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UK Built Hardingle HLV Carrier Feed Motor Wiring Question


Aug 17, 2020
Hi Guys,

Let me start out by saying that I am neither practical nor a machinist, but basically all of my google searches on this piece of equipment point (or link) directly back to this website, so here I am. I will go ahead and thank you in advance for your patience with my dumb questions, as I'm sure there will be more than a few. :willy_nilly:

I recently bought a Hardinge HLV (not an HLV-H!) from a ~local gentleman who was retiring and selling off his equipment. The HLV is UK built, and apparently it was purchased stateside in 1985 from an importer out of Mobile, Alabama. I'm a bit of a novice when it comes to lathes (and machining equipment in general), but I'm aware of the Hardinge reputation, and after meeting the seller and seeing how he treated his equipment, I decided to take a chance on it.

The machine has a few quirks to it (reflected in the price), but in it's current condition it will meet all of my foreseeable needs. I think that some of the quirks can be fixed, and it might be fun to one day to take on some sort of a restoration project.








The biggest bummer is that the original 440v 2-speed motor had been replaced some time ago with a 230v single speed motor. In so doing, an auxiliary forward/stop/reverse switch was added to the side of the cabinet and the remainder of the factory features/wiring is now inactive/bypassed/defunct. Mechanically, the spindle is quiet throughout the speed range, the threading system works perfectly, the carriage seems to move nicely with reasonable backlash, and the machine came with a fair amount of accessories/attachments... so if none of the factory electronics can be salvaged I would be disappointed, but at least with a usable machine.

If possible, I would like to resurrect the power feed for the carriage. My earlier research suggests that the 100V DC motor actually takes 100V AC as an input, through a rectifier. I found a wiring diagram for an "early" UK machine at the following link, and at first glance it *looks* applicable to my machine, but I haven't gone through it with a fine toothed comb, and if I'm honest, I'm nowhere near an electrical wizard. In fact, I'm very much on the other end of the knowledge spectrum.

Dropbox - Hardinge HLV Wiring Diagram Early UK.jpg - Simplify your life

The drawing is dated 06/02/1955 and my machine serial # is HLV-0069. I found some links to relate the US serial #'s to dates, but I couldn't find something equivalent for the UK built machines. Any idea what time frame I would be looking at for my lathe? I think I remember reading that the layout of the carriage feed controls had changed at some point in the production of the machine, and I want to say that my machine has the later style controls (knob in the center, switches in the corners)? I'm assuming that these machines were built in the US for a period of time before UK production begun, so even though I have a low UK serial number, this machine is likely newer than some US built machines with even higher serial numbers? :crazy:

If I remove the variac knob I see the following 5 pin connection, with clearly some contemporary looking electrical splices. I'm thinking that may turn out to be a not-so-good sign, although I was told that the carriage feed motor had worked properly before the original 440v motor went out.


On the side of the machine, there is a 12 pin junction block where power would have originally been passed through to the variac. I was thinking that maybe I could work backward from the variac and determine where 100V AC was input, and then supply power there directly from a 110v wall outlet?


I have a ton of other questions as well, but I wasn't sure if it was considered a forum best practice to dump them all in the same thread or create unique posts for each? I know that the search forums here are a wealth of information, and there are also yahoo/google groups for these machines. For now, I am hoping to start simple and get the carriage feed system going again, but I'm sure this is only the start of the journey.

To summarize, because I rambled a bit...

1) Can anyone help me date a UK built machine with SN HLV-0069?
2) Can anyone help me confirm that the wiring diagram I have found is correct? Perhaps this is contingent on the outcome of #1.
3) Can anyone offer any advice/recommendations about powering the carriage feed motor from an offboard 110v AC supply?

Thanks for reading,

Barry Stone

Jul 16, 2020
Hi Lee, I'm Barry, an ex-apprentice (later, skilled fitter) from Hardinge, Exeter, UK between 1965 - 1979. It's been a heck of a long time in between, I know, and I'm not that great electrically either but, the HLV model you have was built in Feltham, Middlesex, UK around early to late 1950's. You are extremely lucky to have a wiring diagram, but it looks correct from my memory and about right for its date (1955) - I also worked in the drawing office for a short while before I left. MTE control equipment was fitted to various models of lathes (and mills). The Dymec motor had 2 field coil wires and 2 armature wires (DC, I believe) and an earth connection wire if you were lucky. The lead went from the back of the motor, through the bed casting to the end box that has the Rotary Regavolt (variac). Inside the end box should be a diode board with several resistors wired across connection pins. The Dymec motor (later replaced by a Croydon motor) was wired to a row of connections on the diode board - A1, A2, F1, F2, (and a common earth) The Rotary Regavolt was wired via the switches on the front legend plate to the diode board also. (230v AC, I believe) voltage was fed to the diode board from the electrical end panel on the left hand side of the m/c and linked with the Rotary Regavolt to vary the voltage for the Dymec motor. I remember having to repair the feed motors, diode boards and change variacs at times.
Your spindle main motor would probably have originally been a 0.5/1.0 hp (or maybe a 0.5/1.5 hp) Newman motor made in Yate, Bristol, UK.
I hope the above helps, even if in part help, but please forgive me, I'm no longer 16 yrs old with a memory like a sponge!
Best of good luck to you, from Barry.