Seneca Falls Star #30 lathe Resto-Mod

No doubt that chuck will be re-purposed for something, if nothing else a door stop.
All of the 6" chucks that I looked at had a mounting bolt hole pattern of 5.591", and the current back plate is only 5.620" in dia. This presents a dilemma, as I really do not want to have to turn and thread a raw casting. I did find one back plate for 1"-8 tpi, that I could just open up and re-thread for 1-9/16"-10 spindle, but I'd rather not go through the process of first making a spindle replication for a means of checking the threads.
After a few cups of coffee and much thought, it was then when I discovered an un-used chuck underneath my Jet lathe. I had totally forgot about this, as it was the original 3 jaw that came with my 1340, but I never mounted it because I installed a Bison 6 jaw adjust tru on that lathe right off the bat. This particular chuck has a D1-4 mount, so I tore the back off and realized that the studs screw into the back half of the chuck, not on a separate back.
After a gander at the insides, I realized that there was enough meat to remove the studs, and counter bore the back to inset the existing back plate.
I have turned many back plates, but I have never actually turned the back of a chuck. I figured the best way to accomplish this is by clamping the chuck itself to a trued bar between centers. The chuck has an 1-1/2" through hole, so I used an 1" round bar to clamp it to. This gave ample room to counterbore to 4.625" dia. and .250" deep.
I then turned the back plate to a snug fit, and proceeded to the mill and drilled and tapped 3 places 3/8-16 and countersunk the back plate for flat head screws.
Once I had it together, I mounted it on the spindle and checked for runout. I musta done something right....it was right on par with what one would expect from a 3 jaw chuck.
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Sure , it's chinese, but what isn't nowadays. I tried to decipher the chinese chicken scratchin' and came up with 2 possible translations: #1. "manufactured by Lon Ding Dong, toolmaker to the royal emperor", or #2. "soy sauce"......:grin:
 
After lots of hours of dirty but enjoyable work, I can say this project is pretty much done. Unless the owner comes up with a DRO to install, this lathe is ready to make some serious chips. I'm ready to christen this ole' gal with a magnum of cutting oil and let the chips fly!
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Thanks for watching and all the kind comments.
 
Hello everyone, I believe this is my first post. I am the owner of this fabulous machine and I am in complete awe of how it turned out. I never thought it would turned out so well. Anyhow this was an amazing project and I was able to contribute a bit here and there. I made a couple of the knobs and some other small parts using another lathe, nothing as impressive as the rest of the work, but it brings a smile to my face when I look at them small projects. I got to create some chips on this lathe as well and I absolutely love the powe lead screw. There is a lot of other work that went into this build, but for the most part it’s all accurately and amazing well covered in this thread. I can’t say thank you enough as I feel I have a truly awesome machine. I have some beginner projects in mind, and I have no doubt that this machine is well able to complete them and as I grow in experience I am sure this machine is far able to do functions beyond my capabilities. Hopefully you enjoyed this thread as I have enjoyed being involved in this build.
 
derf said:
When we first got this machine moved into some good light and give it a good once over, I noticed some peculiarities that needed to be addressed. The first thing being the oddball taper in the tailstock quill. It was not quite right to be a #2 morse because the big end seated before the small end and left some wiggle. The small end of the socket was bigger than a #2, and to clean it up for a #2 was out of the question, so I bored it to a #3 on my lathe then finished up with a # 3 morse reamer. While I was at it, I set it up in the mill and cut graduations on the quill for quick reference.
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It didn't come with a dial on the crank end like most lathes of the era, so while I was on a dial binge, I made one for it. The original retainer nut had to be turned down so a hollowed out dial would fit, and it is large enough to read fairly easy.
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Another thing missing was a graduated dial on the compound. After I pulled the screw, it was found to be a 14 tpi, which comes out to .0714285" per revolution. So when I made the dial, I just made 72 lines and called it close enough.
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Although it was optional at the time, there was no thread dial, or a provision for mounting one. Once I figured out the gear size, I made the unit using a couple of 1" pipe caps for the flares top and bottom, and a scrap piece of barrel for the middle and brazed them together. I added the angle iron bracket and tipped it slightly so the gear meshed with the leadscrew helix.
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It was cramped fit around the half nut lever, so a knob was added to the lever to better access.
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chips&more said:
Looks good! I had a Seneca Falls lathe about 50 years ago? The one thing that stands out and I will tell you is: Check the head stock babbitt bearings. AND check the end shake and then check it again. Mine had some kind of fiber washer on the end of the rear bearing. Maybe try making a Delrin washer? I still have the taper attachment from it somewhere in the shop???...Dave
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I might be interested in that taper attachment for this lathe, if you find it please let me know.
 
Great job of restoring and documenting all the little things that make an older machine even more useable. I know the new owner will be proud of all the work that went into this build. Thanks for sharing -- Jack
 
Wow, I sure wish my Seneca Falls lathe looked *half* that nice!
 
derf said:
Even though the color coded gears and the cheat sheets make it easier to set up for threading, I find it slightly annoying to have to change gears around for general turning. I have 3 lathes with quick change gear boxes, so I might be a bit biased. To get around that monkey motion, the best idea that I've seen in many moons was to power the lead screw with an electric motor. I found enough info here and other places on the net to proceed.
I did give this some fore thought however when I had the machine down to basics. While the lead screw was out of the machine, I drilled and reamed a 1/2" hole in the tail end of the screw, and added a 1/8" crosscut for a way to drive it. The screw was retained by two flat bottom plugs for end play. I removed the plugs and made a threaded bushing that would retain the end play and allow a 1/2" drive rod to protrude out to a motor drive. The 1/2" shaft fits into the screw about 1", and is driven with a 1/8" pin in the crosscut. The crosscut is about .135" deep, so the drive pin is slightly below flush and the bushing controls the end play of the screw with a jamb nut. On the other side of the jamb nut is more threads and a nut to locate a motor mount.
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The mount was made to be dis-engaged when using the spindle powered drive train, so the motor and gear simply swing away from the screw gear.
Basically I used a wiper motor like everyone else had success with, that was rated at 50 rpm on the hi side and 35 rpm on the low. I originally made the gearing 1:1, and it proved to be too slow, so I went with 2:1, with a little concern about torque loss. I actually checked the rpm with a tach and it was 42 rpm on the hi side and 34 on the low. At first I wired it for 2 speed operation and it made absolutely no sense to have 2 speeds when you have a pot to adjust current. So I eliminated a switch and just wired up the hi speed side. For the speed control we used pwm and crammed that and the power supply into a control box that I had left over from an old Bridgeport. I had to made a new cover to accommodate the switches tastefully.
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The power supply is wired through the drum switch so the screw has no power if the spindle is not running. As a safety feature, so the electric powered screw is not conflicting with the spindle powering the screw at the same time, a push button momentary switch was installed below the banjo. The banjo must be swung down, dis-engaging the gear train, then activating the switch.
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By doing this, the only way to get power to the screw is obvious.
In the same circuit, there is also a limit switch. This switch can be set to stop the screw, thus stopping the carriage at any point. It can also be operated by hand, which is handy when the feed clutch is a star knob. I find feed levers more natural and responsive than a knob. So you can depress the button at the end of a cut, and then release the feed clutch knob without the worries of bad timing.
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As I mentioned before, I had some reservations about loss of torque by going 2:1 on the driver motor, so I figured the best way to find out is to turn something. I found an old stainless rifle barrel and chucked it up. I set the spindle speed in 3rd gear (715 rpm) and was using a ccmt insert, took a .015" doc and flipped the switch. I turned it up to full throttle and watched nice little chips fly off with no effort. Then I decided to go from feed, to using the half nut, which is the feed rate x 2.77.
I noticed a small slow down, (at least it sounded that way) but still with the throttle up, it was throwing chips faster than I could get away from them! From my best guess, it was about .025" per rev. Needless to say...I was impressed. Now that I know it works well, I dressed it up with a gear cover.
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Great project! How is the spindle drive synchronized to the chuck for threading?
 
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