# Building a Lathe from Scraps: An Interactive Build Log



## JohnMcClure (Aug 24, 2016)

See this scrapyard?









If you look closely you'll see these:









A few months ago I salvaged a 3HP PMDC (variable speed) motor from our old treadmill. I recently powered it on and decided it should power a wood lathe. I considered building one from scratch but was discouraged by the complexity of the project (I don't have a lot of free time). But then I walked into the scrapyard and saw the above, and obtained permission to help myself. Now I have the beginnings of a plan for how to proceed.

This thread is intended as a build log and a place for me to post the myriad questions I'm bound to have. I've never turned before, or even watched turning up close. I welcome the input of the turners and master builders among us, as I stumble forward on this project!


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## squazo (Nov 23, 2013)

it would probably be easier to keep track of if you started a blog. Nice going though I hope it works out.


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## JohnMcClure (Aug 24, 2016)

The blue lathes in the background above were used for polishing the OD of tubular products. They appear to be "homemade" in a small shop, as there are small differences between each; but well-built. They've been in the sun and rain for years!









*Episode One: The Tailstock*
I liked the tailstock on the foreground lathe above best, but the lathe is about 10' long; the one behind it is closer to 8' long and would fit more easily on my shop porch. So the first step was to remove both tailstocks, and bring my favorite one home.










The live center turns out to be a Riten Pipe Nose Center, 4.5" OD and 4.5" long, on a #4 Morse Taper.
I may have destroyed it because I didn't know how to remove a Morse Taper properly, so I knocked the cone right off the taper shank. 
The tailstock center is about 7" above the lathe bed. The housing sits between the ways like this:








There's an iron plate that rides beneath the ways and cinches up on them to hold the tailstock in place. The cinching was done semipermanently using a hex bolt; I'll need to find something with a lever so I can reposition more easily.
The shaft (What do you call this?) is 12" long, 2" OD, Acme thread (presumably) 4 TPI:









The housing is about 8" long giving about 4" of travel via the attractive handwheel. I may need to drill and tap in the top of the housing for a component that prevents the shaft backing off under load.

*Some questions!*
Should I try to repair the live center, or is it unsuitable for wood turning?
If not, am I going to struggle to find 4MT live centers for wood turning? This stuff is HUGE!
What kind of grease should I use on the Acme thread and in the live center, if I rebuild? I suspect WD-40 isn't appropriate.


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## JohnMcClure (Aug 24, 2016)

Thanks for following along Squazo!
I chose this format instead of a blog because I feel this is more welcoming of continual input from others, whereas a blog is better suited to having each chapter posted after a milestone is accomplished. I've done a couple of those though, when I felt I knew what I was doing!


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## PCDub (Sep 24, 2017)

Those are monster lathes! I'm following to see how this goes. Looks like a fun project. It appears that you could cut the ways and move the legs to make a shorter lathe, if you didn't want to turn 8 ft long pieces.


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## GR8HUNTER (Jun 13, 2016)

well i'm not a turner nor master builder but i think i will follow this thread as older iron fascinates me :<))))))))


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## HokieKen (Apr 14, 2015)

And so it begins… )

I wouldn't worry about that center. It's too big to be practical for woodturning. It would end up being in the way and live centers for woodturning aren't expensive. I'd get a MT reducing sleeve like this. Most things you may want for the tailstock (centers, arbors, drill chucks etc.) will be readily available with MT2 shanks. Not likely true with MT4. MT4 is big even for metal-working lathes.

Typically what you'll have in a tailstock is a keyed spindle with the internal Morse Taper on one end and a female thread on the other. This way the part that advances can be held to a tighter fit than the necessary clearance for machined threads. In other words… I'm not sure how well this tailstock will work for you. There is probably a fair amount of radial play that will prevent it from consistently staying on center with the spindle. There are ways that could be worked around though by machining a bore ahead of the female thread in the tailstock that's a tight fit with the OD of the threads. You'll just have to evaluate for yourself. A quick and simple check is just to extend the threaded rod about halfway and see how much you can move it left/right/up/down by hand. If it's a lot, you may want to explore alternatives.

Hopefully, you'll be confident that it's rigid enough though and you can work with it. It may not be a traditional design but, with live centers and accessories, I see no reason it can't work! You would probably need to drill and tap the top of the stock to put a locking screw in there though. I would use a brass screw fairly large to prevent damaging the threads. With an Acme thread (flat peaks and valleys as opposed to UN threadforms) you might get away without a locking screw but I wouldn't have a lot of confidence in that being the case.

I use a white lithium grease on acme threads on my machine. Mine are fully enclosed though. You might want to use some sort of dry lube or maybe even just paste wax since yours will be exposed to dust. Your threads will see very low cyclic duty so I wouldn't be too concerned. You will know it when they need lube there will be a notable increase in friction.

I would continue to lock the tailstock down with the hex bolt. Just get a box end wrench and leave it laying on the ways behind the tailstock. I'm not a fan of levers sticking out where I might decide I want to lean while turning. If you do decide to go with a lever, I'd try to get it on the back side of the stock.

Good luck, I'll be following along and looking forward to your progress. I must admit to being a little jealous ;-)


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## HokieKen (Apr 14, 2015)

One other thought… Before I spent a lot of time or ANY money on the tailstock, I'd be inclined to seriously evaluate the flatness of the ways on the main event. If they aren't really close to flat and coplanar, you'll be fighting an uphill battle that can't be won with head and tailstocks…


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## JohnMcClure (Aug 24, 2016)

Thanks for following PCDub and Tony!
Tony, it's not exactly "old iron" like the Clausing that is parked next to the blue ones (though I may get some parts from that); I think refurbing that beast would be beyond me at this point!
But it is iron, and it is old!

Kenny,
Thanks for the continued help. I checked the play in the Acme shaft and as you suspected there's plenty. No sophisticated measurement here but I felt like 1/16 total play when fully extended. I'm not going to let that concern me too much at this point; but if it becomes a problem there are a few ways to deal with it.
How is tailstock advancement normally accomplished on a wood lathe? Sliding the whole thing along the ways, or is there a threaded micro-adjust to sneak pressure up onto the live center?

Anti-rotation in the tailstock will be needed, especially if I'm to mount a drill chuck on it. There's plenty of room and material to bring something substantial down on the Acme thread.

The MT reducer looks to be essential. One issue I see with it though - I'll be able to knock it out of the Acme shaft from behind, but how will I remove the 2MT that I insert into it? Is that what that crossmilled slot is for? I'll hold off on purchasing until I'm further along, in case this whole tailstock proves to be a waste.


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## HokieKen (Apr 14, 2015)

This is a cross-section of a typical tailstock John:









When you turn the screw with the handwheel, the spindle will advance. The spindle is a tight fit with the barrel to eliminate radial slop and is keyed to the barrel to avoid rotation.


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## HokieKen (Apr 14, 2015)

And yes, the slot in the MT reducer is to use a wedge to remove the mating taper inside. But you can get reducers that have an open back end too. That would probably be preferable. Some centers and other accessories may not have a shank long enough to use the wedge to release it. I should have paid more attention to my search results before just linking the first one….


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## JohnMcClure (Aug 24, 2016)

Thanks Kenny! That drawing is very helpful. I'll hopefully make more progress extracting the lathe from the scrapyard this week, and have more updates and questions.


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## JohnMcClure (Aug 24, 2016)

I think Grant would like to see this. Is he around?


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## JohnMcClure (Aug 24, 2016)

The existing 120v 1750rpm motor has an integrated 10:1 gearbox. This isn't suitable for my application, but if it still works it may be valuable, for me or someone else. 
When it was on its side in my truck, thick oil (like honey) leaked from the gearbox. Anybody know what oil I should replace it with?

I think I'll dismantle the drive assembly tonight. I love those beefy bearings. 
Should I remove the bearing blocks from the base, or should I try to remove those set screws and slide the shaft out?


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## JohnMcClure (Aug 24, 2016)

Good news, bad news.
Safely removed the motor and gearbox; will mess with that later.
After much heartache over a woodruff key, removed the drive shaft from the bearings. It's a beautiful 2" diameter shaft… that is one piece with the giant 7" cone drive point.









If its not one piece, it's a compression fit. Theres no setscrew and no bore on the backside from which to tap it out.

So it looks like I'll be buying Keeblers Comet shaft. But man I'd love to keep these gorgeous 2" bearings…

Edit to add. Fired up the motor, it runs fine. 175rpm output shaft for a v-belt. That's gotta be good for something.


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## JohnMcClure (Aug 24, 2016)

Well that's about it for tonight. I may end up using less of this than I hoped. But even if it turns to scrap iron at least I have a template for some of the pieces.


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## HokieKen (Apr 14, 2015)

Moror might make a good grinder/buffer John.

Any gearbox oil should work fine for that unless it requires high pressure lube and I doubt it given the application.

If the spacing between those bearings works with Keebler's shaft, let me know. We can probably come up with a reducer that fits over the shaft and in the bearings.


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## MadMark (Jun 3, 2014)

Tip. You can always append tomorrow original post as the saga unfolds. This way new readers can get the full story without scrolling thru the comments. Preface new stuff with dates.

Looks like a fun project. What's the swing? Center of tail stock spindle distance to ways.

That's a production tailstock. You'ld turn the same basic length over that long bed. The bolts instead of a lever shows that.

Given the size of the thing, I doubt play and backout are an issue. The backlash is taken up when the tailstock is tight. The fact that you've got a 1/2 turn before it releases, matters not.


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## JohnMcClure (Aug 24, 2016)

Kenny, thanks - grinder idea is a good one, and some custom parts would be really cool! I'll update once I have dimensions from Kevin. Cant seem to find info on that spindle online.

MadMark, great to have you along! It's about 7" from the center to the ways. 
Good points on the tail stock. The machine was indeed originally intended for one very specific application and the tail stock rarely was repositioned. 
I seem to have ruined that live center though anyway…


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## JohnMcClure (Aug 24, 2016)

Based on email conversation with Kenny I am zeroing in on the ideal spindle for this lathe.
The goal is to make use of the existing bearings, bearing housings, and "head box" on the big blue beast.
Here's the concept:









It may make sense to have the full 2" OD on the middle portion of the shaft. If for some reason it needs to be narrower as show, (say if the 2" bits were bushings instead of having a 1-piece shaft) I could still put a shop-made 2-piece drive pulley on the shaft. It may also be true that I don't need a drive pulley at all since the belt is flat.

What do you guys think? Does the LH thread on the outboard end make sense? Anything else I need to account for?


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## HokieKen (Apr 14, 2015)

Make the center slightly larger than 2" so the shaft can't move axially in the bearings. Or make a couple of collars to mount on there.


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## JohnMcClure (Aug 24, 2016)

Kenny,
Would the set screws shown here on the existing bearings not be sufficient?
(Ignore the old shaft, pulley, and belt)


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## HokieKen (Apr 14, 2015)

Yep, that'll work. I didn't realize the bearings were like that. Not sure I've ever actually seen bearings like that but it'll work!


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## JohnMcClure (Aug 24, 2016)

Bearings update:
The housings are marked Nachi F211.
The bearings themselves are marked UC211-32SU, NSK, Japan.

My measurement of the original shaft OD shows 2.000". Is that the nominal shaft dia for these or am I off by a thousandth or two? Are these bearings suitable for lathe speeds? (The original hardware was only run at 175RPM).

Question for any lathe owner: On the 1"-8TPI thread of your spindle, what length of the shaft is threaded?


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## HokieKen (Apr 14, 2015)

The shaft diameter should be 2.000 +0 / -.0008 (h6 fit) and they're rated for up to 3000 rpm. Should be fine for a lathe.

Here's a catalog that has bearing information.

I'm not sure what that thread length should be but it brings up a note about your shaft design. You want a shoulder behind the threads so when you thread on a chuck it references a shoulder that's square to the axis of the spindle.


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## Lazyman (Aug 8, 2014)

If you decide the MT4 is too much of a pain to deal with, You could always use this to make a leg vise for a workbench.










I suppose you might have to cut the tailstock apart to weld up a nut for it since a tap like that would be expensive.


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## JohnMcClure (Aug 24, 2016)

A new milestone tonight. Drilled through the 5/8" steel drive housing to allow the new shaft to extend outboard. 1.5" diameter. As I lack the proper tools, it was difficult. But its done.

















Nathan, that's a great idea. If you would like to try it, I can send you a similar acme rod + handwheel. Let me know!


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## DavePolaschek (Oct 21, 2016)

John, if you've got a source of more big-ass screws with hand wheels, I'm guessing you'll be a very popular guy. I'd use one for a leg vise, but it wouldn't be soon, so I wouldn't ask to be at the front of the queue.


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## JohnMcClure (Aug 24, 2016)

Roger that, Dave. Just one or two extra. Stay in touch on this.


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## Lazyman (Aug 8, 2014)

Thanks John but I just ordered myself a leg and wagon vised from Hovarter as birthday present from my wife so I don't need a them.


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## HokieKen (Apr 14, 2015)

I agree, those screws would be great leg vise hardware. I have the Hovarter leg vise too though so I'll pass. You made the right call Nathan ;-)


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## DavePolaschek (Oct 21, 2016)

Sounds good, John. If you come up with one that isn't otherwise spoken for, I'd be happy to add it to my "pile of parts for prospective projects" for a reasonable price.


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## therealSteveN (Oct 29, 2016)

John, when that puppy starts working for you, you'll be able to turn pencil post bed corners in one piece.


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## JohnMcClure (Aug 24, 2016)

That's what I'm thinking! Architectural lathe work!


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## JohnMcClure (Aug 24, 2016)

Project is back on, now that I have this:


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## HokieKen (Apr 14, 2015)

That's looking right John


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## Lazyman (Aug 8, 2014)

I don't have any use for it but when I see a piece of steel milled like that I just want to have it.


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## HokieKen (Apr 14, 2015)

That's turned steel, not milled Nathan ;-)

Update when you test the fit please John, I'm curious!


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## Lazyman (Aug 8, 2014)

Dang machinists.


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## bigblockyeti (Sep 9, 2013)

Looks ground to me?


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## HokieKen (Apr 14, 2015)

Possible Yeti. I think I see the tell-tale signs of a fed turning tool though. Certainly can't be sure from the photo resolution on this site though…


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## GR8HUNTER (Jun 13, 2016)

cant wait till your first turned bowl LOL :<))))


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## JohnMcClure (Aug 24, 2016)

I easily inserted into the first bearing, then realized I need the serpentine belt before I could proceed! I'd been delaying that purchase until I had the shaft, but wish I'd have bought it a couple days sooner! The last thing I want to do is perfectly seat the shaft in the bearings, then be unable to remove it once I have the belt.
The fit is close enough that to make life easier I'll probably freeze the shaft before I push it in next time.
I went ahead and ordered a cheap MT2 spur center on Amazon too.
Once I get it turning I'll need to adjust the bearings to true the shaft to the bed. Any suggestions for how to test for true-ness?


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## HokieKen (Apr 14, 2015)

You don't necessarily need it true to the bed but you need it true to the tailstock. The simplest way to check that is to put a test indicator in a chuck mounted in the spindle and put a test bar in a chuck in the tailstock and check for concentricity at several points along the length of the test bar.

I'm not sure that's going to be practical in this case though because IIRC, the tailstock has some variability depending on how/where you lock it down? It may be sufficient to just use something like a MT2 test bar. I would try to figure out a way to consistently lock down the tailstock to minimimize alignment error. For instance, always push it against the back of the bed before tightening it. Or the front, whichever seems to be the straightest along the full length.


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## OSU55 (Dec 14, 2012)

You can check alignment of spindle and TS easily with MT2 drive and live centers installed, pushing the TS up to see if the points meet. This does not tell how much out of alignment exists with the TS at various positions along the bed. Using a pointed metal rod in a chuck in the HS, extending a chosen distance and adjusted for "0" runout, then check alignment with the TS live center point. It does not have to be perfect, you are turning wood.


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## JohnMcClure (Aug 24, 2016)

Thanks for the tips, Kenny and OSU55!
I've installed the shaft, have not torqued down the bearing housings yet, but the next step is to mount the treadmill motor and get it running. Then I'll do exactly as OSU said and touch tips for an initial alignment. Don't have a chuck yet but will get one, and a faceplate, and some turning tools… lol… Dave's bedan looks like a good one… tools are a deep rabbit hole.


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## DavePolaschek (Oct 21, 2016)

If you need a bedan, John, let me know the size. 6, 9, or 12 mm (basically 1/4, 3/8 and 1/2 inch) are what I have HSS stock for. I'm just about to a stopping point on my boring tools till, and the lathe will be getting fired up next for the swap, so turning a handle and pounding a piece of HSS into it won't be a big problem. I think I've even got some short M42 6mm stock if you want one that'll really last (but will be a smaller tool).


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## Lazyman (Aug 8, 2014)

Does making dowels qualify as a swap turning project?


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## Lazyman (Aug 8, 2014)

Sorry about that. I posted this in the wrong thread.


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## JohnMcClure (Aug 24, 2016)

Dave, that's very gracious. I am guessing a 3/8 would be a good all-around size for someone just starting out? I'd be grateful to own one in any size.

Nathan, that's a cool old piece of iron. I love gadgets like that.


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## DavePolaschek (Oct 21, 2016)

Yeah, John. I'm pretty sure there's a reason 3/8 is the only size commercially sold at the moment. A 1/2 is a real beast (also to make), and while it's useful for roughing and fast hollowing, I think a 3/8 is probably a lot more manageable. 1/4 is too small for any real heavy use, but it's great for detail work.

I'll set aside a chunk of the 9mm HSS for you. I've got two mailing addresses for you from previous swaps. PM me and let me know which to send things to.


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## JohnMcClure (Aug 24, 2016)

Thanks Dave!!


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## DavePolaschek (Oct 21, 2016)

No problem, John! Hopefully I can get it done and to you before you have the lathe ready to go. ;-)


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## JohnMcClure (Aug 24, 2016)

> No problem, John! Hopefully I can get it done and to you before you have the lathe ready to go. ;-)
> 
> - Dave Polaschek


You probably will. My pace is extremely slow as you know.


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## JohnMcClure (Aug 24, 2016)

Today's project: Motor mounting bracket:


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## Lazyman (Aug 8, 2014)

Maybe you said already but what are you going to use to control the speed?


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## GR8HUNTER (Jun 13, 2016)

at this pace you will be able to join the swap LOL :<)))))


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## HokieKen (Apr 14, 2015)

Nice John. That wood mount should work fine. I made a "temporary" wood mount for the motor on my belt grinder a couple of years ago. I still haven't gotten around to machining a metal one and haven't had any issues.


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## JohnMcClure (Aug 24, 2016)

Nathan,
I should be able to conjure something up. I'm a EE by day so may go overboard, but in the short term I can tie an Arduino to the driver board that came with the treadmill.

Ultimately I would love to do RPM feedback, reversal, braking, etc, but for now I'll settle for "it turns".


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## MadMark (Jun 3, 2014)

Arduino? I'm in the middle of an Arduino project! I bought the Griz G0923 3D filament printer just to build Arduino mounting brackets. I've got one for the mega 2560 & Uno that is extra wide for screw terminal shield clearance on cults.com that people have been downloading. I've got a couple of dozen mounts & pieces and parts up on TinkerCAD.com for LCD mounts, connector shrouds etc.


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## JohnMcClure (Aug 24, 2016)

Cool, Mark!
I'd be using it as a temporary pwm generator. This treadmill control board is… complicated, even for me, but I'm pretty sure I experimented with pwm and had a successful result.


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## Lazyman (Aug 8, 2014)

I was wondering if you were going to use an Arduino. Tinkered with it few years ago and had a couple of projects in mind but didn't really do much beyond just experimenting with the basics via a tutorial kit. I suck a soldering so decided that the DIY Segway was probably not going to be "quick' project.


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## bigblockyeti (Sep 9, 2013)

Is it already using a standardized mosfet bank? My concern is lower speeds (with lower cooling fan speeds) coupled with the heat generation of a high torque application such as turning a large bowl could cause the motor to get toasty. I believe those small treadmill motors are spinning 4-5Krpm with a belt running speed of 10-12mph.


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## MadMark (Jun 3, 2014)

The only soldering needed is to buss bars which don't have to be pretty. Everything else plugs in or screws down on a terminal block. The cable shrouds combine loose pins into usable connectors-permanently if you add a dab of gel superglue.


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## JohnMcClure (Aug 24, 2016)

MadMark, I like your Arduino accessories. Very creative. If I ever look to "permanently" use an Arduino for anything, I'll check out your TinkerCad products. Thanks for sharing!

Yeti, I don't know what you mean by standard mosFET bank.

I do share your concern that the motor may not perform well at low speeds and high torques. It's the best motor I have at the moment, though, and with a 3HP rating I suspect it will be OK for a while.


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## HokieKen (Apr 14, 2015)

I dunno if you've ever tried to stall a treadmill at low speed (like to check for belt slippage) but those motors generate a good deal of torque on the low end. I think it should be fine for the application.


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## bigblockyeti (Sep 9, 2013)

Pictured below is what I believe is a MOSFET bank for the variable speed controller I used for my Craftsman tube lathe after I upgraded it to a more powerful DC motor. I'm starting to think some of the "3hp" ratings on some of these not very big motors might be generated using the same math as a 6hp shop vac running on 120V, there appears to be some optimism in the specs. This Baldor motor only has 1hp and weighs over 40lbs.


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## JohnMcClure (Aug 24, 2016)

Yeti,
Can you post a really clear picture showing the part numbers on those chips?

I like the layout of this. Clean and simple. How I would build it. Whereas my treadmill board is understandably complicated.

What I'm guessing you have isn't 5 mosFETs, but 2 diodes, 2 more diodes or possibly SCRs (total of 4 rectifying elements) and one N-channel mosFET.

If I can see the part numbers I can look them up and possibly RE the whole board from here.

Thanks!


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## HokieKen (Apr 14, 2015)

What a nerd.

;-)


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## MrUnix (May 18, 2012)

In all of the treadmills I've pulled apart, only one had a controller that I couldn't use out of the box (a MC-2100). Most were MC-60 or MC-80 based, and all I needed was a 5K pot to control speed. Well, I did get a commercial treadmill once that had a 120v three phase motor in it and used a proprietary VFD to control it, but that was certainly not the norm!

So I'm curious, what controller came with your treadmill?

Cheers,
Brad


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## bigblockyeti (Sep 9, 2013)

Here's some closes up of the board. I had another that looked almost identical and was also from Minarik but I can't find it after the move 3.5 years ago. Too much was forfeited or lost, moving stinks but not as much as living in Hoth.



























You're right, there's no bridge rectifier so these are all MOSFETs, nor would they need to be. I'm remember my R/C days when some of the modified motors would be pulling 35amps even through an anemic 1200mAh NiCad pack, it was a blast for ~3 minutes.


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## Lazyman (Aug 8, 2014)

You mentioned earlier possibly adding braking. Be careful with that. Braking can cause a chuck or faceplate with a large blank on it to unscrew itself from the spindle. Probably better to let it just wind down. I've actually had that happen (didn't completely come off) even with just the normal resistance of the motor, pulleys, etc. slowing down faster than the large mass wanted to. For the same reason, you may want to make sure that when you have it in reverse, that you ramp up the speed more slowly than in forward. You typically use a set screw to lock the chuck to the spindle for reverse turning but with a large blank, a sudden start could still loosen it since the set screws are pretty dang small.

Being an EE you might not need this and there really isn't that much info there but LJ Wood Knack (Rick McQuay) did a brief write up of his project to add a treadmill motor to a lathe on his blog website.


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## OSU55 (Dec 14, 2012)

Regarding braking and chucks - a set screw in the chuck will keep it from unscrewing. My lathe has e braking, and I routinely hollow in reverse. It holds just fine with 16" dia x 12" deep hf's and bowls. Hopefully your new spindle will seat the screw in a flat area, but if into the thread just file a spot for it to sit.


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## JohnMcClure (Aug 24, 2016)

Yeti,
Those 5 power ICs are SCRs, S6020L, so I'm guessing that constitutes a fully controlled bridge rectifier, plus one more.
The gating of the 4 rectifier diodes would set the DC bus voltage.
Then the 5th one could just be used as an on/off control; more tolerant of high voltages than most mosFETs.
However, the pots are interesting. Is there tachometer feedback?

Nathan, OSU - thanks for the mentions on braking and setscrews. I'll keep that in mind.

MrUnix, I'll put up a picture of my controller in just one second (from my phone). It wasn't "plug-and-play" for me - seemed to be dependent on a complex group of signals from the other part of the treadmill, and possibly even the tachometer (which was in a separate part of the treadmill, not on the motor). I couldn't get it to drive the motor without soldering some wires onto the board and forcing the signals it needed.


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## JohnMcClure (Aug 24, 2016)




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## HokieKen (Apr 14, 2015)

Could it be the missing signals were just from the deadman switch on the treadmill John?


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## JohnMcClure (Aug 24, 2016)

It could be. I had the impression the deadman was read by the upper control panel, and that the upper control panel communicated serially with the motor controller board. I could have been wrong.
There's an FPGA on this thing for goodness' sake.


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## MrUnix (May 18, 2012)

Yup, what you got is a MC2100, which needs a bit more than a 5K pot unfortunately 

But it's a pretty common controller and a quick google search for "MC-2100 controller" will return lots of ways it can be used to control the motor if you want to go that route.

Cheers,
Brad


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## HokieKen (Apr 14, 2015)

This looks pretty handy. I'm sure it's elementary for you


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## JohnMcClure (Aug 24, 2016)

Ah, so I should have googled it all along! I had it running from PWM but had soldered wires to components on the board to get the signal to where it was needed. Looks like I can simplify now.
Thanks 'jocks!


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## bigblockyeti (Sep 9, 2013)

No tachometer feed back for this board, there is an external pot for speed control, the three terminal to the left of the capacitor. It maintains low speed torque very well but it does require fine tuning when powering different motors. I also had a 56 frame Lesson PM DC motor, also 1hp and it had to be set quite differently than this Baldor. Unfortunately that motor, like too much else, was collateral damage in prepping for the move.


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## JohnMcClure (Aug 24, 2016)




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## JohnMcClure (Aug 24, 2016)

U4 (opto-isolator) and Q4 (N-channel MosFET) must be on to drive the motor.
PWMing Q4 should control speed, but I don't understand why SCR1/U4 exist.
Belt and suspenders?
I'll read through the reference Kenny linked and be back with more details.


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## HokieKen (Apr 14, 2015)

I don't have a clue John. That board and that schematic don't even look related to my monkey brain ;-) On that page I linked, there's a link to this pdf. There is a breakdown of the components and function of that board in there. Maybe that will shed some light?


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## JohnMcClure (Aug 24, 2016)

Youtube video showing where I am so far.
How do I get this to display a watchable thumbnail?

As you can see I still need to make a toolrest, and quite likely a new tailstock. This giant live center isn't actually turning with the workpiece; and as this is MT4 anyway I may end up using Keebler's old drive shaft as the shaft of a tailstock. To be determined. I'm at an hour per week or less of available project time, so…

Oh. And while the motor is running, em, it's running at 30V 6A from my benchtop (lab) power supply. I really need to get the drive electronics up to my satisfaction… I messed around using Arduino to provide PWM to the treadmill controller, but… don't want to talk about that right now 
I suspect the native PWM frequency of Arduino is too high so the MosFET doesn't have time to fully turn off. 
And I don't think the motor enjoyed dealing with that…


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## Lazyman (Aug 8, 2014)

I don't think that the site supports embedded videos anymore. I've never tried it but you might be able to add an image and make that image a link?

That lathe is coming a long. One thing you may have to address with a tool rest is how far out the parallel ways are from the head stock. Even adding a chuck, it may be difficult to turn the chuck side of a bowl without a really long and curved tool rest.


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## DavePolaschek (Oct 21, 2016)

Nice, John! It's coming along.


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## HokieKen (Apr 14, 2015)

Awesome John! Nathan's right, you'll have to figure out a way to get the banjo to move closer to the headstock. But I can think of a few ways that's doable. And that tailstock may not be ideal but it will serve the purpose until you get something else cobbled up.


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