Chassis rivets

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
dgrev
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Re: Chassis rivets

Post by dgrev » Sun May 02, 2021 10:22 pm

That's a surprise.
I thought steel rivets went out of fashion in mid-WW2.

But, in deepest darkest Outback Australia I think I would only
get very puzzled looks if I went to a fabrication company.
The ones I know of, all use MIG, TIG or Stick Weld (for the big jobs).

Thanks
Doug.
donk_316 wrote:
Sun May 02, 2021 6:53 pm
There are local companies that still sell the huck bom rivet AND rent you the tool.


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Re: Chassis rivets

Post by dgrev » Sun May 02, 2021 10:37 pm

20210501_153808 snip.jpg
Bolts in chassis
Those who have read this thread from the start will have seen that I have just acquired a GPW chassis that had been "restored" decades ago using large bolts in place of every single rivet. It is a mystery what went on with this chassis, but it has obviously lead a very hard life and a lot of work went into saving it.
I suspect with quite limited resources.
Thankfully the chassis was saved, I just want to try improve it.

Today I went and removed one of those bolts.
It was 3/4" AF, 1/2" UNC. x 1" long. As are all the others.
The area in front of the front cross member where you can see the threads and nuts for the spring hanger etc is very noticeable.

The scenarios I have come up with so far:

1) Sit there with an Oxy/Acetylene set with a copper backing plate and fill in the holes, redrill and install the Brent Mullins fake rivets.
Long and tedious.

2) Replace the bolts with Allen key dome head bolts, then put filler in the Allen socket, of course these would be still 1/2" shank and the dome would
be oversized. With the bolt just long enough that the nut sits flush.
Quick and simple.

3) Replace with 3/8" Allen key dome head bolts, making little collars on the lathe so that I can use the 3/8" dome heads and they will look better than
oversized ones - flush nuts too.

I know that using scenario (3) won't give a great deal of head diameter to hole diameter difference, but looking at a GPW chassis, any movement would tend to be in shear rather than in tension, so I discount any tendency to pull the head through the hole. I would buy high tensiles.

What I do about the spring mounting plates/hanger is far more critical and I think scenario (2) at the worst and scenario (1) at best.

Thoughts?

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Re: Chassis rivets

Post by wynnski » Mon May 03, 2021 1:05 am

You are between a rock and hard place.
Bolts of any sort are not a good solution for the chassis. They do not swell and grip the metal like a rivet does.This swelling and gripping of the rivet provides torsional rigidity to the chassis helping the chassis resist flexure. With bolts, your chassis will move and twist over uneven ground more than it was designed to,which was 3 inches over its length. This will put more stress on the body and the body might end up cracking and the body mounting holes could wear excessively.
Below is the tool and hydrualic power rig for fitting the Huck bom rivets and a picture of the bom rivet.
IMG_8988.JPG
IMG_8986.JPG
IMG_8548.JPG
IMG_8550.JPG
And this is the tool for fitting the solid steel rivets which are done hot. It is powered by the hydraulic rig. The tool is not finished yet. I am having the tips made to form the head of the rivets
IMG_8989.JPG
I know this kit is hard to get and expensive, but the huck gun and power rig is used by lorry repair companies for building and repairing chassis's.
There is a forum thread at the top of the technical section showing how to do all of this and it may give you some ideas. You may have already read it.
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JAB
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Re: Chassis rivets

Post by JAB » Mon May 03, 2021 3:53 am

dgrev wrote:
Sun May 02, 2021 10:37 pm
.........

What I do about the spring mounting plates/hanger is far more critical and I think scenario (2) at the worst and scenario (1) at best.

Thoughts?
Aren't the rivets used primarily to locate the hangers, prior to them being welded? If so, (my GPW frame is welded there) "cheat a little" by doing a little better (longer beads) job of welding them. When welding keep the bead about 1/2" away from the edges where the hanger bends to prevent stress cracks from forming there. With a better weld the rivets on the hangers become a less critical item.
-Jeff

GR8GPN2U!!!

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dgrev
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Re: Chassis rivets

Post by dgrev » Mon May 03, 2021 3:56 am

Good point.

I will investigate doing that.

Thanks.
JAB wrote:
Mon May 03, 2021 3:53 am
dgrev wrote:
Sun May 02, 2021 10:37 pm
.........

What I do about the spring mounting plates/hanger is far more critical and I think scenario (2) at the worst and scenario (1) at best.

Thoughts?
Aren't the rivets used primarily to locate the hangers, prior to them being welded? If so, (my GPW frame is welded there) "cheat a little" by doing a little better (longer beads) job of welding them. When welding keep the bead about 1/2" away from the edges where the hanger bends to prevent stress cracks from forming there. With a better weld the rivets on the hangers become a less critical item.

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Re: Chassis rivets

Post by wynnski » Mon May 03, 2021 4:47 am

JAB wrote:
Mon May 03, 2021 3:53 am
dgrev wrote:
Sun May 02, 2021 10:37 pm
.........

What I do about the spring mounting plates/hanger is far more critical and I think scenario (2) at the worst and scenario (1) at best.

Thoughts?
Aren't the rivets used primarily to locate the hangers, prior to them being welded? If so, (my GPW frame is welded there) "cheat a little" by doing a little better (longer beads) job of welding them. When welding keep the bead about 1/2" away from the edges where the hanger bends to prevent stress cracks from forming there. With a better weld the rivets on the hangers become a less critical item.
Yes the hangers are welded after rivetting
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Re: Chassis rivets

Post by dpcd67 » Mon May 03, 2021 6:33 am

I used bolts on my GPW and I guarantee you that my frame has not stretched 3 inches, or at all!
And I have used grade 8 bolts on spring hangers too; most recently on my M606. Those have not moved either. Yes they are welded after riveting.
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Re: Chassis rivets

Post by wynnski » Mon May 03, 2021 6:54 am

dpcd67 wrote:
Mon May 03, 2021 6:33 am
I used bolts on my GPW and I guarantee you that my frame has not stretched 3 inches, or at all!
And I have used grade 8 bolts on spring hangers too; most recently on my M606. Those have not moved either. Yes they are welded after riveting.
I think you may have misunderstood me, flexure does not mean stretch. Flexure is the action of bending or curving. The chassis on a Jeep is designed to twist by up to 3 inches over its length during use and still be able to return to normal. The rivets contribute to the stiffness of the chassis.
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Re: Chassis rivets

Post by dpcd67 » Mon May 03, 2021 2:42 pm

Let me re-phrase; I guarantee that my GPW frame has not flexed and failed to return to normal every time. You are welcome over and see for yourself.
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