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Monarch 610/612 tailstock crank design question.

rabler

Cast Iron
Joined
May 25, 2020
Location
Rural S.W. Indiana
The Monarch 610/612, and probably other larger lathes, had a manual crank on the tailstock that engages the carriage rack to allow the fairly heavy tailstock to be moved. My lathe was missing that crank mechanism when I bought it, so I am fabricating a replacement.
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Does anyone have an original crank mechanism? I am curious how Monarch designed this so that the pinion gear engaged the rack but didn't rub against the bed. Maybe it did? The parts diagram does not give me any ideas.
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I don't have a great pic, but zooming in I think someone modified the collar just before pinion gear, and added a stop or foot bearing. That step appears to ride on bed rack just above the gear teeth.

Also it appears the TS drive is stationed just right of the TS, but that's a Series 61. Presumably to let TS fit close into carriage. Not sure how long your TS is and how deep in fits into carriage.

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The two methods I considered are a similar collar, or a teflon plug on the bed side of the pinion. It appears the bed was milled to clear the pinion in the same pass as the rack, unlike on earlier models including your picture where the rack sits on a milled shoulder.

The 612 tailstock is quite large, looking at the original parts diagram that mechanism is directly on the tailstock rather than on an extension.
 
I will get some pics of the gear on my series 62 tomorrow, the arm as I recall tends to swing away from the bed without much persuasion.

There should be a detent and a sliding pin on the outer saddle wing and tail to tow the tailstock under power with the saddle. I rarely use the crank, either just nudge the tailstock or tow it.

Steve
 
The bed on a 612 should be pretty close to the bed on a series 62, the area under the rack is smooth. The gear is lightly crowned so the friction/rubbing is minimized. You may be over thinking the assembly. My lathe is 102 C-C and has intermediate shaft supports on either side of the carriage that move on a dovetail directly below the rack. The entire face of the bed is machined smooth above and below the dovetail to allow the supports to slide. There is nothing fancy on the pinion gear shaft it has a sleeve and the shaft has enough in-out movement to allow the pinion to start aligning with the rack as it arcs into position. The pinion is not a close mesh with the rack, there is plenty of daylight between them when in place.

I am not sure if the short bed lathes have some of these features present? The bed casting may not be finished with these features where they are not used. The button for the tailstock tow pin is at the far right of the saddle the cup for the pin is on the headstock end of the tailstock base.

Here are a few pics to detail the above commentary.

Steve
 

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The 612 has the machined face on the casting. I went with a belt and suspenders approach and put a collar on there as well as a nylon button (which contacts first). This tailstock is long enough that there is plenty of room for the crank to not interfere with the carriage. I was going to make a crank handle but the ratcheting 7/8 wrench works well and also (intentionally) is the size that fits the carriage lock, so I'll dedicated one to that.

Interestingly, although it is a 1967 machine, it does NOT have the carriage pin to use the carriage to move the tailstock. While there is a face in the carriage casting that corresponds to that pin, no hole or other feature is present there. Nor does the tailstock have a button or any other feature that such a pin would engage. I wonder if they decide that was a problem with the rapid traverse on the carriage which I have, or if perhaps the 2516 tailstock was heavier than Monarch thought reasonable to pin to the carriage?

Mine is (I believe) cataloged at 48" bed length. It was a government sale machine so it doesn't have the typical Monarch plate. No intermediate shaft supports, I think that kicked in when you got the center leg.

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Regarding the pin; my lathe has rapid traverse and it is no problem. I wonder if this was an option or only on the long bed machines? I don't think the weight of the tailstock is an issue, my 2 speed tail stock is a massive chunk of iron. Glad you got the project done, I know moving the tailstock takes a great deal of effort.

Steve
 
Regarding the pin; my lathe has rapid traverse and it is no problem. I wonder if this was an option or only on the long bed machines?
It does strike me as odd that mine has a short bed but includes the rapid traverse option. I would think if someone was going to the expense of adding the much more complicated rapid traverse, they'd also include the tailstock/carriage pin option. Mine originally had an electronic tracer, but I can't see any reason that would have precluded the tailstock pin. Could it be at least for the later models, that pin was a feature only available on the model 62 as another way of up selling? What year is your 62?

I'll leave a few additional pictures here in case someone else comes along looking for ideas on how to build a simple tailstock crank mechanism:
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It does strike me as odd that mine has a short bed but includes the rapid traverse option. I would think if someone was going to the expense of adding the much more complicated rapid traverse, they'd also include the tailstock/carriage pin option. Mine originally had an electronic tracer, but I can't see any reason that would have precluded the tailstock pin. Could it be at least for the later models, that pin was a feature only available on the model 62 as another way of up selling? What year is your 62?

My series 61 from 1956 does not have rapid traverse. But I do have the push pin towing mechanism.

I've heard some find the push pin mechanism cumbersome to hold the pin while rolling the apron hand wheel. Not sure, as I have not used it complete yet. But I was considering adding the the TS hand crank as you have anyway.

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Jeeze, you guys. Just squirt a little juice on the ways and give 'er a shove. They don't weight that much, these don't swing 40" !

Hey ! Some of us are at the age we need to think more and man-handle less. :D

About a month ago I thought I blew a hip out after a real nice date night with the wife. Could barely walk for a week. Omg, is this what life is now ? :D
 
I wonder how much that damn thing actually weighs?

The grand total of mine I put in the 400 lb range. And I've had it off and apart to know.

Based on your beast compound rest/tool post set up, being rather larger than mine, I would think your tail stock heavier than mine.
 
My lathe is a 1959 not sure how late they produced series 62 machines? Seems like the pin may have been a long bed feature? Do you have a saddle parts page, see if that was available on the 612?

Steve

Nothing on the parts diagram I have but it is a generic one for the 610/612 from vintagemachinery.org so I'm not sure what year(s) it applies to.


Hey ! Some of us are at the age we need to think more and man-handle less. :D

About a month ago I thought I blew a hip out after a real nice date night with the wife. Could barely walk for a week. Omg, is this what life is now ? :D

In a word, yes. :) The real question is, would you do it again anyway?
 
The grand total of mine I put in the 400 lb range. And I've had it off and apart to know.

Based on your beast compound rest/tool post set up, being rather larger than mine, I would think your tail stock heavier than mine.

Well, curiosity killed the cat.
At 687 lbs, that tailstock would not only kill the cat, it would pretty much pulverize it.
 








 
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