Friday, 7 September 2012

Wooden Morgan:1950 DHC - Week 2

This week's work started with taking the 2x4s over to Al's to get them thickness planed so I can glue them together into a block.  While the glue was drying I got to work on the wheels, as I'll need them to check their fit in wheel wells and the spare tire slot.  I want to make those cuts in the Black Walnut block before any car shaping is done. i.e. while the block is still square and easy to line up in the drill press.

From the photographs of flat rad drop head coupes I have, I came up with this cross section of a wheel. In the bottom of the picture, the tire is to the left, the brake drum on the upper side, and the hub cap on the bottom.

I then used a Hole & Plug cutter to make several cuts into the wood at significant points of the profiles of each side.  I had room on the board for six wheels so I decided to make six just in case something happened to one.

First cut is the outside of the tire radius, cutting half way through.

Then the same radius cut on the other side, just a quarter way through to make it easy to line up for the final cut to remove the wheel.

Still on the back, I cut the brake drum.  I had to remove the protective cover over the cutting bit to cut this small a circle. Watch out, as the other end of the arm swings in a wide circle!  Fortunately I had just turned off the power when I got my knuckles rapped.

 Cut the line between the tire and the rim.

And some more grooves across the area between rim and brake drum which will be left flat.  Too bad the Plug & Hole cutter bits are not the standard 5/16" square cross section of metal lathe bits.  I could have made a flat cutter to finish the side in one go.

For the front side I reset the tool to the rim radius and cut that first.

Then the deep cut around the central plateau.

Turned the bit to hole cutting, and then cut the out side of the deep part of the profile.

Then up and out a little further towards the rim.

The central plateau was flattened with a 1" Forstner bit.

The board was then flipped over and the outer diameter circle cut until the wheels came loose. Here they are. The upper row shows the back side, the lower row the front.

I then tipped the table top drill press onto its side to make my 'lathe'. See the section on using it in the Morgan Plus 8 model build at:  

I used a cone burr to clear the flat area on the back and to curve the sides of the tires, then a 1/8" ball burr to excavate the profile on the front, and finally the tiny ball burr to remove the remaining tool marks from the plug & hole tool and to make the tread marks. As soon as each side was shaped I sanded it using grits from 80 through to 280.

When all the wheels were done I gave Al a call, he was free so I took the Black Walnut block and the glued 2x4 block over for final dimensioning to 3" thick and 5 3/8" wide.

Voila!  Here are the wheels on the freshly dimensioned block of Black Walnut.

Change in plans, I've been told that the standard spare tire set-up for a DCH in the early '50s is twin spares like in the photographs I have.

Since I have six wheels I'll modify the plans to twin spare layout.

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