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course thread stud - torque
- Thread starter Mark L
- Start date
Bob Kuykendall
Well Known Member
I think what you're looking for is in this table from AC43.13:
Thanks, Bob K.
Thanks, Bob K.
alpinelakespilot2000
Well Known Member
Can't help you directly, Mark, b/c I'm not sure about that pad, but you are correct that engine studs are often torqued to a much higher spec than 43.13. The carb attach studs are one such place and were, I think, 200 in-lb. If I remember correctly, someone pointed me to a Lycoming manual and/or something at Sacramento Sky Ranch.
rzbill
Well Known Member
Need to use the Lycoming Specs
Mark,
I'm travelling and don't have these readily at hand. I got the Lycoming document from a post here on VAF. I think it was from Gil but maybe Mel.
Do a search and I think you will find the right doc. The studs you are using will be in the section on standard torques. There is a considerable listing of "special" torques, but the two pads you are fiddling with are not included in the special section.
I can attest that the Lycoming torque values will make your sphincter tighten up after being accustomed to the light AN values.
I know $$ signs danced before my eyes while I was installing the prop governor. Its OK, they really mean them to be that tight.
EDIT ** Thanks for helping my neighbor, Walt
Mark,
I'm travelling and don't have these readily at hand. I got the Lycoming document from a post here on VAF. I think it was from Gil but maybe Mel.
Do a search and I think you will find the right doc. The studs you are using will be in the section on standard torques. There is a considerable listing of "special" torques, but the two pads you are fiddling with are not included in the special section.
I can attest that the Lycoming torque values will make your sphincter tighten up after being accustomed to the light AN values.
I know $$ signs danced before my eyes while I was installing the prop governor. Its OK, they really mean them to be that tight.EDIT ** Thanks for helping my neighbor, Walt
az_gila
Well Known Member
Mark,
I'm travelling and don't have these readily at hand. I got the Lycoming document from a post here on VAF. I think it was from Gil but maybe Mel.
Do a search and I think you will find the right doc. The studs you are using will be in the section on standard torques. There is a considerable listing of "special" torques, but the two pads you are fiddling with are not included in the special section.
I can attest that the Lycoming torque values will make your sphincter tighten up after being accustomed to the light AN values.
EDIT ** Thanks for helping my neighbor, Walt
Probably one of my posts. From the Lycoming overhaul manual - note the bit on lubricating the threads, unlike airframe bolts.
Watch out!
The table that Gil attached shows 204 in/lbs for bolts, but it's not clear if it applies to Lycoming exhaust studs, which are 5/16-18 on my O320-E2A. I used this number, which I found in another post a while back and now have the pleasure of installing Heli-coil repairs on at least one exhaust stud.
Larry Vetterman's page recommends a much lower number, 140 in/lbs, and that's more in line with the data that Bob K attached.
The table that Gil attached shows 204 in/lbs for bolts, but it's not clear if it applies to Lycoming exhaust studs, which are 5/16-18 on my O320-E2A. I used this number, which I found in another post a while back and now have the pleasure of installing Heli-coil repairs on at least one exhaust stud.
Larry Vetterman's page recommends a much lower number, 140 in/lbs, and that's more in line with the data that Bob K attached.
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az_gila
Well Known Member
Is that for putting the stud in, rather than the nuts?
The exhaust system is usually an airframe item on a certified plane, so I checked my Tiger Maintenance Manual which gave 110 - 130 inch pounds for the exhaust flange nuts using new star lock washers - fitting in with the previous Larry Vetterman number.
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Here is some information I just recieved concerning this from Mattituck:
Your email requested the torque values to be used on ( 5/15" and 3/16" course threaded steel studs )
When installing studs, one end will thread a nut with ease and should go towards the accessory to be installed. The other end is made oversise to install into the case or accessory cover with difficulty, to help to lock the stud into the fixture. This prevents having a rusted on nut acting as a bolt and remove the stud instead of the nut.
When installing studs, red loctite #271 is used on threads entering the case or accessory cover. Common sense must be observed as to not shear the stud during installation. Studs are to be installed to a dtiven height that will allow at least one thread showing above the nut with a flat and lock washer installed where required.
There are no stud torques, just nut torques.
Taken from the "Piston Engine Table of Limits and Torque Value Recommendations", bolt, screw, and nut torques:
Thread In. Lb.
10 49
1/4 96
5/16 204
3/8 360
7/16 600
1/2 900
9/16 1320
5/8 1800
3/4 3240
I hope this helps you find your answers
John R. Haas
Chief Inspector
Mattituck Services, Inc.
I guess I still am not sure about those 3/16" studs though.
Your email requested the torque values to be used on ( 5/15" and 3/16" course threaded steel studs )
When installing studs, one end will thread a nut with ease and should go towards the accessory to be installed. The other end is made oversise to install into the case or accessory cover with difficulty, to help to lock the stud into the fixture. This prevents having a rusted on nut acting as a bolt and remove the stud instead of the nut.
When installing studs, red loctite #271 is used on threads entering the case or accessory cover. Common sense must be observed as to not shear the stud during installation. Studs are to be installed to a dtiven height that will allow at least one thread showing above the nut with a flat and lock washer installed where required.
There are no stud torques, just nut torques.
Taken from the "Piston Engine Table of Limits and Torque Value Recommendations", bolt, screw, and nut torques:
Thread In. Lb.
10 49
1/4 96
5/16 204
3/8 360
7/16 600
1/2 900
9/16 1320
5/8 1800
3/4 3240
I hope this helps you find your answers
John R. Haas
Chief Inspector
Mattituck Services, Inc.
I guess I still am not sure about those 3/16" studs though.
AK4x4
Well Known Member
drive torque
The info relayed from mattituck is a good procudure for stud installation however while turning the stud, before it is compleatly installed, you must exceed the listed minimum drive torque for the stud size being installed. This ensures proper friction fit of the stud. A correctly sized stud will require a bit over the min. torque listed not tons. There are various oversize studs available for stud holes that have been "streched". Choose a std. or oversize based on required install torque vs. specified. Good luck, Russ
The info relayed from mattituck is a good procudure for stud installation however while turning the stud, before it is compleatly installed, you must exceed the listed minimum drive torque for the stud size being installed. This ensures proper friction fit of the stud. A correctly sized stud will require a bit over the min. torque listed not tons. There are various oversize studs available for stud holes that have been "streched". Choose a std. or oversize based on required install torque vs. specified. Good luck, Russ
