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Old 10-02-2021, 04:53 PM   #1
Russell Reay
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Default Holes in frame rail

In the top chord of the frame at the ends of the front crossmember are a set of three holes, 1 3/8" between each pair. They correspond to the same holes in the fender, but this seems like an odd pattern if the only purpose is to bolt the fender to the frame. Is there something else that is attached to this trio of holes ? Other hole pairs are for the hold-down brackets as well as the fender. I might make a grand discovery upon reassembly, but like to minimize surprises.
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Old 10-03-2021, 07:36 AM   #2
BRENT in 10-uh-C
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Default Re: Holes in frame rail

If they are in alignment with the front crossmember, they are holes for flush-mounted rivets.
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Old 10-03-2021, 09:54 AM   #3
Russell Reay
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Default Re: Holes in frame rail

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Originally Posted by BRENT in 10-uh-C View Post
If they are in alignment with the front crossmember, they are holes for flush-mounted rivets.
You can see the three holes which are countersunk. On the web of the frame there are two hex head bolts which appear to be 3/8 diam. There are no nuts on the inside Is it possible that the rivets were drilled out, and those two bolts are now of structural importance? See picture of fender showing the three holes, one showing head of carriage bolt.
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Old 10-03-2021, 10:34 AM   #4
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Default Re: Holes in frame rail

In your first picture you are missing the three rivets.
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Old 10-03-2021, 11:49 AM   #5
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Default Re: Holes in frame rail

The major attachment of the front cross member to the frame rails are those three flush head rivet holes. They don't attach with anything else. It's not uncommon to find bolts replacing missing rivets on these old cars. Flush head screws were not common in that size back in the day so folks used what ever method they could to extend the usefulness of the car. It looks like they bolted plumb through the fender to affect a fastening method.

Bolts don't hold up well for a frame joining method due to the flexibility under stress and strain. Rivets were used to effect a very tight fastening method since they expand into the rivet holes during the squeezing process that Ford used. There are still a lot of old steel frame buildings and bridges that were put together with rivets. Some are older than the model As
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Old 10-03-2021, 12:34 PM   #6
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Default Re: Holes in frame rail

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This is all good information, and comes as no surprise. I am inclined to replace the rivets, but have never done so. I understand there is a tool called a bucking bar, which, I presume, holds the back of the rivet while the other end is being swedged. Since these missing rivets are directly over the bottom chord of the frame could I fill that void with pieces of heavy steel to resist the pounding on the rivets? I presume (lots of presuming here) that the rivets should be heated red hot, and the first blow is intended to expand the rivet into the hole, and subsequent blows to peen it over (installation of brake tracks on steroids). When thoroughly peened, these particular ones should be ground down--right?
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Old 10-03-2021, 01:39 PM   #7
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Default Re: Holes in frame rail

If you go with bolts, use Grade 5 fine thread hex head bolts and tall nuts underneath. There were three rivets at that point so place three bolts. Tap the holes for a threaded fit and smooth down the bolt heads to the height of the original rivets with a grinder.

I have seen some real dodgy jobs where somebody punched indents in the fender and bolted it all up through the fender with carriage bolts then slathered on bondo to hide the mess. Pretty sad fix as flexing of the joint eventually causes the bondo to lift up and break off.
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Old 10-03-2021, 02:07 PM   #8
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Default Re: Holes in frame rail

I had help and a bare frame.
I would concentrate on making up a bucking bar.
I used nuts and bolts to position and keep the cross member in position, replacing one bolt at a time, the bucking bar was made with a cup to nest the round rivet head in, and rested on the concrete shop floor.
Realize there will be a lot of rust between the cross member, and the frame. Remove and prime, or at least use etch/ metal prep to stop that.
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Old 10-03-2021, 04:54 PM   #9
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Default Re: Holes in frame rail

There is another thread currently on the Barn pertaining to the same rivet holes. See https://www.fordbarn.com/forum/showthread.php?t=304641 Some good information about installing the rivets and where to source them.
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Old 10-03-2021, 07:13 PM   #10
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Default Re: Holes in frame rail

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There is another thread currently on the Barn pertaining to the same rivet holes. See https://www.fordbarn.com/forum/showthread.php?t=304641 Some good information about installing the rivets and where to source them.
I read part way through that thread, but at the time didn't see how it applied to me. I now see that my front crossmember has been replaced and is held in place by four 5/16 bolts (not 3/8) on each end. I think I have no choice but to remove the crossmember, clean it up, and replace it using rivets. I will need to investigate some of the 'how to' contacts. A question that immediately comes to mind is whether I can remove the front crossmember w/o also loosening up some rear-ward connections, eg rear motor mounts. I can unbolt the front motor mount and front spring, and remove the long spacers which mount the radiator splash, but how should I spread the frame rails to remove the crossmember?
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Old 10-03-2021, 07:36 PM   #11
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Default Re: Holes in frame rail

You may want to measure your frame to check for straightness before you do the final setting of the rivets.
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Old 10-03-2021, 09:14 PM   #12
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Default Re: Holes in frame rail

Rivets and bucking tools, rivets set tools, are available here....

http://bigflatsrivet.com/


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Old 10-19-2021, 12:24 PM   #13
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Default Re: Holes in frame rail plus new mystery

Update--I bought the set of rivets for the front X-member and the bucking tool that is inserted into the C-section of the frame. The rivet tool that goes in the air hammer doesn't fit mine, but an 8-lb hammer and acetylene torch is an effective substitute with rigid support from frame to concrete floor. The other four connections per side that should be rivets had been replaced with 5/16 bolts. I replaced them with new grade 8 bolts. Will monitor carefully when the vehicle goes on the road. I installed the new brassworks radiator today, not as a sign of progress, but to move it out of the shop. Discovered that the crossmember is a 28-29 instead of 30-31 as evidenced by the raised mounting pads. The mounting holes are 19" apart, perfectly matching the new rad, but there are other holes just outboard of the originals. I see in the catalogs that 28-29 rads are different than 30-31. Can I assume the wider holes are for the old rad?
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Old 10-20-2021, 11:34 AM   #14
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Default Re: Holes in frame rail

I use the 100 degree countersunk screws but I don't think if these type screws are available in Torx head yet. They are Phillips head cross recess style. They are MS24694 and can be purchased through Aircraft Spruce. These are 125,000 to 145,000 psi tensile strength depending on size and in alloy steel.

Big Flats rivet calls out flat head rivets for the top on the front cross member but the ones I've delt with seem to have a countersunk hole. I'm not sure what Ford used due to the condition of most holes after so many years and farmer fixes. I weld them up and re-countersink them but All my aircraft stuff is 100 degree countersunk so that's what I use. I'll have to look for an 82 degree countersink if I ever try to use the torx screws.

I haven't tried to use them yet but there are some torx head 82 degree countersunk screws available that have a very high tensile strength value (140,000 psi). I would use some form of countersunk screws until they can be riveted. I use them to mock up frames and keep them in place until the riveting is ready to be done. McMaster Carr is a good source for the 82 degree.

If Ford used flat head rivets with no countersink then they will stand up a bit proud on the frame rail unless they had the head on the underside and mashed the buck tail down into a countersink. If this is the way they did it then the way I do it turns out the same way in the end since I don't try to round off the buck tail on those. It looks like a flat head using a flat bucking bar

The early 28/29 cross member fit the shorter radiator used on them. The 30/31 used a taller radiator to mach the belt rail height. Due to the taller radiator, the cross member has a depression in the frame rail area where the radiator mounts while the 28/29 stands up a bit higher and has a raised look to it. THis link has a photo of one in post #9. https://www.fordbarn.com/forum/showt...nt+crossmember

Last edited by rotorwrench; 10-20-2021 at 11:54 AM.
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Old 10-20-2021, 11:46 AM   #15
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Default Re: Holes in frame rail

Based on the number of rivets per size in the kit I think you are correct about the flat head on the frame rail and them sitting proud. Knowing that I couldn't install the other rivets correctly I used the longer round head. I was able to almost totally fill the countersink with the red hot rivet using an 8# hammer.
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