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10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 12:31 pm
by FundyTides
Just sorting through some parts that I bought at one time and found what I think is a Model T 10 tooth pinion gear. It looks to be in pretty good shape except for some surface rust. I would appreciate it if someone would confirm that this is in fact a Model T pinion gear. As can be seen in the pictures, there is a divot on the back of one of the teeth and another divot on front of the gear with either a 9 or a 6 stamped beside it. What your call?
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 12:58 pm
by Oldav8tor
Looks like one - here is a photo that might help.
- 10_T_2.JPG (82.81 KiB) Viewed 2686 times
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 3:03 pm
by Jerry VanOoteghem
The divot on the back is where the hardness of the gear was tested when it was made. A Brinnell mark. The divot on the front face is "damage". Shows signs of use, but probably still got life in it. Looks like a Model T pinion to me. That's my O'Pinion
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 3:37 pm
by Pep C Strebeck
Jerry VanOoteghem wrote: ↑Thu Jun 30, 2022 3:03 pm
The divot on the back is where the hardness of the gear was tested when it was made. A Brinnell mark. The divot on the front face is "damage".
Not necessarily. The page below is from the Ford Service Bulletins, published by Ford Motor Company of Canada, and it directly references the mark on the gear. One may very well be a mark from hardness testing, but the one in the center of the tooth would correspond to the Service Bulletin.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 3:55 pm
by Jerry VanOoteghem
Pep C Strebeck wrote: ↑Thu Jun 30, 2022 3:37 pm
Jerry VanOoteghem wrote: ↑Thu Jun 30, 2022 3:03 pm
The divot on the back is where the hardness of the gear was tested when it was made. A Brinnell mark. The divot on the front face is "damage".
Not necessarily. The page below is from the Ford Service Bulletins, published by Ford Motor Company of Canada, and it directly references the mark on the gear. One may very well be a mark from hardness testing, but the one in the center of the tooth would correspond to the Service Bulletin.
924515.png
924514.png
Cool!
I learned a thing today!!! Thanks!!
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 5:56 pm
by FundyTides
Pep C Strebeck wrote: ↑Thu Jun 30, 2022 3:37 pm
Jerry VanOoteghem wrote: ↑Thu Jun 30, 2022 3:03 pm
The divot on the back is where the hardness of the gear was tested when it was made. A Brinnell mark. The divot on the front face is "damage".
Not necessarily. The page below is from the Ford Service Bulletins, published by Ford Motor Company of Canada, and it directly references the mark on the gear. One may very well be a mark from hardness testing, but the one in the center of the tooth would correspond to the Service Bulletin.
924515.png
924514.png
Thanks Pep. I had seen that reference to the Service Bulletin before. It is very possible that this pinion came from a Canadian built car considering where I live and most of the T's in this area, including the one I own now and one previous one, are Canadian built cars. There seems to be no end of differences, from wheels and spokes, to Touring back seat cushions and of course Robertson screws, between the US and Canadian built T's. I will clean this gear up a little to see if there are any other markings.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 9:11 pm
by Allan
That divot looks to be machined, like ones on gears I have on the shelves. Hardness testing usually leaves just a small pin prick like a light centre punch mark. Perhaps it had another purpose. Or perhaps the machined divot has a pin prick within?
Allan from down under.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Thu Jun 30, 2022 10:02 pm
by FundyTides
Allan wrote: ↑Thu Jun 30, 2022 9:11 pm
That divot looks to be machined, like ones on gears I have on the shelves. Hardness testing usually leaves just a small pin prick like a light centre punch mark. Perhaps it had another purpose. Or perhaps the machined divot has a pin prick within?
Allan from down under.
Hi Allan, There is a pin prick mark 180 degrees across from the divot with the 6 (or 9) beside it. It is much smaller and I didn't see it until I cleaned the gear up with a wire wheel. Would that number be an indication of the hardness?
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Fri Jul 01, 2022 1:11 am
by Allan
David, that sounds more like a hardness test mark. I presume the 10 stamp is for 10 teeth, but have no idea what the others are about.
Allan from down under.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Fri Jul 01, 2022 8:20 am
by FundyTides
Allan wrote: ↑Fri Jul 01, 2022 1:11 am
David, that sounds more like a hardness test mark. I presume the 10 stamp is for 10 teeth, but have no idea what the others are about.
Allan from down under.
No 10 mark on mine Allan. That was Tim's picture
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Fri Jul 01, 2022 8:41 am
by Jerry VanOoteghem
Allan wrote: ↑Thu Jun 30, 2022 9:11 pm
That divot looks to be machined, like ones on gears I have on the shelves. Hardness testing usually leaves just a small pin prick like a light centre punch mark. Perhaps it had another purpose. Or perhaps the machined divot has a pin prick within?
Allan from down under.
The pin prick comes from a Rockwell hardness test. These gears were tested with a Brinell hardness tester, that uses a ball indenter. Rockwell testing is for higher hardnesses, Brinell is for softer materials.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Fri Jul 01, 2022 8:00 pm
by Allan
Jerry, my experience comes from watching the fellows in my favourite machine shop hardness testing alloy heads after they have been overheated. If they are too soft, they are not worth working on. This is soft material, and the testing tool leaves the small centre punch mark referred to. It seems counter intuitive for a ball type test on harder materials like a steel pinion gear. Rather than just a falling weight for the head testing I mentioned. Such a test on a pinion gear would require a much more robust testing tool. I need further education, again!
Allan from down under.
Re: 10 Tooth Driveshaft Pinion Gear
Posted: Fri Jul 01, 2022 8:43 pm
by Jerry VanOoteghem
Allan wrote: ↑Fri Jul 01, 2022 8:00 pm
Jerry, my experience comes from watching the fellows in my favourite machine shop hardness testing alloy heads after they have been overheated. If they are too soft, they are not worth working on. This is soft material, and the testing tool leaves the small centre punch mark referred to. It seems counter intuitive for a ball type test on harder materials like a steel pinion gear. Rather than just a falling weight for the head testing I mentioned. Such a test on a pinion gear would require a much more robust testing tool. I need further education, again!
Allan from down under.
My experience comes from 35 years in manufacturing. Trust me, it's a Brinell mark.
