Gear cutting from scratch

Checking my gear cutting program a few ways and a 1.75m cutter with a 20 and 40 tooth gears would be center to center 2.0669 (52.4993mm) not sure if that is close enough to 50mm.
1.75m is close to 14DP which is a popular one. at 14dp the center distance is 2.1429 (54.43mm)
My 14dp cutters are stamped .154 tooth depth. My program shows a .152 tooth depth for 1.75m.
Here's a cutter set on ebay 1.75m:
https://www.ebay.com/itm/Involute-G...179157?hash=item3f8957e795:g:KWAAAOSwMmBVuQS5

There are probably lots of tooth counts that would get closer to the 50mm center distance but uneven counts would need better indexing.
 
savarin said:
There is another way of cutting gears.
I made a 40 tooth spur for my tumbler reverse thats still in use today.
Click to expand...

Nice!
My first gear was cut somewhat in that style, and in 2012. HSS bit ground to tooth profile, but I did it in a mill. It was a approx 6" gear for the drive on a snowblower. It's still going strong.
 
Hello Moper361, here's a little program from W.M.Berg Engineering that I have found very useful. Not only good for blank dimensions but also when reverse engineering to find out what a mystery gear is. Hope it helps.
 

Attachments

  • gearspec.zip
    2.3 MB · Views: 44
Here's another one that may also be of use and my take on setting backlash.
Cheers,
Barry.
 

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  • ShopCalc_win32.zip
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  • Setting change gear backlash.zip
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Hi everyone just a brief question will the chinese 22mm involute cutters fit on a 7/8 arbor or will i need new arbor to suit specific 22mm cutters
 
Just like to thank all who replied with information to my origanal post it has helped a lot and i have gained lots from it hopefully ill be busy knocking out gears next time im home
Regards Nat
 
7/8" X 25.4 = 22.225mm
-22 = 0.225mm
0.225/2 = 0.1125mm or 0.00443" to small.

In the real world your arbour may be slightly over or under,(usually on or just under nominal size), and the cutters are usually a fraction oversize so most likely they wil fit. If slightley tight that's good but a quick hone with a bit of fine emery cloth in a slotted dowel held in a drill,(work from both sides or reverse drill), will clean up the inside to make them fit. Can polish the arbor as well.
The drive is through the key and the clamped faces so as long as they go on no worries aye.
 
Hey Moper361,
I just had a thought, you well may know this but it sometimes is easy to overlook. Imperial cutters,(DP), of the Brown & Sharpe pattern start cutting low tooth numbers,(12 & 13), at cutter No.8 working to high tooth numbers,(135 to rack),at cutter No.1.
Metric cutters,(Module), are the reverse. Pick Imperial or Metrickery depending on the application. They ARE NOT interchangable.
Have a play and you will be fine and heed Bill Gruby's advise, Ivan Law's book is an extremly valuable bedside reader.
P.S. Go to page 37 in the downloads section. :encourage:
 
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