MintJulep,
AS = Aerospace Standard. Pretty sure it's GE Aviation division.
GE spec's installation torque has no mention of preload/axial load at all, the protrusion is what defines the "installed" state for the max installation torque.
SWComposites,
sign...as if these countless different torque names are not confusing enough already, and who came up with these names, my god. They might as well as remove the words and name these torques with number sequences, so we know exactly what phase the torque belongs to.
In the case of self-locking nut. Is it normal to have different definitions across different specs, within the same industry? I am so confused, AS spec should in theory be aligned with GE spec. However, I am not seeing that, am I interpreting it correctly?
AS spec says: Assembly torque is the...
Thanks Ed, the actual mating bolt is made of Inconel 718 with a min hardness of 36 HRC.
I wonder why they allow the nut hardness to be 32 - 44 HRC and the test bolt to be 32 - 42 HRC in the first place.
Tugboat,
The nut needs to be reusable; the test assembly is only used for a single test run (15 cycles). I don't believe it's meant to be re-plated; the test procedure only allows oil lubrication in-between cycles.
The supplier informed us that the test bolt threads are experiencing wear during a reusability test for a self-locking nut. They observed a change in thread dimensions after just 2-3 cycles, along with increased heat generation. The nut is silver-plated and waxed, and it is crimped to create the...
mfgenggear,
The DFL's max operating temp is 800 F. The drawing calls for a spec which requires reusability test, this spec (active since 1985) is used for other similar nuts as well, I would have to assume it can be reused under some conditions, otherwise, I don’t see the point of the testing...
Ed,
The picture above is all I have right now, it looks like a lot of material is stripped off. The previous supplier did not have this issue, and the new supplier have been having issues with parts lately.
Dave,
The required dry film lubricant is EVERLUBE® ESNALUBE™ 382 Gray PWA-36545T Spec Low VOC Thermally Cured Mos2 Solid Film Lubricant, pretty much exactly what you said. The spec does require coating the lubricant prior to any 750 F+ heat and allows the coating to be reapplied between cycles...
The new supplier stated that the thread of the nut is chipping out during the first removal cycle after baking (image attached) and the nut is getting stuck after 3-4 cycles of room temperature torque test.
https://imgur.com/a/c18sqkU
.190-32 UNJF Nut material: A286, hardness 24- 37 HRC, 130...
The tiny keys are the allowance for the mismatch, the fillet radius is not part of the profile per my interpretation. Since the profile callout has no datums, its only controlling the form and size, so maybe I could break up the profile into length and angle which is easier to measure? To...
Forgot to update the thread. I later realized that the profile is only on one side of the seal, so the fixtures that I initially proposed would only be checking the max/min material condition of entire part, which is not exactly useful. See link below for the actual drawing...
mfgenggear,
Thanks for the idea. It's flexible. the hardness is about 75 shore A. The goal for the go fixture is to go in without any compression on the seal, would it be better to cut the fixture in half to expose the cross-section? that way we have a better view and perhaps can use feeler...
I have a rubber seal ring about 30'' in diameter. See cross-section below:
https://imgur.com/a/Lmu1AN0
I was asked to make a Go/No-Go fixture to check the profile. I wonder how other companies perform quick checks on this type of profile. All I can come up with is checking half of the seal...
Thanks guys on the inspection methods.
As Jboggs has pointed it out, any point/line contact would likely to damage the sealing surface. I am assuming that means both male and female angles need to have a nominal angle of 45, or having the same angle within a very tight tolerance, but what kind...
