# Yet another PM-1236



## tino_ale (Sep 14, 2014)

Hi guys,

After a long long wait I finally got my PM-1236 delivered here in France near Paris. I can't tell you how excited I am as I've been willing to jump into the metal lathe world for almost a decade now. I got hooked by aluminium then titanium flashlights in 2005 thanks to http://www.candlepowerforums.com/vb/forum.php.
Long story short, never had the place for a metal lathe until a year ago, when I ordered the PM-1236, and the delivery of my machine tool that long.

The machine crate arrived safe and sound but it was on a stack of two pallets and those pallets were almost completely crushed. In the delivery truck I discovered a machine tilting maybe 20 degrees to one side  

After it made the trip to my garage (an interesting moment I must say) I used a car jack and some wood lumber to lift one side at the time, place a support underneath each end, and remove the pallets entirely. What I removed was pieces of crushed wood, barely recognizable as a pallet.

Here is how it looks now :







I removed the tooling and the tailstock to get a clear view on the machine itself, as well as the 3 jaws chuck (came out quite easily with just gentle tapping with a wood mallet).

Now there is no obvious damage to the lathe but there are a few rust spot both on the bed ways and on the spindle nose :










What do you guys recommend to make them go away ?
I would rather use a chemical solution than scrubing

Now I need to rent an engine hoist and install the lathe at it's definite location. How much room do you suggest I leave from the wall at the back ?

Overall aside from an obvious lack of attention to details (paint job, paint mist on several spots, crude junk in place you would not expect, bent dial lever...) the machine seems sound. After some good cleaning and maybe refinishing of some parts I'm confident it will be a good machine for me.

Thanks for your advise
Cheers


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## wrmiller (Sep 14, 2014)

Congratulations! There are several people here that own these, and I am keeping it in mind for when I'm ready for a bigger lathe.

The best source for specific info on this lathe would be Ray C. He is the local (on this board) rep for Precision Mathews and a good guy.

Have fun with that thing,
Bill


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## darkzero (Sep 14, 2014)

Congrats, good to see you finally got it!

For chemical you can use a rust/gun blue remover but often it will make the shiny surface look dull.


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## wrmiller (Sep 16, 2014)

To the OP: Looks like your thread got hijacked. Did you find something chemical based to remove the rust? Maybe navel jelly?

Bill


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## darkzero (Sep 17, 2014)

wrmiller19 said:


> To the OP: Looks like your thread got hijacked.
> 
> Bill



Yeah, a bit OT & not fair to the OP, I have moved those posts into their own seperate thread. Please continue the discussion related to those posts here CM 12x36.


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## tino_ale (Sep 17, 2014)

wrmiller19 said:


> To the OP: Looks like your thread got hijacked. Did you find something chemical based to remove the rust? Maybe navel jelly?
> 
> Bill



I'm probably going to give a try either to phosphoric acid (would 15% be appropriate ?) or if I can't source it locally, just go with the finest household scotchbrite sponge I can find along with WD40.


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## wrmiller (Sep 17, 2014)

I personally would go with the scotchbrite and WD40. You won't hurt those ways unless you really scrub with something fairly aggressive.

Bill


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## John Hasler (Sep 17, 2014)

tino_ale said:


> I'm probably going to give a try either to phosphoric acid (would 15% be appropriate ?) or if I can't source it locally, just go with the finest household scotchbrite sponge I can find along with WD40.



Phosphoric acid can be had from a farm store labeled milkstone remover.  Diluted it about 2:1. and leave the part in it overnight.  You'll have to polish off the gray finish if you want the chuck to look bright and shiny, though.  I wouldn't: the gray phosphoric acid finish is rust resistant.


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## tino_ale (Oct 9, 2014)

Ok, some report after a TIR measurement session.

First, the spindle nose.
1. At the "nose" taper OD, TIR measures 0.00071"
2. At spindle OD, TIR 0.00051"
3. At inner taper, TIR 0.00035"

Nose and OD measurements were not the easiest as the ground surface isn't that smooth, the dial indicator was jumping around, I had to turn the spindle really slow.
The inner taper was smoother, and as you can see, the best TIR of the spindle.

I then proceeded with the 3 jaw chuck. I first wanted to try all 3 cam lock positions, but couldn't as only one position fits. I have tried unscrewing the studs a bit as suggested but it didn't change anything. I have tried relocating the studs but it didn't make a difference either. My guess is the back plate is the culpit.

So what I did is try all 3 positions of the chuck on the backplate instead. A slower process but probably worth it :
position 1 : chuck OD TIR : 0.00078
position 2 : TIR 0.00059
position 3 : TIR 0.0011

I chose position 2 and marked the backplate and chuck OD for future reference.

Finally I moved onto the actual chuck TIR.
I used a US made solid carbide spotting drill, it is ground to a polish finish and my micrometer can't pick a discrepency in roundness.
I have tried all 3 positions of the jaws on the chuck, and for each, tightening with all 3 tightening bolts. That's 9 different TIR.
At first I didn't think the bolt would make a difference but it did !
- As much as twice the TIR on the bolt choice alone.
- As much as FOUR times on the jaws position only.
9 possibilities ranged from TIR 0.00078 up to 0.0039

So I end up with a TIR just shy of 0.0008" (close to the chuck, and using a 3/8" drill). How good is that ?


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## MarioM (Oct 9, 2014)

Nice machine....congrats!.  I would agree with Bill.....scotchbrite and WD40.


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## tmarks11 (Oct 10, 2014)

MarioM said:


> scotchbrite and WD40.


++1
Remember, this is a working machine, not a car.  Doesn't need a beautiful coat of wax and polish.  You will get other stains on the ways as time goes on.

If you do want to use a chemical rust remover, than you can try Boeshield Rustfree.  It works great, but will leave darkened spots where the rust use to be. I have used it on the cast iron top of a table saw.  

http://boeshield.com/catalog/


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## gregg (Oct 10, 2014)

http://www.frontiermetalcleaner.com/

You can find this at gun stores. works very well . Pulls rust right out pores of little pits. I should say cuts it out. Use it and cannot live with out it.
Gregg


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## coolidge (Oct 10, 2014)

You want to remove rust...EVAPORUST!!! Will not harm paint, plastic, other metals, non-toxic, no petroleum's, no acids, you can re-use multiple times and pour the stuff down the drain when finished its that mild but it will flat out remove every spec of rust.


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## tino_ale (Oct 20, 2014)

Hey guys,

I have a question about the gear change.
There is the 24T, 48T gears, then the two sided 120/127T gear. Then for imperial threading, some more Z gears.

The manual doesn't say how you change the gears, that may be obvious, but it isn't to me.

I've removed the screws and found that :
- both my tiny gear at the top position (spindle gearbox out shaft) and bottom position (threading gearbox input shaft) are stuck. How am I supposed to pull them out ?
- the double sided large gear is easy to remove, but the collar on which the bearings sit, how am I supposed to reverse it ? The bearings seem press fit onto it, as far as I can tell

Do I need to invest in some sort of gear extractor for this ? Even if I do, using it every time I need to change gears doesn't sound too convenient, or I am missing something ?

Thanks for your time


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## darkzero (Oct 20, 2014)

Just my 24T gear was tight. Used a puller to get it off, threw it in the lathe & skimmed the bore. The double middle gear set does not need to be flipped, the gear under it is what gets moved, either meshes with the inner or outer gear by changing the placement of the spacer.


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## tino_ale (Oct 21, 2014)

darkzero said:


> Just my 24T gear was tight. Used a puller to get it off, threw it in the lathe & skimmed the bore. The double middle gear set does not need to be flipped, the gear under it is what gets moved, either meshes with the inner or outer gear by changing the placement of the spacer.


Thanks for the feedback. I need to get my hands on a puller then...

About the double middle gear : I have a metric machine and things might be different for my gears setting.

For example (telling you this from memory) :
setting one :
top gear : 24T
middle gear : 120T
lower gear : 48T

setting two :
top gear : 48T
middle gear : 127T
lower gear : 24T

*In both cas the top and bottom gears mesh to the same large gear (either 120T or 127T).*

I can see how you get the lower gear to mesh with either the 120 or 127T by just flipping the spacer on either side of the lower gear.

What I fail to see is how you get the top gear to mesh with either 120 or 127T without flipping that large double gear. There is no room for a spacer at the top output shaft. If that top gear position is fixed, then, the big double gear has to be flipped, or am I missing something


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## Rbeckett (Oct 21, 2014)

I too would use some scotch brite and wd-40, then coat it with way oil to keep it from rusting again.

Bob


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## GA Gyro (Oct 21, 2014)

tino_ale said:


> Thanks for the feedback. I need to get my hands on a puller then...
> 
> About the double middle gear : I have a metric machine and things might be different for my gears setting.
> 
> ...



Not sure if this helps...

Some information in the latter posts of this thread may help:

http://www.hobby-machinist.com/showthread.php/26119-Recieved-the-PM1236-metric-to-imperial-kit-today

Seems there were some 1236's shipped with some parts metric and some imperial/SAE.  I have not studied the whole issue... however the thread noted may be of some help to understand the theory behind the gear drives.  

Hope this helps.

BTW: When you figure it out... please post the answers!  Be interesting to understand this from both sides... that is: metric and imperial/SAE.

GA


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## tino_ale (Oct 21, 2014)

Thanks for the pointer.

So it seems to confirm that flipping the large double gear involves a flip of the spacer and bearing assembly.

The ones that have retrofitted their PM1236 back to imperial had to do it only once, that is one thing, but on the 2 metric configurations I noted in my previous post, the small upper and lower gear have to engage the same side of the double sided gear at the same time.

I can't possibly reverse the large gear spacer each and everytime I need to change my range of feeds/threads.

We are missing something. I wonder if I could reverse the large double gear without swaping the press-fit spacer around. But then the gear will rub against the mesh adjustment assy. Maybe that is what the copper washer that I found in the toolbox is for ???


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## darkzero (Oct 21, 2014)

tino_ale said:


> I can see how you get the lower gear to mesh with either the 120 or 127T by just flipping the spacer on either side of the lower gear.
> 
> What I fail to see is how you get the top gear to mesh with either 120 or 127T without flipping that large double gear. There is no room for a spacer at the top output shaft. If that top gear position is fixed, then, the big double gear has to be flipped, or am I missing something



Look at your chart closely & you will see. In your case you will see that for metric the chart is only showing 1 middle gear & for imperial it shows the double middle gear. Same for us with imperial machines except that we need to use the double gear for metric & is why your double gear set is flipped from ours. It does not ever need to be flipped (except for those who are converting from metric to imperial)

The top gear always meshes with the inner 120T gear (in your case having a metric machine) & the bottom gear would mesh with the the 120T for metric threads. For imperial the top gear meshes with the 120T & the bottom gear to the 127T.


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## tino_ale (Oct 21, 2014)

Ok here is my table (metric machine) :





and





Right now the machine is in configuration where top = 24, middle = 120, bottom = 48 and both top and bottom mesh on the 120 side.

I just can't see how I'm supposed to switch to the second metric configuration without flipping over the middle gear.
To me the drawing is clear that both mesh on the 127T side of the middle gear, with the 48 up and the 24 down.
Look at the configuration to cut imperial threads, in that particular case yes it is very clear that both sides of the middle gear are used at the same time.

Do I make sense ?


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## darkzero (Oct 21, 2014)

Now I see your confusion. Your chart is much different, not consistent with my chart for metric vs. imperial. I'm very familiar with how my lathe works so I doubt yours would operate much different. Looking at your chart makes me think the gear configuration diagrams are mislabeled. How yours is labeled for the middle gear for metric does not make any sense according to the top & bottom gears. You should only need to use the 120T for metric & the 120T to 127T for imperial just as it is for mine vise versa.

I think your best bet is to contact Matt. I can't think of anyone here that has the PM1236 in metric as ordered (only the guys who received metric by mistake) that could give you advise.

I still think what I said is how it should be used despite what your chart diagram for the gears say. For instance, lets look at your chart for cutting a .4mm pitch thread B4, MI, 24T-120T-48T. Focus only on the B4 column, now when you switch to MII it doubles, hence the .8mm pitch. Now when you switch the top and bottom gears to 48T (on top), 120T, 24T (on bottom) it doubles again giving you 1.6 & 3.2. But for 1.6 & 3.2 it says to use the 127T instead of 120T. I think that is wrong. If you did use tbe 127T like it says, that would give you a totally different thread pitch rather than doubling the previous thread. Look at my chart below & for imperial which my lathe is configured for vs yours metric, it does not specify what the middle gear tooth is meaning the  inner gear of the double set would be used, make sense?

So do this, try cutting a 1.6mm pitch thread. B4, MI, 48T on top, but use 120T instead of what the chart says (using 127T), then 24T on bottom meshing to the 120T. I bet it will cut a 1.6mm thread. Then switch to MII & it should cut a 3.2 thread. Please do that & let us know the results.


(Sorry for the bad pics, it's what I had on hand)


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## tino_ale (Oct 22, 2014)

Thanks for taking the time, thank you !

Looking at your chart I also notice that your feed tables are different for the metric and imperial section : you are using both sides of the 120/127T gear to achieve metric feed. Which makes sense. Your imperial values are a bit different than mine.
On my chart, the settings are the same for both metric and imperial feed values, and the imperial values seem to be simple rounded value in inches of the metric values.
It's just feed values, not worried about that.

I will wait for my gear extractor that I have ordered to arrive (my gears are stuck...) and will definetely try what you advise.
I must admit I did not imagine the chart could be wrong. But that would be the best imaginable outcome.


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## tino_ale (Oct 22, 2014)

OK I haven't tried it yet but gave more thoughts to it.

What Darkzero said makes perfect sense.
B4 column, speed I, the pitch is x4 from the first to second gear configuration.
KEEPING THE SAME MIDDLE GEAR, going from 24T to 48T gear at the top would double the pitch.
On top of that, going from 48T to 24T on the bottom gear would double that again.
in B4 column, we go from 0.4 to 1.6 pitch, that is x4, makes PERFECT SENSE.

BRAVO for the heads up. I did not think outside the box, I feel dumb !!
 I still can't believe they actually printed a wrong table!

Problem solved. Will check for good measure but I know it's right.


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## darkzero (Oct 22, 2014)

Dumb, not at all. Things are often overlooked or not thought of when you are focusing at the "issue" at hand. We've all been there. That's what these forums are for, to get other opinions. Again, I'm sure the gear chart diagrams for your lathe is not right, but once you confirm if it's right or wrong you can move forward.


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## srbh (Oct 27, 2014)

Room at the back. I added 50cm but later found on the internet that more was recommended. The more the better, especially if you need access to shelves etc on the wall. I have cut a new hole in the tailstock end cabinet to access the coolant pump from the front.


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## tino_ale (Nov 3, 2014)

Hi guys,
Investigating those motor issues (see other thread), I found an oil leak at the back of the pulley arbor.
Disassembled the whole gears section.
Cleaned every single part.
Blasted the gears and parts (I didn't like the way they looked)
Fixed the leak and reassembled.

I don't think my gear assy will ever look as neat again !













I gave a shot at machining brass. Alloy is free cutting brass (alloy 360).
What a blast ! super easy to machine, nice little chips, finishes really well, shiny and sharp look.
I loved it !
Made a replacement "knob". Much less play in it now. If I like the way it looks after some tarnish, I'll do the same for all the levers/commands of my lathe. Kind of a cool way to identify where the functional parts are.
The part is turned, blasted, then turned again to get the shiny rings/bevels.


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## drs23 (Nov 3, 2014)

Nice job, looks good. Keep us posted.


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## wrmiller (Nov 3, 2014)

You're as bad as I am, in that you no sooner get a new machine and you have to make a modification to it to 'make it yours'. I love it.  :thumbsup:


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## tino_ale (Nov 22, 2014)

First project that kinda want to show off... a brass Top!
Got it spinning for 6 min on a glass plate


















Got a cheap knurler off eBay, but I'm amazed how well it works on brass


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## coolidge (Nov 22, 2014)

Love the brass replacement knob, I can't stand the 'feel' of the supposed satin chrome finish on the knobs and dials. I know its for anti-corrosion purposes but I hate touching it. It should feel smooth and polished like my 44. mag Ruger Super Redhawk imo!

I like the brass top, can you tell us more about how you made it? I have a bunch of 360 stock, one of my favorite metals but damn expensive.


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## tino_ale (Nov 23, 2014)

About the Top, I did not do anything very specific or odd to machine it.

Just chucked the stock and made the whole part before parting it out. I eyeball everything, I had no plan and no measurements whatsoever.
I would be actually embarrassed if I had to make a second one exactly the same.

Some more brass work :


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## GA Gyro (Nov 23, 2014)

tino_ale said:


> About the Top, I did not do anything very specific or odd to machine it.
> 
> Just chucked the stock and made the whole part before parting it out. I eyeball everything, I had no plan and no measurements whatsoever.
> I would be actually embarrassed if I had to make a second one exactly the same.
> ...




An artist in a machine shop....

Your posts are gonna be FUN!

Please keep them coming...


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## tino_ale (Nov 24, 2014)

Which one do you prefer ?

Stock ?





Or home made

























Eventually, all the controls knobs will be replaced in brass. Color will indicate the lever holds a function.
Totally unnecessary but since I'm a beginner, it is good practice!


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