Jay Laifman wrote:
> >On my Tiger I welded in a plate into the front corners of the parcel
> shelf.
>
> >Without the backup plates the bolts will pull through the sheetmetal when
> a
> >large load is applied. You have to decide whether it's going to be a 'roll
> >bar' or a 'show bar', and put in the appropriate mounting.
>
> I have been told by two people, Rick at Sunbeam Specialities, and AutoPower
> where the roll bar was made, that bolting is better than welding. The
> reason given was that the sheet metal itself is very weak - in fact, weaker
> than the bolts and washers, and heating it in the welding process will make
> it even weaker.
>
> That being said, it does come with large thick backing plates. I don't
> know if they total 20 square inches, but they might. The plates easily fit
> on the rear two mounting spots. Its the front ones that are close to
> impossible to do that without cutting a very large hole into that boxed
> section underneath. I guess you could cut it open, get the plate in, then
> weld back the box. But, that doesn't seem quite right either.
>
> Note that I didn't even realize this box was down there until I slid
> underneath to try to bolt it up. I even thought I saw light coming through
> when I looked down into the holes. That light must have been coming though
> the oblong holes along the box.
>
> Jay
Jay:
The advice you are getting re: welding is only valid if the Alpine frame was
originally made of high strength steel (HSS). If welding is done on HSS, the
heat treatment of the original frame is destroyed and cannot be restored
without knowledge of the original specs. and heat treating facilities.
However, if the Alpine frame is not HSS, (and I think this may be true), then
any welding properly done should have the same tensile strength as the
original mild steel (or slightly higher) - 60000 - 70000 p.s.i..
Another solution to your problem might be to drill a hole large enough to
insert a piece of appropriate tubing to keep the frame from collapsing when
bolts are tightened, and use bolts which pass through the frame and the proper
sized reinforcing plate below. (This is
suggested without examining the frame area in question, and may not be
possible).
Ron Tebo
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 08:47:35 CDT