Rivets for the #2 shear plate brace?

[Ted Idlof]

What do you guys do?

I've been using 3/16" steel rivets which seem to be failing more frequently. I have come to religiously check them and replace them if they don't look snug. But now I can't seem to keep up and they failed on me last time out resulting in the right side #2 shear plate failing and me sailing off into the weeds. Got it home and see that both left side rivets were failed and gone as well. Holy crap, this is getting tiresome. Do I have to drill out and replace every race?

Mo discussed the trade off of using bolts instead of rivets a few years ago.

http://formulamazdaforum.yuku.com/re...vets#reply-446

So, when you hit something, what's the damage done with a bolt instead of a rivet? the holes get boogered up?

What do you guys do? bolt, screw or rivet and what size/grade? And how did you decide?

[kea]

If the rivets have come loose or broken often, then I have to wonder if the holes are already opened up, which is aggravating the situation.
Not being familiar with the part in question, could something else be having an effect on this?

[Ted Idlof]

could something else be having an effect on this?

my question as well.

The first time I can write off to aluminum rivets that had been in service for awhile. With the 2nd time and again last weekend, I have a #1 shear plate that's not painted and I'm wondering if it's not stock and not stiff enough.

It's a bit of a mystery from an engineering POV. The thin rod that makes up the main part of the brace looks wimpy enough to give up (bend or break) before the frame gets damaged. The brace to frame fastener should be as stout as all the other attachment points on the frame. Logically, it should not be the main sacrificial part of this subsystem since it's subject to fatigue and variable installation techniques.

But whatever, I'm not alone, I know that several experienced hot shoes have dealt with it including Mo. So it's ultimately a question of which way to go.

[Darryl Wills]

Hi Ted,
Those rivets should be 3/16 stainless steel. Once the holes are enlarged then your only recourse is to use 1/4 inch socket screws in place of the rivets. My car is using the socket screws and all of the other shop cars still have the rivets. I agree that the single wire support is wimpy enough to give in a crash(experienced that this weekend on one of the shop cars) and damage the frame.

Darryl

[Purple Frog]

What about using a 1/4" structural rivet?

[Darryl Wills]

Two corrections on my post....
1) Not 1/4 inch but 7/32
2) Not "damage the frame" but "not to damage the frame"

Apologies to all who were trying to figure out where I was going with that post...

[Ted Idlof]

I had the wrong link in the first thread; here's the right one:

http://formulamazdaforum.yuku.com/re...vets#reply-446

Thanks Darryl, I think I'll try the stainless steel rivets next and be looking them over every session.

[Todd TCE]

Got tired of those things long ago. Drill them clean through for a #10 bolt with a nut on the inside- tough to get at tucked in the corner of the frame but easy to work on later and still shears if necessary or just bends the arm anyhow. But never comes lose on its own.

[Ted Idlof]

Got tired of those things long ago. Drill them clean through for a #10 bolt with a nut on the inside- tough to get at tucked in the corner of the frame but easy to work on later and still shears if necessary or just bends the arm anyhow. But never comes lose on its own.

Never could understand the wimpy rivets so this makes sense to me. Especially that the brace will fail before the frame gets boogered up.

Not sure it's worth tattooing this on my arm, but I'm definitely putting this in my super-secret owner's manual.

[Ted Idlof]

Well, I opted for Todd's advice and put in #10 machine screws w/ nylock nuts. Had to cut away a bit of the vertical "flange" on the triangular brace to get the nut on and tightened up. Don't think that will make any difference to the structural integrity and makes it easy to get those in and out.

I fully expect that I've seen the last of normal in-service fatigue failures of those frame attachments.

[Todd TCE]

Well, I opted for Todd's advice and put in #10 machine screws w/ nylock nuts. Had to cut away a bit of the vertical "flange" on the triangular brace to get the nut on and tightened up. Don't think that will make any difference to the structural integrity and makes it easy to get those in and out.

I fully expect that I've seen the last of normal in-service fatigue failures of those frame attachments.

Exactly how I've done them. If one were to be overly concerned about the strength of it; just use some cheap machine screws rather than socket heads, they are not overly strong. *And don't over tighten them, no need.