Harrison Horizontal/Vertical Mill Restoration

[Carl Wilson]

Hello All,

It is time to start a thread to document the restoration of my Harrison horizontal/vertical milling machine.

Most of you will have already seen some pictures of it and read the sorry tale of woe of it's journey to get to me in my thread "EBay-tastic".

Well, this is not going to be a particularly salubrious first post, but you have to start somewhere.

Anyway, here is a picture of the VFD I've bought to run the main motor on the mill. It's a Delta 1.5kW unit.

 

[Carl Wilson]

As I've said elsewhere, I'm concentrating on getting my lathe VFD conversion finished before starting on the mill in earnest.

That said, yesterday my youngest son and I spent a pleasant hour de paneling the machine.

We removed the louvred covers surrounding the coolant tank in the base of the machine. As well as the clamp mounted coolant pump, this area is also home to the flange mounted main motor.

Removing the lower front panel revealed the switchgear controlling the main motor, feed motor and the coolant pump.

Having withdrawn the cables for the coolant pump, we removed it, complete with its mounting clamp. It was absolutely manky with congealed coolant and general gunk.

The interior was accessed to check the windings. They were in good health and the megger pronounced the insulation to be sound.

The inside of the base that forms the coolant tank was also manky, just like the pump itself. At first glance the main motor looks alright, the next job is to take it out and test it for continuity and insulation.

There must be 50 years worth of accumulated coolant residue, tramp oil and swarf in there.

There is a lot of general dirt both inside and outside the machine. That said it seems to be in good overall condition and will clean up nicely.

 

[slim_boy_fat]

There must be 50 years worth of accumulated coolant residue, tramp oil and swarf in there.

There is a lot of general dirt both inside and outside the machine. That said it seems to be in good overall condition and will clean up nicely.

That's a good starting job for your apprentice - "Clean that lot out, son"

Looking forward to the updates/progress reports on this.

 

[Carl Wilson]

It's a nice idea to get my "apprentice" to clean out the coolant tank. However he is just coming up to three years old! He can handle a 1/4 drive air ratchet with a bit of help from Dad. Chlorinated hydrocarbon solvents are a bit advanced for him at the moment.

He loves to be in the workshop though, and he is learning all the time. Not just about tools, machinery and mechanical principles. Foundations are being layed for his numeracy and literacy too.

By the way, if you look carefully in the picture of the coolant pump motor connections you can see the star point.

 

[slim_boy_fat]

Not just about tools, machinery and mechanical principles. Foundations are being layed for his numeracy and literacy too.

Have you taught him to swear yet?

 

[Carl Wilson]

To be honest I try to steer clear of it.

 

[Carl Wilson]

The lathe DRO is finished. At long last. Time to get back on with the Mill...

 

[Carl Wilson]

Finally got a chance to do some work on the mill. I'm starting by removing what will be redundant electrics. Found this in the table feed switch enclosure.

It appears that at some point the cable between the feed motor and Square D switch has been replaced with 2 core and earth.

Still early days at the moment so I haven't yet decided if I will use the original switch gear to signal the Vfd inputs.

 

[Carl Wilson]

Continued removing the redundant electrics last night.

The lamp, which I intend to restore and refit, still had the spare fuses in their stowages. The transformer is 440 to 24 volt. The ratio should work to give me about 12 volts on 240 mains, which is a voltage I can work with. I may need to limit the current though.

I am hoping to get the main motor off today. Everything that I intend Re using will be megger tested.

I found a tag inside the body of the machine with the original machine number on it. I was hoping for a date, but no such luck. Last part of machine number is 68, so possibly 1968?

Here is the interior of the lamp transformer box. It's an interesting set up. The transformer sits in here and makes contact with sprung terminals. The switch works in a similar way.

Here is the transformer portion.

And here is the enigmatic tag. The Harrison grey colour the machine is meant to be is apparently called "School".

 

[Carl Wilson]

Removed the motor this evening. First I slackened the mounting plate bolts which allowed the plate and motor to slide upwards. This released the drive belt tension, allowing the belts to be removed.

The motor is flange mounted to the plate by four bolts. The plate is then in turn fixed to the machine frame by a further four bolts.

In order to remove the motor, I positioned a piece of wood underneath it prior to slackening the mounting hardware. The wood was secured using a clamp. Once the bolts were removed, the motor was then slid out along the wood. The photo below shows the motor about to be removed after taking off the plate.

The motor is very dirty. Having said that the windings megger test well. The bearings feel smooth. I will have to strip the motor in order to Re wire the windings for connection to a Vfd.

I found a piece of paper pushed into the back of the motor. It turned out to be this:-

 

[Carl Wilson]

Last night I began to look at the measures required to remove the table assembly from the knee. I want to separate the whole knee/table unit whilst it is still on the mill. This will make for easier modules to work on and move around the shop.

I removed the cross slide leadscrew keep and wound out the leadscrew. Nice SKF thrust bearings in the keep.

It wasn't strictly necessary to remove the leadscrew as the cross slide nut simply sits in a bore in the bottom of the cross slide assembly. At least according to the parts drawing. At any rate, removing it will prevent any issues when lifting the table assembly.

The clamps shown in the following picture now need to be removed to allow the whole table assembly to be lifted off. On the RH side of the table, the gib grubscrews have sheared off in 3 places, as can be seen.

 

[Carl Wilson]

It was pouring with rain this morning, so I decided it was a good day to pressure wash the main electric motor.

I treated the whole unit with some aqueous degreaser first, followed by a rub down with a stiff brush. The pressure washer then took 50 years worth of crud off the motor.

After pressure washing the motor was thoroughly blown dry using compressed air. It is now clean enough to be worked on easily. Any residual dirt will come off with solvents now.

 

[Carl Wilson]

Started stripping the motor down this evening. The pressure washer had dealt with the vast majority of the dirt. There are still one or two areas where a dunk in solvent wouldn't go amiss.

Removed the pulley without issue.

Then with the motor securely held, the front and rear covers were removed.

I took the front and rear grease nipples out prior to more invasive dismantling. They were completely dry. I think the grease in the bearings was that left from the original build.

The bearings both had grease/debris seals.

Once the rotor was out I pulled both the front and rear bearings off. The rear one also sported a retaining circlip.

Both bearings felt quite rough. After 50 years with no maintenance I'd say they don't owe anybody anything, and deserve retirement. I will try to replace them with sealed, shielded types.

The rotor seemed in good condition. It looks as though I will be able to access the winding connections in the stator to convert the unit to delta.

There will be a need for more in depth cleaning. I have a strong urge to put the end caps and a few other parts in the dishwasher...

I'm also tempted to mount the rotor between centres, just to ensure it isn't bent. That said, I can't think of any reason why it would be.

 

[Dieselman 63]

Started stripping the motor down this evening. The pressure washer had dealt with the vast majority of the dirt. There are still one or two areas where a dunk in solvent wouldn't go amiss.

Removed the pulley without issue.

View attachment 185926

Then with the motor securely held, the front and rear covers were removed.

View attachment 185929

I took the front and rear grease nipples out prior to more invasive dismantling. They were completely dry. I think the grease in the bearings was that left from the original build.

The bearings both had grease/debris seals.

View attachment 185935

Once the rotor was out I pulled both the front and rear bearings off. The rear one also sported a retaining circlip.

View attachment 185936

Both bearings felt quite rough. After 50 years with no maintenance I'd say they don't owe anybody anything, and deserve retirement. I will try to replace them with sealed, shielded types.

The rotor seemed in good condition. It looks as though I will be able to access the winding connections in the stator to convert the unit to delta.

View attachment 185937

There will be a need for more in depth cleaning. I have a strong urge to put the end caps and a few other parts in the dishwasher...

I'm also tempted to mount the rotor between centres, just to ensure it isn't bent. That said, I can't think of any reason why it would be.

I bent a rotor doing just that, turning between centres. The tailstock wasn’t quite locked in place - the whole thing was thrown across the room, really frightened me! If I could turn back time I wouldn’t have bothered.

 

[Carl Wilson]

Thanks for that. Good observation. I meant just to spin it by hand between centres with a clock on it. What I think I will do is sit it in two vee blocks and clock it that way.

 

[Dieselman 63]

Thanks for that. Good observation. I meant just to spin it by hand between centres with a clock on it. What I think I will do is sit it in two vee blocks and clock it that way.

Someone hadn’t fully tightened the grub screw on the pulley and it had gouged out the shaft and along the keyway, I was trying to smooth it out with just a skim (which worked) then sandpaper which I think pulled it off balance. Easy to forget the forces at work. Lovely cool breeze from the fins as I was sanding though!

 

[Carl Wilson]

I can well imagine. Stuff breaking free from the lathe is something I wake up sweating about.

 

[Carl Wilson]

Just ordered two new bearings for the motor. They are 1 each of Dunlop 6203-2RS and 6204-2RS. Got them from bearing boys.

 

[eLuSiVeMiTe]

I bent a rotor doing just that, turning between centres. The tailstock wasn’t quite locked in place - the whole thing was thrown across the room, really frightened me! If I could turn back time I wouldn’t have bothered.

That was surprisingly anticlimactic.

Homemade fixed steady supporting the bearing and the other end in the collet. Center wasn't drilled in the center so had to improvise.

Looking forward to seeing this rebuild develop Carl.
Did a top job on the lathe.

 

[Carl Wilson]

Excellent way to hold the rotor with the collet and steady. Thanks for the kind words Elusive. I'm determined to do as best a job as I can on this mill.

This evening I have been cleaning all the parts of the motor in equipment cleaner. This stuff is a mixture of Acetone, Toluene and IPA. It cuts through grease and dirt. Even after pressure washing the motor, the solvent was black with dirt after all the parts, stator included, had been dunked and agitated with a stiff brush. Everything came out sparkling clean.

As I usual I filtered the dirty solvent back into another container. This means it can be used again without contaminating my bulk supply. The container thus becomes the working quantity for parts wash off.

Here is a photo of some nice clean motor parts.

I did some work on the stator this evening, too. Having painstakingly removed all the lacing cord from the end of the windings, I carefully lifted out the star point and removed the insulating sleeve from it. The photo below shows this. The next job will be to desolder this and then reconnect the windings in delta to allow the motor to be run from a 240 volt 3 phase VFD.