Defense pins?

[bobbysq]

Does anyone know what type of hardware the defense pins were? We recently got ahold of some official defenses and would like to know how to hold them in place.

[Mark McLeod]

FIRST HQ used "S" hooks from peg boards. This kind of hook
Some Districts (MAR) used simple threaded hardened bolts-threaded all the way to the head/no smooth shank (loose in the hole not screwed in).

[Nate Laverdure]

Curved J-Hooks for Pegboard - 5/8" - U-LINE H-2694

[marshall]

Originally Posted by Mark McLeod

FIRST HQ used "S" hooks from peg boards. This kind of hook
Some Districts (MAR) used simple threaded hardened bolts (loose in the hole not screwed in).

Did the bolts hold up any better than the hooks?

[Mark McLeod]

The bolts hold better because the threads catch and hold, while the peg board hooks are softer metal and gradually stretch out and have to be replaced.
The peg board hooks sometimes need to be cut out when they get shoved into an awkward position, while the bolts can usually be unscrewed if necessary.
But the hardened bolts do gradually enlarge the holes in the defenses, so if you're planning to use the defenses many times the holes will get damaged by repeated use of the bolts.

[marshall]

Originally Posted by Mark McLeod

The bolts hold better because the threads catch and hold, while the peg board hooks are softer metal and gradually stretch out and have to be replaced.
The peg board hooks sometimes need to be cut out when they get shoved into an awkward position, while the bolts can usually be unscrewed if necessary.
But the hardened bolts do gradually enlarge the holes in the defenses, so if you're planning to use the defenses many times the holes will get damaged by repeated use of the bolts.

I genuinely appreciate that thorough explanation of the pros and cons of defense retaining fastener selection. Thank you!

[Mark McLeod]

There are other nuances where the pegboard hook can be more effective than the straight bolt in holding a particular style defense down, but a lot of that depends on how the robots are interacting or lifting the defenses.
There are also variations that can work even better like tying down the S hooks if the defense will never be moved or replaced, e.g., low bars.

[Karibou]

Originally Posted by marshall

Did the bolts hold up any better than the hooks?

The bolts worked great until they started enlarging the holes, as Mark said. During the season, the bolts would occasionally get jammed at an odd angle if a defense was hit hard, but it didn't happen often and even in that scenario they were pretty easy to take out using a drill with a hex bit (from my experience). But, they didn't deform or break like the hooks.

However, at this point in the off-season, some of the MAR defenses that typically get hit the hardest during the match (moat, rock wall) have holes too large for the bolts to keep the defenses securely in place during a match. We're looking at drilling new holes for Ramp Riot this weekend because of the issues they had at the last event.

If the defenses you acquired have holes that are still approximately circle-shaped, you'd probably be fine with using bolts. I doubt that one robot using the defenses for practice/demos (which is what I'm assuming you'd be doing) would cause the holes to enlarge to an unusable point before you decide to retire the robot

[marshall]

Originally Posted by Karibou

I doubt that one robot using the defenses for practice/demos (which is what I'm assuming you'd be doing) would cause the holes to enlarge to an unusable point before you decide to retire the robot

Sadly not, genuinely just curious because all I ever saw were the hooks and they definitely didn't hold up.

[Michael Kaurich]

Just make sure to have a set of bolt cutters on hand if you are looking to swap the defenses out. It is easier to cut a 10 cent bolt/hook than spend the time trying to get the things out of the holes.

[bobbysq]

So if my team were to get the hooks, (which I doubt we will, since we have plenty of 1/4-20 bolts laying around) how would we put them in?

[Mark McLeod]

Think of the hole in the defense as a pegboard and insert the pegboard end of the hook into the hole.
Swing the hook to the side out of the way.

[Cothron Theiss]

Originally Posted by Mark McLeod

Swing the hook to the side out of the way.

This part is really important, especially on the Cheval-de-Fries. At Battle for the Bluegrass, I noticed that if the hook part was facing inwards, the corner of the outermost sections could get caught under the hook and stay in that position. Granted, this was with the holes looking rather oval-ish, but it was something the field reset crew had to check each match.