Author Topic: Battery hold down clamp bolt  (Read 4293 times)

GaryL

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Battery hold down clamp bolt
« on: November 07, 2007, 05:15:52 AM »
Sorry for this small anal question, but what is the orginal bolt for the battery hold down clamp? The size is 5/16NC but does it have a captured washer and no threads on the end just like a door hinge bolt?
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

JohnZ

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Re: Battery hold down clamp bolt
« Reply #1 on: November 07, 2007, 04:38:02 PM »
Mine, which I believe to be original, is a 5/16"-18 recessed hex head with a captured conical washer and a reduced-diameter round flat point (we called them "dog-point" bolts in the plant).
'69 Z/28
Fathom Green
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KevinW

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Re: Battery hold down clamp bolt
« Reply #2 on: November 07, 2007, 07:22:03 PM »
Nice timing on this! :)  John, what size is the captured washer? Thanks!

GaryL

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Re: Battery hold down clamp bolt
« Reply #3 on: November 07, 2007, 08:59:51 PM »
That souinds like what I bought, but the washer has teeth. It lokks exactly like a door hinge bolt.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Marty

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Re: Battery hold down clamp bolt
« Reply #4 on: November 07, 2007, 11:52:46 PM »
I have an original bolt off a 68 full size car that I will look at when I get home. I think the head markings are RBW but I'll double check. I'll try to take an image of it tomorrow.
Martin Foltz
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68 Van Nuys Camaro

JohnZ

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Re: Battery hold down clamp bolt
« Reply #5 on: November 09, 2007, 12:16:17 AM »
Washer is 7/8" in diameter, and it does have serrations ("teeth") on the bottom.
'69 Z/28
Fathom Green
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Marty

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Re: Battery hold down clamp bolt
« Reply #6 on: November 09, 2007, 12:27:37 AM »
The one I have also has a 7/8" diameter washer but it doesn't have serrations on the bottom. The length is 1" including the washer.
RBW head marking, grade 5 (three lines). Remember, this is off a 68. Anyone else have an original bolt?
Martin Foltz
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68 Van Nuys Camaro

GaryL

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Re: Battery hold down clamp bolt
« Reply #7 on: November 09, 2007, 01:40:17 AM »
Washer is 7/8" in diameter, and it does have serrations ("teeth") on the bottom.

That's what I thought. It is exactly a door hinge bolt, but the closest they could come. There is no AMK Products listing for the GM part number in the AIM.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

GaryL

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Re: Battery hold down clamp bolt
« Reply #8 on: November 09, 2007, 03:08:36 AM »
Wow. I go out to my spare bolt bag and find 2 like you guys describe. If only I had known.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Dave69x33

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Re: Battery hold down clamp bolt
« Reply #9 on: February 12, 2008, 02:39:35 AM »
JohnZ,

What is the marking inside the head?  Is it an "N" like the one shown?

This is AMK's individual bolt kit #G4352, $1.50.  It is also avalible in a set of (6) for $5, item #B-11915.

Its a 5/16-18 x 7/8, 1/2 across the flats, 3/4 conical encapsulated washer, phosphate gray-black color.  It has a "lead point" tread start nose tip w/o treads for about first 1/8".

JohnZ

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Re: Battery hold down clamp bolt
« Reply #10 on: February 12, 2008, 03:17:17 PM »
<<JohnZ,

What is the marking inside the head?  Is it an "N" like the one shown?>>

Here's a photo of the bolt on mine. Although the overall configuration of the bolt is similar to the door hinge bolt, I wouldn't expect them necessarily to have the same headmark - Fisher Body released and purchased the door hinge bolts under their own part number, and Chevrolet released and purchased the battery hold-down bolt under their own part number.
'69 Z/28
Fathom Green
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Pex68

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Re: Battery hold down clamp bolt
« Reply #11 on: March 19, 2008, 12:47:29 AM »
John,

See your clamp is painted, is that correct?  I always thought those were phosphate like in Dave's photo.
Chris P
1968 Sequoia Green SS 396/325 M20

JohnZ

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Re: Battery hold down clamp bolt
« Reply #12 on: March 19, 2008, 04:13:56 PM »
John,

See your clamp is painted, is that correct?  I always thought those were phosphate like in Dave's photo.

I suppose they could have been either way, although I've only seen them painted; mine is original to the car.
'69 Z/28
Fathom Green
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Dave69x33

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Re: Battery hold down clamp bolt
« Reply #13 on: March 24, 2008, 01:13:03 AM »
I purchased mine hold down clamp from Paragon Corvette Reproductions, Kit Item #1515K, $5.00 which includes bolt Item #1498, "E" head mark.  I must assume there could have been a couple of different bolt head markings uses.