3D printed change gears

[G-ManBart]

Is there a link to the group and files section?

I think you have to join to access the files section, but I'm not 100% certain on that. Lots of good info and helpful folks!

sheldonlathe groups.io Group

Sheldonlathe is for sharing information about Sheldon, Sebastian, and Vernon machine tools. The Files, Photos, and Links sections contain basic information. Members may upload machine photos to the Photos section. For a manual or parts for your Sheldon, check the Files for "Sheldon Parts FAQ"...

groups.io

 

[D.sebens]

Thank you! I signed up and downloaded the file. I’m also missing an 80T and some other gears. My lathe is supposed to have two 80T’s. Looking at the chart one is keyed to the 127 gear(for certain pitches) and the other is the screw gear.

My compound gear combos are 127/110 and 127/80 depending on the pitch. But if the 127 gear works then I’ll know for sure my pitch and pressure angle and can model other gears.

 

[Huub Buis]

You can make such a gear in FreeCad (and probably Fusion360) in 2 minutes. I have attached the FreeCad project of a Module 1 (16DP) T127 gear, 8 mm thick and a 12 mm hole. The stl file is also included

 

[pressingonward]

I recently printed a 30 tooth idler gear for my Sheldon EXL-56B - it's a 1953 based on the serial number. It uses DP 16 gears with a 14.5 degree pressure angle. I'm pretty sure all the older lathes are the same, not sure about the newer ones.

For metric threading gears you need a different gear bracket (I forget what they call the part exactly) to handle the large 127 tooth gear. I think the Sheldon.io group has a drawing for it in the files section - I need to look into that soon. The alternative option is to use a smaller metric conversion gear set that's not mathematically perfect but close enough, and it fits on the standard gear bracket

If you need any more gear info I'm happy to help

 

[G-ManBart]

I recently printed a 30 tooth idler gear for my Sheldon EXL-56B - it's a 1953 based on the serial number. It uses DP 16 gears with a 14.5 degree pressure angle. I'm pretty sure all the older lathes are the same, not sure about the newer ones.

For metric threading gears you need a different gear bracket (I forget what they call the part exactly) to handle the large 127 tooth gear. I think the Sheldon.io group has a drawing for it in the files section - I need to look into that soon. The alternative option is to use a smaller metric conversion gear set that's not mathematically perfect but close enough, and it fits on the standard gear bracket

If you need any more gear info I'm happy to help

Not all Sheldons were the same, even in that timeframe. My current Sheldon is serial number 19024, which should be 1953 and it absolutely has 16DP 20PA gears. I checked it with a pitch gauge and they are definitely 20PA. Sheldon did use 14.5PA gears on some lathes, so people can't assume either is correct.

 

[pressingonward]

Not all Sheldons were the same, even in that timeframe. My current Sheldon is serial number 19024, which should be 1953 and it absolutely has 16DP 20PA gears. I checked it with a pitch gauge and they are definitely 20PA. Sheldon did use 14.5PA gears on some lathes, so people can't assume either is correct.

lol, mine is serial number 18542 (and is an Army Ordnance Department model if that has any bearing on anything). Wonder if they switched the pressure angle somewhere between building mine and yours, or if it was more random than that?

 

[G-ManBart]

lol, mine is serial number 18542 (and is an Army Ordnance Department model if that has any bearing on anything). Wonder if they switched the pressure angle somewhere between building mine and yours, or if it was more random than that?

If I had to guess, and it's really just a guess, I'd say maybe the switch didn't happen on all models at the same time. If they made a lot more of one size machine maybe they ran through their supply of gears faster so they switched PA sooner on that size...something along those lines. I think I recall John Knox (former Sheldon employee from the Sheldon Yahoo! group) said they made their own gears at Sheldon, but I'd have to go do some searching on that.