Picked up an old lathe (1 Viewer)

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I've done a bit of interrupted cutting on (what I assume is) induction hardened axle shaft splines, and yeah, carbide inserts don't hold up great to that. Brazed carbide tooling works much better, as does solid triangle carbide inserts. Hss didn't hold up at all to that, literally turned to dust before making a cut.

Copper is so soft that I don't think it'd be an issue though. My first attempt on a commutator would be a positive cutting carbide insert, then failing that, a nice sharp hss tool.

I wouldn't even consider diamond cutting tools until I trashed everything else I had trying, lol.
 
I've done a bit of interrupted cutting on (what I assume is) induction hardened axle shaft splines, and yeah, carbide inserts don't hold up great to that. Brazed carbide tooling works much better, as does solid triangle carbide inserts. Hss didn't hold up at all to that, literally turned to dust before making a cut.

Copper is so soft that I don't think it'd be an issue though. My first attempt on a commutator would be a positive cutting carbide insert, then failing that, a nice sharp hss tool.

I wouldn't even consider diamond cutting tools until I trashed everything else I had trying, lol.
I'm honestly tempted to try first with diamond, given how limited the supply of workable rotor assemblies there is. I need to sit and do much more reading though before figuring out exactly what I'm going to start with. Today will be doing the brakes and a tune up on my mother's 4Runner, but possibly this evening I'll be able to do a little more teardown and tinkering on the lathe.

Keeping my eyes open for a treadmill locally too so I can take the motor out and get a speed controller for it. Then once the lathe goes back together I can fab up a bracket for it all and do the electrical.
 
Interupted cuts can be aches with correct inserts but requires a robust rigid setup or you'll kill your insert. A sharp HHS tool bit with a correct relief would work for what you're after. Run the largest HHS tool bit you can fit in your holder although it looks to be under 3/8". BTW, you'll need a tail stock center to support the commutator or any longish item.

On your spindle bushing. I use oilite bushing on machines that won't spin faster than 120 RPM spinning that fast. Example, I rebuilt a 72" Box and Dab break and used these oil impregnated busing for all pivot points and added ball oilers to keep it flushed prior to use. The Oilite bushing sweat oil at the fist sign of friction, then reabsorbs the oil once the friction stops (cools). Using this type of bushing on a spindle more than likely will pull all the oil from said bushing. You lathe should have oilers of some sort over the original bushings. If you di decide to use Oilite bushings that require machining, a very sharp HHS is recommended to keep from smearing the oil pours closed. This material is pours and relies on these pours to sweat the oil.
My recommendation is use bronze bushings and keep them oiled.

Lastly, Your chuck is too big for that size lathe. That much rotating mass on that anemic sized spindle could spell disaster resulting in injury.
Large chuck will tempt you to turn something too large and if it doesn't fail it will surly stall your machine. My 1640 lathe uses an 8" 3-jaw chuck and a 10" independent chuck so

I'll share a couple of shots on machining Oilite and show the how its sweats when friction is applied.

The Oilite bushing I sourced from a local bearing house along with other sizes (no machining required).
This particular bushing has a 4" ID and came in 5" length. I needed two for the Dries& Krump break. The break manufacture is still in business but they quoted me $80 each plus shipping, these are not Oilite material . I ordere the larger single Oilite from the bearing house and made the two I needed for $48 and some left over.

Here, I'm cutting a slight bevel prior to parting.
4D0BA263-21EF-42BB-9AF8-8C85457FAD35.jpeg

The two new Oilite replacements. In the backrounf you can see the original still in the large link. Its made from bronze and had a oil groove machined into the middle. The link has a small hole for lubrication that lined up the the groove.
2576A0FA-A166-4774-A906-71987757BF02.jpeg

After removing the old sloppy bushing (from lack of oil) the new Oilite bushings were pressed in after the link was blasted and painted.
The photo you see shows were I drilled a small hole. Look closely and you'll see the oil that sweated out during the drilling process. Drilling took less than a minute as you can imagine but the amount of oil speaks for the Oilite. Once the bushing temp was normalized the oil was reabsorbed. You see why I wouldn't recommend this for a higher RPM application.
794DB7C9-838C-4168-8680-07605EEFAA4D.jpeg

The original oil hole on the links were opened up to accommodate a ball oiler. The white thing inside the hole resembles a cigarette filter. The idea is to soak the inset via ball oiler to keep a slight drip on the new Oilite bushings to flush out ware particles during use.
87E76FDD-D16B-4578-949E-3E641DC117BF.jpeg

The ball oiler installed.
AB4544B2-B1EC-4132-B6E4-11A148808D21.jpeg

For your lathe, I bet you have a spring loaded flip up style oiler. Some upgrade these to larger vial type that show the oil reservoir and they also have a small needle valve for metering the oil delivery.
Something like this;

Not trying to rain on your parade over the chuck size but I would regret not saying something and you get hurt. Remember, You're standing in harms way if the chuck separates at RPM.
If I may ask, what parts are you hoping to turn with this lathe? Lastly, post up a photo of the front of the machine so we can peek at gearbox.

I hope this helps.
 
Speaking of interrupted cutting here an examples of turning 3/4 CR on a lathe using an CNMG432 in a 3/4" sq holder.
This was the press tool I made to assist in pressing out the old link bushings and pressing in the new Oilite bushings.

The blank was cut on the band saw.
5644DA62-6EB1-46AF-8323-B713C2FA5B4A.jpeg

After machining the arbor a hole was drilled to mate the two as one.
516DD97E-1DE6-4721-B593-EBBBFCFD2A1F_1_201_a.jpeg

The weld set up to keep things square.
AE555175-6F51-406F-89F6-96DA983E56C9.jpeg

Ready for interrupted cuts. The Depth of Cut (DOC) was .060 per pass at 550 RPM with a very nice surface finish the carbide insert has a rounded nose not pointed.
34FF6B10-4F4A-4957-940A-01F0845D74BB.jpeg

No drama cutting but the set up is fairly rigid. Im running an Aloris CXA QCTP that supports 3/4"insert holder. This lathe was my older 1440.
A1FE9C9C-50D1-4A67-8BBA-24A9E33442B2.jpeg

Just wanted to show interruption lathe cutting. This operation can be frustrating on a machine laking rigidity.

Later...
 
The first lathe I bought was a Southbend 10K. I also bought a very used up early Bridgeport and a larger 18" x 72ish sized flat belt lathe from the 1910's. When I found myself self employed and needing to make parts for money I struggled a lot with those machines. I wasn't a good enough machinist to make nice parts on worn machines and certainly not very fast.

Pretty quickly after going on my own I bought industrial sized machines and never looked back.

There's most certainly a place for every machine tool and everyone must start somewhere, but I would be hesitant to recommend putting a lot of effort into fixing up a sears or similar lathe. They are useful for some jobs, but if you find it a struggle to make what you need it might be time to ponder devoting a bit more space to a larger machine.

There's kind of a wall the hobby type machines hit where they just aren't capable or productive.

Here's a 48" bucket coupler I made for a friend yesterday morning. The pins are 1.75" prehard, the bushings are 2.75" 4140N and the plates are 3/4" A36. The pins are necked down in the center 6" to 40mm to fit the quick change on the machine. All that lathe work was done in about an hour on a 14x30 15HP 4 ton engine lathe from the 1950's. The longest time was spent drilling 1-5/8" through a combined 10" of 4140 to make the bushings. The rest was quick with decent tooling and a heavier machine.

My favorite advice from a close friend/sharp old German toolmaker is "Never forget the three R's of machining-

1) Rigidity
2) Rigidity
3) Rigidity

Nates bucket2.jpg
 
Beautiful workmanship!
Rigidity is paramount when machining….period.
It not only give you a quality surface finish, it’s also safer to the operator and tool life.
 
Beautiful workmanship!
Rigidity is paramount when machining….period.
It not only give you a quality surface finish, it’s also safer to the operator and tool life.

Thanks!
I'm fairly afflicted with ADHD and the tendency to rush things unsafely or get safety complacent during a long repetitive operation using a light machine is very real for me. If the machine can keep up with my mind wandering I'm much more productive and safe.
 
Interupted cuts can be aches with correct inserts but requires a robust rigid setup or you'll kill your insert. A sharp HHS tool bit with a correct relief would work for what you're after. Run the largest HHS tool bit you can fit in your holder although it looks to be under 3/8". BTW, you'll need a tail stock center to support the commutator or any longish item.

On your spindle bushing. I use oilite bushing on machines that won't spin faster than 120 RPM spinning that fast. Example, I rebuilt a 72" Box and Dab break and used these oil impregnated busing for all pivot points and added ball oilers to keep it flushed prior to use. The Oilite bushing sweat oil at the fist sign of friction, then reabsorbs the oil once the friction stops (cools). Using this type of bushing on a spindle more than likely will pull all the oil from said bushing. You lathe should have oilers of some sort over the original bushings. If you di decide to use Oilite bushings that require machining, a very sharp HHS is recommended to keep from smearing the oil pours closed. This material is pours and relies on these pours to sweat the oil.
My recommendation is use bronze bushings and keep them oiled.

Lastly, Your chuck is too big for that size lathe. That much rotating mass on that anemic sized spindle could spell disaster resulting in injury.
Large chuck will tempt you to turn something too large and if it doesn't fail it will surly stall your machine. My 1640 lathe uses an 8" 3-jaw chuck and a 10" independent chuck so

I'll share a couple of shots on machining Oilite and show the how its sweats when friction is applied.

The Oilite bushing I sourced from a local bearing house along with other sizes (no machining required).
This particular bushing has a 4" ID and came in 5" length. I needed two for the Dries& Krump break. The break manufacture is still in business but they quoted me $80 each plus shipping, these are not Oilite material . I ordere the larger single Oilite from the bearing house and made the two I needed for $48 and some left over.

Here, I'm cutting a slight bevel prior to parting.
View attachment 2764589
The two new Oilite replacements. In the backrounf you can see the original still in the large link. Its made from bronze and had a oil groove machined into the middle. The link has a small hole for lubrication that lined up the the groove.
View attachment 2764590
After removing the old sloppy bushing (from lack of oil) the new Oilite bushings were pressed in after the link was blasted and painted.
The photo you see shows were I drilled a small hole. Look closely and you'll see the oil that sweated out during the drilling process. Drilling took less than a minute as you can imagine but the amount of oil speaks for the Oilite. Once the bushing temp was normalized the oil was reabsorbed. You see why I wouldn't recommend this for a higher RPM application.
View attachment 2764591
The original oil hole on the links were opened up to accommodate a ball oiler. The white thing inside the hole resembles a cigarette filter. The idea is to soak the inset via ball oiler to keep a slight drip on the new Oilite bushings to flush out ware particles during use.
View attachment 2764592
The ball oiler installed.
View attachment 2764594
For your lathe, I bet you have a spring loaded flip up style oiler. Some upgrade these to larger vial type that show the oil reservoir and they also have a small needle valve for metering the oil delivery.
Something like this;

Not trying to rain on your parade over the chuck size but I would regret not saying something and you get hurt. Remember, You're standing in harms way if the chuck separates at RPM.
If I may ask, what parts are you hoping to turn with this lathe? Lastly, post up a photo of the front of the machine so we can peek at gearbox.

I hope this helps.
I completely missed this when you first posted it. Good advice on the chuck and the bushings. The largest parts I've been intending to run on this are rotor assemblies from FJ60/62 HVAC motors in an effort to restore serviceable commutators and possibly turn whole new commutators. Ideally, I'd want to hold them by the armature since that would give me a good reference to ensure the entire shaft that supports the commutator and sits in the bearings in the motor housing is straight (using my dial indicator and rotating the chuck by hand). The armature is about 2.5" diameter, so even my current chuck barely fits it. With what I've been told and having not attempted it at all yet, it sounds like a higher speed and very slow feed speed are necessary for turning copper. I had considered your exact point with the roational weight on the tiny spindle that this has from the factory, so I've been considering a solid (much stronger) spindle that one enthusiast makes that's the same size, or there's a size upgrade that can be made using the stock components and an appropriately sized chuck for high speed turning on this. What's your thought on the best avenue for the spindle upgrade? It's inexpensive either way, so worth doing IMO while I save up for a larger lathe (ideally I'd love a combination lathe/mill for my bench top).
 
So you could use a solid spindle but understand you would be limiting your ability to work on longer stock. As for turning your armatures, they should be supported at both ends using a center on your tail stock. You could move forward with your spindle modification and dedicate your lathe for armature type work until you find a larger machine. As for enters, I’m a fan of live centers but a dead center works fine so long as you lube the tip. What size taper is your tail stock?
 
You’ll soon find out what the runout is on your three jaw and spindle. If you find it unacceptable when you chuck a shaft and support the other end on a center, you’ll need to consider a different option such as a four jaw. Again investing into a small lathe is a crap shoot if your looking for precision.
A sharp HSS cutter cuts copper well.
I’ve mentioned before, I’m not a fan of mill/lathe combination machines. Too limiting as you grow and learn more. If space is limited as is the wallet, I get that. Keep your eyes peeled as Craig’s list still offers machines of larger scale.
Check eBay for centers and such but make sure you know what you have before buying something that won’t fit.
You can always pm me with questions or keep it public. I will answer honestly and to the best of my ability. I just enjoy knowing other folks are into the same.
Some food for thought. Machining is unlike other skills. Once you understand the level of tolerances you will strive for the best possible outcome. Unlike welding and fabrication, +/- 1/16 is totally acceptable.
The problem with close tolerances, it requires a machine, tooling and metrology and the last two mentioned cost more than the machine in my experience. The good…when folks learn you can achieve this, you’ll stay busy and make some scratch and buy more😎.
Buy once cry once…
 
It's not ideal to turn a commutator by holding onto the OD of the armature plates. It would be a great struggle to get both planes in alignment.

You can 4 jaw or collet one end and support the other with the tailstock or, ideally, you run it between centers (point or cup) and drive it with a dog.

I can't comment on a replacement spindle for an Atlas. I would have a difficult time believing an effort to upgrade the spindle would increase it's usefulness. If you find you need more than the Atlas offers it would be a good idea to upgrade machines.

I have a theory that fixing up metalworking machinery or trying to make a small China machine tool shaped object do something it cannot is a separate hobby from making things from metal.

You can buy anything in this world except time. Choose how you spend yours wisely; If you want to make parts from metal, make parts!

Good machines are very affordable compared to the time it takes to fix up an old one.

This is dog turning a short shaft between centers. That shaft is the center support bearing for an 1810 dumptruck driveline that was bent when the driveline exploded. It had to be torch straightened, built up with weld, new centers cut in alignment with the old splines and then the OD turned to keep the tube concentric with the splines. That was done on a Sunday while the truck owner waited for $300/hr. Good lathes make money.

You can't see it in the picture, but there's a penny in there protecting the splines from the grub screw in the dog.

splines between centers.jpg
 
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You’ll soon find out what the runout is on your three jaw and spindle. If you find it unacceptable when you chuck a shaft and support the other end on a center, you’ll need to consider a different option such as a four jaw. Again investing into a small lathe is a crap shoot if your looking for precision.
A sharp HSS cutter cuts copper well.
I’ve mentioned before, I’m not a fan of mill/lathe combination machines. Too limiting as you grow and learn more. If space is limited as is the wallet, I get that. Keep your eyes peeled as Craig’s list still offers machines of larger scale.
Check eBay for centers and such but make sure you know what you have before buying something that won’t fit.
You can always pm me with questions or keep it public. I will answer honestly and to the best of my ability. I just enjoy knowing other folks are into the same.
Some food for thought. Machining is unlike other skills. Once you understand the level of tolerances you will strive for the best possible outcome. Unlike welding and fabrication, +/- 1/16 is totally acceptable.
The problem with close tolerances, it requires a machine, tooling and metrology and the last two mentioned cost more than the machine in my experience. The good…when folks learn you can achieve this, you’ll stay busy and make some scratch and buy more😎.
Buy once cry once…
The tailstock on mine is a pretty small one. Only an MT0. I had saved this page showing how someone had done a small upgrade to his. I like the idea of doing some of this myself where I can since it would also give me practice that once done right would land me with something useful: Craftsman 109 Improved Tail Stock Ram - http://www.deansphotographica.com/machining/projects/109/ram/ram.html

It would definitely take a lot more time and effort that it would be worth to make it a high precision machine, but a project to tinker with in my shop when I have free time that I could get a few extra bucks out of would be fun.
 
Screw on chucks don't have any kind of accuracy nor can they power tap or run a left hand drill.

12L14 is not steel for making tooling. If you're going to stand in front of a lathe and mill for 10 hours making a new tailstock quill do it from a worthwhile material like 4340PH or stressproof.

IMO, if you can't drive a drill chuck with the tailstock because the center is too small you should use a conventional JT taper chuck and modify an existing JT adapter to slip OVER the outside of the tiny tailstock quill. Mill a small flat on the top of the existing tailstock quill and install a setscrew in your adapter to clamp on the flat.

Then you can run MT tooling or a drill chuck.

I have made many tools that register on the OD of the tailstock rams on my lathes for pressing and locating parts.

Another useful accessory is a revolving tailstock chuck. These are great for tube and roller work.
 

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