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Picked up my TH54 lathe last night
- Thread starter Waldo1
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- Feb 2, 2013
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Hi Waldo,
what you have there is a Mica Under-cutter for use in reconditioning MOSTLY DC starter and generator armatures.
the lathe is not powered up during these operations
you would mount the armature between headstock(chuck) and the special drill chuck that is contained in the lil box with bronze jaws.
you'd center up the cutter on the mica segments and work the carriage laterally to cut the mica insulating material that lies between the copper bars of the armatures commutator portion. You'd set the desired height with the elevation screw and lock it down, fire up the lil motor and advance with the carriage until the cut is complete. you'd manually turn the armature to the next mica segment and repeat the process until the mica is sufficiently undercut on all segments.
it's a time consuming process but works well.
if you are going to use it i would highly recommend that you oil and cover the lathes ways and cross-slide with towels or rags before you start.
mica is some nasty stuff and will scratch machined surfaces of your lathe like you would not believe, and very quickly i may add.
as to how rare they are i can't say for sure.
i don't own an atlas lathe anymore but, i still have a unit very similar to yours sans the literature.
nice score by the way.
you'll have a lot of fun with the TH54
good luck
mike
)
what you have there is a Mica Under-cutter for use in reconditioning MOSTLY DC starter and generator armatures.
the lathe is not powered up during these operations
you would mount the armature between headstock(chuck) and the special drill chuck that is contained in the lil box with bronze jaws.
you'd center up the cutter on the mica segments and work the carriage laterally to cut the mica insulating material that lies between the copper bars of the armatures commutator portion. You'd set the desired height with the elevation screw and lock it down, fire up the lil motor and advance with the carriage until the cut is complete. you'd manually turn the armature to the next mica segment and repeat the process until the mica is sufficiently undercut on all segments.
it's a time consuming process but works well.
if you are going to use it i would highly recommend that you oil and cover the lathes ways and cross-slide with towels or rags before you start.
mica is some nasty stuff and will scratch machined surfaces of your lathe like you would not believe, and very quickly i may add.
as to how rare they are i can't say for sure.
i don't own an atlas lathe anymore but, i still have a unit very similar to yours sans the literature.
nice score by the way.
you'll have a lot of fun with the TH54
good luck
mike
)
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The process described by Ulma Doctor is done after turning the commutator to make it smooth and round again.
The commutator chuck kit and the mica undercutter are fairly common. Not evey one has one, but I would not call them rare. What is rare and hard to find are the tiny saw blades used on the mica undercuttter. What else is rare is the replacement jaw kit used in the # 100 chuck - those are brass jaws used to hold the centerless shaft end of the armature assembly at the TS end of the lathe while turning the commutator. Use plenty of oil as the shaft will be turning in the brass jaws and they do wear. Replacements are indeed rare - no longer manufactured by Jacobs. The only sources I have found are NOS someone picked up in an estate sale or going out of business sale and then re-marketed on E-bay.
BTW: Don't try to use that # 100 chuck as a "keyless" chuck to hold a drill or other tool or workpiece tightly. It is a steady rest support for a shaft being turned and the shaft is expected to turn in the well-lubricated jaws. Tighten only enough to remove all free play.
The commutator chuck kit and the mica undercutter are fairly common. Not evey one has one, but I would not call them rare. What is rare and hard to find are the tiny saw blades used on the mica undercuttter. What else is rare is the replacement jaw kit used in the # 100 chuck - those are brass jaws used to hold the centerless shaft end of the armature assembly at the TS end of the lathe while turning the commutator. Use plenty of oil as the shaft will be turning in the brass jaws and they do wear. Replacements are indeed rare - no longer manufactured by Jacobs. The only sources I have found are NOS someone picked up in an estate sale or going out of business sale and then re-marketed on E-bay.
BTW: Don't try to use that # 100 chuck as a "keyless" chuck to hold a drill or other tool or workpiece tightly. It is a steady rest support for a shaft being turned and the shaft is expected to turn in the well-lubricated jaws. Tighten only enough to remove all free play.
Thanks, Guys! The attachment actually runs and the switch even works although the cord is brittle and cracked. I'll probably end up selling/trading this to someone actually knows how to use it, as I don't mess with electric motors at all and I'll be plenty busy with the basics on this lathe for the next few years (AT LEAST). It is nice to finally have a machine large enough that I can really get into trouble... Not to be overly sappy, but unpacking this lathe, its tooling and components over the last few days has actually become a rather humbling- and probably healthy- experience. When I first got it into my garage and began unpacking everything I was like a kid on Christmas morning, gleefully tugging open drawers full of this dead guy's tools and pawing through the shiny bits like a pet coon. As I found more and more things that I didn't even recognize I started to realize how much this man had known about this craft. I'm looking at tool bits he ground; boring and threading widgets that he created for some specific task and the understanding that it took to even figure out what he needed- much less the skill set to go to his shop and make it. I'm no dummy and its sobering to realize that at least in a shop environment, I would not be fit to carry this guy's jockstrap. And now I'm the custodian of machine tools that he knew like the back of his hand. I wish I could have known him well enough to pick his brain.
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Waldo you brought back some fond memories with the words near the end of your paragraph. Years ago I bought my atlas 618 from a retired machinist who was using it to make a scale model steam locomotive out of mostly brass. It was a lovely work of art, but he wasn't quite finished when his wife died. He put the lathe and all the accessories up for sale. When I got there he said when his wife died he lost interest. He made a bunch of accessories and tonnes of hand ground bits or all shapes and sizes. I marvel at his craftsmanship, and before I attempt to grind and perhaps ruin some tool steel, I sort thru the bits hoping to find what I need...with perhaps a bit of modification and marvel again at his skill. Indeed humbling.
Thank you for sharing,.
David
Thank you for sharing,.
David
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Hi Waldo I don't think parting with the cutter is a good idea it may make a very useful internal grinder if turned 90°
and the chucks are very useful if I remember correctly it spins on its arbor in the tail stock you may regret parting with it.
and the chucks are very useful if I remember correctly it spins on its arbor in the tail stock you may regret parting with it.
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- Feb 8, 2014
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Waldo, I would disassemble the mica under cutter, clean and grease it so it doesn't rust, and put it on the shelf along with the tail stock chucks until you need them some day. They are not that rare, but handy to have around.
I couldn't sell it, but I have a lot of trouble selling tools.:rofl:
I couldn't sell it, but I have a lot of trouble selling tools.:rofl:
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Mike,
As Mike AKA Ulma Doctor wrote earlier, the tailstock chuck doesn't spin. It has brass jaws and the commutator end bearing of the armature spins in them. Some armatures were center-drilled, in which case you would use a live center instead. But most are centerless. The chuck is keyless but not actually intended to grab and hold anything. However, when you are undercutting a commutator, you do snug it down on the bearing journal to make sure that the armature doesn't rotate while actually cutting.
The headstock armature chuck, on the other hand, can be used in place of a Jacobs 58B or 59B if you need a headstock chuck and don't have either of them.
Robert D.
As Mike AKA Ulma Doctor wrote earlier, the tailstock chuck doesn't spin. It has brass jaws and the commutator end bearing of the armature spins in them. Some armatures were center-drilled, in which case you would use a live center instead. But most are centerless. The chuck is keyless but not actually intended to grab and hold anything. However, when you are undercutting a commutator, you do snug it down on the bearing journal to make sure that the armature doesn't rotate while actually cutting.
The headstock armature chuck, on the other hand, can be used in place of a Jacobs 58B or 59B if you need a headstock chuck and don't have either of them.
Robert D.
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- Dec 8, 2013
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My Logan came with a Jacobs 59B headstock chuck which I find very useful.
would you be able to post a photo of the blade holder?