# Monarch 10ee



## Rmany31 (Feb 8, 2013)

Hello to everyone! I would like to hear what everyone thinks about the Monarch10EE engine lathe's electrics.I understand they all used Vacuum tubes and that there are kits to convert them to digital electronics. I would like to purchase one of these lathes,I used to use one off-and-on at former employers years ago.I would just like to know about the tubed system reliability and practical conversion to a tubeless system.
Thank you for your help!


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## twstoerzinger (Feb 8, 2013)

I don't claim to be an expert on Monarch 10EE's but I know that Monarch was an early adopter of DC motors to get around complex gear boxes and other variable mechanical drives. I have read that Monarch rolled out DC driven lathes right after WWII using motor-generator sets to supply the DC power. Later they moved on to electronic (vacuum tube) style DC drives to provide the DC power instead of MG sets. When solid state DC drives came along - they adopted that technology.

So I guess you need to figure out which generation of DC drive is on the lathe you are looking at. In the past, I worked on several machines (not lathes) that were powered by MG sets with vacuum tube regulators. They were fairly easy to troubleshoot because the failure was almost always a failed tube. Back in those days, tubes were readily available and not too expensive - it was quick to change out the tube and get back running. These days, tubes are getting hard to find - especially the odd versions that you might find in a MG regulator set. Cost can also be a real factor to consider.

Modern, digital, solid state DC controllers have become pretty reasonable in cost (around $200 in the 1 - 2 HP range). You wouldn't have to buy very many tubes before you could justify the cost of a new DC drive. You don't need a high-end DC drive to run a lathe - IMO you don't need tach feedback. If the existing vacuum tube drive had this, you could just not use it with a replacement drive.

It's also worth looking at the condition of the DC motor. If its an older machine, the motor may have been reworked one or more times - and might be due again. DC motors have consumable brushes. The brushes are easy to replace, but eventually the commutator needs to be turned down - and at some point the commutator needs to be replaced. Motor overhauls can get to be expensive. An experienced DC guy can usually pull the access plates to the brushes and quickly get a good idea of how much time remains before the motor needs a re-build. 

Another issue is voltage. Most of the industrial grade DC motors have 180 VDC fields, so you need 220 VAC to run the drive. Single phase drives are available up to about 3 or 5 HP. At around 5 HP and above most manufacturers use all 3 phase.

You need some more information on the type of DC equipment currently on the lathe. If it is an MG driven machine - then for sure you would want to update to a modern solid state drive.

Terry S.


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## DMS (Feb 8, 2013)

You need to know the year the thing was built to figure out what type of drivetrain it has. You can also open up the cover on the tailstock side to see if it has a bunch of electron tubes. It looks like this (that's my machine in the picture)

https://picasaweb.google.com/lh/photo/sLCRd9nOatBMKaU4sCtPHtMTjNZETYmyPJy0liipFm0?feat=directlink

I purchased my 10EE recently, and at first was worried about having to replace the electronics. Now I don't think I would ever do that. The thing is rock solid, and whoever designed it really knew what they were doing. Speed regulation is dead on, starts and stops on a dime.

I have a the 3HP version, the good thing there is that, while it shipped with some electron tubes that are now rarer than hens teeth and twice the price of gold (C16J), they will run just fine on a more common tube (C6J). These alternate tubes are only about $30 a piece, and last YEARS.

Twstoerzinger had good advice about DC motor condition. Something to keep in mind, but most of that stuff can be serviced (the previous owner of my machine took care of turning the comutator and caring for the brushes for me).

The best thing to do is see the machine in action, make sure you don't hear any "ca`chunk ca`chunk" in the bearings. If it's mechanically sound, and it's within your budget, these are fantastic lathes.


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## cjsamples (Feb 8, 2013)

We have an old Monarch at work. Beautiful machine. They keep it power up 24/7 to keep the electronics warmed up. Apparently they don't want to have anything burn up on startup. For the right price it is a great addition to any shop.

Chris


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