Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Search this Thread Display Modes
Old 06-26-2010, 07:46 AM   #1
wrndln
Senior Member
 
Join Date: May 2010
Location: Lakeville, MN
Posts: 2,496
Default Bucking frame rivets

I have never installed frame rivets before and am not sure what type and weight of bucking bar to use. I have installed many body rivets with a buck and waffle tool, but frame rivets are much larger. I need to install running board brackets using 5/16" rivets. Making the end of the bucking bar fit the head is no problem, as I have done that before. I have a long solid 1" rod I was going to use, but I am unsure of how much weight is required to adequately buck the finished end of the rivets. I have access to a heavy duty riveting gun and 5/16" bit that goes in the gun. I think I know how much to heat the rivet - cherry read, before hitting it with the rivet gun. So the unfinished end I have covered, I think. I don't know if I should try to tightly wedge the 1" rod inside the frame somehow or just try to hold it against the rivet head while a friend operates the riveting gun. Any help from someone that has installed large rivets would be appreciated.
wrndln is offline   Reply With Quote
Old 06-26-2010, 09:35 AM   #2
forever4
Senior Member
 
Join Date: May 2010
Posts: 298
Default Re: Bucking frame rivets

Rusty
I can't find any picks, but John Brady in Maryland made a very nice machined steel bucking bar for frame rivets and posted it on the old fordbarn and ahooga several times. I don't think the one inch bar has sufficient mass to do what you want.

The best solution is to squeeze them cold with a hydraulic riveter, but most people have no access to one.

So the next best thing is to rivet them hot.
That means the whole rivet cherry red (like building the Empire State building), and then setting them pneumatically as fast as possible.

This will fill the hole, and the rivet will continue to shrink and exert clamp load as it cools.
__________________
http://www.fordgarage.com/
forever4 is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 06-26-2010, 09:45 AM   #3
rotorwrench
Senior Member
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 3,472
Default Re: Bucking frame rivets

They will have to be heavy enough to take whatever hammer blows you dish out. The old Restorer series of books has some good ideas. They would make them out of heavy say 1" steel plate and fabricate them to set on the ground so you can hammer into a dead man. They would extend high enough off the ground to reach any given corner or tough spot on the frame. With running board bracket rivets, they have to clear the brackets to the ground so those would have to be fairly tall. With the help of a friend to hold things, you can flip the frame over & do the other side. You can shape them to fit the heads of the rivet or to form the buck tail you desire. I only have a 5X rivet hammer so I have to keep heating the 5/16" rivets with the oxy/acetylene torch every so often to get them to shape.
rotorwrench is offline   Reply With Quote
Old 06-26-2010, 09:48 PM   #4
pat in Santa Cruz
Senior Member
 
pat in Santa Cruz's Avatar
 
Join Date: May 2010
Location: santa cruz, calif
Posts: 1,893
Default Re: Bucking frame rivets

I recently bucked some running board rivets. I stood the frame against a wall, tying it with a piece of rope to secure it from falling forward. I made a heavy plate with a recess shaped like the rivet head that fit inside the frame over the rivet head. I placed a heavy steel shaft against it (made from an old drive shaft) that was long enough to reach the floor. I had to shim it with some other metal bars to get the weight of the frame against the bucking plate. When turning the frame over, it will be wider by the length of the running board brackets so you will need to raise the bar with a large solid brace ( I had a large piece of I beam) or use a longer bar stock. Then I heated the rivets red hot, especially at the mid body of the rivet near the frame, with an oxy-acetylene torch and riveted them with an air hammer. It worked really well. As mentioned above, due to rapid cooling, it might be necessary to do it twice to get the head fully formed.
pat in Santa Cruz is offline   Reply With Quote
Old 06-26-2010, 10:06 PM   #5
Marco Tahtaras
Senior Member
 
Marco Tahtaras's Avatar
 
Join Date: May 2010
Posts: 2,793
Default Re: Bucking frame rivets

For the record, I saw a 1930 (silent) Ford film years ago showing a frame being riveted together. It was very dark footage except for the cherry red rivets! The rivets were indeed squeezed. the riveter was a large device suspended from above so one man could swivel it into place and set the rivet. A second man simply transferred the red hot rivet from what looked like a coal bed to the hole that was to be riveted.

The following is the text of something I've posted several times over the last ten+ years. Other riveting suggestions that have been posted just don't do the job correctly. I've tried them all!!!



Riveting ---

As with many tasks, More time is invested in setting up than performing the actual task.

The cross members were riveted with 1/4" rivets. You'll find that the the holes to be riveted measure almost 5/16" (and were intended to be). The shank of the rivet MUST swell to fill the hole to be effective over the long term. For this reason it is difficult if not impossible to tighten a loose rivet. You can tighten the "set", but not swell the center.

For bucking we start with a ready made 8" bucking bar with the proper recess for the rivet head. We then cut the bar short enough to fit within the frame rail. This short bar is then welded along the side to a heavy piece of steel forming an off-set bar that extends around the edge of the rail. The bucking bar should be at least 3-4 lb.., but 5 lb.. is better.

For setting the rivet we use an air chisel or air hammer. I've been told they are commonly available in short stroke and long stroke versions and I use the long stroke or long barrel version. I think way too much is made of the type of air hammer as the rivets swell like butter when the shank is properly heated. The setting tool for the air hammer is matched to the rivet size similar to the bucking bar.

The riveting requires two people in almost all cases. The first person holds the rivet by the head with pliers while the second person heats the rivet with a torch. The rivets are heated red from the middle first, then towards the outer end.

Next, while the first person slips the rivet into the hole and backs it with the bucking tool, the second person sets down the torch, picks up the air hammer and proceeds to rivet.

The result is a rivet that completely fills the hole as it should. The process requires approximate 30 seconds per rivet.

Additional Notes:

1. If you attempt to back the rivet with a stationary object it will actually manage to walk back some appearing loose on the head side.

2. Anything functional can be used a bucking bar, but the head of the rivet WILL take the shape of the tool.

3. As a general rule the un-set rivet should extend through the hole 1-1/2 times the diameter of the rivet, i.e., 3/8" for a 1/4" diameter rivet. However our frame rivet holes are oversized by design requiring a little extra length to completely fill the hole.

4. Mild steel round head rivets up to 1/4" are readily available at many hardware stores.

Prior to assembling the frame for my Roadster we heated rivets in place with acceptable results. Since my frame was being completely assembled from parts I decided I wanted a good quality sealer applied to all the parts prior to assembly to prevent future corrosion in the joints. I didn't want to burn the sealer off the frame at the rivets, so we attempted the method described above. It worked so much better that I will never go back to heating the rivets in place! Once the frame was assembled with bolts and confirmed to be absolutely symmetrical, It took approximately an hour to install all seventy rivets.

Since most people won't go through the riveting process more than once, it makes sense to acquire or make the tools as a group or club project.

Links:

Big Flats Rivet Link: http://www.bigflatsrivet.com/

My frame project: http://www.abarnyard.com/roadster/frame.htm
__________________
http://www.abarnyard.com/

Last edited by Marco Tahtaras; 09-22-2012 at 05:03 PM.
Marco Tahtaras is offline   Reply With Quote
Old 06-27-2010, 02:27 PM   #6
wrndln
Senior Member
 
Join Date: May 2010
Location: Lakeville, MN
Posts: 2,496
Default Re: Bucking frame rivets

Thanks to all that responded, especially Marco and Tom Moniz (emailed me directly) for the riveting help. It seems that the rivets need to been heated almost to the melting point then installed into the hole. I will try it that way. My 1" x 3' steel bar is pretty heavy. I can try it and if it doesn't work well, I can try to find a heavier bucking bar. I have already drilled out 12 runningboard rivets to remove the stamped steel brackets without enlarging the holes, so if I mess up, I can always drill the rivets out and try again until I (we) get it right. I bought a few extra rivets to account for mistakes.
wrndln is offline   Reply With Quote
Old 06-27-2010, 03:25 PM   #7
Brentwood Bob
Senior Member
 
Join Date: May 2010
Location: brentwood, ca
Posts: 1,717
Default Re: Bucking frame rivets

Took 3 of us to rivet a replacement front cross member. The frame was suspended from the rafter and had the running board brackets in place. We used the acetylene torch and a bucking bar that rested on the concrete floor. Did this manually, so you can do it with out a rivet hammer. Marco's technique is optimum, but there are other ways to get the job done.
Brentwood Bob is offline   Reply With Quote
Old 06-27-2010, 09:36 PM   #8
Jim Mason
Senior Member
 
Join Date: May 2010
Posts: 503
Default Re: Bucking frame rivets

I have a page on rivets on my site...fwiw,jm
Jim Mason is online now   Reply With Quote
Old 06-28-2010, 05:29 AM   #9
Stinch
Senior Member
 
Stinch's Avatar
 
Join Date: May 2010
Location: Connecticut
Posts: 218
Default Re: Bucking frame rivets

Great information in this tread. I need to rivet two of my RB brackets back on the frame but have been putting if off. Never thought of standing the frame on it's side with a bucking bar against the floor. Maybe now I can get that finished in the next couple of weeks. BTW, I got my rivets from Big Flats in New York.

I did most of the front cross member rivets last year using the techniques Marco posted. Worked great and had to heat each rivet twice to get the job done. Now I say most of the rivets because I still need to do the two outer rivets of each side of the frame rail. The shape of the X-member prevents a straight line for the bucking bar. Perhaps the bucking bar needs to have a slight angle to it?

Rich
__________________
E30 68-B Cabriolet
Stinch's Ford Model A Site
Stinch is offline   Reply With Quote
Old 06-28-2010, 01:43 PM   #10
rotorwrench
Senior Member
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 3,472
Default Re: Bucking frame rivets

I've been bucking rivets for quite a few years in helicopter rebuild projects and have made all sorts of funny shaped bars to fit in all sorts of funny shaped places. The key on big rivets as Marco mentioned earlier, is the weight behind the bar. The offset in a non-straight shot has to be kept to a minimum for the hammer blows to get optimal effect. Also, the rivet head has to be held firmly against the materiel being riveted so that it doesn't get pushed back out. This is critical in the first few blows that expand the rivet then less so after expansion has taken place.

In aircraft construction we don't bother to form the buck tails like they did back in the hey day of steel construction. The buck tails are just flat and about as thick as half of the rivet's diameter. For authenticity you can mill a half round or pan head form into the bucking bar. Some body rivets had the waffle tails since that pattern would keep the squeezer dies from slipping during the original manufacturing process.

I think the reason a lot of the frame holes are so large after rivet removal is that the original expansion pushed the hole that way. Originaly the hole was only around .003" larger than the rivet shank diameter.
rotorwrench is offline   Reply With Quote
Old 06-28-2010, 02:29 PM   #11
Marco Tahtaras
Senior Member
 
Marco Tahtaras's Avatar
 
Join Date: May 2010
Posts: 2,793
Default Re: Bucking frame rivets

Quote:
Originally Posted by rotorwrench View Post
I think the reason a lot of the frame holes are so large after rivet removal is that the original expansion pushed the hole that way. Originaly the hole was only around .003" larger than the rivet shank diameter.
The holes were actually quite large. Where 1/4" rivets were used the holes were just under 5/16". This allowed a looser tolerance for the hole locations since most if not all the holes were punched into the stock prior to final forming of the shape. The rivets still fill the hole entirely including any off-set.

__________________
http://www.abarnyard.com/
Marco Tahtaras is offline   Reply With Quote
Old 06-28-2010, 02:47 PM   #12
d.j. moordigian
Senior Member
 
Join Date: May 2010
Location: Fresno, Ca.
Posts: 2,641
Default Re: Bucking frame rivets

Marco...Is that a correct statement, the holes were punched before forming,
just checking
d.j. moordigian is offline   Reply With Quote
Old 06-28-2010, 05:17 PM   #13
Marco Tahtaras
Senior Member
 
Marco Tahtaras's Avatar
 
Join Date: May 2010
Posts: 2,793
Default Re: Bucking frame rivets

Quote:
Originally Posted by d.j. moordigian View Post
Marco...Is that a correct statement, the holes were punched before forming,
just checking
Ok, I mis-spoke. I know from experience that holes did not align accurately, but were close enough. It turns out that each section or piece was done a little differently. The side members were done pretty much as I described but the steering holes were done much later and reamed for accurate alignment. This is VERY early information so procedures may have changed at a later date. Below is a snippet from a 1928 American Machinist article.

__________________
http://www.abarnyard.com/
Marco Tahtaras is offline   Reply With Quote
Old 06-28-2010, 05:32 PM   #14
d.j. moordigian
Senior Member
 
Join Date: May 2010
Location: Fresno, Ca.
Posts: 2,641
Default Re: Bucking frame rivets

Marco...OK...I'm dazzled...then they had 2 line for punching( L & R) rails, at least
in 1928
d.j. moordigian is offline   Reply With Quote
Old 06-28-2010, 06:32 PM   #15
rotorwrench
Senior Member
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 3,472
Default Re: Bucking frame rivets

I wouldn't be surprised if they punched the holes as long as it is in a controled way(jigged). In more current manufactureing processes holes are punched or drilled as pilot holes to give the correct quantity and location of all holes but these pilot holes are smaller than the final hole so as to get a more accurate fit during assembly. FoMoCo did everything they could to speed things up so they might have just taken the chance that they would be close enough to fit.

Today we start with the pilot holes then drill to fit Cleco fasteners to keep things aligned. Even with fair alignment the holes still have to be chased with a drill. Too bad Ford was so paraniod about keeping its business from prying eyes of the competion. We would have a lot more information about how things were actually done back then. Henry probably would have thought keeping track of it a waist of time anyway.

Body mounting holes,shock mountings, etc. were definitely pressed. You can tell by the way the metal is rounded on one side then sharper on the other.

Last edited by rotorwrench; 06-28-2010 at 06:40 PM.
rotorwrench is offline   Reply With Quote
Old 06-28-2010, 06:54 PM   #16
d.j. moordigian
Senior Member
 
Join Date: May 2010
Location: Fresno, Ca.
Posts: 2,641
Default Re: Bucking frame rivets

rotorwrench...I'm familiar with the proses, I just thought it would be the other way around, to control shift and drift in the dies. Also why 2 sets of punching dies,
l & r, Henry could have saved money with just 1, or did I miss something?
d.j. moordigian is offline   Reply With Quote
Old 06-28-2010, 07:17 PM   #17
rotorwrench
Senior Member
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 3,472
Default Re: Bucking frame rivets

Maby it was one for vertical holes and one for horizontal holes. I'm sure what ever it was that is was the only way it would work most efficiently at the time. If they pierced the holes before they formed the rail it would be really difficult to get a good alignment. Left and right are different enough to warrant same processes for both sides but different jigging. I sure wish there were pictures of the process.

Last edited by rotorwrench; 06-28-2010 at 07:29 PM.
rotorwrench is offline   Reply With Quote
Old 11-10-2010, 09:35 PM   #18
Rusty
Junior Member
 
Join Date: May 2010
Posts: 9
Default Re: Bucking frame rivets

Marco, So the rivets in the pic appear to be perfect round on both sides, I am working on a stock 32 chassis and all the rivets are round on the outside and smased or bucked on the inside, So my question is If the buck is on the outside how do you get the air hammer into the frame rail to ram the rivet? Or does the buck need to have have the round recess as well as the ram in the air hammer? Also some of the rivits appear to be 3/8 on the Kmember, thanks for any help
Rusty is offline   Reply With Quote
Old 11-11-2010, 01:30 AM   #19
pat in Santa Cruz
Senior Member
 
pat in Santa Cruz's Avatar
 
Join Date: May 2010
Location: santa cruz, calif
Posts: 1,893
Default Re: Bucking frame rivets

if you don't want to smash the head, the buck needs a round recess.
pat in Santa Cruz is offline   Reply With Quote
Old 11-11-2010, 05:44 AM   #20
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 5,920
Default Re: Bucking frame rivets

Rusty, an air hammer will not work doing this. It must be a Rivet Gun ...and generally speaking a 3X is most suitable for frame rivets. Do an internet search (eBay) to see what they are. Once you have used one, you will understand why there is a difference.
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 05:48 PM.