The Stovebolt Site Forums The Parking Lot Big Bolts Boxing frames, tempered frames, etc.

The frames of today and for a long time often have stickers on them about welding. That is placed there because of the hi-tensile material used in the frames which may exceed 110,000 psi. Generally above that they are reinforced by adding L sections or by doubling or tripling the rail. Sometimes frame are increased to 3/8" material as in the case of aluminum rails. Just depends on what RBM the Engineers are going for. However there are no "tempered" frame rails in my experience. Your 59' schoolhack is pretty likely to have a std 50,000 psi frame. As for the holes, put bolts in them. I have to echo crenwelge on the "why" part.

Frame rails can be welded but it takes real knowledge and is generally discouraged which is why you see the stickers/stencils. There is also the liability issue which can be very real in todays litigious society. Messing with a frame is like having your spine operated on and having your neighbor do it IMO.