Hi Everyone,

I am having trouble finding what I would call a carriage bolt, it
looks just like a carriage bolt except that it has a spline round
shape under the head instead of a square shape that is usually under
the head of a carriage bolt. The round shoulder under the head is a
fine spline that looks about 8 mm long.

The bolts are used to secure a steel gas tank support arm to the frame
of a truck.

I need a source of supply I can order from here in the USA but I'm
having trouble finding this item.

Thread specs = 10 mm OD X 1.5 mm pitch
Length under head = Need at least 40 mm long but can cut down a longer
bolt if needed.
Head diameter = Approximately 20 mm OD, but can use a little larger if
needed.
Grade = Prefer a 10.9 class or whatever the strongest grade available
is.
The round spline shape or shoulder that is directly under the head has
an 11 mm OD.

I have tried local hardware and autoparts stores along with www.mcmaster.com.
I also looked through the www.auveco.com/ catalog but have not found
anything yet.

Does anyone have an idea of where I might find something like this ?

Thanks
John

On Sep 18, 1:23*am, John2005 wrote:
Hi Everyone,

I am having trouble finding what I would call a carriage bolt, it
looks just like a carriage bolt except that it has a spline round
shape under the head instead of a square shape that is usually under
the head of a carriage bolt. The round shoulder under the head is a
fine spline that looks about 8 mm long.

The bolts are used to secure a steel gas tank support arm to the frame
of a truck.

I need a source of supply I can order from here in the USA but I'm
having trouble finding this item.

Thread specs = 10 mm OD X 1.5 mm pitch
Length under head = Need at least 40 mm long but can cut down a longer
bolt if needed.
Head diameter = Approximately 20 mm OD, but can use a little larger if
needed.
Grade = Prefer a 10.9 class or whatever the strongest grade available
is.
The round spline shape or shoulder that is directly under the head has
an 11 mm OD.

I have tried local hardware and autoparts stores along withwww.mcmaster.com.
I also looked through thewww.auveco.com/catalog but have not found
anything yet.

Does anyone have an idea of where I might find something like this ?

Thanks
John

John,
I found "ribbed neck bolts": http://www.chicagofastener.com/products.htm
You’ll have to contact them to see if they can supply exactly what you
need.
Another possibility: http://fasteners.wbparts.com/Fastene...ners/1972.html
McMaster Carr has ribbed neck bolts, but only Grade 2, SAE thread –
closest size for what you need is 3/8”-16.
I assume that you’ve already tried getting them from a dealership or a
salvage yard.
There are many similar bolts if you want to search the web some more.
Try: self-clinching, self-broaching, wheel bolts, spline-bolts,
knurled-bolts, etc

You might also try

www.mutualscrew.com

They have *lots* of types of fasteners

Thanks guys,

I think this is a custom made bolt, it's not like the "ribbed neck
bolts" because the splines on those bolts are too course and long. The
splines on these bolts are short and fine, like those on a common
wheel stud. They look exactly like a wheel stud, except with a
standard carriage bolt round domed head.

I'm just going to use a 7/16" OD thread, grade 8 hex / flanged head
bolt and a grade 8 flanged head nut.

I think the only reason they used the custom fastener is to speed
assembly at the factory. The splines keep the bolt from turning as the
nut is torqued down, and you don't have to hold the bolt with a wrench
as you torque the nut down.