Fabricating an Under Seat Gas Tank Door for your 1909 – 1916 Model T Ford

henry ford thomas edison harvey firestone packard twin six touring
Henry Ford with Thomas Edison and Harvey Firestone leaning against Henry’s 1919 Packard Twin Six touring.

Our 1910 touring was in pretty nice shape but had a few flaws when purchased. One of the flaws was a missing door below the front seat. The purpose for these doors is somewhat murky but essentially it perhaps kept mud from splashing directly into the bottom of the seat cushion. It also serves as a good place to park the gas cap while filling the tank. In any case we needed one. With that in mind a few measurements were taken, and a trip to the local home improvement store yielded some pieces of 1/4″ basswood board in various widths, some 2X1 basswood boards, some Gorilla brand wood glue, and a box of wire nails.

basswood, model t ford under seat panel
The materials from the store and a few tools are all it takes to make this part.
We started by cutting one of the widest pieces to length so it would have 1/16″ clearance on each end. This piece will end up over the gas cap. We wanted a piece of lumber at least wide enough for the hole to clear the cap.
We cut the rest of the pieces needed to make the entire door, choosing the boards so that the end result fit the opening with about 1/4″ clearance overall from side to side.
We cut the 2X1 basswood pieces so that they would have 1/4″ clearance from either end of the finished assembly.
We laid everything in place to visualize and plan the next steps.
Each of the cut pieces of wood was finish sanded on the cuts. Here we apply some Gorilla brand wood glue so that the wood support can be nailed to the 1/4″ wood permanently. The glue provides as much if not more strength than the nails.
We predrilled the pieces with a #60 AWG bit, then installed the nails, using a punch to set each nail so there would not be any strawberries around each nail on the finished product. The end boards were clamped together and checked with a square prior to drilling so all would be exactly right.
We attached the other end piece of wood to check fit on the car before proceeding.
The rest of the boards were laid in place and numbered so their positions could be kept upon assembly.
A spare piece of straight lumber was clamped to the work bench as a “fence” to make assembly quick and accurate. a 36″ machinist’s scale was used to lay out the positions of all the nails.
We laid down a nice bead of Gorilla glue.
A piece of heavy card stock was used to provide a fine even gap between boards. Nails were placed in the pre – drilled holes and set on each board.
Wejust set the box of nails on the panel to show what we were using. The 3/4″ nails are exactly the right length so they do not have to be trimmed after installation.
With all the nailing complete we test fit the panel again before the glue dries. It fits well.
With the panel removed we use a square to locate the center of the gas cap and mark the body so it can be transferred to the door.
With the door in place we transfer this mark to the door over the area where the gas cap access hole will be.
With the door removed we measure to the center of the cap.
The measurement is then transferred to the door. We drilled a 1/4″ hole first and checked to be sure we could see the vent hole in the gas cap prior to making the big hole!
We purchased the 2 3/4″ hole saw just for this job. At $13.75 it was the most expensive part of this job. Total materials cost $35.
We smoothed the edges of the gas cap hole first with a half round wood file, then with 80 grit sandpaper.
4″ back from the front edge, and centered from end to end we cut a 1 1/4″ finger hole.
It’s looking pretty good.
We put some primer on the wood to protect it until such time as we paint the entire body Brewster Green as the build sheet says it should be. The door under the front seat normally should not have hinges on these early cars, and we do not plan to use any.