Here's a question...

[cmp_uc_guy]

I have to replace a rotted cross member in my F15a Frame with a good one, should I find a way to rivet it like original or bolt and weld? HMMMM?

[Hanno Spoelstra]

Originally posted by cmp_uc_guy
...should I find a way to rivet it ...

Cold rivetting will be difficult without access to heavy machinery, however hot rivetting should be possible. Try asking a blacksmith or steam boiler manufacturer for advice.

[Mike K]

I have not tried hot rivetting , but I have been told it's a skill that needs much practice to achieve good results .

A friend here tried the hot rivetting process on a 1/2 ton Dodge chassis replacing a crossmember , he had some success but it was only after many failed attempts . The problem is keeping the rivet hot enough - once it's in the chassis , the heat is sucked out of it quickly .

Most restorers these days use high tensile bolts and this seems to work OK . I guess you could also weld where it is not seen .



mike

[Phil Waterman]

I've been reading a lot of old Chev and CMP manuals of late and what they consistently seem to say is if riveting is not possible bolting is better than welding. The service bulletins that Alex has just made available has instruction about process. The major point being to make sure that fit of the bolt needs to be a drive fit through both parts. Line drilling or reaming is important for a tight fit so that shearing force of movement is prevented.

Welding of frames is/was universally frowned on and at the same time it is done all the time.

The CMP Service Bulletins that Alex has just started reprinting have some wonderful bits on things like this.

[Pete Ashby]

You can hot rivet if you cheat.
First off you need to have the right sized dolly and snap make the snap out of two big bolts screwed together into a heavy duty spacer.

Next find a supply of rivets not always as easy as it may seem these days.

Now you need an oxy torch.

Fit the rivet into the hole in the frame and cross member pre-formed head down (as you stand above the frame) it needs to be a light hammer fit

Support the lower frame rail, ie: pack with solid packing to the floor, you'll see why in a moment

put the snap into the frame rail and screw the bolts appart until the rivit is pushed up hard to the frame rail(if you put a bit of scrap steel strip say 14 gauge under the lower bolt head it spreads the load better)

Take the Oxy torch and heat the tail of the rivet ONLY not the frame until red/white heat do not start to burn the rivet, ie you will see spakes coming off if you have over cooked it.

Give the torch to your mate, take the dolly and a good sized hammer and with one or two blows close and form the rivet. Thats why you pack the frame otherwise all you do is bend the lower rail, not good and ends in tears!!!.

There you go, I've done it and it works and I know several other people who have done it as well.

If you don't want all the trouble bolt it, the problem with welding cross members is that the torsional strength of the weld can be a problem, frame rails are les of a problem as the load is axial.


Pete

[cmp_uc_guy]

Thankyou very much for the info, it'll come in handy soon.

[chris vickery]

Rob, talk to me at the CMP Weekend at Caldwell's if you're gonna be there. I might have some ideas for ya.

[cmp_uc_guy]

ok chris!

Oh yea, guy's I'd never weld on a frame. what i ment to say was "weld the nuts to the bolts" so they wouldn't come undone.

This forum is great, all the main players are here.