Tabbed washers -- not very safe at all?

[Paul Eastham]

Hi,
I installed my airbox yesterday and safetied the bolts into the carb with the tabbed washers Van's provides. The washers are square, and only one of the two tabs really lines up to press against the flat of the bolt head.

After getting the tab down as tight as I could (with a punch and small hammer), I tried to loosen the bolt and it slipped right past the tab. I could detect no resistance provided by the tab.

Am I missing something here?

I was thinking I'd just swap in drilled-head bolts, but those are a little hard to come by in the coarse thread pitch. Mcmaster has some, though at a lower strength (grade 5). The ones in the kit are grade 8 undrilled.

Paul

[mlw450802]

Originally Posted by Paul Eastham

...I was thinking I'd just swap in drilled-head bolts, but those are a little hard to come by in the coarse thread pitch. Mcmaster has some, though at a lower strength (grade 5). The ones in the kit are grade 8 undrilled.

Paul

You can always just drill the heads yourself.

-mike

edit: PS aren't grade 8's usually fine pitch threads?

[Paul Eastham]

Originally Posted by mlw450802

You can always just drill the heads yourself.

-mike

On a drill press, I presume...will that give good results, even if your drill press has a tiny bit of run-out like mine? I suppose you would use a drill press vice to secure the bolt?

[mlw450802]

Originally Posted by Paul Eastham

On a drill press, I presume...will that give good results, even if your drill press has a tiny bit of run-out like mine? I suppose you would use a drill press vice to secure the bolt?

Use one of these critters http://www.wicksaircraft.com/catalog...673/index.html

This was from Wicks but there are many variants from lots of sources.

-mike

[Walt]

But I haven't run across any yet either. I lock-tited mine and used the tabs and have not had any problem in 400+hrs but would prefer the safety wire. I pull the air cleaner at least evey 100 hours to keep an eye on this area but not problems so far. If anybody buys some of these bolts get 4 extra for me!
Walt
7A

[DanH]

Drill the heads on some coarse thread Grade 5's. No reason to use a Grade 8 on an airbox.

Dan

[Gsuit]

Just finished up the Superior Build School two weeks ago, and there were several places inside the accessory case we used loctite and tabbed washers.