Looking for high-quality security fastener in small quantities.
March 26, 2010 8:13 PM   Subscribe

I'm looking for a high-quality tamper-reistant nut (like a Bryce penta-nut) in 8x1.25mm (8mm coarse), and in small quantities.

I only need two, but I'll pay for a box of 20 or so (I can give away or re-sell them to others who have the same need, but there aren't a lot of these people). I'll also need the driver.

Small Parts Inc. doesn't seem to carry anything similar to it, and Google has utterly failed to find any online retailers or wholesalers with "no minimum order" policies. Bryce will only sell them in lots of 2000 @ $1.25 each, and I'm not certain if they use coarse or fine threading, only one 8mm part was listed.

This is to secure a Brooks triple-rail bike saddle to the seatpost. The seatpost is secured with a pin-in-head allen screw in a non-QR collar, but a thief with a set of vice-grips coud still walk away with the saddle itself. It's hoped the smooth-sided penta-nut would be enough of a bother where a casual thief would just move on to easier pickin's.
posted by Slap*Happy to Technology (8 answers total) 2 users marked this as a favorite
Have you tried a local hardware store? Perhaps they either carry them or are willing to start if you ask?
posted by brainmouse at 8:16 PM on March 26, 2010

People at your local bike store might have encountered others with a similar need. Maybe you could convince them to buy them wholesale if the minimum order is reasonably small?

Occasionally fire companies and other municipal outfits have some of this sort of thing on hand. It's usually larger, for securing fire hydrants and the like, but I know I've seen some small-ish ones lying around my station. Ask around?
posted by skyl1n3 at 8:37 PM on March 26, 2010

mcmaster.com has a sloped-face nut (98789A220) in that thread in packs of 5 for $4.72 but I'm not sure if that would work for your application because the base is about one inch square.
posted by Rhomboid at 9:08 PM on March 26, 2010

The slope-faced nut - Less than a buck each in a pack of five: good! A driver that can't be fitted to a ratchet, has a t-handle that will snag on the saddle, and costs $50 each: bad! Close, yet no cigar.

The pin-faced fastener beneath it looks great, but isn't available in metric. Frowny face!
posted by Slap*Happy at 9:30 PM on March 26, 2010

I have seen spanner nuts used for similar applications... (the pin-faced ones you saw at McMaster)

They do have 8mm:
Spanner Nuts: Removable Security

The site above does have a cart that allows one to just enter X number of parts (but the cart looks like it is just a quote builder).
posted by crenquis at 10:01 PM on March 26, 2010

I have seen people with a small cable lock securing their saddle to the frame. Many different ideas among NYC bike messengers.

Check a bike messenger blog, I bet there's many good ideas for the same situation.
posted by KenManiac at 8:20 AM on March 27, 2010

Talk to your local machine shops, they might be able to get them from their suppliers.
posted by glip at 5:05 PM on March 27, 2010

These things are interesting, but they don't seem to sell the kind of bolt you need.

It's unusual, because you are describing a pretty common problem. (My reaction is, "nobody's going to steal my saddle," but maybe that's not the best plan.)
posted by jrockway at 5:12 PM on March 27, 2010

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