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Need Source For Flange Head Bolts

May 20, 2017, 05:09:21 pm

There are a lot of these 5/16 X 18 X 1 flange head serrated screws/bolts in my FT and I need a few more.  Mine taper to a point with threads the full length.  They are like GM body bolts. 

Does anyone know where to get them? 

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Re: Need Source For Flange Head Bolts

Reply #1 – May 20, 2017, 05:31:32 pm

Here you go

Dorman® 700-304 - Captive Washer Head and CA Point Body Bolt (Steel, 5/16-18...

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Re: Need Source For Flange Head Bolts

Reply #2 – May 21, 2017, 08:27:37 am

I'm replacing my entry steps and there are six of them holding the steps on.  A few of them are stripped, and the tubular framework
the steps are attached to has too many holes.  One screw has five holes, all in close proximity to each other.  The old steps look original, so I guess the holes are factory too.

The screws aren't self-tapping, so maybe FT drilled holes first and then just screwed them in.  That would explain why they're stripped.
There seem to be others holding things (compressor/HWH pump) to the floor of the electronics bay.

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Re: Need Source For Flange Head Bolts

Reply #3 – May 21, 2017, 08:32:21 am

They actually are self taping in sheet metal and thin wall tubing.

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Re: Need Source For Flange Head Bolts

Reply #4 – May 21, 2017, 08:45:46 am

.

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Re: Need Source For Flange Head Bolts

Reply #5 – May 21, 2017, 08:58:12 am

That looks like it is single use only in whatever gauge steel it goes into. They use those to hold fenders to frames and other body parts in cars without pre taping. With the point it would cross thread a pre taped hole most of the time.

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Re: Need Source For Flange Head Bolts

Reply #6 – May 21, 2017, 09:00:12 am

These type of bolts actually force the metal to deform and create thread. The amount of thread created (%) is dependent on the pre-drilled hole size.
I have even gone so far as to grind a cutting "edge" on bolts so they first function as a piloting cut tap and then as a form tap. This involves nothing more than using my 4-1/2" grinder with the wheel square cornered outside dia. and then grinding a short lead parallel to the axis of the bolt. This lets the bolt start the thread easier, provides a place for chips to go, and helps form the threads without tearing the thread form loose from the part being threaded into.
Not all materials are conducive to thread forming, and the one you are putting these bolts may be one of those materials. Also  materials that are not compatible may have adverse corrosive effects on the threads.

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