This could change glue-in bolts forever #climbing #breaktest

A friend sent us these flat glue-in bolts that were stamped from sheet of stainless steel. This means they don't have welds that could introduce corrosion, and also have a very simple manufacturing process. We tested it in our glue-in adapter with DeWalt Pure 110 Epoxy and it performed great, deforming around 20 kN and breaking at over 33 kN. The only downside we could see is that it has sharp edges, which could easily be remedied by tumbling them! Hopefully this design catches on because it could make manufacturing a lot cheaper!

[cconnon]

It would even be stronger if it didn’t have those hard corners. the concentrates the stress at that fracture point.

[kwk]

This is not stamped, it is laser cut my friend. You can see the laser cut lines on the side, a bit wave, stamp parts have "flat side and round side plus visible shear line. Take a closer look at any hardware store washer

[everettplummer]

We put a radius on metal parts for a reason. Sharp corners are the same as a score on glass. Hardened shafts have a radius to match the bearing radius. So the bearing presses flush. Sharp corner shafts are to breaking and snapping off. Sharp corners focus the stresses.

[jakubpipek]

Ryan - if you want to, I can prepare a lot of different DXF designs to be laser cut/punched out. Because with proper curves in proper places, the MBS is going to be even higher with the same amount and material used.

[arthurphilipdent]

I would also run it through a FPI test ( fluorescent penetrant inspection). This checks for any unintentional damage during the manufacturing process.

[jantchorzewski]

Are you sure it will be weaker in tension? The way it looks to me it could bend quite badly and form fractures early on when pulled in shear

[mfree]

You could go with 2/3 the thickness and actually press stamp it, have an oval hole to get rid of the stress risers, tumble for sharp edges, maybe even engineer the stamping die to stagger the bolt notches for better hold, and still probably have a max strength above anything you ought to have clipped to it.

Fiddle with the profile a bit so you get as many parts from a single sheet with as little waste as possible, and you've got a super good-enough glue in for a couple bucks with profit.

[thorstenl.]

You should give the four sharp 90° corners (of the D shaped hole and outside whre the shaft is attachet to the ring) a radius. There you have stress concentration, you could redirect and distribute by adding a radius instead of a sharp notch 👍🏻

[taoroalin]

yeah the sharp edge is such an easy problem to fix! they need to fix that!

[hyperphrog]

Considering it broke at the 90 degree angle, you should try one that is rounded

[luapele]

Hey Ryan just a heads up that is not punched it is cut from water jet plasma or laser.

[joshnicolson]

I’m not a climber, but wouldn’t the stress be perpendicular to the bolt?

[Therealphantomzero]

Being tumbled might affect the adhesion. Mechanical adhesion is necessary for epoxy. So scratches on the surface probably around 80 grit and up in metal but that depends so if like to see the effects of surface prep

[Jookyforever]

Need to do a test in shear pulled towards in the least thick dimension

[asdfasdf]

That sharp radius (were it broke) does not make sense... you're multiplying the stress there...
You're not limited to the traditional Form with a continous width... and you can top it of with a FEM optimized Form factor. Pretty Sure when optimized you'll get 30kn with Sams weight and identical production cost. Contact a buddy who studied mechanical engineering

[mcrut]

All the comments here have done you great, radius those bottom 2 corners and you’ll get some more load potential on that. That being said, 20kN is wild and at this point you are playing with safety factors.

Also! Think about force/stress like the flow of water, your metal is really made of a bunch of small chunks of other metal that through some chemical bonds link together like fingers. The finer those small chucks are and more homogeneous, the better they will do when they are pulled, pushed, twisted. Back to the water analogy, you also have a bunch of sharp turns from the epoxied end to the tangent of the “D.” Stress, like water, will flow better if the transitions are smooth and in the direction of the flow. Adding some material to radius the corners at the epoxy point will make it an easier transition for the stress to “flow.”

Love these kind of problems and look forward to your future videos in how you solve this for maximum strength to weight or maximum strength to shape and volume. Thanks for sharing your process!

[everettplummer]

The two inside corners needed a larger radius, the thinest area on the part. A larger radius on the bottom corners would eliminate the four failure points. Bad design. Point stress at four points.

[isalivegaming]

How many KN is considered survivable? 😂

Maybe we can get him to make up a scale.
Like if this one fails, you're only dead 3 times over or something along those lines.

[jessepletcher]

The notch effect on the bottom corner increases the chance of fracture or fatigue failure by a lot. If it was rounded this wouldn't be an issue.

[alanhillyard]

Dunno who designed it but get them to get someone that has actually done a bit of engineering design to look it over next time before hitting the go button on the laser cutter