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Monarch 12CKK, Prepping to Get Back in Service

I think the theory is, the lead screw, feed rod, clutch rod, and potentially LS reverse rod can flex a little. So by only lowering end bearing, you have relieved some strain, and thereby improved.

There is a horizontal guiding trench for both end bearing and qcgb that make adjusting higher or lower a complicated endeavor. As both are aligned and held in place with that trench.

Something like a South Bend, both end bearing and qcgb are bolted to underside of bed way, and can lowered with shims a bit more simply.
Lowering just the right side would relieve some stresses and the drive rods involved would flex. There would be unwanted stress but less than if nothing at all was done.
A less than perfect solution but we have to live with those sometimes.😬
 
Lowering just the right side would relieve some stresses and the drive rods involved would flex. There would be unwanted stress but less than if nothing at all was done.
A less than perfect solution but we have to live with those sometimes.😬
All lathes will wear at saddle/carriage, but it seems to me that Monarch has a high percentage of adjustments/repairs that involve raising the carriage through turcite, moogalice, or other. Which to me would be the most correct way to resolve it.

An added benefit of raising carriage is you would improve contact/ gear back lash on pinion to bed rack, as well as keeping rods between qcgb and end bearing true.

Which the bed rack would not be quite so easy to adjust down either. To do that, you need to knock out taper pins, and resize or relocate the holes if shimming rack down.

So really, I'd have to think raising carriage is the best way. On this lathe, based on pinion to bed rack slop, I think I could raise carriage easily .020".

In fact, I was thinking of giving it a go while I have it tore down. I prefer metal to turcite. I was checking McMaster Carr, they have brass, copper, and bronze shim stock. I'm going to experiment with the bronze shim stock. See how well I can get it stuck to carriage, scraped in, oil trench etc.

Not a super duper hardcore rebuild. But if I can get the cast iron mostly flat, with contact areas spread out on wings of carriage. . . Might not be too time consuming, or too excruciating to get done.
 
Building up the apron and tailstock to bring them back up is most of what I have seen.
I like the bronze shimstock Idea. I know they have bronze alloys that are pretty hard.
They make good adhesives but using some soft countersunk drive screws like tag fasteners. as a secondary fastener on lhe ends and edges may help.

With two different materials they may be different in rate or amount of expansion. The bronze is thin and may just go along with whatever the cast iron is doing..
The bronze would make a good bearing surface.
Your experiments may answer these questions.

I have learned with adhesifes that some require a little thickness to hold. Squezed to thin they fail. Etching your bonding surfaces may help.

Something tells me that you have already covered everything I said here in thoughts and or research..

Edit
Using the small drive screws would pucker bronze shimstock
 
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Without lowering both ends the bushing on the right would also have to be bored at a very slight angle.
Up by the headstock that method would have little effect and still put down pressure on the leadscrew and could try to raise the carriage.
I dont doubt that rebuilders may have done that but its not doing it right. I havnt pulled a gearbox so dont know what lowering it would entail but could see a possible can of worms. Maybe not?
Lower both ends or nada.

Hey! It could tighten up sloppy half nuts a little:nono:
I've posted about this before:
Several machines, including my own, have shown up that have had a "field expedient" rebuild performed on them. The saddle ways were apparently machined down to remove wear (in the case of my machine by 0.040" [1.0mm]). The right bearing bracket was dropped by the same amount and apparently nothing else was done to handle the fact that the carriage was lowered. My leadscrew and feed-rod run down hill 0.040" over their length. They apparently relied on the ability of the leadscrew and feed-rod to flex as the carriage moved towards the headstock. Since the half-nuts and leadscrew worm don't move much left of center, the rods only have to flex about 0.020" with the carriage at the headstock end. (On some machines the rack was moved over and down as well, but that was not done on my machine.)
link

Some photos here:

Surprisingly, the feed-rod doesn't show unusual wear as you move left towards the middle. I didn't discover this until after I had the apron off and I didn't check to see if the feed-rod bushings were worn oblong.

I'm not suggesting that this is the preferable way to handle a worn saddle, but I imagine that it does improve things over having a badly worn saddle.
 
I've posted about this before:

link

Some photos here:

Surprisingly, the feed-rod doesn't show unusual wear as you move left towards the middle. I didn't discover this until after I had the apron off and I didn't check to see if the feed-rod bushings were worn oblong.

I'm not suggesting that this is the preferable way to handle a worn saddle, but I imagine that it does improve things over having a badly worn saddle.
After explaination I can see that lowering the right side would relieve stress on the feed rod and leadscrew.

Forty thousanths drop over a rod length.of about 36". [estimate]
The points of apron contact somewhere in between where they can flex.
Its not a bad option considering the function.

It hit me wrong at first without knowing lowering the gearbox is not feasable.


It would be nice if we lived in a world where everything is perfect. I ran machinery for years that every adjustment handle you grab you learn how far to fudge. All our handwheels werent marked in thousanths but some adjustments were that close.

These lathes were only new for the first cut, from there wear begins. Much more slowly with this generation of new owners.
 
I've been working a job a few hours from my home shop. Working a ton of OT, plus spending an average of half my week away from home. Its put a serious damper on my own projects and home shop. Plus while away, I've had a few occasions where I could use my machine tools, and not having them readily available has become a real pita.

I've considered moving some of my machines down to the Corpus Christie area, but ultimately, I'm not going to relocate or give up my home or shop in the Houston area. My Monarch Series 61 is still my priority project at home, I've just not had the time to dive into while there. Hopefully soon, as I clear work and add more people to the job in the Corpus area.

All this has led me to wanting to add a machine or two (:D) in the Corpus shop. I had been casually looking for another Series 61, Pacemaker, or Pratt & Whitney Model C. I came across a Monarch 12CKK at HGR that was fairly cheap, due to a broken coupling at qcgb for the clutch lever. This looked like a relativly easy fix for me. Not a toolroom lathe, but has taper attachment and leadscrew reverse just above qcgb. I was thinking this could be be a decent purchase, and handle basic work for me. So I bought it.

Some Pics from the HGR advert:

View attachment 384065 View attachment 384066 View attachment 384068

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Hey there. I own a 12KK from 1937 and am looking for the elusive taper attachment bed clamp. It looks like yours came with on hiding under the bed at the tailstock end. Could you post pictures and a drawing with dimensions of yours with dimensions so that it could be replicated? I'm sure others would also appreciate having the information. There's a lot of info for the 10EE clamp but not so much on others and having an original for the '12' size Monarchs would be great. Thanks.
 
Hey there. I own a 12KK from 1937 and am looking for the elusive taper attachment bed clamp. It looks like yours came with on hiding under the bed at the tailstock end. Could you post pictures and a drawing with dimensions of yours with dimensions so that it could be replicated? I'm sure others would also appreciate having the information. There's a lot of info for the 10EE clamp but not so much on others and having an original for the '12' size Monarchs would be great. Thanks.

I should be back at the location of that lathe next week. I'll get some pics and such when I do.
 








 
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