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Pratt and Whitney Model C 16/30

binzer

Plastic
Joined
Apr 25, 2022
Hi there!
I recently picked up my first lathe, Pratt & Whitney Model C 16x30. I have found and read mostly everything I can about these lathes and I think I am now starting to re-read all the same stuff. It seems in pretty good shape, ways are great, spindle bearings are good, and just gave it a solid wipe down. Next is starting it up as I only got it on Saturday. I need to ensure the fluids are all good. Hoping this post revives some conversation on these lathes, I know they are getting more and more rare and hope to bounce some questions on some others that own or have owned one before.
 

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binzer

Plastic
Joined
Apr 25, 2022
Thank you so much for the manuals. I did just see them now.

Such a great post, amazing seeing all the old pictures - this is a great capture of history!

Really appreciate it!
 

binzer

Plastic
Joined
Apr 25, 2022
Does that have the 1000 rpm gearbox or the 1500 ? Really sweet old machine. Dave

Yes it is the 1000 rpm gearbox. Unfortunately I only had a limited amount of time researching before buying it and then have been learning more and more since. Some good news and some bad of course. But I think the condition of it makes up for it. I hope.

When I picked it up the oil was drained for the leadscrew gear box. It is a bit of a puzzle, is there a drain plug under the level indicator? (see pic)
 

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tailstock4

Aluminum
Joined
Mar 3, 2013
Location
Oklahoma, USA
Congratulations on your Pratt & Whitney. They are an amazingly well-made and smooth machine.

The end of the feedbox that you are pointing to is a little different from my 12C’s which is a later model but still reasonably close. Inside that end of the feedbox is the gearing for the ABC lever and the thread and feed gears. There is also a piston oil pump that works off a fork that is connected to the clutch rod. Every time you engage the clutch, it provides a shot of oil to a manifold located under the top tray casting. The whole change gear box is not too complicated to remove or to disassemble. Be aware that Pratt & Whitney really loves taper pins.

The apron is a little different story and is the most complicated apron I have yet worked on – more so than the 10EE or Rivett 1020S. But it is beautifully made. I think I will start another thread on my 12C as I have quite a few restoration pictures which might be helpful to you if you decide to work on yours.
 

binzer

Plastic
Joined
Apr 25, 2022
Congratulations on your Pratt & Whitney. They are an amazingly well-made and smooth machine.

The end of the feedbox that you are pointing to is a little different from my 12C’s which is a later model but still reasonably close. Inside that end of the feedbox is the gearing for the ABC lever and the thread and feed gears. There is also a piston oil pump that works off a fork that is connected to the clutch rod. Every time you engage the clutch, it provides a shot of oil to a manifold located under the top tray casting. The whole change gear box is not too complicated to remove or to disassemble. Be aware that Pratt & Whitney really loves taper pins.

The apron is a little different story and is the most complicated apron I have yet worked on – more so than the 10EE or Rivett 1020S. But it is beautifully made. I think I will start another thread on my 12C as I have quite a few restoration pictures which might be helpful to you if you decide to work on yours.

That would be great! I don’t want to start it up until I have a good understanding and confident that the fluids are all good. It had a lot of gear oil on the the tray when I picked it up (that wasn’t there when I first looked it over) and I expect it came from the feed gearbox. Seems like there is a drain hole under where my arrow is. I have spent more time cleaning up all the gear oil so that I can investigate more clearly. What oil is used in the gear box, headstock and carriage? I’m planning on cracking into it over the next few days now that’s it’s cleaned up.
 

tailstock4

Aluminum
Joined
Mar 3, 2013
Location
Oklahoma, USA
That would be great! I don’t want to start it up until I have a good understanding and confident that the fluids are all good. It had a lot of gear oil on the the tray when I picked it up (that wasn’t there when I first looked it over) and I expect it came from the feed gearbox. Seems like there is a drain hole under where my arrow is. I have spent more time cleaning up all the gear oil so that I can investigate more clearly. What oil is used in the gear box, headstock and carriage? I’m planning on cracking into it over the next few days now that’s it’s cleaned up.

The oil you see after you moved it would be from the headstock. There is a gear box on the back of the headstock that holds the single-tooth clutch for the feed. This gear box drains through a tube at the bottom back into the headstock. Where it drains into the headstock is somewhat open. If you allow the tailstock end to be elevated high enough, it will just run out.

As far as fluids, I use Mobil heavy medium ISO 68 in the headstock. I use Schaeffer molly lube 160 ISO 68 in the apron and feed gear box.

I would also highly recommend disassembly of the apron and saddle. This machine has quite a few meter valves and volume rods that come from several different directions and are interlocked. If you are not going to disassemble, I would pull the front cover and change the felt in the oil pump. I would also verify that there is oil being distributed everywhere it should which may not be the case given the age of the meter valves.

I will have pictures of all this in my post.
 

binzer

Plastic
Joined
Apr 25, 2022
The oil you see after you moved it would be from the headstock. There is a gear box on the back of the headstock that holds the single-tooth clutch for the feed. This gear box drains through a tube at the bottom back into the headstock. Where it drains into the headstock is somewhat open. If you allow the tailstock end to be elevated high enough, it will just run out.

This is a relief - when they lifted it, the headstock would have definitely tilted down. It was weird seeing all the gear oil and that concerned me, although what you are saying makes sense.

As far as fluids, I use Mobil heavy medium ISO 68 in the headstock. I use Schaeffer molly lube 160 ISO 68 in the apron and feed gear box.

Thank you, I will look up the available of these in Canada or hopefully reasonable substitutes

I would also highly recommend disassembly of the apron and saddle. This machine has quite a few meter valves and volume rods that come from several different directions and are interlocked. If you are not going to disassemble, I would pull the front cover and change the felt in the oil pump. I would also verify that there is oil being distributed everywhere it should which may not be the case given the age of the meter valves.

I will have pictures of all this in my post.

Very interesting! I will do that as well, these are great tips and I wouldn't have thought of that. I will also post some pictures of my progress.

Very big help!
 

binzer

Plastic
Joined
Apr 25, 2022
I just started opening the cases up to clean out for new oils. Here are some of the pictures so far. I actually think it's better than it looks and definitely understanding where all the spilt oil came from. Unfortunately have found a few missing and broken bolts, to fix and replace. Nothing too serious though.
 

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binzer

Plastic
Joined
Apr 25, 2022
Congratulations on your Pratt & Whitney. They are an amazingly well-made and smooth machine.

The end of the feedbox that you are pointing to is a little different from my 12C’s which is a later model but still reasonably close. Inside that end of the feedbox is the gearing for the ABC lever and the thread and feed gears. There is also a piston oil pump that works off a fork that is connected to the clutch rod. Every time you engage the clutch, it provides a shot of oil to a manifold located under the top tray casting. The whole change gear box is not too complicated to remove or to disassemble. Be aware that Pratt & Whitney really loves taper pins.

The apron is a little different story and is the most complicated apron I have yet worked on – more so than the 10EE or Rivett 1020S. But it is beautifully made. I think I will start another thread on my 12C as I have quite a few restoration pictures which might be helpful to you if you decide to work on yours.
Hey tailstock4. I have been setting up and testing the lathe and everything seems to be not bad so far, although I was just testing the power feed tonight and it seems weak in forward (apron moving toward spindle), I am guessing this runs off a clutch, reverse seems to be much stronger. I looked through your pics for some clues but didn't see anything. After your experience would you know anything about this? Also looking at your restoration, it is hard not to drool. Amazing job!
 

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
Hey tailstock4. I have been setting up and testing the lathe and everything seems to be not bad so far, although I was just testing the power feed tonight and it seems weak in forward (apron moving toward spindle), I am guessing this runs off a clutch, reverse seems to be much stronger. I looked through your pics for some clues but didn't see anything. After your experience would you know anything about this? Also looking at your restoration, it is hard not to drool. Amazing job!
Manual on parts can be emailed if you don't have it yet. Or you could look on Vintage Machinery for same. As far as "weak" both left and right FEEDS are handled by the same cast iron cone clutch on the left. What would be differing are the pair of little taper pinion gears on the feed rod. The most used one can be more "worn out".

Here is the VM link


have fun

The OTHER systems involved could also contribute to "weak" and this is the lead screw reverse and its gearing in the left end of head stock / gear case. This uses single tooth clutches which can get "hammered" over the years
 
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binzer

Plastic
Joined
Apr 25, 2022
Thank you! What I meant by weak was that I can stop it with my hand. The other way now so much, but as for the thread it seems fine. Going to check again tonight. We have a newborn so my time checking this thing out has been limited. So assuming it is the clutch, is there any option to repair since I’m pretty sure there are no parts available for this thing anymore. I looked over the parts manual last night after posting and I was wondering if anyone has had this issue or any pics of the clutch assembly a part. I think yourself and tailstock are the only people on the internet that I have found with such extensive knowledge about this lathe. Really appreciate how helpful you both have been.
 

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
Thank you! What I meant by weak was that I can stop it with my hand. The other way now so much, but as for the thread it seems fine. Going to check again tonight. We have a newborn so my time checking this thing out has been limited. So assuming it is the clutch, is there any option to repair since I’m pretty sure there are no parts available for this thing anymore. I looked over the parts manual last night after posting and I was wondering if anyone has had this issue or any pics of the clutch assembly a part. I think yourself and tailstock are the only people on the internet that I have found with such extensive knowledge about this lathe. Really appreciate how helpful you both have been.
Reading the first line I'd guess you no longer have the single tooth on either of the pair of clutches. What you can make out in the scan is the "cone clutch synchromesh" taper parts which would be reasonable to assume what you could stop with your hand.

These are Lead Screw Reverse parts but would equally effect feeds
 

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binzer

Plastic
Joined
Apr 25, 2022
Yeah that sound unfortunate. Hmm do you think that is it even worth getting into? Ever heard of anyone with the same issue and repairing it? I read that the headstock needs to be removed to break that down. I’m thinking about my options. I like everything lease about the lathe, but I have been on a mission looking for the bad news. I think I just found it.
 

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
Yeah that sound unfortunate. Hmm do you think that is it even worth getting into? Ever heard of anyone with the same issue and repairing it? I read that the headstock needs to be removed to break that down. I’m thinking about my options. I like everything lease about the lathe, but I have been on a mission looking for the bad news. I think I just found it.
I do know the gear box those pieces are in un-bolts from left end of head stock - so good chance you do not have to have head stock off
 

binzer

Plastic
Joined
Apr 25, 2022
Il investigate further. I’m game for trying to make this work. Moving a 4000lb lathe isn’t a great time. Lol
 

tailstock4

Aluminum
Joined
Mar 3, 2013
Location
Oklahoma, USA
Binzer...
You said when hold the apron handwheel, it will stop the apron. When you do this, does it also stop the feed rod? If yes, I would suspect the feed clutch and single point dog tooth as johnoder has said. If the feed rod continues to move but the handwheel does not, your problem would be in the apron. There is a procedure for adjusting those feed clutches.

You can check the dog tooth clutch by stopping the machine, putting the spindle in neutral, putting the feed reversal in neutral (which releases the two synchronizing clutches, but the dog clutch is still engaged.) Next both clutches on the apron should be in their neutral or off position.

Grab the feed rod with both hands and twist it forward and reverse. You should hear it hit the clutch dog. It is possible for the dog to be broken or gone and still have some feed power through the synchronizing clutches. The longitudinal feed may have less power because it has more wear on that clutch.

As far as getting into it, on the C models you can just open up the back of that ratio box. The clutches are at the top. There is an adjustment, but this only adjusts the shifting fork. As far as not being worth it, I don’t think I would give up just yet. Let’s confirm that’s actually what’s happening as there are other possibilities too.
 
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binzer

Plastic
Joined
Apr 25, 2022
Binzer...
You said when hold the apron handwheel, it will stop the apron. When you do this, does it also stop the feed rod? If yes, I would suspect the feed clutch and single point dog tooth as johnoder has said. If the feed rod continues to move but the handwheel does not, your problem would be in the apron. There is a procedure for adjusting those feed clutches.

You can check the dog tooth clutch by stopping the machine, putting the spindle in neutral, putting the feed reversal in neutral (which releases the two synchronizing clutches, but the dog clutch is still engaged.) Next both clutches on the apron should be in their neutral or off position.

Grab the feed rod with both hands and twist it forward and reverse. You should hear it hit the clutch dog. It is possible for the dog to be broken or gone and still have some feed power through the synchronizing clutches. The longitudinal feed may have less power because it has more wear on that clutch.

As far as getting into it, on the C models you can just open up the back of that ratio box. The clutches are at the top. There is an adjustment, but this only adjusts the shifting fork. As far as not being worth it, I don’t think I would give up just yet. Let’s confirm that’s actually what’s happening as there are other possibilities too.
Thank you tailstock4. When I grab either the feed rod or the thread rod (when selected) I can stop the movement of them with my hand, although in reverse I can not. Just tested them both again. The apron seems to be functioning correctly as it does move longitudinal on reverse and also moves carriage. Of course no forward unless I help it.

In the attached pics, I have put both the spindle and feed in neutral. When I turn the feed rod with my hand back and forth the end gears turn. I feel like I can hear it hit the clutch dog before turning the gears. Thanks guys for the help and let me know if im missing any important info. I'm new to this and learning. Without completely understanding how the clutch system is set up from looking at the parts pic. It does feel like a clutch issue. If so, are they parts that I can make of have made? Also let me know what else I can test prior to tearing down the ratio box.
 

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