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Gallery, Projects and General => Oooops! => Topic started by: chipenter on September 09, 2013, 10:43:28 AM

Title: Gear cutting
Post by: chipenter 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 .
Title: Re: Gear cutting
Post by: awemawson 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?
Title: Re: Gear cutting
Post by: chipenter 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 .
Title: Re: Gear cutting
Post by: Meldonmech 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
Title: Re: Gear cutting
Post by: Pete. 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.
Title: Re: Gear cutting
Post by: chipenter 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
Title: Re: Gear cutting
Post by: ALB 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
(http://img.tapatalk.com/d/13/09/12/6y3u5ugy.jpg)

Then made a 50 tooth gear out of nylon round this was my first ever gear cut Well pleased with the result
(http://img.tapatalk.com/d/13/09/12/9ajavudy.jpg)

Next is to try and make one out of steel

Alb
Title: Re: Gear cutting
Post by: awemawson 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.