# A couple 16" lathe questions



## tbone8 (May 17, 2021)

Hi, the tension spring broke on my lathe. In the CE3458 manual, it does not list a part number for the 16" model. Unfortunately, the eBay doesn't have any currently listed for a 16" but there is one for a 13" but counting the twists it appears too long. Has anyone ever mig welded one of these before? Open to any suggestions. One other thing I was curious about, there does not appear to be a thrust bearing on my lathe, just a thin washer up against the bearing mount. Looking at a pic of a bearing setup on the eBay, it seems too thick to fit in that space. Parts manual lists one for the 16" model so not sure what is up here? Thoughts and or comments appreciated.


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## graham-xrf (May 17, 2021)

I get it that the spring goes on a South Bend 16" lathe, but what would be the actual length of the coiled up part, and how thick is the metal?

Attempts to weld can only work if the entire spring is heat treated, back into being a spring again, because however you weld, there is some point further along where the heat took out the spring property. Even if you temper the welded bit, there is a place away from the weld where it got messed up.
Making springs is relatively easy. You do need the spring steel wire. It will modify some while being wound onto a mandrel, because the steel is being taken beyond it's yield point into the "plastic region".  It returns having the same modulus, but a new, "higher" yield point.

There are videos on YouTube of how to make your own spring. You do need a bit of rod, or some old bolt, whatever, to be the mandrel. It needs to be a little smaller than the inside of the present spring, because a new wound spring "unwinds" a little to a larger diameter when you let go.

Some folk wind these set up on a lathe, perhaps turning the chuck by hand. I made one using a long M6 bolt, and I did the winding using a vise grips clamped on the bolt head. The rest of the jig was a couple of holes in plywood. Admittedly, it was a feeble thing compared to yours, and I got the spring material by carefully "unwinding" an existing spring.

There are lots of jigs, and tricks. A handy one is to make a guide by drilling a hole through a nut. However you do it, getting up a new spring by re-purposing a different one, perhaps with a bit of stretching, or cutting shorter, or rolling up a new one is way easier than trying to weld on a broken one.

Check out the video by This Old Tony. There is another by Mr. Pete. Around them are links to a whole array of jigs and DIY things for spring making. Get the wire from Amazon.


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## benmychree (May 17, 2021)

The actual thrust bearing is on the other side of the bearing cap.


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## tbone8 (May 17, 2021)

Ahh, good, the thrust bearing thing is cleared up, figgered it would be something like that. As far as the spring, it is wound from a good 3/16" diameter wire and is stiff like a garage door spring so I don't think I will be able to wind something like that myself...


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## RandyWilson (May 17, 2021)

PT2638FH1


As that only supplies the over-center forces on the tensioning lever, I suspect there is wiggle room in the spring specs. A wander through a hardware/farm store or a lawn mower shop might get you something close.


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## graham-xrf (May 17, 2021)

tbone8 said:


> Ahh, good, the thrust bearing thing is cleared up, figgered it would be something like that. As far as the spring, it is wound from a good 3/16" diameter wire and is stiff like a garage door spring so I don't think I will be able to wind something like that myself...


Looking at it, if you put it in a vise, with a bolt up most of it, use your biggest screwdriver, and forcibly "spread the last turn at the broken end, just a little. Then you can conjure up a hook of your own. I was thinking a little steel fishplate, about 3/16 thick, with a 3/16 (+ a tiny bit)  hole in one end, and something else on the other end intended to provide the hook or achorage to the whatever it hung onto in the past . Push it onto the broken end about 1/2 a turn. For the other end of the fishplate, maybe even just another hole, and you use whatever creative dodge you like to attach the other end. A piece of coat hangar comes to mind, but I am sure we can do better than that!

Almost none of the % of extensible turns are sacrificed, and you might even end up with a fix you like so much you end up showing it off!



	

		
			
		

		
	
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A quick 'n dirty sketch to get across what I think I would attempt. You would have to file out the hole a little to get it over the spring, and maybe bend the hook end a bit. I don't say the dimensions are even the best, and what it gets made of depends on what off-cuts are lying around.
Just an idea..

Before you sweep the shop for potential donor scraps, I would give the idea from @RandyWilson  serious consideration. Try not to raid the lawnmower, nor oven door, nor any other working machine within range!


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## RandyWilson (May 17, 2021)

Looks like the spring lifts the motor carriage. So it needs to be stout enough for that, otherwise the ball socket may separate. Here's the parts diagram.


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## tbone8 (May 17, 2021)

RandyWilson said:


> PT2638FH1
> 
> 
> As that only supplies the over-center forces on the tensioning lever, I suspect there is wiggle room in the spring specs. A wander through a hardware/farm store or a lawn mower shop might get you something close.


Ya, I didn't even realize the spring was broken until I was lubing the bearings inside that cabinet door. That spring just helps to ensure the lever is engaged then? If so, a guy could just use a bungee cord then on the lever if I needed to use the lathe before I figger out a fix?


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## RandyWilson (May 17, 2021)

The spring lifts the motor carriage to slacken the belt. And keeps tension on the lever once you are up and over-center.  If the ball socket didn't separate (it might be pinned) and you can adjust the belt as needed, then it appears to be only to lower effort.


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## tbone8 (May 17, 2021)

graham-xrf said:


> I get it that the spring goes on a South Bend 16" lathe, but what would be the actual length of the coiled up part, and how thick is the metal?
> 
> Attempts to weld can only work if the entire spring is heat treated, back into being a spring again, because however you weld, there is some point further along where the heat took out the spring property. Even if you temper the welded bit, there is a place away from the weld where it got messed up.
> Making springs is relatively easy. You do need the spring steel wire. It will modify some while being wound onto a mandrel, because the steel is being taken beyond it's yield point into the "plastic region".  It returns having the same modulus, but a new, "higher" yield point.
> ...


After seeing a video on the spring winding, I agree with you, making a spring ain't all that difficult. The spring is 7/32 which is readily available, however, after some calculating, I need a 90" piece to make it. Interweb only has lengths of 36" so daggummit!


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## sdelivery (May 18, 2021)

Mcmaster Carr?


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## graham-xrf (May 18, 2021)

tbone8 said:


> After seeing a video on the spring winding, I agree with you, making a spring ain't all that difficult. The spring is 7/32 which is readily available, however, after some calculating, I need a 90" piece to make it. Interweb only has lengths of 36" so daggummit!


The underneath drive of my South Bend 9C (admittedly a much smaller lathe) has exactly the same crank arrangement to slacken the belt, but I can't help much on that because the belt was broken, and when I got the lathe, all those bits were partly in a box, and the rest dangling.

Regarding that the spring steel is only available in 36" chunks, that sucks   but tension springs do work in series!
One plan might be to hang together about two and a half chunks.
Keep looking, not only for a coil of 7/32 material, but for scrap gadgets that might have a spring that can be re-purposed.

Given what that spring does, I think you may have some room to go your own way here, and design up your own. Unless it is important that every aspect of a machine is preserved/restored to original, most machines have some modifications .. shall we say "extras and improvements" during their turning life.


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## FOMOGO (May 18, 2021)

I have an abundance of springs of all types. Give me all the specific dimensions, and I will see if I have something to fit the bill. Mike


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## mksj (May 18, 2021)

Many spring companies with different stock or they will custom wind what you need.




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						The Spring Store - The Spring Store
					

Stock, off the shelf compression, extension & torsion springs.  Ready made, quick delivery. Springs for sale through our massive online spring catalog.




					www.thespringstore.com
				











						PE207-1500-68425-CS-16000-MH-N-IN
					

Stock, off the shelf compression, extension & torsion springs.  Ready made, quick delivery. Springs for sale through our massive online spring catalog.




					www.thespringstore.com


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## tbone8 (May 18, 2021)

FOMOGO said:


> I have an abundance of springs of all types. Give me all the specific dimensions, and I will see if I have something to fit the bill. Mike






Mike, Hi, it is 8" long, 1" diameter and 7/32" material. Thanks for looking!


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## FOMOGO (May 18, 2021)

This one should work for you. PM me your shipping info and I will get it in the mail to you in the next day or two. Mike


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## aliva (May 18, 2021)

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						Lee Spring | Stock and Custom Springs - Engineering Support
					

Lee Spring is your go-to supplier for stock and custom springs, wireforms, fourslide parts and stampings. With thousands of products in stock and engineers standing by, Lee Spring ensures that you get the part you need for your project smoothly and efficiently.




					www.leespring.com


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## tbone8 (Jun 2, 2021)

Wow, had to pull a rabbit out of my hat to figger out how to get this spring in. FOMOGO was kind enough to send me a similar spring and got around to putting it in today. Thought it would be a 5 minute deal but took a couple hours, mostly thinking. Anyway, these springs are quite stiff and almost threw in the towel. Very awkward and limited working space under this lathe. Came up with the idea to stretch the spring with my floor jack and slip some thin washers in. Luckily had a bunch of just the size I needed.  Got it installed and quite happy with the results...


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## Superburban (Jun 2, 2021)

That is clever. Great job.


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