26-01-2014 19:34

MrBasse

Re: pic: Bumper Pockets

Are you going to open those up a bit to allow room for fabric? Or do you have way to mount that doesn't involve the fabric wrapping around the plywood?

We got flagged at MSC last year for dadoing all the way top to bottom on our bumpers, it might be worthwhile to think about a reinforcement at the top. We only went through 1 ply maybe 1.5 too. Our plan for this year was to just dado up far enough for the bolt heads to fit, but then we just made them bigger instead.

26-01-2014 19:40

Richard Wallace

Re: pic: Bumper Pockets

Thanks for the heads up. Our pockets are blind, not top-to-bottom. They only extend far enough to reach the minor protrusion.

And yes we will need to adjust a bit to fit the fabric -- this is a work in progress.

26-01-2014 19:51

MrBasse

Re: pic: Bumper Pockets

No problem, I loved it when we did those last year. We had ours set to fit so tight we almost didn't need to anchor the bumpers. The only downside was the one time per competition we removed them for inspection. Another thing to think about...Be sure that you can remove them straight up off the robot with no need to angle them if they are a one piece bumper.

Fit looks great, good luck this year, and we'll see you guys on March 27th!

27-01-2014 07:52

Rosiebotboss

Re: pic: Bumper Pockets

Are the bolt heads less than 1/4"?

27-01-2014 09:00

Richard Wallace

Re: pic: Bumper Pockets

Wood backing used in FRC bumpers is 3/4" thick, so by looking at the picture I'd say the bolt heads are less than 1/4".

McMaster shows the head height for 1/4-20 x 1" used for chassis assembly as 5/32", and the head height for 3/8-16 x 4" used as axles as 15/64".

So yes, less than 1/4".

27-01-2014 11:10

MrBasse

Re: pic: Bumper Pockets

The complaint that we got wasn't the fact that the gap was greater than 1/4", it was that we compromised the structure of the plywood and didn't have a full 3/4" backer of plywood. We got though when one of my students cited the rule book almost word for word. In my mind it is fine the way they have it and was fine the way we had it, but it got us placed on a "watch list" of some sort. I don't know what exactly that meant, but I guess if our bumpers exploded or otherwise failed structurally then they would have said "I told you so."