8N bumper

Here's some more bumper pics at different angles. It was pretty beat up when I got it. I ground out all the rivits and beat each piece back into shape with Oxy/Acetylene using the main beam as a pattern. Just-Eight-Ns had the rivets. The two bars on either side of the main beam are the same length, the one at the top is a little shorter.

Hope this helps. Thanks for the compliments.

flathead

The third bar is the main beam that is bolted to the axle. The two uprights horns that come off of it are indeed welded to it. The top two and bottom bars are then riveted to the uprights.

flathead

That is one beautiful machine there! You did a fantastic job on your restoration. Thanks for the pics.

Rick

Thats funny, I had Derek send me two extra rivets also for the same reason.

1) I got the original rivets out by grinding the heads off the back side of the bumper and driving them out with a combination of a pin punch and just beating the bumper silly until it came apart.

2) I was lucky in that the big thick center bar was straight (well curved like it was supposed to be). In any event it didn't need any fixin. The other three bars were pretty bad and I wasn't sure I could fix them. It took about three nights of heating each deformed area with oxy/acetylene torch and beating it over an anvil, stump, and between two 2 by fours with a 3 lb hammer. I also c-clamped the bars to the base of my engine hoist and used heat and a piece of water pipe as a cheater bar to un-twist the twisted areas. Basically heat the bars up as hot as you can stand and beat the tar out of em. The vertical horns were aslo bent but they straighten out pretty easy with heat and the bfh.

3) To put the new rivets in I clamped each bar in place one at a time and stuck the rivet in from the front. I used my anvil as a bucking bar by propping the bumper up on top of my anvil with the rivet head resting in the top of the pritchel hole. I made a rivet setting tool out of a 3/4 inch grade 8 bolt by grinding a half round in the end of it with a die grinder. Then I just heated the rivet stub on the back side of the bumper with the torch till cherry red and set it with 4 or 5 blows.

4) See # 3. Anvil = bucking bar, Rivet Set = Ho-made from bolt, Heat and hammer. I had the bumper propped against the stump to hold the rivet upright on the anvil but a teenage boy would do just as well. My boys are 2 yrs old and 3 months old and Mrs. Flathead won't let me use them for such worthwhile activities yet.

5) No the replacement rivets are only round on one side like the originals. If they had heads on both sides you wouldn't be able to get them through the holes. The shape on the back side is determined by the shape ground into the setting tool. The ones I took were more of a flat cylinder in shape with a bit of a crown on the back side and thats what I ended up with - with the replacements. From the front, they have the same store-bought half-round shape as the originals.

I know what you mean about lying awake trying to figure this stuff out. Just go for it with a vengence. I just figured I couldn't make it any worse.

Hope this helps,

flathead

My original bumper has the half round ends on BOTH sides of the bar - front an back. In other words - both sides of my bar's rivets look like the fronts on your picture. I wonder if the originals were studs like the replacements, but had a very tight fitting round cap that you pounded on the end(?) When I sheared them, it sheared in the middle where the bar rests against the vertical support bar.

My bottom bar is bowed, but not inwards like it was hit by a stump or something. Rather, it is bowed as if you could grab the bar (while still attached to the bumper) with both hands - one on each end, and bow it down. Looking straight at the bumper - it looks kinda like it is smiling at you. I would assume bending it back across the thick width would be tougher than if it was just bent inward...

Thanks a ton - you sure did a great job on yours.

Dan

On the setting tool made out of a bolt - No, the half round shape is ground INTO the end of the bolt such that it makes a negative half round profile. Basically the same shape you would get if you stuck the factory rivet head in a gob of silly putty. The idea is to make the stub end of the rivet look like the factory formed head. In practice, they usually end up with a slighly flatter more cylindrical profile. I bet if you look close at the original rivets the back sides don't have the exact same perfect half-round profile as the factory formed heads on the front side. By factory-formed, I'm talking about the head forged onto the rivet by the rivet supplier not the secondary head formed at the assembly plant.

I think we may be a little off the same page here with regards to the way rivets work so forgive me if it sounds like I'm telling you something you already know. A rivet is basically a piece of mild steel round bar with a head formed on only one end (a stud like you said). That is what you will recieve from Just-8ns. To make it work, you stick the rivet through holes in the two pieces of metal you want to join so that the straight portion of the rivet is protruding out the back side of the joint (in this case I think it will protrude about 5/16") This "stub" has to be heated cherry red and driven down against the joint using a setting tool with a negative profile of the shape you want to end up with. To keep the rivet from just being driven back out the front again, you have to back the head up with something heavy (called a bucking bar). Normally the bucking bar will also have a negative profile of the rivet head but I just used the hole in my anvil instead. Two things happen when you form the secondary head onto the rivet. 1) The shaft within the joint expands and takes up any shear slop within the joint 2)As the rivet cools the "now" two rivet heads draw towards each other further tightening the joint.

In other words, there is no separate head that's driven onto the end of the "stud". The secondary head is formed in place from the stud itself.

Where your old rivets are sheared, you should be able to use a large pin punch to drive the old rivets out. Heat and PB-blaster may be needed. Also, you may need to support the metal around the rivets to keep from bending it. In the worst case, you can always drill them out.

My bars were bend every way imaginable. Yes, it's real tough bending them back against the thick dimension. You just have to be creative in setting up fixtures to hold it so you can manly it back into shape.

Thanks for the compliments,

flathead

Now, I just hope my Father-in-Laws shop has an anvil...

Thanks again,
Dan

Dan

Have fun.

flathead

flathead

Dan