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14 1/2 degree pressure angle gear rod stock from Grob in Grafton, WI

1dogandnoexes

Aluminum
Joined
Jan 20, 2019
I needed a new 14 1/2 PA spur gear in a face width that I could not find. I've read from various sources that a 20 degree PA is compatible with 14 1/2 PA but vendors say otherwise. So I decided to match the original gear to avoid headaches.

When I searched, I discovered that Grob Inc. sells 14 1/2 PA gear rod stock. They have an online tool to reverse engineer the diametral pitch. Dakota Koffarnus checked stock and found the correct rod stock. He cheerfully filled the smallest order they could do without a bunch of guff over a small order. The packing job was excellent. A heavy cardboard tube had wood ends inserted to protect the rod ends and the tube had a cut line line indicating where to saw it open. So I'll cut it to length, bore it, and wind up with a nice gear. At the same price as purchasing a single gear, I'll have enough left over to cut 20 or so more. I might even break even by selling them online. So if you're looking for 14 1/2 PA gear rod stock (some call it pinion wire), you might want to check out Grob.
 
It's a small gear:

24 tooth
o.d. = 1.071 (likely a bit off to age and wear)
their formula #of teeth +2 / o.d. = DP
so 24+2/.071 = 24.27
14 1/2 degree PA
my face width was 3/8" but since it's rod stock, you can cut what you need.
bore size can be anything you want

According to Dakota, for whatever reason, 1" (nominal dimension) would more likely an o.d. of 1.083"
This makes sense. The gear is about 50 years old. So it's not difficult to believe
that it wore by .012, or it just wasn't made to a precise level to begin with.

Using the same formula:

24+2 / 1.083 = 24.00739" DP, almost perfect

So I ordered the gear rod stock with a DP of 24. If there is any difference between the new and old geometries, I can't detect it.
Just FYI, I have seen two terms in use, "gear rod stock", and "pinion wire."

Also, the alloy they had on the shelf was 4140, which should be more than adequate for a lathe gear moving at relatively low speeds.
So a 12" piece of gear rod cost just over $50.00 with a cut charge, taxes, and deliver. Even if each cut wastes an additional 1/4" of width, this yields 24 gears.
So materials are just over 2$ per gear.
 
john.k:

Their website specifically advertises gear rod stock and their ability to make whatever you want. They apparently maintain a stock of drops and rods in the sixish foot lengths of various 14 1/2 DP sizes. You can always call or E-mail (I'd recommend email) to see if they can match what you're looking for from their existing inventory. Good luck.
 
It's probably called pinion wire as a holdover from the days when clockmakers used it. It was made in module sizes using drawplates. Not modern tooth forms, however.
 
We at Grob, Inc. thank you for the positive remarks. I will pass them on to Dakota (I am the band saw guy). Please let us know if you need anything for gears, splines, or other shapes.
 
I needed some 5-6' 1" splined shaft a while ago and Grob had what I needed at a very reasonable price.

I needed some pulleys for one of our robots, a T5 profile if I remember correctly. There are suppliers that sell any tooth profile in lengths just like pinion wire gears. The robot people wanted $660. ea. I got enough stock and flanges to make 12 for less than $75.
So not just gears.
 








 
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