What is a Fish Plate
Admom
Joined: Feb 2001
Posts: 9,414
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From: Silver Springs
What is a Fish Plate
The term Fish Plate refers to the repairing of a cracked frame rail by first welding the cracks and then reinforcing the rail by welding another plate that covers and extends well beyond the repaired area.
Posting Guru
Joined: Jul 2001
Posts: 2,119
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From: Southern New Hampshire
What is a Fish Plate
When repairing or modifying a frame be sure to NOT weld the patch completely around; instead leave a slight open area on all 4 corners. A complete weld creates new stress risers that could eventually crack.
Note I say "could". Lots of frames done the wrong way survive.
Also when splicing a frame for shortening or lengthening do a Z cut. Weld, grind smooth and then fish plate.
Note I say "could". Lots of frames done the wrong way survive.
Also when splicing a frame for shortening or lengthening do a Z cut. Weld, grind smooth and then fish plate.
Posting Guru
Joined: Jul 2001
Posts: 2,119
Likes: 2
From: Southern New Hampshire
What is a Fish Plate
John its hard to put it into words.
Looking at the side of the frame the ideal cut for max strength would be at a 45* angle, 30* or a tad less is OK if its not a BIG truck or a real long stretch. The same for the tops and bottoms. Use wide masking tape to line/mark up all the cuts, measure 3 times, cut once. Use a new, quality Sawzall fine tooth blade; if the blade binds and bends get another.
By keeping away from 90* cuts you spread the stresses and leave no new risers to cause problems. The fishplate should extend 12" either side of the cut so choose the location carefully.
Take a look at a stretch limo, airport Explorer or similar.
Looking at the side of the frame the ideal cut for max strength would be at a 45* angle, 30* or a tad less is OK if its not a BIG truck or a real long stretch. The same for the tops and bottoms. Use wide masking tape to line/mark up all the cuts, measure 3 times, cut once. Use a new, quality Sawzall fine tooth blade; if the blade binds and bends get another.
By keeping away from 90* cuts you spread the stresses and leave no new risers to cause problems. The fishplate should extend 12" either side of the cut so choose the location carefully.
Take a look at a stretch limo, airport Explorer or similar.
Senior User
Joined: Mar 2003
Posts: 274
Likes: 0
From: SW Wyoming
What is a Fish Plate
Carl,
That's what I thought, but wanted to be sure. (have we talked about this before?)
I just pictured more of a zig-zaging cut than an angled one. Zig-zags would be hard to do, angles aren't that bad.
Thanks.
That's what I thought, but wanted to be sure. (have we talked about this before?)
I just pictured more of a zig-zaging cut than an angled one. Zig-zags would be hard to do, angles aren't that bad.
Thanks.
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