2 Series 60/61 questions: Broken Spindle Gear- Why no noise??

TheOldCar · May 24, 2015

My '54 Monarch Series 60 has a broken spindle gear, the "Large and Small Spindle Drive Gear". It has two clutch dogs completely snapped off taking sides of gear teeth with them.

What I don't understand is why it doesn't make noise when I run the lathe. I admit I'm not aware of which spindle RPMs engage the broken part of this gear (CORRECTION!!! It's the SMALLER gear). I have ran many of the speeds and turned lots of pieces with it.

Am I foolish to continue using the machine as-is? I do have the new replacement spindle gear but fear I will open a can of worms when I try changing it. I especially don't want to find out it should have more parts (bearings... :ack2:

) replaced.

Second unrelated question: What alloy is proper for making new spindle take-up nuts? I want to make a new one since one of the two are banged up from lots of hammer & punch blows. Who does that?!?! :angry:

I ruined two of my spanner wrenches just trying to loosen the nut! Any help appreciated.

WHHJR · May 24, 2015

Are they standard bearing locknuts?

Locknut Technical Details | Nook Industries

TheOldCar · May 24, 2015

I imagine they are, but may be I'm totally wrong. Thanks for the link; I would love it if they can be made from mild steel. Monarch stocks them, but I would like to make my own.

johnoder · May 24, 2015

Similar to this CW16 from the fall of '46, the gear will not be in use unless you are in one of the eight lowest speeds. Spindle gear is on left, photo from rear

http://img.photobucket.com/albums/v337/johnoder/Monarch/DCP_0829.jpg

TheOldCar · May 24, 2015

johnoder said:
Similar to this CW16 from the fall of '46, the gear will not be in use unless you are in one of the eight lowest speeds. Spindle gear is on left, photo from rear

http://img.photobucket.com/albums/v337/johnoder/Monarch/DCP_0829.jpg

Thanks for the answer. I just realized I described it wrong, though! I said originally that the LARGE gear was the busted side. It is actually the SMALL gear which faces toward the spindle nose.

So it is the clutch dogs that engage in the highest speeds, right???

Here's the pictures, viewing from the front, back when I had the cover off:

Or maybe I'm wrong... After looking at your pictures and mine, it seems the "Large and Small Spindle Drive Gear" does what you said. And it engages from exactly that single clutch. Sorry for mudding the water; I'm still just a wannabe!

beckley23 · May 25, 2015

This may be of some help in explaining the headstock gears. The biggest worry I would have is that there could be further damage to a damaged gear that will really screw things up.
http://www.practicalmachinist.com/vb/monarch-lathes/12-ck-headstock-gearing-oil-pump-293420/
Harry

TheOldCar · May 25, 2015

beckley23 said:
This may be of some help in explaining the headstock gears. The biggest worry I would have is that there could be further damage to a damaged gear that will really screw things up.
http://www.practicalmachinist.com/vb/monarch-lathes/12-ck-headstock-gearing-oil-pump-293420/
Harry

Thanks for this link and your diagrams!

I probably should change the gear! I imagine it will be a big undertaking to remove the spindle carefully. I know about cleanliness and care, but fear what I might discover.

moonlight machine · May 25, 2015

You don't hear any noise because the last dogs are doing the work. You will sure hear some noise when they come off though. Probably safe to say by the look of things they are cracked and could come off anytime. I would get on it straight away, if something the size of a dog goes through another pair of gears the damage will get expensive.

Ray Behner · May 25, 2015

I'm surprised it didn't explode when they first broke.

TheOldCar · May 25, 2015

moonlight machine said:
You don't hear any noise because the last dogs are doing the work. You will sure hear some noise when they come off though. Probably safe to say by the look of things they are cracked and could come off anytime. I would get on it straight away, if something the size of a dog goes through another pair of gears the damage will get expensive.

Thanks for the help. I will begin figuring out a plan to replace the gear.

asdf · May 25, 2015

TheOldCar said:
Thanks for the answer. I just realized I described it wrong, though! I said originally that the LARGE gear was the busted side. It is actually the SMALL gear which faces toward the spindle nose.

So it is the clutch dogs that engage in the highest speeds, right???

Here's the pictures, viewing from the front, back when I had the cover off:

View attachment 140328

View attachment 140329

Or maybe I'm wrong... After looking at your pictures and mine, it seems the "Large and Small Spindle Drive Gear" does what you said. And it engages from exactly that single clutch. Sorry for mudding the water; I'm still just a wannabe!

Those gears look surprisingly "low quality" at least for the section in between. I find it quite odd to see such rough surface (deep machining marks) on a critical ground and hardened gear. Can it be that at some point the gear was actually replaced with a custom made one? Can other owners of the same lathe confirm the surface finish on that part?

n.

TheOldCar · May 25, 2015

The NOS one Monarch sold me is the same. That area isn't critical, but the machined teeth and inside diameter are excellent.

As far as my other question, do you guys think I'm foolish making my take-up nut out of mild steel? It should be fine, right?

Panza · May 26, 2015

The only downside I can see to making the nut from mild steel is that it might be easily damaged again when adjusting it. Heat treated 4140 is quite a bit harder but still no problem to machine.

TheOldCar · May 26, 2015

I'll dig through my bin. I think I only have some 12L14 and maybe some O1 tool steel that is big enough diameter. I imagine the O1 is not the best idea (It might be pre-hardened). I'll look for some 4140.

Thanks for the stern warnings about my gear. The spindle is officially out and new gear should be in tonight after work. The front bearing looks better than I thought it would. Not excellent :eek:

, but not terrible...

TheOldCar · May 31, 2015

New gear is in! And I learned some things along the way, like how much redneck mechanics like me still don't know what they're doing with machining and precision machines.

TheOldCar · May 31, 2015

Here's my homemade take-up nut nowhere near done. I had to check it for fit, being so impatient to put the Series 60 back together. Using the South Bend 13" I turned threads with a little HSS boring bar I ground to cut threads. I have so little time to do these projects; finishing the nut was not going to happen Friday.

Tomorrow I will sneak out after work and part the take-up nut, soften the edges, drill for pin slots and the set screw/brass.

TheOldCar · Jun 9, 2015

Finished.

Panza · Jun 15, 2015

Lovely work !
How long did the gear-out gear-in take you ?
Would you like to disclose how much they wanted for that gear ? I am afraid of the answer.

TheOldCar · Sep 5, 2015

Thanks! It took me a couple of evenings, mainly due to repeatedly dropping the half clip thingies inside the gearbox and trying to fish them out, and making the spindle front gasket too thick...twice! :dunce:

The gear was about $1750.

Panza · Sep 8, 2015

That was not a cheap gear but you can't exactly get a new Monarch either. And there is something about the machine one already have, compared to getting a new old one.

2 Series 60/61 questions: Broken Spindle Gear- Why no noise??

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