Mike,
The reason for not allowing weld on the hitch is the same as on
the frames of large tractor (truck) units. Welding produces stress around
the weld area and if not heat treated after welding, can produce fractures
and eventual failure of the welded piece due to constant flexing. There is
also the possibility of a poor undercut weld which reduces the thickness of
the welded piece.
Same applies to pressure vessels such as propane tanks and railway
tank cars ( I used to work at a tank car manufacturing plant). All welding
is done on the tank and then the whole unit is placed in a large furnace,
heated to ~1200F and held there for 1 hour and then cooled in the furnace
to 600F and then air cooled. Nothing can be welded to the tank after stress
relieving.
Later,
Bob
At 11:16 AM 6/2/2000 -0700, Mike Lee - Team Banana Racing wrote:
>Just curious if anyone knows if it's safe to modify a hitch.... I have a
>class III
>Draw-tite receiver hitch on the back of my XJ. I recall when I bought it,
>that there
>was a warning not to "drill, weld, or modify" the hitch. I'm guessing it
>was there
>for liability reasons more than anything else, but I'm curious....
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Robert (Bob) A.C. Hamilton, Waverley, Nova Scotia, Canada
The Man of Many Sunbeams - Alpine, Drophead and Saloon 1953-1954
[Stable mates - 1973 Midget and 1968 M-B 280SE]
Home Page: www.navnet.net/~hamilton
BATANS Home Page: www.batans.ns.ca
E-Mail: hamilton@cast.navnet.net
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