Author Topic: Gear cutting  (Read 2949 times)

Online chipenter

  • Hero Member
  • *****
  • Posts: 726
  • Country: gb
Gear cutting
« on: September 09, 2013, 10:43:28 AM »
Made a 20 DP 20 tooth gear today , there wasn't enough metal to cut the key way and it split , guess I should have cut the key way first , the cast iron came from a dumbbell so something had to go wrong .
Jeff

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5531
  • Country: gb
  • East Sussex, UK
Re: Gear cutting
« Reply #1 on: September 09, 2013, 11:03:01 AM »
Bad luck - how frustrating.

There's not a lot of meat left between the dedendum and the keyway, can the keyway be reduced in depth?
Andrew Mawson
East Sussex

Online chipenter

  • Hero Member
  • *****
  • Posts: 726
  • Country: gb
Re: Gear cutting
« Reply #2 on: September 09, 2013, 11:10:21 AM »
Thank Andrew I will try the fit before I cut the next one , I want a 20 tooth one as well my have to make that from steel .
Jeff

Offline Meldonmech

  • Hero Member
  • *****
  • Posts: 894
Re: Gear cutting
« Reply #3 on: September 09, 2013, 12:53:17 PM »
Hi Chip
                   Can the size of the shaft be reduced, it looks large in comparison to your gear?


                                                                    Cheers  David

Offline Pete.

  • Hero Member
  • *****
  • Posts: 793
  • Country: gb
Re: Gear cutting
« Reply #4 on: September 09, 2013, 01:10:34 PM »
What kind of tool are you cutting the teeth with? Looks like you have a burr or it's dragging the back edge of the tool and carving a small step in one side of every tooth.

Crack looks like it's due to built-up stresses in the cast iron. I sometimes have to cut out cast iron tunnel sections and I've had quite a few split with a loud bang half way through cutting.

Online chipenter

  • Hero Member
  • *****
  • Posts: 726
  • Country: gb
Re: Gear cutting
« Reply #5 on: September 09, 2013, 02:45:04 PM »
It was a home made cutter using an and mill to get the profile , I split the gear using a standard broach knocking it though with a mallet , I have since successfully made another gear cutting the key way first .


Jeff
Jeff

Offline ALB

  • Jr. Member
  • **
  • Posts: 28
  • Country: scotland
  • Aberdeen
Re: Gear cutting
« Reply #6 on: September 11, 2013, 02:38:58 PM »
Hello All,

I made this little gear cutter out of an old boss from a lawn mower shaft


Then made a 50 tooth gear out of nylon round this was my first ever gear cut Well pleased with the result


Next is to try and make one out of steel

Alb
Don't put all your eggs in one basket

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5531
  • Country: gb
  • East Sussex, UK
Re: Gear cutting
« Reply #7 on: September 11, 2013, 02:47:42 PM »
Difficult to tell from your pictures, but is that an involute form? It looks more triangular but maybe that's the lighting.
Andrew Mawson
East Sussex