The Stovebolt Site Forums The Shop Area Interiors Building Bench Seat with plywood and Foam.

This nothing new.

I am a big guy with a big belly so fitting in behind th 18" wheel was impossible with the after market seat being bolted on top of the original seat pedestals.

Bought a 51 parts truck for the seat, original wheels and spare 235.

Yanked the after market seat and cutout the extras and installed factory bench. Fit better but not good enough.

Option 1 shorten the steering column
Option 2 go with after market seat mounted to floor
Option 3 build a replacement seat
Option 4 small steering wheel and power steering/ tilt column

I am working on option 3

Purpose of this post-- the middles support brace on the seat frame sits about 1/4" higher than everthing else... I added 1/4" on bottom of the 3/4" creating a grove for the center brace.

Foam next!

My first project... just had to share

Take some photos to share. Measurements also. Many of us full grown folks are in the same boat.🛠

The first time I saw this idea was at HAMB: https://www.jalopyjournal.com/forum/threads/rebuilding-the-stock-bench-seat.909740/

I will be following his lead.

However, I think I am going to build the bottom of the back so I can tip the bottom up to get to under seat storage.

Seat Measurements: I measured the spring base ignoring the rounding of the corners and the narrowing at the back (for now) Cut a rectangle of 20 1/4" x 54 1/4" Note: your measurement maybe different.

Seat Back measured 21 3/8" x 50 3/4"

Nothing exciting here, accept when I put the base plywood in and a 3" pillow with a piece of plywood for a back, I FIT, the pedals feel good...there is hope!

Some pictures of the starting point

Seat project so far


End result probably will have 3" of foam on base and no more than 1.5" to 2" on the back.... we will see how that stands up when I get foam

The debate in my head --

Do I drill out the rivets holding the clips from the old seat frame and use them to mount the plywood?

Yes - makes the springs useless for anybody to use in the future but makes my life easier in mounting.

No - Allows me to sell the seat or throw it up in the garage rafters for later use ... but now I have to fabricate clips.

Do bench seat springs even have any monetary value?

I tossed mine because they are all worn (differently) from 60+ years of someone sitting in them. One of my upholstery friends told me long ago that you would need to replace a number of the springs if you had one broken one because they collapse in a large area around your butt but only one or two will actually break. If you replace one with a new one, it will poke you. I am sure someone out there may want them if rebuilding a seat and wants old ones to save some $$ but, I like thew foam so much better!

Thanks for the info on the usefulness of seat springs; first time working with them. Part of me wants to save them as I invested time into de-rusting them. However, it did not take much to push me off of the idea of saving them intact as it makes for much easier project! Lazy side wins!

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Cutting out the seat platform

Some pictures from cutting out the seat platform out of 3/4" plywood. (I measured and cut the rectangle than laid the spring base over the top and traced additional cuts).

Base after cutting the rear of the seat


NOTE: I did not cut the round corners out of the front until I attached the sub-floor to the seat base (see next post on what and why sub-floor).


Passenger Side's back corner , Zoom , Full Side , Front Corner

Driver Side's , Front Corner

The Seat Base

The bench spring frame sits on ribs that provide strength to the spring frame as well as raising the seat's spring frame up about a 1/4" above the frame.

Spring Frame's Ribs

The Gap

Seat Frame's Center Rib


This gap gives the seat cable mechanism room to work with out interference:

Passenger side cable mechanism: Top View and Front View

Driver side cable mechanism: Top View and Front View

The implications of the above is that allowances must be made to use a plywood base for the cable mechanism to work. In other words, the plywood base cannot just be cut out and thrown onto the seat frame. My solution was to create a "sub-floor" for a lack of a better term, I cut out two 1/2" plywood prices that fit between the seat frame's center rib and the outside edges with notches cut out for the cable mechanism.

Passenger Side's Sub-Floor Cut Out
Driver Side's Sub-Floor Cut Out
Front view at the seat frame's center rib

With the sub-floor in place, I can now use construction adhesive and screws to join the sub-floor to the 3/4" plywood seat base. The bench seat platform is almost ready for the foam --- Still need to cut the front corners and add the clips

Base Glued and Screwed
Base Glued and Screwed: Passenger Side
Base Glued and Screwed: Driver Side

Cut the front corners and the seat base is basically done! (I still need to put the clips on the bottom, but that will be later). By cutting the sub floor and base together, the radius of the cut matches; no messing around. .

Base Glued and Screwed: Driver Side

THE BACK

Same procedure as base - Measure the back and cut the rectangle out of plywood; I used the rest the 3/4" sheet that the base was cut out of.

One could lay the seat back spring frame onto the plywood rectangle to trace the corner cuts. I probably should have but did not as I got carried away by cutting the clips out of the frame with a cutoff wheel. On the plus side, this gave me the seat spring frame ends including the corners in a more use able size, granted they are in two pieces.

Passenger Side of seat back after the cutting wheel
Center of seat back after the cutting wheel
Driver Side of seat back after the cutting wheel

Sorry no pictures of cutting the round corner but here are the two pieces of the seat back spring frame that I used to trace the corners onto the seat.

SAVE THESES for making your seat back

I should have used the finished edge as a bottom of the seat back as a factory square edge will make the next step easier -- that step being the installation of the clips.

The top and bottom clips are located directly above and below each other. Thus, a factory square edge would allow a t-square to draw lines that would guarantee they line up with far more confidence.

Drawing the lines
Unfortunately I did not take any shots of how I marked where the seat back clips go. It was hot in the garage that day even with a fan! So I will try to describe what I did:

1. Do a dry run of the the plywood seat back after the corners are rounded making sure the top corners matched the curvature of the seat frame. The plywood seat back should be sitting a bit low as it is resting on the ledge of the seat frame.

2. Lay the plywood seat back forward so it is sitting on the edge of the seat frame (were the bottom clips are inserted) forward over the previously made seat plywood base. This exposes the holes in the frame's ledge which the bottom clips side into -- makes marking the location easier.

3. Square up the plywood seat back in the opening of the seat frame. Lots of measurements knowing I had to hit the mark!

4. Marked the plywood denoting each side of the seat frame's cut out for the bottom clips.

5. Used a drywall t-square and extended the marks the full height of the seat back.

The seat back once the clips are mounted.


Location of the clips

I took some pictures before I cut the clips off the spring frame. This will help locate the clips after I cut and ground the seat ribs off the clips. (I will insert a picture of the clips after the grinding and cutting)

Clip location showing why you need some space on the seat back to upholster the seat

The vinyl will need to bunch up behind the clip

Clip location on a bare frame

I believe I will have to notch the plywood to provide room for the vinyl to bunch up. Perhaps running a router to give room for the vinyl to be bunched up during re-upholstering .


AVOID a possible "oh [censored]" as they wipe out 1000 atta-boys

1. Mount the top clips First. I used 1/2-20 bolts and a large washer.

2. Once the top clips are mounted, hang the back in place and center the gabs.

3. Make sure the bottom still lines up - it should! Mark any adjustments needed.

4. Trace the top of the ledge (which the bottom clip slides into) onto the back of the plywood. The mounting bolts for the bottom clips MUST be above this line for the seat back to fit properly. I did not and I have to round out the mounting holes for one clip so the bolt is above this line

5. Take seat back out, drill holes and bolt in the clips.

The seat back once the clips are mounted.

The seat back in frame
The seat back in frame
The seat back in frame
The seat back in frame

The seat back in frame from the back


What is next:
1. Take the clips off take a few pictures and paint them.
2. Order the foam (why did I wait?)
3. mount the foam.
4. shape the foam.
5. Drive around testing the shape for fit and comfort.
6. Go back to #4 until the foam fits me into the truck.


Unfortunately, I go to loose some gut or shorten the steering wheel or .....

<to be Continued>

I forgot to add the reason why I got carried away with the end grinder with a cut off wheel.

I discovered, after drilling out the rivets, that the clips are also welded. Makes sense. Having the clips on the back makes it hard to trace the corners on the plywood.

Choice was cut the clips off and use the peices to trace the corners
OR
Trace the corners with the clips on with the spring frame not sitting flat ... this would be a bit less precise.

Since I was going to cut them off anyways, I went to town and hoped for the best; it worked fine.

I'm following this thread as well- I'm going to ditch the seat springs and build something like you are building... my reason is because I cannot stand bouncing up and down on the seat!

Looking for feedback.
I was thinking of doing that for the 2 ton COE because there were no seat cushions to start with,
However, I was talking to the client of the '48 2 ton I delivered last year. He was asking if there was any way to soften the ride in the big truck.
I mentioned the foam seat and his response was NO. The springs are the what takes up most of the road bumps, they are working all the time. A firm foam will not move nearly as much and the ride will be harsher.
Comments??

If ride is an issue, and the owner isn't hung up on keeping things original, it might be time for a truck seat. http://www.bostromseating.com/en-us/products/seats You just need to make sure you have enough head room for full travel with the driver in the seat. AND, I believe most of those require a compressed air source.

We were considering the optional optional split seat of the time (can't remember the name) that offered a better ride.
He is a big dude 6-2 or so, 280, seat is at the full back stop and he fits comfortable but not much head room for bounce.
Anyway, my post was about the possible harsher ride without seat springs.

I expect the ride to be a bit harsher, perhaps that depends on the foam stiffness. The HAMB link has good description of foam firmness rating.

I am doing this because I am, to be honest, to Fat. I have not continued as I am new to that truck and I am trying out different padding in order to provide me a seat that fits me in it comfortable. For now, it is plywood and moving pad; plywood and sofa cushion, .... until I find a mythical sweet spot.

Btw, I did not want to chop the old spring frame up. I debated for a long time. It was hard to do.

As for truck seats, the air ride ones are sweet but probably may not give head room. Yrs back, being the rookie at the moving company, I got stuck with an old international that had a mechanical spring seat similar to air ride. Either of which are probable to big for application mentioned above... not really sure as I have never seen a coe in person(the international was a day cab conventional abt 1972 vintage and was small

Maybe. Cabs these days don't seem to be much taller. You may know already, but try sitting in a box spring truck, no seat belts and a bumpy road. Or even with a seat belt! Air ride seats start looking real good after hurting your head/neck a few times!

I used foam for the seat in my 58 2-ton with no issues (stock suspension). I also used foam in my 59 Suburban but, I had different suspension on it and we are talking 1/2 ton which would be a softer ride anyway. 4" of firm foam and then 1" soft and 1/2" sewn to the back of the upholstery to make the ribs.

Just a comment. I put 2002 Buick LeSabre seats in mine for the built in the shoulder harness. They may not address you issue for more room but they work great for me. The seats are available in other GM cars around the same year and mine has a center console.

The History channel show "Iron Resurrection" that aired on 8-8-17 just did a 1950 Chevy truck. They showed some detail not a complete tutorial by any means. They ditched the stock springs back and bottom and replaced it with foam cut to the shape of the stock seat. Glued the foam to a ply wod base and custom fit the foam to the driver.

S02 E05 · Silver Stallion
Aug 8, 2017
A client loves her trucks, particularly the 1950 Chevy, but with a list of customizations the size of Texas, this build is going to seriously test Joe's mechanical genius.

The project is on hold. I have to cut the steering column to get additional belly room. This is a winter project. So I have been bombing around town sitting on a moving pad and back to plywood.

I did see the episode. I might have to bite the bullet and by a tilt column. Rather spend money on other fixes.