New Machine Day! Another New to Me Monarch 10EE Lathe! 

I have a 1961 10ee. When I got it someone had removed the thyratron electronic drive and replaced it with a variac. Of course it was awful. I'm an electrical engineer, which came in handy, for a change, in the shop. The drives for the 10ee were actually two variable power supplies. A big one for the armature that could go from about 20V up to 200 volts at 20 amps. The other power supply was normally 100 volts but could reduce its output to around 20 volts or so. This smaller power supply provided current for the field winding. If you started the lathe at the lowest speed, the field voltage would be 100V and the armature would be at the lowest voltage, anound 20V or so. As you increased speed, the big power supply feeding the armature increased its voltage to 200V. At this point the motor would be running about 2000RPM. The armature voltage could not be increased any more at this point to increase the speed. To increase the speed, the big power supply continued to output 200V while the little power supply started to reduce its voltage to the field. The speed of the DC motor is controlled by the motors back EMF, or voltage the motor itself is generating. When the back EMF equals the applied voltage, the motor stops drawing current and regulates itself at that speed. When the field voltage is decreased, the generator (back EMF) effect is reduced, causing the motor to run faster so that its back EMF matches the applied voltage to the armature. That's why a shunt wound DC motor can explode if it loses power to the field winding. The 10ee has all kind of safety circuits to shut the motor down if the field current drops too low, so no worries there. I built a motor control system for my 10ee and it has been working great for the last 24 years. My 10ee was geared (pulleyed) for 3000 RPM spindle speed.

I was an electronic technician at NASA on SkyLab and Soyus keeping the Apollo Command Module simulators running. This is what we would charitably call a kludge.

Willy Beamis is our hero for the day! A 10EE as a gift to the Rucker Museum!!!

Dear Keith, so happy to see the lathe in your shop! Thank you for your wonderful channel. Willy

Hi Keith, regarding electric motors, there is a book on the market (written by a man in the USA) “electric motor repair” Rosenberg is the author. I encouraged many apprentice armature winders to get this book as a learning aid that would help in almost any circumstance. The beauty of this book is that it isn’t written for engineering students and graduates . I qualify this statement with over 40 years experience in the manufacture, repair and maintenance of electric motors. Great show as usual👍👍

What a kind gesture by this man to give you that lathe. And how awesome it is that we all now get to watch it come back to life.

Keith, you should get in touch with Uncle Doug, or Terry @ D-Lab,, those old tube rectifiers are way more reliable and simpler to repair. If you have the schematics they can rebuild/ repair what you have.

I ran one of those lathes back in the late 60's and loved it. I worked at the united airlines maintenance base at San Francisco airport and they had several of them.

Discouraging when such an old machine tool is younger than me !!

On the account of old electronics, tubes the likes, I HIGHLY recommend getting in touch with Mr. Carlson from "Mr Carlson's Lab" (channel name) here on RU-vid. There is nobody that i know of that has a better skill set in repairing tube tech in this land. He knows just about everything there is to it and has an extensive library of videos on the subject. He breathes this kind of stuff from the smallest to the largest and i'm sure he would be willing and jumping at the opportunity of potentially working on something like that.

Of course, VFDs would have only been a dream in 1956. The variable speed motor enabled Monarch to build the lathe with no transmission in the drive train. They did have a back gear, but that was only in the drive train if you wanted the granny gear. Belt drive is quiet and produces an excellent finish.

You’re doing it right!

Keith is a staunch monarchist.

I learned how to run a lathe on pretty much an identical machine. It was originally a 10EE with the tube rectifiers that had been converted to a modern DC drive. The electrical engineer who owned it used a modern electronic DC drive and then hacked/modified the power section so it would run at the motor's rated voltage. For him it was less about getting per-spec torque out of the thing as much as it was a humble brag whenever the mechanical engineers would show up.

Oh good, another stray that followed Keith home to satisfy his iron deficiency . 😁

There is a u-tube channel called I C Welds. He makes it clear that what he shows may not be the best way or only way but it's the way he does it. I believe this to be a good philosophy. I wouldn't necessarily do things the same way but I learn a lot by watching how he does a project and you can't argue with sucess. This is the same way that I watch Keith, Adom, Clarke, and host of others.

Beautiful piece of history, looking forward to the restoration.

Can't wait to see you working on it thanks!

It's amazing that there is always someone who tells you you're doing something wrong, but the funny thing is most of them don't have a RU-vid channel showing how it should be done. They're armchair experts, and like you said, if you get the result you needed it doesn't matter how you get there. Keep on keepin' on.

What a great gift!

Lots of good info thanks for sharing

I was an appentice Armature Winder in the 60's but didnt do a lot of DC. My guess why that setup pulses is I didnt see any capacitors. It would need some large ones and that setup looks potentionly lethal. Good decision to replace the speed control from scratch.

Still looking for one of those. Cant wait to see your restoration completed as well!

Love the colour!

Enjoy whatever you do Keith and thanks for the video.

Plenty of info on Practical Machinist: Monarch 10EE forum, dealing with the "works in a drawer" old system and converting them. Great to have another project to follow!

We had two pristine Monarch with the tube controllers. A manager sent them out as scrap metal and replaced them with a modern cheap lathe!

You could contact KB Controls in Florida. They have cost effective DC drives. Or take the tube drive offered below if it is the correct size and get Uncle Doug to fix it.

Nice machine and a very generous viewer!

Keith, I really appreciate your down to earth approach on things. Thank you so much for sharing this little lathe with us. I do hope to see how you overcome the "contraption". Take care and be well.

Nice bucket list machine. Almost a perfect match, I was born one month off of this lathe of 1956. Thanks for sharing.

Looks splendid.

Thank you so much for sharing Kieth. I know absolutely nothing about machining but you have a talent for explaining things that helps me understand. You would have made an excellent teacher.

Great video Keith, keep'um coming..

Best way to do it. Is do it your way.

Thank you for sharing. Enjoyed.👍👀

A lathe for each corner of the shop is a good rule of thumb.

Those are classics. I want one of those very machines.

Wish you had the Tubes. They were state of the art and still are in some conditions. The Big round unit with knob on top is a "Variac" (trademark) or a variable transformer. Loss of power at lower voltages is the problem. The tubes were phase adjustable - gave pulse with at max voltage different and as you increase the width of power is wider. Tiny pulse is low speed but pulses to full voltage. That variable transformer is useful for some things like lights and such but likely not that even. Light need log based windings.

Keith Great looking lathe. I’m excited to see you’re not giving up on the round dial 10ee. I have a 1939 10ee and I’m following your rebuild on yours. Keep up the good work Jim Murphy

Thanks Keith. I hope you are able to get those things worked our.

You are absolutely right that keeping the DC motor will allow a wide range of speeds at full torque. Look at the Ward Leonard control, which is a fairly simple way of getting 0 to full speed forward and reverse. The Ward Leonard control system was widely used for elevators until thyristor drives became available in the 1980s, because it offered smooth speed control and consistent torque. Many Ward Leonard control systems and variations on them remain in use.

Wow!Nice present. Sounds like a challenge for the brains at American Rotary.

That's an easy conversion you've got there if the DC motor is working fine.

Beautiful.

We had a variac in our repair shop where I worked and it was just for testing electrical equipment, mostly trip points and such. I never heard of anyone trying to run it as a power supply.

What a joy it is to use these fine lathes for precision part making when they are cleaned up and looking new. We had 6 of these yrs ago, 2 with longer beds. They were replaced with newer ones in the early 80's at 80K each with all the attachments. Now you have 2 gems, lucky are you !! 😁

Love those little 10EE's. Put in many hours in front of one over the years and made countless parts on them. That is what I plan on getting when I go to buy a lathe again.

I'd love to have a machine where I can say something like "I'm waiting for the thyratrons to heat up" like the old 10EE when I power it on.

A new toy. What a way to start August 2022.

Another iron to put into your fire. Thanks for the video. Jon

They are a great looking machine very solid.

Thanks for sharing 👍

A 240V Variac hooked up to an appropriately sized rectifier and a sufficient sized capacitor would give the DC motor enough voltage range to take advantage of all the power it can output. However when you rectify AC you’ll get a higher peak DC voltage because the AC Voltage is RMS (Root Mean Squared) or an Average. A full bridge Rectifier will take the AC Sine wave and transform it into a rippled DC voltage going from 0 - 169.7v (for single phase AC 120V) or 0 - 339.4v (for single phase AC 240v) so to better approximate a steady voltage a capacitor(s) can be added to “store” up the voltage and discharge it to the motor during the low points of the incoming rippled DC voltage. As you mentioned you still have the inconvenience for changing the variac dial AND you would have to set a hard stop on the Variac somewhere around the 163V to prevent from creating over 230v DC and frying the motor. All and all the I think the person who wired that had an OK train of thought but they just executed it HORRIBLY and made a train wreck of the power supply system. I’m not very familiar with Monarch lathes so all of this is solely based around there being no other systems requiring electric voltage. The ENGINEERING MINDSET on RU-vid did a fairly good explanation of how to change AC to DC that is worth watching.

Find you the biggest three phase motor that will physically fit in the machine. Preferably a 6 pole motor, these have more torque than a 4 pole. Keep the shaft from the DC motor, but remove all the armature windings, machine the three phase rotor to fit the DC motors shaft, that way you can keep the gear case and still have a back gear. You should be able to get 3600 rpm or more even with the 6 pole. I have did this on a machine that was originally a belt drive. It's still running strong and it's under a high load. I like DC motors but with today's low prices on VFD's you can't beat an AC setup if properly applied. Just something to ponder, I know that's what I would do with it. You will be far better off than keeping the old DC setup. A testament to AC motors & drives is a lathe I converted in 1997 that had a reeves drive setup that was in bad shape, the original motor was a 3HP, I put in a 5HP with a slightly lower (higher ratio) gearing and I can drill with a 2" spade bit in direct drive, in fact I had to install a torque arm on the tailstock for fear of taking out the tailstock's keyway. The Lathe has the same speed range as It did originally, I hardly ever use back gear. I'm no engineer but I have done lots of motor and drive setups for old machines, both AC & DC. Also rewired and updated a few CNC machines as well. I know you could handle the machining part of this, would make for some great episodes for the channel too!

Man I wish someone would give me a gift like this! I could do so much with it, extremely jealous right now.

I smell a collaboration with Mr Carlson’s Lab.

I'm liking that two tone blue!

I never looked at DC POWER different to work with just follow and understand the difference a little to get yous to .

In a DC motor you have a shunt field, a serial field and the armature winding for a total of 6 wire. The speed variation is cause by the serial field. The serial field increase or lower the magnetic field depending of the wire connection. When the magnetic field increase, the torque increase and the speed decrease. So leave the serial field unplug (wire tag S1 and S2 ) will correct your speed variation.

I would love to own one of those one day!

Good stuff

also the front bottom left knod is your DC field/speed control

Hi Keith very nice Monarch lathe.

Keith you do need another 10EE! 👍

Been thinking on this one. I actually "built" (partially reengineered) a high voltage DC power supply as part of my senior project when I was studying for my EET degree. It was part of a fixed frequency variable amplitude inverter for an inductive casting machine. And it did run and produce 240V The HVDC primary stage consisted of an SCR bridge (bridge rectifier with the two positive side diodes replaced with SCRs), a pair of isolation signal transformers (too high power for opticouplers) and a discreet SCR controller IC (similar to TRIAC controller in a dimmer switch). That IC was controlled by a DC input... Which for this could just be a potentiometer. If on the off chance this is of interest, I open sourced the hardware and software and would be willing to share. There were a couple issues I ran into but the overall design was previously proven.

I'd sure like to get my hands on that Variac! Another great machinery score and video Kieth. Keep up the great videos!

There should be plenty of DC motor controllers available that will run a motor of that voltage and hp rating. Preferable to get a closed-loop controller which will give you really good low speed torque for threading and large drilling.

The viewer was very generous. Sadly high quality old lathes like this are extremely rare in Australia.

From my days as a Sales Engineer selling Reliance Electric motors (among other things) I learned the 208V motors were used in areas where the supply voltage was not a solid 220-240 but dropped below 220. Usually, rural applications far from a substation, or industrial areas with a lot of loads on the system.

I would love to see you bring it back to stock with the tubes and all. My 1957 10EE works as new.

Modern VFDs can produce 100% torque at low rpm running AC motors. Look for drives with sensorless vector control that have constant output torque.

If the motor is good then it needs a suitable converter for the DC voltage. Maybe American Rotery can make one. But you will need a transformer to adjust the voltage.

A 10EE is mechanically a great lathe and as long as the electrics are working, a terrific addition to any shop. If you try to repair the electrical system however, you will soon see why often the guts are pulled out and replaced with one of the options Keith mentions. There is no simple or inexpensive way to repair the electrics back to original operational specification. These design of these lathes are a precursor to the problem with CNC machines. Mechanically, no worries. Electrically: you need to be VERY good at diagnosing a problem exactly because the proprietary repair parts (if you are lucky enough to find them) ain't cheap. 15 years ago I ran a VMC that they thought needed a board. $3,000 for one of the control boards and that was rebuilt. Turned out the board was ok, but the control panel was shot. There were no repair parts for it, rendering the machine almost useless.

I was convinced by the folks on the PM forum for 10EE's to keep the motor-gen set. I kind of wish this update kept those original parts in play so I could see how far a competent rebuild takes it. My machine is dated 1954. I did not rebuild the AC or DC motors nor the generators....always felt I sort of stopped short of doing it right. Being a hobbyist one has to decide how far to take it to be happy with it. I did not have the bed reground either.

Built to last I've used lathes and milling machines most of my adult life and the old machines are much better than some of the the newer ones

I have a 10a variable transformer right now controlling the fan in my bedroom I never turn it below 60 percent as the current to the motor increases. Makes it possible to slow fans down so they are quiet. I vary the speed of my finish sanders too. That looks like a 30 or 40 amp variac probably around 500 dollars or more. I had an accident with my variac. Somebody gave me a good used jumbo jet landing light. 250w @28 volt spot light. I live about 2 miles from a big sign on a hill. I adjusted the variac to 28 volts. Put a lamp cord on the landing lamp. I had set the variac on a wall in my back yard and tried to illuminate the sign . I pulled too hard on the lamp cord and knocked the variac off the wall. I caught it by the knob and it twisted to 110% the now purple white and humming landing light swung illuminating the apartment building across the freeway for a second with a light that was brighter than sun light as the bulb burned out. A few tenants opened their windows and stuck their heads out wondering what the heck was that crazy bright flash of light. That was almost 25 years ago. I really should go over and ask if anybody had seen a crazy bright flash of light in the late 90s. That sign awaits. My variac awaits. A 12 foot hospital grade power cord awaits. I just forget to stop by the aircraft parts place to buy another crazy bright landing light bulb.

It is a variac plus a diode converter! The variac gives you variable output!

I think you should consider doing a collab with a youtuber who is focused on electrics and such. I don't know a great candidate off the bat, but I bet they're out there. Maybe Jeremy Fielding? I believe he's at least sorta local (North Alabama, I think).

Would be nice to restore the original Tube system in the lathe, for history purpouses of course. Maybe we can do a shoutout to Mr.Carlson? He could probably either fabricate a new drive, or atleast give som pointers.

Your discussion of the pros and cons of different drives was very helpful. I’d been wondering why my 70 year old mill had such an elaborate variable speed belt drive, and would the makers do things differently now? I’d wager no electronic drive will still be working in seventy years time, but I won’t be around to know! I might add the belts still work beautifully , though I did have to make a new intermediate shaft as the original didn’t see much lubrication in its life. Really can’t complain.

Looks like a death toaster with that motor control setup!

What a score! That rectifier is missing a huge capacitor bank to smooth out the DC

Thanks for all you do! Love your work. One of my favorite channels. There's always more than 1 way of doing something. Some people like there way. You always find a way that works well for you ( one of the best ways of most). Keep it up. You are great at it. THANKS 😊 Let us know when you decide to sell something before you make an agreement. Many of us trust your opinion. I am looking for equipment. Don't always have the funds or knowledge of what I am being, but if I do. I will buy from you

Hey Keith, I have tons of respect for you and the stuff you do.. youtube comments and forums in general are just full of folks who like to complain... You could post a link that if everyone who clicked it would get a free 1lb bar of gold... there would be a few that bitch about a scratch on theirs or it wasn't packaged right...

I might be wrong but in a DC motor drive, to maintain constant torque at all speeds, you want to maintain a constant currant and vary the voltage for rpm changes.

208 Wye with a neutral is standard household voltage. 240 Delta is for industrial loads. The reasoning being, according to Ohms Law the higher the voltage, the lower the amperage. I = E/R, P = I x E. The 240 Delta is also called a corner tap Delta. Every 3rd phase is known as a high leg, meaning phase to ground measures 240V. This was not practical for household due to overvoltage mistakes. A garage shop may only have 208 Wye available.

Keith, I have a 1954 Monarch 10EE that was converted with a 5HP AC motor and VSD. I have never been able to stall it when running a very low speeds. The only difference between the way it runs now and when it had the DC dive is it is only capable of 2,000 RPMs rather than 4,000 RPMs. I haven't had the need for 4,000 RPMs so far. I look forward to seeing the drivetrain conversion you do on this lathe. Should help out lots of folks who are saving these wonderful old lathes. By the way, I got a quote from Monarch to rebuild a 10EE and install a new drive...around $60K!

Keith, Another you tube guru named Steve Watkins went thru an exact same scenario with surging and goofy electronics, on his Monarch 10EE he was able to fix his successfully, maybe contacting him might help in the long run with your conundrum, 2 heads alot of times are better than 1.....just saying.....Good luck....

I realize you have had medical problems. . But whatever happened to the Jimmy Diresta handsaw work, it just vanished, it was very interesting.

Keith, To get the electric motor run better for now. Check rectifier if all diodes do function. Or get it to someone who knows rectifiers. Check carbon brushes on motor and collector/comutator. Also check variac, it has a carbon brush on de downside which can wear out or make bad contact.

Servo drive motors with a vector drive can do it down to zero-rpm because the right ones have a seperate blower motor for cooling.

You work in two shops; maybe you should keep one of the 10EE's in your home shop and the other one out at the museum shop. I am sure you can find the right electronics set up to run the newer one!

Oneo f my dreams is to buy my OWN Browne and Sharpe 3G Automate Screw machine. So long ago (What like 40 years ago) I was trained by a expert production machinist, in the set up and operation of such a machine, I can't imagine getting much work for it :) Back in the day I turned down any jobs under 300 pieces, and 1000 plus piece jobs were preferred , Biut I still want one :)

I'd love to get my hands on a Monarch 10EE someday with the original vacuum tube electronic drive... and I *AM* an electrical engineer! :)

Beautiful Art Deco chrome strips on the cabinet. Looks like a Pontiac Chieftan from 50s.

Run a geiger counter over it. A lot of those lathes were used for shaping radioactive material for weapons production.

Take the motor to a reputable motor winder, tell them the HP and TQ requirements you need. Ask them to rewind and size a DC driver. It costs more, but the end result is magnitudes better than anything else.

I wish I had a spot for one of those lathes. I know, I know, get a storage unit...I HAVE ONE...FULL! Storage is SUPER expensive. Trying to talk my wife into building on our property....we're allowed a single structure to be built before a home, and I could put a 80 x 40 barn there without having a home put on it....biggest downfall there is the 200A max service (thank you very little pot grow facilities...). Wish I had the room I'd be talking to you Keith...and I was JUST down there over the weekend...LOL.

What an amazing gift! Fix it up and donate it to a school? That kind of generosity needs paid forward!