| Author | Message | ||
     Brian McKinney (Bmckinney) |
At the point where almost all fiberglass work is complete in the wing and need to do final install & torque of hardware before closing. Anyone have a good source for a torque wrench that will cover the smaller bolts(AN3-AN5)? Seems torque ranges will be from 20 to 140 in/lbs. for these fasteners. Best deal I can find is from McMaster-Carr: 1/4" drive with a 20 to 150 in/lbs. range for $135. I already have a higher range wrench for the bigger bolts (120+ in/lbs). By the way, I came across many areas of my manuals that say "torque to stardard limit". Standard limit, huh? Took me awhile to find AC43-13 on the web that has the ranges for all AN bolts. Ended up finding all kinds of good stuff on standards for building and maintaining planes. I probably should have known this sooner, but I guess now is when it counts... (http://av-info.faa.gov/dst/reference.htm) Thanks, Brian | ||
| Eric Holmberg (Erich) |
Hi Brian, I just use a Craftsman 3/8" drive torque wrench. Because it's the spring-type, you do need to be careful to always set it back to the minimum setting immediately after use to prevent excessive loss of precision. It has a range of 25-250 in*lbs and should be in the $80 range. I believe they have two different ones with one of them being calibrated in ft*lbs and the other in in*lbs. Speaking of torque wrenches, has anybody else rebuilt their Lycoming engine? The connecting rod bolts are stretch bolts which means that you have to have a special torque wrench that measures the change in torque as the bolt stretches and then tells you when the maximum torque has been reached (i.e. going past this point will make the part fail). There is also a procedure that entails tightening the bolt and measuring the length of it with a micrometer to get the proper stretch. I will probably do this, but the special torque wrench would be really neat  I've just never used one outside of mass production where speed is more important than cost. -Eric |