Calling all metal workers... Need backing plates

[Icansmelldiesel]

I have a fwc hawk on a 2014 f-150, and recently removed it to find that the eye bolts are bending/pulling up the truck bed around the washers. I found several similar threads and most people just add 1/4" backing plates to solve the problem.

I want to have some backing plates made to custom shape/size to fit the dimensions underneath my bed.

Questions:
1. How important is it to have "radiused edges" and "radiused corners" on the plates? Seems like a good idea so no sharp edges to cone through the bed.

2. Do I need them made of any special steel?

3. Where should i go to have these made? An auto body shop? I am not sure where to start.

**Is there anyone on this forum that is a metal worker? I would happily pay someone here. I could make cardboard templates and send them to someone to create in steel.

Thanks all

 

[Icansmelldiesel]

 

[Beach]

To answer question # one; ever used a can opener to open a beer/coke back in the day before pop tops? Well it's the same deal. I made my backing plates from 3/16 marine grade aluminum, easier to work with, no rust and I was able to add rocker to the fwd plates to match the curve in the truck bed to maximize contact area of the plate to better distribute the load.

 

[ntsqd]

I radiused mine and bull-nosed the top edges. Can opener is an exact analogy.

The thickness needed depends on alloy chosen, how wide the plate wants to be, and how high the load might get. Most make an edumacated guess on this, and most plates I've seen are likely thicker than is really needed, but better to err in this direction than the other. Use of aluminum will increase the thickness over a steel plate of same size and loading. I'd choose cold rolled over hot rolled for both tensile strength and cleanliness.

In steel pretty much anything better than 1010 (mildest of "mild steels") should be fine. 1018 and 1020 would be what I'd be looking for.
In aluminum 6061 is the most common and perfectly suitable. Any of the 2000 or 7000 series are overkill, but will work. Avoid the 1000, 3000, & 5000 series as they are not suitable at all or not suitable w/o more knowledge on how to form them for strength.

 

[ckent323]

I went to HD and got some Simpson square bearing plates. Put one on bottom of bed at each eye bolt. I ran the threaded end of the eye bolt down through the bed and plate and double nutted the eye bolt with a washer between the double nut stack and the plate.

Has held fine. A caveat however, my camper is not on the bed all the time so not a proven long term robust solution but It seems plenty stout to me.

 

[Icansmelldiesel]

In aluminum 6061 is the most common and perfectly suitable. Any of the 2000 or 7000 series are overkill, but will work. Avoid the 1000, 3000, & 5000 series as they are not suitable at all or not suitable w/o more knowledge on how to form them for strength.

Do you think 1/4" is good thickness for 6061 aluminum?

 

[Potts208]

I also used the simpson plates on mine. Has worked great in two different trucks (2001 Ram and 2015 Ram):

http://m.homedepot.com/p/Simpson-Strong-Tie-3-in-x-3-in-Slotted-Bearing-Plate-with-5-8-in-Dia-Bolt-BPS-5-8-3/202329560?cm_mmc=Shopping%7CTHD%7CG%7C0%7CG-BASE-PLA-D22-BuildingMaterials%7C&gclid=CMfti57xy84CFQKMaQodKbsBMQ&gclsrc=aw.ds

 

[ntsqd]

Do you think 1/4" is good thickness for 6061 aluminum?

Yes, I do though I'd be more inclined to use 3/16" steel.

 

[Icansmelldiesel]

Well I ended up going to a metal shop and having 1/4" steel plates cut to size. 4"x6" for the front backing plates and 4"x4" for the rear.

I spent some time on my bench grinder rounding the corners and taking off the top edges.

Under my truck bed there are cross supports. Now I can either have the plates overlap the supports or not.

Here is a picture of a plate not overlapping the support. The benefit here is that the plate is flush up against the bed...

 

[Icansmelldiesel]

...Or I can overlap the support with the front edge of the plate. Seems like this would give more strength however, the plate isn't flush to the bed if I do it this way.



Thoughts on which is the better option?

 

[Icansmelldiesel]

Here is a picture of the eye bolt hole, with the cross support above (towards front of truck).

 

[Atlin]

Personally, I would NOT overlap the cross support as that creates a stress point at the other end of the plate. The alternative (this is real overkill) is to add a second plate that is the thickness of the cross support between the bed and your fabricated plate.

Be sure to paint these well so they don't rust.