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Hi!
I have Aeroquip aluminum -6 hose ends for my fuel lines. Their manual says minimum torque 140 and max 195. I'm doing leak tests and put ~100 in-lbs on the fittings and they don't leak. I assume I'd crank it more until I hit at least the 140 mark? Same question for my -4 fuel pressure line and -8 oil cooler lines, i.e. go to at least the minimum stated. I'm trying to reach that happy medium between having fuel sprayed all over and stripping the threads or damaging the seats.
Thanks,
Dan
Dan,
How 'bout asking one of the many hose builders? Bet they would be happy to give you the manufacturer's recomendations for this. Sac Sky Ranch also makes hoses. Let us know what they say.
Good luck!
Torque spec is going to depend on line and fitting materials as well as service. I can look up our spec chart at work tonight. Here is one chart that assumes that fittings are Al, and in standard service.
http://www.vansaircraft.com/pdf/Torq...m_Fittings.pdf
Here is another:
http://www.tpub.com/content/chinookm...40-23-1_40.htm
Sorry about not responding. I wasn't notified by email that anyone had replied. Then I tried to login and couldn't. Then I filled out the 'lost password' thing and haven't been contacted by EAA. Sounds like the bugs are being worked out. So I reregistered under another username and email.
Anyway, I'll contact John at SSR, good idea. That first chart Craig mentioned is from Aeroquip and identical to the one I've got. I expect to hear that minimum torque means exactly that. Put on at least 140 (the minimum listed for -6). I'll post what I find out.
I hate to show my ignorance........but I do on a regular basis so it shouldn't bother me anymore. How do you measure torque on a fitting? Crows Foot on a torque wrench?
Legitimate question Sirota and there is no ignorance in asking, especially if it's some process that you have never done or do very rarely. We use multiple methods to torque fittings. When installing bulkhead fittings and caps or plugs, a correctly fitting socket on a torque wrench is perfectly fine. Where access is limited, or you are working with lines or hoses, then a crow's foot on the torque wrench is used. When you have to use a crows foot and have to shift the axis of rotation, you have to remember to correct the applied torque via the correction formula. Adding standard extensions does not require any correction to the torque value until you are using several feet of extensions and torque values are in the hundreds of foot pounds. When you start working with values like that, torque multipliers and Sweeney wrenches start coming into play.
If you use what is known as a torque extension, then the compensation may or may not be needed. If you are able to torque with the t.e. at 90 degrees to the torque wrench handle, no compensation. Any other angle and you have to correct for it.
One other tool that often comes into play in the manufacturing world, is preset torque wrenches with specific sized open end wrenches or crows feet attached. These units are calibrated to a specific torque value and are not user adjustable.
Something to think about on torque tools, especially ones that are adjustable or the beam indicator type. Accuracy is usually stated for a range of values from 20% to 80% of the overall range. In otherwords, if you are trying to use one at the very low, or top end, the accuracy can fall off enough to cause you to provide a torque out of the required limits. Also, if you drop a torque wrench on a hard surface... ie like knocking it off your bench to the floor, you need to get the calibration checked. The probability that it will be off calibration is pretty high.
Also, in the absence of specific installation instructions otherwise, all torques should be with dry threads. There are instances when lubricated or coated threads are torqued, but when called for, the designer/engineer has taken that into account with the torque spec.
Probably more than you wanted to know......