Another blind nut failure

Wow!

I had a very scary blind nut failure over the weekend--thought it was curious that we were all just talking about the various brands and failures.

I have an adjustable spacing handle that uses 6-32 socket hd cap screws and blind nuts to clamp the sliders.

I was 3/4 of the way through the third inside loop when the UP line slider slid all the way to the center position----Duh..oh!.

I was very lucky and saved the plane.

The blind nut was completely stripped out. Unfortunately I dont know what brand it was.

Whew!

Wow!! I have always been affraid of that happening. Maybe you should go to the Nylon bolts insted of the blind nut. It might be more trouble to make adjustments. It might hold better. Mine is threaded aluminum that I screw into and it holds tight.

Yup! THreaded solid aluminum sliders are the way we're making the latest ones.

LAST EDITED ON Jun-11-02 AT 06:54 PM (CST)

Might have been a sig one. The sig ones I have are stamped and seem to be made of soft steel. The last! time I put a sig one in the nut bent(pulled in a little) when tightened. The dubro ones are better, a little smaller in dia, and thicker flange, but I have seen some of their's that were threaded twice or something. The blind nuts were 4-40s.

I've been using the Dubro blind nuts as they are available from my local hobby shop. They look like they are made of a softer metal. They also look like they were made out of two pieces, a seperate barrel, and flange. I have had these separate from being over torqued.

The two piece construction of the Dubro only seems to be true for the three smallest sizes, however. The larger ones don't appear to have this construction.

Accurate Fasteners describes their t-nuts to made of mild steel. This may not be good enough to mount see
http://www.accuratefasteners.com/Inventory_6.php?ProdID=GZA

However, I also have some from Brodaks, that I received in a 4-40 hex bolt pack. They have the look of anodized hardened bsteel. They also look like they were formed from a single piece of metal. Like they were stamped, then threaded. So there are differences in the 4-40 blinds nuts that are available.

Maybe we could get information from Brodak on where he sources his product, and get the technical information.

The old machined-looking Perfect(?) blind nuts were the best. I've never had a failure with those but the stamped looking ones (Dubro?) were prone to stripping or just pulling the flange off. I have a lot of the machined ones, some that are probably 30-40 years old that are still giving great service. The stamped ones I threw away. I don't believe I've seen two piece ones.
Bare

Had a similar thing happen at a recent contest. Only for me it was the cable hold down. Threaded into a blind nut (8/32). Guess I over tightened it one too many times. It was a real thrill when the handle cable started sliding back and forth! The plane is almost fixed anyway.

Randy