New to me Pratt and Whitney 12x54 lathe

[CaptainNemo]

Hello all, I just bought a lathe (and mill) at an auction. It seems well taken care of, but I haven't run it yet. I looked at the motor, but I don't see a motor plate. The serial number is 322. I'd like to know when it was made. I also need to know the motor hp so I can get the right size vfd. Does anyone have any suggestions?

 

[michiganbuck]

That machine has run for a long time with not having a VFD.
likely came with a 3 HP.

Pratt & Whitney Engine Lathes

 

[CaptainNemo]

It came out of a machine shop that was running it on 3 phase, but I only have single phase in my shop

 

[johnoder]

It came out of a machine shop that was running it on 3 phase, but I only have single phase in my shop

Came with 3HP on the 12".

Looks like related pubs are in this list

Pratt & Whitney Co. - Publication Reprints | VintageMachinery.org

322 is from the early to mid nineteen forties - making it more of a "slope head" than a "square head"

There were also 12" Model Bs being made at this time - they have only 8 mechanical speeds compared to the Model C's 18 speeds

 

[Greg Menke]

I put an older 10hp vfd on my American lathe w/ 3hp motor- the vfd derates by 50% on single phase so is effectively a 5hp vfd. I've never been close to overloading it.

 

[CaptainNemo]

Thank you all for your help. I can't wait to make some chips. We have mostly cnc equipment at work and some jet and Clausing lathes. At least without running, my p&w is a much better piece of equipment

 

[Salem Straub]

You're gonna love that lathe. My 16' P&W model C is super nice to run. I have found lots of good info on these on the forum here actually, some very good rebuild threads particularly for the 12", and there's plenty over at vintagemachinery too as linked to above.

 

[Doozer]

Someone on here has a 18 speed 12C with a 2 speed motor.
36 speeds is just showing off. I like it !
I still never read the speed chart.
I just start rowing levers until I get a speed that looks right.
It kind of feels like shifting a Mack truck with the 2 boxes !
Blissful confusion is the best way I can describe it !
My lathe has the optional reverse contactor.
I like the hand brake, but I think it would have been really
cool to have forward-reverse clutches. Tailstock tapping
would seriously kick azz! Side note, some or many of the
Mack trucks have shuttle shift transmissions. They have as
many forward gears as they do reverse gears. Believe it
or not, Spicer made a 9 speed like that. Not sure what
Mack used. That guy Nick Collier on youtube has what I
believe is a Russian copy of a Pratt and Whitney lathe.
His lathe has the fwd-rev clutches. You can see the chuck
drift sometimes in forawrd, sometimes in reverse when it
is in neutral. I do think it is interesting that the Russians
copied these lathes.
There are some of the fixes that I have done on my
Doozer's Shop channel. There is this guy Kimber Zellek
that has an old 12B that he got from HGR. This cat has
fixed about 20 things that were messed up on his lathe.
I really think the model C is the high point of this lathe
design. The horizontal headstock gear layout is worlds
better to service than the B model vertical headstock
gear layout.
All said, there are better lathes. Monarch has helical cut
gears (better) and Sidney had herringbone cut gears (even
better). All designs have compramises. The problem with
helical or herringbone gears, is you can not do sliding
gear shifting. It has to be constant mesh with shift dog
clutches. More parasitic drag but less running noise.
The single dog threading is just kick azz. The same as
the Hendey and the Hardinge. The oiling on these lathes
is really good too. My lathe has an oil pump in the apron
that oils the bed ways, and an oil pump in the Norton gear
box. Both these oil pumps give a shot when you actuate
the clutch/brake lever. Also there is a pump in the head
stock that sprays the gears. This has a AMF Cuno filter.
It is self cleaning with a twist of the handle. Pretty neat.
I actually bought a Cuno filter and I want to put it on my
parts washer to filter it.

--Doozer

 

[CaptainNemo]

I got everything set up and she is running, but I noticed two problems.

1. The right hand clutch release doesn't more far enough to stop the spindle. I'll move it until it stops, but then it will move again to the right and the spindle starts back up. If I use the left hand lever, it engages the brake and stays in place.

2. The carriage feed lever doesn't stay in place. When I raise it up to engage, the feed starts, but the lever slowly moves back down and starts to make a clicking noise as it comes out of gear

I will do more trouble shooting, but I was hoping that someone might know of what adjustment I can make to fix the problems.

 

[CaptainNemo]

On the plus side, she runs smoothly and quietly. Also backwards, but that'll be easy enough to fix

 

[johnoder]

I got everything set up and she is running, but I noticed two problems.

1. The right hand clutch release doesn't more far enough to stop the spindle. I'll move it until it stops, but then it will move again to the right and the spindle starts back up. If I use the left hand lever, it engages the brake and stays in place.

2. The carriage feed lever doesn't stay in place. When I raise it up to engage, the feed starts, but the lever slowly moves back down and starts to make a clicking noise as it comes out of gear

I will do more trouble shooting, but I was hoping that someone might know of what adjustment I can make to fix the problems.

Parts book here if you don't have a copy

http://vintagemachinery.org/pubs/1412/20054.pdf

 

[tailstock4]

I got everything set up and she is running, but I noticed two problems.

1. The right hand clutch release doesn't more far enough to stop the spindle. I'll move it until it stops, but then it will move again to the right and the spindle starts back up. If I use the left hand lever, it engages the brake and stays in place.

2. The carriage feed lever doesn't stay in place. When I raise it up to engage, the feed starts, but the lever slowly moves back down and starts to make a clicking noise as it comes out of gear

I will do more trouble shooting, but I was hoping that someone might know of what adjustment I can make to fix the problems.

It is possible that your clutch linkage is out of adjustment or time. The clutch linkage on the back of the headstock attaches by means of a taper in the shifting forks. You loosen the nuts and give them a tap and they will move. They are infinitely adjustable. If you take the control rod bracket cover off, there is a fork and a ball. This all must be in correct timing with the main clutch handle and the apron clutch handle. You must fool around enough that you see how it works, and then it will make sense. When it is operating correctly, the brake works well with little force and the clutch engages smoothly as the counterweight helps with the engagement.

In response to your second question, the longitudinal and cross feed clutches are adjusted the same way. At the handle connection points there should be a screw and a nut. You loosen the nut and turn the screw. It is an eccentric. With the clutch handle up, adjust the eccentric until it makes good contact then lock the nut. This is spring loaded and when there is an overload, the serrations of the clutch skip over each other and that makes a clicking sound. It sounds like yours may not be fully engaged. The clicking you hear is probably those serrated teeth.

If you are going to use the machine much, I would consider pulling the apron and the saddle and inspecting and servicing the oil system. It is a little bit of work but worth the effort not only in terms of machine operation, but it can also increase your understanding of what is going on. I’ve documented this in my Pratt & Whitney rebuild post in the Heavy Iron section.

All this assumes that you are talking about a model C.