Help with big gear

[skeptonomicon]

I am new to machining, and have a 13" lathe and can borrow a sizable rotary table. I need to make a large metal gear, 10.5" diameter. I am thinking that the lathe is probably not going to be the right tool for the job but thought I would ask. I thought about building a mount to hold a rotary table to the cross slide, with the gear either to the front or above the cutting area, and the gear cutter in the head stock. This seemed like a lot of precarious mounts which would end up with excessive play. I also thought of mounting the gear on the headstock, but this requires a second cutting tool. Is there any ingenious method I am missing here or do I really just have to get access to a milling machine and rotary table (or hire out EDM)?

 

[ttabbal]

I've seen people make gears on a lathe. There are a number of videos on YouTube showing setup options. The rotary table would need indexing plates for the best accuracy. You might be able to do it without the plates, but you might end up with a tooth or two misplaced.

If you mount the cutter in the headstock, I recommend using an end mill holder that matches the headstock taper and rig a drawbar through the headstock. That helps keep the cutter in the right place. A lathe chuck has a tough time holding cutters sometimes.

Ideally one would use an indexing head on a mill, but it can be done. If you want to go old school, check out Clickspring on YouTube. He's made gears without electricity.

 

[markba633csi]

Doable but iffy. The center of the gear would need to be sitting more than 5" above the spindle axis which makes for a rather ungainly setup
If you do decide to do it this way, post pictures for sure. What material for the gear?
The play of the cross slide would have to be adjusted for the absolute minimum, and you would need to mount the index head directly to the slide
-Mark

 

[benmychree]

Sketchy to say the least.

 

[Weldingrod1]

Could you 3D print?

Sent from my SM-G892A using Tapatalk

 

[lordbeezer]

Thought I might have you a gear but it’s appx 10.75”.