MTFCA Forum

As some of you know, I restore Ford 6v generators (model T. A and flathead V8), and I refurbish original Ford generator cutouts. Occasionally I'll refurbish other brand cutouts too. Last weekend at the Luray pre-war swap meet I picked up this unusual Auto-Lite cutout with side mounted terminals.

It was dirty and missing some hardware on the underside, and the point tension spring was missing. Fortunately, I was able to replace the missing hardware and make a new tension spring. With this done, the points were dressed and closure voltage was adjusted to 6.5 volts. It was then painted and the original brass terminal screws polished. It now works like new.

My question is - what is the application? I'm pretty sure its not model T. But with the tremendous knowledge base here, maybe someone knows. What car is this appropriate for?

Thanks,
Steve Blancard

The first of the 1919 had the cut out mounted on the firewall, could be the same or a replacement?

I'd call that a bingo.

Very close to an original early cut out, but the early firewall mounted cut out had 3 screws and this one has 2. The middle screw is for the ground.

https://www.mtfca.com/discus/messages/7 ... 1495407992

That one certainly is similar. Mine has "This base must be grounded" embossed on the base. Knowing the importance of a good ground, perhaps a latter version added the ground screw ?

Or you have the later that bolted to the generator.

ndnchf wrote: ↑

Wed May 14, 2025 7:36 pm

That one certainly is similar. Mine has "This base must be grounded" embossed on the base. Knowing the importance of a good ground, perhaps a latter version added the ground screw ?

I won't say that could not have happened (2 screw to a 3 screw) but the firewall mounted cutout did not last long and then it went to the generator mounted rectangular cutout (separate wire from the generator to the cutout and then going to the ammeter, not in the wiring harness for both of the early cutouts, 1919 only and the switch to the generator mounted cutout also happened in 1919) and then the round cutout we all know and love.

big2bird wrote: ↑

Wed May 14, 2025 7:47 pm

Or you have the later that bolted to the generator.

That certainly seems plausible. A firewall mount would need a ground wire. While it is not needed when mounted on the generator since it grounds through the generator case.

An observation - on this cutout the feet are flat. That indicates it was mounted on a flat surface like a firewall. If it were mounted on a generator, they would be curved to match the generator's contour.

Weren't the early cutouts mounted to the frame rail for a short time?

One comment about above mentioned reverse current cutout "cutin" adjustment.
The third brush regulation generator on the Model T should be adjusted for Armature cutin and contact closure at 7.2 volts.
Ron Patterson

I appreciate you experience and insight. I'm not speaking specifically to model T generators here, but reviewing cutout servicing sections of several Auto-Lite manuals I find:

"Servicing Auto-Lite Generator Regulators" publication SD-123, page 34 stated "Slowly engine speed and observe the voltage when the contacts close. It should be 6.5 volts".

"Maintenance and Operation of Auto-Lite Electrical Equipment", publication S-24, page 41 states the "contact closing voltage - 6 volt units 6.5 - 7.25 volts."

"Electrical Equipment (Auto-Lite), publication TM 9-1825B, table IX lists specifications for a large number of regulators and cutouts. The specs vary slightly from unit it to unit, but all fall in the 6.4 - 6.9 volt range.

Lastly, Ford Motor Company publication "Repair Manual Generator and Starting Systems 1933 - 1947, Form 3672-47, figure 3 on page 8 shows cutout part number B-10505 closure voltage specification as "6.1 - 6.3 volts".

I have found that exact closure voltage is not critical and it varies with temperature. When I refurbish a cutout, I adjust them in the 6.5 - 7.0 volt range. I've found this works just fine on model T, model A and flathead V8 generators. Your mileage may vary

Back to my original question of what does this cutout go on? On another forum, someone said that he has one just like it on a 1920 Buick. So that is a start. I image it was used on others as well.
Steve

One possible explanation is that the cutout in question is an after market replacement for a 1919 car that has had a steel firewall replacement installed for a rotted wood firewall around 1923.

I found one of those rectangular cutoffs in a box of T parts - glad that I know it IS a T part

Here's an original early generator mounted cut-out. Ron Patterson was kind enough to "diode" this for me many, many years ago. I've been playing with these T's for over 50 years and have not seen nor got my hands on another !

Unobtainium.

Steve, I have a couple of rectangular black script units.
Very hard to find. I love the Ford script.
I use one on both of my Allen generator spin testers.
They definitely bring good money when you can find one.
Here’s a brass unit that I got in a bucket of junk.
I’m not sure of the age, but being brass, I think it’s early.
Brent

That's a great find Brent!

FWIW, I'm a proud owner of an early Ford generator cutout, as well. Rich C.

Great find, Brent ! Appears to have been a firewall mount - first one I've seen of that type.