up and = you find some below torque, back each out in sequence one full turn to allow = some lube to migrate onto the threads and torque up in one continuous motion. = If you have to stop the motion before the wrench clicks, then back up one full = turn and try again.

 

=

If it was not a single motion from = the last torque step to the wrench click, then the bolt has  not been = torqued and shame on you.

 

=

Torque is called out to control = some other factor. In this case how much pressure is on the stack, and that = controls beam stiffness and some torsional stiffness. =

 

=

In very highly stressed bolts in = tension, the bolt is torqued into a tensile stress above the maximum load = expected. SPS (Standard Pressed Steel) makes all kinds of bolts. The = great tension bolts have a dimple on both ends. You stick a special dial indicator jig on these = bolts and you torque the bolt until it has stretched a specific amount, like .007" for rod bolts. It is best to have a spare set of SPS bolts = that you use just during resizing you rods. The clown who runs that machine = generally torques rod bolts to 35 pounds for = everything.

 

=

You want you rods resized with = bolts close to 50 pounds and stretched to .007" That is if you = actually want round big ends. (Higher HP and lower oil = temps).

 

=

The torque callouts for most bolts = have nothing to do with the bolts at all. It is to prevent your ham fisted = brother in-law from jacking the threads out of an aluminum casting. So bolts in aluminum for most applications can be made of crap. Since not into their working range, there is no way to keep them from backing out without = some positive locking system. Not Locktite as it will glue the bolt in tight = and require much heat to kill it before removal, lest the threads come out = with the bolt.

Or, Locktite just under the bolt = head and washer. Or drill the bolt head for safety = wire.

 

=

The aircraft bolts with thin heads = and very short thread runs, are shear bolts. Always used in double shear to = avoid a bending load, and very lightly torqued as they are poor in tension. They = have a hole through the threads for a safety pin or split cotter to keep the = half height castle nut from falling off. 

 

=

Went to Kermit Weeks Fantasy = of  Flight museum today. Went on all of the tours. Well worth a side = trip up I-4 while at Sun&Fun.

 

=

Lynn E. = Hanover

 

=
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