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Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 12:36 am
by Matt in California
I am helping a friend with there Model T and discovered that the steering gear ball had the wrong key and there was play. Since that is the only part I need I figured I could go to the hardware store. So I looked up the size and was surprised that I came up with two dead ends.
#1 Steve Jelf's world famous reference just has "???"

see:
http://www.mtfca.com/discus/messages/82 ... 904367.pdf
#2 This thread on the MTFCA from last year left me with more questions than answers:
http://www.mtfca.com/discus/messages/82 ... 1525568272
Is the Woodruff Key for Steering Gear Ball Arm Part#3548 just a standard key or something else?
Thanks,
Matt
Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 9:29 am
by DanTreace
The Steering Gear Ball Arm Woodruff Key, p/n 3548, is 1/4" wide x 7/8" long x 11/32" tall.
Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 9:38 am
by Ruxstel24
I would say the proper torque on the pittman arm nut, locking the tapered fit together is as or more important than the fit of the woodruff key.
Just sayin...

Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 9:46 am
by DanTreace
Yep, that too, and the cotter pin on that castle nut 
Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 2:22 pm
by rondupree
The problem is that Ford used a big key in a small diameter shaft. If you try to use a standard woodruff key, it sticks up too high and you cannot tighten the pitman arm on the steering shaft. The 'special' Ford woodruff key has been ground to reduce its height by flattening the rounded side. This allows the pitman arm to seat properly on the shaft....Don't ask me how I know..
Ron Dupree
Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Mon Jan 28, 2019 2:31 pm
by DanTreace
Thanks Ron
Your important tip is correct.
Should have posted the sketch.
Many 'hardware store' replacements for Ford parts don't always fit or function like the actual part.
Re: Mysterious Size of Woodruff Key for Steering Gear Ball Arm Part#3548 Question?
Posted: Tue Jan 29, 2019 11:57 am
by Matt in California
Wow! You guys have all been very helpful! Awesome sketch Don!
I plan to go to the hardware store and buy a 1/4" x 7/8". Then I will then grind it to size.
Thanks so much!
Matt