I am trying to design the 3 speed T planetary transmission and I am trying to figure out what pitch gear teeth Ford used. It seems to be finer than a 10 pitch and coarser than a 12 pitch by my measurements.
It sure looks like a 2.5 M pitch (modular/metric)
Here's an interesting post about triple gears where George in Cherry Hill, NJ shares some of his research: http://www.mtfca.com/discus/messages/331880/365730.html?1370446877
Even though Ford made drawings with a standard pitch, George thinks actual production may have resulted in something non standard..?
I remember the T100 project where today's transmission engineers at Ford thought they had a better gear design than original - and the transmissions were quieter - but the running T100 cars at the Greenwich village has worn out all the new triple gears and replaced them with old original gears
Metric wouldn't surprise - remember the three hungrarians fresh out of engineering school in Budapest who were among the staff in the experimental room at Piquette when the T was drawn
It took me a bit of head scratching to understand how to calculate the gear ratios, but I am comfortable with that now.
The T low gear is 2.75-1.
I have come up with 3 options for 2nd gear;
1.72-1 would be the easiest to make. The pitch diameter of the 2nd gear "sun" would be 1.574"
1.625-1 would be the next easiest Pitch dia. of 1.476"
1.53-1 is the absolute limit. Pitch dia. of 1.378"
When you consider that the transmission main shaft is 1" diameter and that the planetary gear train output has to be a sleeve between that and the inside of this gear it all gets really close
I've been thinking about how to control 2nd gear. I think it might be possible to leave the reverse pedal. Add a lever coming out of the transmission cover that then selects which of 1st or 2nd is selected when you stomp on the left pedal. High as usual would be letting the left pedal all the way out.
The gears in my Langbein aux tranny are non-modern standard, and they are ten years later than the T.
According to the drawings, they are 10 Pitch gears.
Les you should snoop around the lenco planetary transmission site. They apply theirs manually, electrically, pneumatically or hydraulically. Theirs are good from 200 to 2,000 horsepower and some use the same clutches as the T.
Les, why not use the reverse gear pedal for second and a lever for reverse.
If you used oil pressure, then a simple lever could be used for all three forward and the reverse gears. If you used a 26/7 hogshead but with an early brake drum, there would be room for the fourth drum. The pressure actuators should be small enough to fit under the inspection cover. Of course you could go wild and add paddle shifters like the F40!!!
OK thank you for that. I could then just buy the gears to ad into the planet assemblies. I would still make to make the sun gears as it will have to be part of the "shaft" assembly.
I will check it out.
Yes you just never know what manufacturers have used.
There are of course many ways to "skin the cat".
Doing some more research it appears that a popular 2nd gear ratio for Ford Flathead V8 cars is in the 1.7-1.8 range.
So the 1.72-1 (which is easier to make would probably be the answer. So that means the planet gear has 38 teeth and the sun gear has 16 teeth. I think 20 degree pressure angle to increase the HP rating of it.
I need to look through my junk and and find a good set of 3 piece planet gears so they can be taken apart to make the job a little easier.
You can pick up three inches length for the tranny by leaving out the magneto and shortening the crankshaft.
While you're putting in a second gear, it would be nice to make low 3:1 or greater.
Unfortunately the crank shortening gets complicated in a hurry, so probably not.
If the low gear on the planet was changed to a 32 tooth from a 33 tooth (with the drum gear being changed to a 22 tooth to suit) then low would become 3.2-1. I will have to think about that. The ratio changes happen in fairly large increments. I consider this project to be a "one off". I can not see producing it.
Les- All the transmission gear teeth are 10 DP.
Thank you for the confirmation. I assume 14.5 degree?
Do the teeth have standard addendum and dedendum? Are they cut to run at standard center distance?
Maybe this will add some insight:
BTW, I have a 42 tooth ring gear that is good enough for a pattern, if somebody can get a deal on a short run of gears.