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Schebler Carburetor Machining

 

It’s the same process to build all the carbs, but I am doing a run of 6 this time for Excelsiors #5 through #10, so you are able to see the process of the Excelsior carburetor manufacturing.  Enjoy!

Machining the “excess” casting at the end of the carb main body.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Six carbs waiting for the next machining operation.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Turning the ID to fit the 1-3/8″ butterfly valve.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Drilling and tapping the mounting flange.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Cutting the excess off the intake manifold in the band saw.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Machining the OD of the intake manifold with a 3/8″ carbide radius tool.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Six intake manifolds close to completion.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Six carbs with the ends bored and threaded for the ported air sleeves.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Milling the throttle shaft boss to the correct height.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Milling the OD of the throttle shaft boss using the rotary table.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Cutting the excess off the float bowl casting in the band saw.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Using a boring bar to machine the ID of the lower float bowl.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Using a fixture to hold the float bowl for the inner machining operation.

Schebler Carburetor, Paul Brodie, Flasbhack Fabrications

Using a 9mm endmill to spot face for the float pin holes.

Paul Brodie, manufacture Schebler Carburetor for OHC Excelsior, Flashback Fabrications

Stainless screws used to hold the float bowl pin.  These get made from stainless hex bolts.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Holding the air horn in the rotary table chuck to mill the 8 sided octagon.  But a hexagon only has 6 sides . . .

Schebler Carburetor, Paul Brodie, Flashback Fabrications

The six bronze air horns are coming along well.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Using the horizontal hacksaw to cut off the excess casting that has been so handy for the previous operations.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Cutting the threads on the lathe using a carbide insert tool. No coolant is required. A 5mm allen screw holds the air horn into the aluminum fixture in the chuck.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

The air horn is now basically machined. Now the bore needs to be smoothed and small parts made. Here, the air horn is threaded into the “ported” air-sleeve supplied by Fred Lange in California.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Knurling a piece of 5/8″ brass in the lathe at very slow speed. Two holes have already been drilled in the end. Short pieces will be parted off soon.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Six knurled knobs that have been parted off and chamfered, now await the installation of the screw and locating pin.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

The screw and locating pin have been installed with a light press fit.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

A small piece of 3003 aluminum is used as the soft jaws, and the ends are carefully peened over using a drift and a small hammer.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

On to the next stage.  I have scoured my shop and found six (6) bits of brass for the carburetor air horn parts to be machined on the lathe.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Here’s the process:  Face the end, drill the center hole, drill the offset hole, turn the OD, and de-burr.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

The bushing is held in the rotary table, and a carbide end mill used to create the cutouts where the pin will reset to hold the air-valve closed with more spring tension. This is a crude way of creating a “choke” for cold weather starting.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

The other end has been machined to size, and now the bushing is ready to be lightly pressed into the air horn.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

Installation is complete.

Schebler Carburetor, Paul Brodie, Flashback Fabrications

More photos to follow …