Metric Lock Wing Nuts? Thule's Self-Loosening Fasteners

[sms]

I have a Thule ski rack as well as a Thule cargo box. Both suffer from a poorly designed attachment system which uses knurled knobs with nuts (essentially wing nuts). They have a tendency to slowly loosen from vibration. On my last trip, one of the ski rack knobs had completely unscrewed itself and fell off inside the ski rack.

On the cargo box I cut some wooden rectangles with cutouts for the knobs which I placed over the knobs so they can't unscrew. Yesterday for the ski rack I drilled two holes on each side of the four knobs and took some aluminum tent stakes and formed then into an arc that goes over the knob and through the holes to prevent the knob from turning.

What I really wanted to find was some stainless metric locking wing nuts, but those don't seem to be available anywhere in the U.S.. SAE sizes are readily available.

[DerbyDad03]

readily available.

Do they need to be stainless? What about plastic? Just a thought...

You could also make your own locking fasteners by epoxying some nylon insert lock nuts into the existing knobs or knobs of your own making.

The only issue with nylon inserts is that they can wear over time with repeated use.

What type of locking wing nut were you thinking of?

[trader4]

Perhaps a couple of drops of loctite on the threads instead?The blue type? I use that on my snowboard bolts to keep them from loosening. You'd probably have to put it on every so often, but I would think it would last for more than one tightening/loosening cycle. It does on my snowboard.

[Ed Pawlowski]

McMaster-Carr has stainless steel metric wing nuts, but they are not locking.

Page 3208 You can always put a locking washer with it.

[Attila Iskander]

Castle Nuts ??

[DerbyDad03]

Castle nuts, by themselves, are not really lock nuts. They require hole in the bolt and a cotter pin or wire to prevent them from turning.

Drilling holes through the bolts in the racks might be problematic.

[Tony Hwang]

Hi, Here we have bolt and nut supply house where we can get some thing like that. How about putting a dab of Silicon sealant after nut is tightened. It is not like epoxy but enough to hold the nut in place until you remove it. Sealant is pliable.

[trader4]

t-email.me...

quoted text -

Not to mention needing a wrench to get them off....

[DD_BobK]

Are knobs of such a design that they could be warmed up and the existing nuts pushed out and replaced with a locking nut?

My son has a Yakima utility rack (ski, bike, etc) for his Jeep and IIRC some of the "knobs" are large plastic "wing handles" with metal nuts that kinda snap in. They can be easily removed & sometimes fall out.

Perhaps you could remove them & replace them....OTOH if the nuts are molded in, it would be way harder. :(

cheers Bob

[nestork]

If the metric thread sticks out from the wing nut, what about just pushing a rubber hose onto the end of the thread sticking out. Once the rubber hose contacts the top of the wing nut, it'll help prevent the nut from turning, and thereby coming loose.

Other than that, me thinks the most practical solution here is to replace those wing nuts with regular stainless metric lock nuts and carry a small wrench in the car with you.

[The Daring Dufas]

A simple way would be some black weatherproof rubber bands to hook onto the wing-nut, wrap it around a part of the bracket and hook it to the other wing of the wing-nut. A bungee cord laying in the middle of the wing-nut, depending on how far apart the wing-nuts are, you could hook a bungee cord to one end of the frame, stretch it to the other end and lay the cord through the wings to prevent the wing-nuts from turning and falling off. ^_^

TDD

[sms]

It doesn't stick out.

I think for the cargo box I'll drill small holes in the ears of the knobs and use a stiff wire between each set of two since they're only a few inches apart. The wooden blocks around the knobs are a pain.

For the ski rack I'll just keep the wire arc through the two holes drilled in the rack that goes over the ears of the knob.

Next trip to Europe I'll buy the nuts I need.

[Stormin Mormon]

Probably cheaper to have them shipped, rather than go to Europe to buy a couple.

Christopher A. Young Learn more about Jesus

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I think for the cargo box I'll drill small holes in the ears of the knobs and use a stiff wire between each set of two since they're only a few inches apart. The wooden blocks around the knobs are a pain.

For the ski rack I'll just keep the wire arc through the two holes drilled in the rack that goes over the ears of the knob.

Next trip to Europe I'll buy the nuts I need.