Broken gear in Mini lathe

[manojd]

I had a small disaster today while working on metal inserts. The gears froze while using auto-feed. Thankfully the lathe turns off automatically, otherwise it would be a bigger disaster. Upon inspection, I found out that the bush which holds gear B and C had been jammed. As a result the 80T gear got damaged along with the keyway.

This is what it looks rightnow:

Is there any way to repair this gear? I had thought about relocating the keyway, however enough material has been sheared that simply relocating will not help.

Thanks.

 

[carlmorrell]

Did you contact the manufacturer to see if they sell replacement parts? Is that part plastic or metal?

Maybe some JB Weld?

 

[manojd]

Did you contact the manufacturer to see if they sell replacement parts? Is that part plastic or metal?

Maybe some JB Weld?

Replacement parts are available. I was looking for a quick fix

It is non metal, I believe it is called Acetal.

 

[carlmorrell]

I am always surprise what I have been able to fix with JB weld. YMMV!

 

[manojd]

I am always surprise what I have been able to fix with JB weld. YMMV!

I will give that a try. Thanks.

 

[ashaw]

Make sure you get a couple of gears as spares. I have heard that is the one problem with plastic gears.

 

[truckfixr]

Littlemachineshop.com sells metal gears to upgrade your mini lathe.

Change Gears Set, Metal - LittleMachineShop.com

 

[low_48]

Metal gear sets are also available.
truckfixr beat me by two minutes.

 

[Donovan]

Just cut a new key way opposite to the damaged one should get you out of the pinch

Donovan

 

[frank123]

Bore it, make a metal or (less desirable) plastic insert with the right ID and an OD to match your bore size, file the key way slot, epoxy it in. Be sure to rough the glued surfaces up (better to file a few matching slots with a small triangel file) to provide both a mechanical as well as an adhesive bond.

Pretty simple, I've made a few non standard sized gears (with the right pitch but wrong bore) fit my mini for odd thread sizes the standard gears won't make doing it this way.

Or just buy a new one, they're fairly cheap and if you want metal gear sets can be found at a somewhat reasonable price.

 

[manojd]

Thanks all for your suggestions. I will try one of these options soon.

For now, the problem has been solved. Spare kit that comes with the lathe for threading has 60T gear. I used a combination of 20-60-20-80, which gives me a pitch of (20/60)*(20/80)*1.5 = 0.125mm. This is closer to the normal auto feed rate of 0.09375mm. This worked just fine with the aluminium parts.