It was bound to happen sooner or later.

websterz · May 25, 2011

I broke one of the 80 tooth gears on my 7x12 yesterday.

I was working on my homebrew ER32 collet chuck when it happened. I was paying a little too much attention to the cut and not enough to how close I was getting to the headstock. I am just so used to having a 4 inch chuck on the spindle, sticking out a couple inches further than my project. Well, this time the chuck-in-progress was bolted directly to the spindle and I was cleaning up the OD in preparataion for cutting the collet boss today. The carriage hit the end of the road, the lathe groaned, then the gear gave way with a pop. I just now placed an order for a full set of metal change gears, including 2 80 tooth gears. Total with 1 day express shipping was just over $126.00 so I'm not complaining. I figure I can use the remaining plastic gears that came with my lathe as fuses, including one plastic gear in each threading setup.

I notice looking at my lathe bed that there is a good inch or more of unused rack gear near the headstock. Has anyone ever milled the bed cut-out longer to take advantage of this unused real estate? It would really come in handy with the shorter ER chuck in place.

On a positive note I got my ER32 collets in today. I scored a set of metric Parlec brand collets on Ebay for just over $71.00. It's an 18 piece set that retails for over $500 and looks like it has never been used!!

Tin Falcon · May 26, 2011

Littlemachinshop.com has metal chancge gears on sale this weel IIRC about 75 for the set instead of $100
Tin

bezalel2000 · May 26, 2011

Stripped gear ! :-[ Yeah I know that feeling.

I was cutting a thread once when Bang!,

I can't really describe it as a pop like yours did, these gears are MOD1 cast iron change wheels.

Checking out the gear train revealed that there wasn't enough backlash to allow a rather bulky bit of swauf to squeeze its way between the gear teeth.
The result, both the gear teeth tore off at the root.

I'm thinking metal gears alone won't stop it happening, they'll just make the fix more expensive. :'(
I guess the 'fuse' idea will help.

Needles to say I'm a lot more meticulous about clean change wheels and backlash nowadays.

So were you feeding or threading at the time?

websterz · May 26, 2011

Tin Falcon said:
Littlemachinshop.com has metal chancge gears on sale this weel IIRC about 75 for the set instead of $100
Tin

You gotta' remember that this set doesn't include the (2) 80 tooth gears that you need to complete the all metal gear changeover. They are an extra $22 a piece from LMS. All in all I saved about $7 over the LMS sale price by ordering from a different source. (Sorry Chris, I am loyal but funds are really tight now.) The change gears I bought are regularly priced at about half what LMS charges, and the 80 tooth gears are $6 less each. Oh yeah, I also opted for one day express delivery. Had I chosen ground service I would have saved even more.

websterz · May 26, 2011

bezalel2000 said:
Stripped gear ! :-[ Yeah I know that feeling.

I was cutting a thread once when Bang!, I can't really describe it as a pop like yours did, these gears are MOD1 cast iron change wheels.

Checking out the gear train revealed that there wasn't enough backlash to allow a rather bulky bit of swauf to squeeze its way between the gear teeth.
The result, both the gear teeth tore off at the root.

I'm thinking metal gears alone won't stop it happening, they'll just make the fix more expensive. :'(
I guess the 'fuse' idea will help.

Needles to say I'm a lot more meticulous about clean change wheels and backlash nowadays.

So were you feeding or threading at the time?

I was feeding. In 3 years with this machine I had never had the need to run so close to the headstock and I just ran out of road. Live and learn I guess. I just completed a metal spindle gear / tapered roller bearing upgrade last week. Who knows what may have happened with 3 year old used/abused plastic gears on the spindle.

willburrrr2003 · Jun 12, 2011

I feel your pain my friend, Just got my mini lathe running after a cnc conversion... was messing with various cuts when I issued the wrong MDI command... sent the tool into the work instead of pulling back from it..... My spindle gears took a big hit, and make a lot of noise now.... my replacements wont be ordered until friday evening. How hard was it changing your spindle gears?

Regards,

Will R. Everett, WA.

websterz · Jun 12, 2011

I spent a total of about 8 hours on the gear / tapered roller bearing upgrade. Part of that was a total strip down of the lathe for a good cleaning and lube job. I had purchased the gear set from MicroMark, got it on sale with all the tools for $60 or so over a year ago. The bearings were about $40.00 for the pair from Ebay. It was a pretty easy job, just take pics of the assembled spindle before you pull it down, makes putting everything back right a little easier. I only changed the spindle gears out, I left plastic on the lower shaft to act as a fuse. That gear is easy to change so if one is going to break I want it to be that one.