WTB 2 SPUR GEARS

T

tkingmo

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I am trying to repair an old Ariens tiller/plow gearbox. I need two spur gears, both 14 1/2 degree PA. One a 12 tooth and the other a 17 t00th. Both a .750 bore, .625 face width, 8DP. 17 tooth 1.550 length thru the bore. 12 tooth .895 length thru the bore. Does anyone have one or both? Thanks.
 
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Boston Gear or one of the other manufacturers may have what you need. I needed some gears a while back and found what I needed on Amazon and E bay. Would have been fun to make but don't think the wife would have thought 500-750 for tooling was better then 50 for the gears lol
 
Yes, you can likely buy them from Boston, Martin, or other.
And yes the cutters can be expensive.
However, you can also have great success making them with a shop made single tooth cutter made from HSS.
You'd hold the cutter in shop made arbor that would look much like a fly cutter but at 90 degrees.

You could make the entire gear, or if you merely have a few broken teeth, you can build up the area with welding processes, normalize the hardness and make chips.
Really depends on if the priority is getting her operable quickly, or if you want to take an old school approach. Really old... But, very functional...

Daryl
MN
 
I may repair the 12T as it is missing only one tooth. But the 17 is missing several; so I would like to buy that one. I am not in a hurry.
 
Both are doable.
Depends on your time vs cash and how quick you need to get her into service.
If you want me to look for some how-to on the process, them please advise.

Daryl
MN
 
"If you want me to look for some how-to on the process, them please advise."
I would appreciate the help D. thanks
 
I've had the privilege of the cutting a few gears under the auspices of the many mentors here at HM.
While I've collected and studied many vintage gear cutting books. One or more of them identify many ways to do a single tooth cutter.
However, the easiest for me to read and understand was: Gears and Gear Cutting by Ivan Law.
Here is a link to the book at Amazon. Ebay, Abe books and others may have it cheaper.
https://www.amazon.com/s/ref=nb_sb_...s=Gears+and+Gear+Cutting+(Workshop+Practice)+

Here is a free well documented link to someone who shop made a cutter.
http://www.deansphotographica.com/machining/projects/multipoint/multipoint.html

Profiled Fly Cutters for Gear Cutting, By Martin Gearing Lathes Home Shop Machinist Vol. 36 No. 3 May-Jun 2017 26
You can purchase the back issue at: https://secure.villagepress.com/store/items/list/group/292/page/5
The easiest I've seen for just a few teeth is to make a fly cutter type arbor. But at 90 degrees to the shaft.
Fly cutter fab can be found at: http://www.hobby-machinist.com/threads/home-made-fly-cutter.32631/
Then use HSS to match the profile you need. It is hand ground to match the profile of the intact teeth.
Somewhere there is a write up of this in one of my vintage texts.

It is easy for me to get lost in all the math. Pressure angles, back rake, etc. All this is huge important. Getting it right may mean several attempts.
And like so many other things, the whole this isn't difficult once you figure it out.
The details will depend on what machines you have available.

I got serious about making this bevel gear when quotes for a replacements came in at around $1000 for a gear (it was a custom one 0ff).
This is a pic of the gear before I shaved the old one off the shaft. You can see how she was worn.
You can do this!!!
IMG_1010.JPG


Daryl
MN
 
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