The assembly situation is most likely to compare with a long rectangular steel tube. The tube has a through hole and shall get tightened against any other part. The other part has an internal thread for the screw. The through hole is as close to the open end of the tube that there is a clash...
@rb1957: I sorry but I can not make any pictures of the situation. The torque is low enough to work with a flex drive, but that would mean that i have to bend the flex drive about 90 degree. That would have a significant influence in torque. Yes, I use self locking thread inserts.
@WKTaylor...
A nut is not possible. The parts are screwed into an aluminium baseplate. I have a strong limitation in accessibility. That means that I can not simply use a extension to apply a ratched or something else. I need to tighten the screws/ bolts with a torque wrench. The standard ratched head/...
Basically yes. The flange diameter of these bolts is negligilby smaller than the head diameter of a NAS1351 screw. But they cost 3 times more and if the socket is attached, they need even more space in diameter.
For me it seems that I did not find the correct search term so far. I was looking...
Gents,
I´m looking for a screw similar to the NAS1351 screw but with another head drive. Obviously, the internal hex at the NAS1351 does only give accessibility every 60 degree. Is there a screw/ head type which provides a better accesibility?
I found a German LN29949 aerospace screw (socket...
I agree, 90% of fty seems to be too much. But what would be the correct torque? I didn´t try this exactly on a NAS1351 screw with undrilled head but many times with comparable sizes of other socket head screws and it worked fine.
Thanks for the attachment Tmoose but i think the tabulated torque...
Hello,
the screw size is 0,1640-36 (dash no.8 of NAS1351). The assembly torque is corresponding to 90% utilisation of yield strength of the stress crosssection. Afaik that´s common practice and fits in most of the cases. For the drilled heads this seems to be too much torque.
The choice to use...
Hello,
I´m looking in vain for assembly torque values for NAS1351 (drilled socket head) screws. The assembly torque for undrilled heads damages the alan key far to early before achieving the desired assembly torque. The damage occurs in a way that it´s impossible tighten or untighten the screw...
Hey guys,
thanks for your replies. An angular contact bearing would be the best choice in order to preload the bearings. The MS27641 is another option, but maybe difficult in terms of preloading because of the ball loading slot.
I´ve found some angular contact bearings using your link above...
Hi,
i´m looking for some small angular contact ball bearings for an aircraft application. The maximum OD shall not exceed 7/8". I found some Mil specs with a suitable type, but all sizes were too big. My own feeling is that there must be a bunch of specs, but i wasn´t able to found something...
Hi guys,
thanks for your replies and recommendations. It took a few days for an update.
I try to answer WKTaylor´s question: "I guess the follow-up question I have is: exactly what kind of installation are You designing/analyzing and why is a high torque-tension preload required and which also...
tbuelna,
thanks for your reply. In the meantime, i had a look on some other topics here in this forum regarding the use of cotter pins. I think you are right, it´s not possible to achieve the correct preload and align the nut slot to the pin hole of the bolt.
In your opinion, the NAS670x is a...
Thanks,
it has to be a bolt with a cotter pin nut (DAL level A). What i found is a NSA5060 nut. Also made of A286 CRES and not as high as the the MS9358 nut. But i still wonder about the bad combination of the MS9358 and the NAS670x bolt.
Hi,
i think it´s the JAR29 or CS-29.
I don´t know exactly what you mean with the stiff nut. It should be a castellated nut to ensure can´t get lost during service.
Oh i see, your thought was a locking tab with a standard nut right? Unfortunately, that´s not possible.
Hi,
i usually choose the combination NAS670x (bolt) and MS17825 (nut) – and the cotter pin of course. During the stress calculations of the bolted connections, a problem raised by the low tensile strength of the MS nuts. The tensile strength of the MS nut is approximately only half of the NAS...