Monarch 612-2516 lathe

[DAM 79]

That looks pretty good in my book and when you get some paint on it that look just like part of the lathe !!!! Great fabrication Skills !!!

 

[rabler]

I was about to say, that is why they have a handle and it is gear driven, but you indicated it was missing. Hopefully you can find a replacement. Would make using the lathe much easier.

I am so envious of that lathe. Hope when we get into our final home, that I am able to find one for my shop. Congrats. Loved watching you go through it. Appreciate your meticulous process and attention to detail.

Getting closer to having that handle Thank you for the compliments!

My first lathe, the benchtop Grizzly, just left packed up in the back of another forum member's hatchback. So I need to get this 612 working, because having only one working lathe is leaving me feeling a bit insecure.

I'm hoping when I'm finished for this 612 to be something to really be a workhorse.

 

[extropic]

Great project. Nice work.

That pinion has no keyway and not much meat for setscrew(s). I guess you're going to match drill and pin?

 

[rabler]

Great project. Nice work.

Thanks!!

That pinion has no keyway and not much meat for setscrew(s). I guess you're going to match drill and pin?

Yes. Either a roll pin (spring pin?), or a taper pin since I have those and the necessary reamer. I ordered the pinion unhardened, I'd rather chew up the pinion, which is easy enough to replace, than the rack. The .875 hex head coupling will get the same treatment, so the shaft is captive on the arm.

One thing I haven't settled on yet but the pinion is going to rub on the bed casting. I left the shaft about .3" shorter than the pinion, so I could put a brass, or maybe a teflon plug on the casting side of the pinion to reduce rubbing.

 

[rabler]

I am so envious of that lathe. Hope when we get into our final home, that I am able to find one for my shop

I should warn you that finding one is the easy part. Moving it is much more challenging.

 

[extropic]

<snip
One thing I haven't settled on yet but the pinion is going to rub on the bed casting. I left the shaft about .3" shorter than the pinion, so I could put a brass, or maybe a teflon plug on the casting side of the pinion to reduce rubbing.

Your weldment looks great.

I would have guessed that the original factory bracket would have been rigid (not hinged). Was the original hinged?

The idea of stopping the swing off of an "as cast" surface feels kind of rough (pun intended) to me .
Alternative idea: make a collar to fit (press?) over the pinion OD and pin it with the same pin. The side face of the collar rubs along the side of the rack.
You might be able to implement a small roller (or two) to follow the side of the rack.
Just thoughts. YMMV.

 

[rabler]

Your weldment looks great.

I would have guessed that the original factory bracket would have been rigid (not hinged). Was the original hinged?

The idea of stopping the swing off of an "as cast" surface feels kind of rough (pun intended) to me .
Alternative idea: make a collar to fit (press?) over the pinion OD and pin it with the same pin. The side face of the collar rubs along the side of the rack.
You might be able to implement a small roller (or two) to follow the side of the rack.
Just thoughts. YMMV.

I'd thought about the collar approach too, using a piece of 6061 or bronze.

Monarch hinged the original in all of the various models of the 610/612 (three swing sizes each). I would guess that being able to swing the pinion out of the way would facilitate sliding the tailstock without using the gear. Monarch made a 1610, 2013, and 2516 version of these, where the first two digits is the swing over the ways, and the second two digits is the swing over the carriage. Since this is a 2516,the largest swing of the variants, sliding the tailstock was probably more realistic on the smaller machines. If I recall correctly, the 610 was a narrower bed version, and thus not as heavy, but had the same swing options.

As far as I can tell they didn't have any mechanism to prevent rubbing on the casting.


I believe the pin (X68) and knob (X69) allowed the crank to be locked out so it wasn't engaged

 

[rabler]

The idea of stopping the swing off of an "as cast" surface feels kind of rough (pun intended) to me .

I need to take a closer look at the bed tomorrow.
I know for sure that the apron actually has a phenolic follower that rides on the vertical face of the bed near the bottom of the apron. That follower is lubricated by oil groves, and has a machined face on the bed to ride along. I think the machined flat for the rack just extends down low enough to permit the pinion to have a machined face rather than a rough casting.

 

[extropic]

Maybe the mesh of the pinion and rack was the swing limiter. That would have been easy enough for the factory to design in (if the two mesh when the pinion is on the upswing.

 

[rabler]

Maybe the mesh of the pinion and rack was the swing limiter. That would have been easy enough for the factory to design in (if the two mesh when the pinion is on the upswing.

Doubtful, if you look at part X11, the pivot point would need to extend farther out from the tailstock for that. These parts diagrams are usually to a consistent scale. As it is that pivot point is very close to vertical over the rack.