# Pm-1340gt Crash -- Now What?



## Coug67 (Apr 25, 2015)

Hi all.

I'm a little sick to my stomach writing this.  I just got my 1340GT a couple of weeks ago and have really been enjoying it.  This afternoon I was parting off some aluminum (with lots of oil) close to the chuck, when the tool stuck and ripped the piece right out of the jaws, which cause the parting tool to kick sideways into the chuck and quickly stop the works.  The idea that I may have severely damaged my brand new toy felt like a kick in the...well, you know.

I hit the e-stop as quick as I could, but by that time the damage is pretty much done.  I was running extremely slow (maybe 60-70 RPM), so I think I managed to avoid any major damage.  I disassembled the work, spun the chuck by hand, then jogged it for a few rounds.  When I started the motor back up, there was a noticeable tick.  I stopped again, pulled the cover off the gearbox, and slowly rotated everything by hand to take a look at the gear teeth.  Nothing looks perceptibly damaged, and to be honest the tick may have been there before but I had just ignored it.  There were no chipped or bent teeth (that I could tell).  The spline shafts don't appear damaged.  The shift palls look good.  Everything moves smoothly.  The tick only happens in low gear.  It doesn't matter if it is L1, L2, or L3, the sound is the same.  The tick doesn't exist at all in high gear.  That lead me to believe I may have damaged the final low input gear that drives the main spindle.  When I jog the machine with the cover off, I can just barely hear it, and it seems to correspond to the rotation of the low input gear.

What would you guys do?  I'm tempted to just run it for a while without a load and let the gears wear back together.  It's not a grinding sound, just a light tick.  I could try to disassemble the gear train and do a deep inspection, but that proposition scares me a little.  I would expect a person needs a pretty decent machine shop to tackle a job like that.  Thoughts?

-- Jason


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## coolidge (Apr 25, 2015)

The good news is you didn't get bashed in the face. Personally I'd start with the spindle and a test indicator to make sure its still turning true and not knocked out of whack. If it turns true, smooth, no binding and nothing is broken via a visual inspection I'd run it a while and keep an eye on it.


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## brino (Apr 25, 2015)

Hi Jason,

5h!T happens. It wasn't intentional. So let yourself off the hook.
Parting-off is always one of my most nervous times.
It sounds like no major damage (to you or the equipment!) occurred; so chalk it up to a great learning experience.
Take this time to figure out why it occurred and how to stop it happening again.

My lathe is flat-belt driven and I tend to loosen the belt just a little for parting, if anything jams it slips and provides a "fuse" in the circuit.

There are some great general suggestions for  parting here:
http://www.hobby-machinist.com/threads/parting-for-idiots.32938/

Yep check the lathe all over, the spindle, the chuck, the tool post, all gears, etc.

Is it possible the tick could be from a sheared-off key under one of the gears (I'm not familiar with your machine). I have just seen one in the gear-box of a horizontal band saw. 
There it looked like the gear had enough friction on the shaft/sheared key to transmit some power and turn the output shaft until the blade touched the work, then it would just spin.
Although in this case the clicking happened only under load as the key way in the gear slid over the rough sheared key.

Pick up, dust off, and back in the saddle.

-brino


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## seasicksteve (Apr 25, 2015)

When it bound the motor belt most likely started to slip. I always make sure everything is locked down when parting things can get ugly fast. I be inclined to agree with the above posts, if it checks out OK id run it the tick will most likely quite down with some time. Nice looking cougar in your avatar


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## Coug67 (Apr 25, 2015)

I haven't put a dial on it yet.  I'm headed back out to the garage to do that now.  I'm also going to change out the headstock oil.  It still has the original oil, and there is a lot of break-in particulate (floaties) making it difficult to see everything.  I hadn't thought about sheared keys, but I don't think that's a player here.  The gears ride on large splined shafts.  Good idea though.  Turning it by hand, I can feel a very slight rough spot as it passes one or two of the input teeth.  I've shined a bright light on the suspect teeth, and I can't see any gouges or rough spots.  I think I'm going to do like you guys said, keep an eye on it for a while and hope that it quiets down.  I need to talk to Matt at PM this week anyway.  Might ask him his thoughts on it.  Thanks for the replies.


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## Coug67 (Apr 25, 2015)

seasicksteve said:


> Nice looking cougar in your avatar



Thanks Steve!  I wish I could claim that one's mine.  I have one that looks nearly identical, but it's in pieces right now.  I've had it since high school.  I had to choose between spending the money on the lathe or finishing the restore on my car.  Guess we know how that turned out! Someday.....


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## Coug67 (Apr 25, 2015)

A picture inside the gearbox.  The cluster in the top right is the final high/low input to the spindle.  You can see some wear/pressure marks on the smaller (low) gear, but the teeth are smooth.  I checked the spindle runout, and it seems to be within a few tenths.  I think I'm safe, just got a good scare.  Like Brino said, "5h!T happens.... so chalk it up to a great learning experience."


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## rgray (Apr 26, 2015)

Feel for a notch worn in the drive belts. If the spindle stopped and the motor was going it takes very little time for the motor drive pulley to make a divot in the sides of the belts. Might be visible but might be hard to see. Rotating till you feel the spot and then checking that spot on the drive belts (part that is then on the motor drive pulley) you might find a wear spot in the sides of the belts that makes the belt jump once per revolution when it passes the drive pulley.

Parting can be intimidating, but to slow sfpm can be a bigger problem than to fast as far as the grabbing.


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## jeff_g1137 (Apr 26, 2015)

Hi
I hate that feeling


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## Doubleeboy (Apr 26, 2015)

Sorry for your trouble with lathe.  Reading the start of your post, you mentioned aluminum , parting and real slow.   Assuming you are likely parting something under 2" in diameter, your speed is way too slow.  I part 6011 T6 at 400 rpms + for one inch stock.  Parting blade has some side relief, dead nuts square and on center.  Too slow gives it a chance to bite in and grab, also power feed and make that feed a little quick as opposed to slow.  

michael


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## wrmiller (Apr 26, 2015)

rgray said:


> Feel for a notch worn in the drive belts. If the spindle stopped and the motor was going it takes very little time for the motor drive pulley to make a divot in the sides of the belts. Might be visible but might be hard to see. Rotating till you feel the spot and then checking that spot on the drive belts (part that is then on the motor drive pulley) you might find a wear spot in the sides of the belts that makes the belt jump once per revolution when it passes the drive pulley.
> 
> Parting can be intimidating, but to slow sfpm can be a bigger problem than to fast as far as the grabbing.



Yea, I won't go into how I figured THAT out...


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## Reeltor (Apr 26, 2015)

I'm glad that nothing appears to be damaged.  It's an instant heart in your throat when something like that happens.

As an aside, what is the break-in procedure on the lathe?  Are you supposed to drain the oil, fill with Kerosene and run for 5 minutes then drain and refill with the recommended oil?  This is the manufacturers' recommended procedure for the old mill (Van Norman) and lathe (Monarch) that I have.  The kero will flush out any manufacturing swarf.  What does PM ask you to do?

Again, glad you weren't hurt and the lathe is OK

reeltor.


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## brino (Apr 26, 2015)

Coug67 said:


> I had to choose between spending the money on the lathe or finishing the restore on my car.



Jason, Look at the good news: you crashed the lathe not the car!!! 

-brino


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## Coug67 (Apr 26, 2015)

Reeltor -- I asked Matt at PM about break-in, and he said I might take it a little lighter on the cuts for a while, but no real break-in procedure was needed.  The oil I took out was pretty black.  I drained it last night, wiped out all the little bits of glitter with a rag, and put in some fresh.  I'll run it for another couple of weeks and see if any more metal shows up.


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## Coug67 (Apr 26, 2015)

Doubleeboy said:


> feed a little quick as opposed to slow.



Michael, I appreciate the advice.  My stock was about 2.75" with a 1.625" center bore.  I'm still REALLY new on all this.  I've been reading and watching all the videos I can.  I was very careful to square up the parting tool to the end of the stock.  Sounds like a little more aggressive feed and speed may be the trick.


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## Coug67 (Apr 26, 2015)

rgray said:


> Feel for a notch worn in the drive belts. If the spindle stopped and the motor was going it takes very little time for the motor drive pulley to make a divot in the sides of the belts. Might be visible but might be hard to see. Rotating till you feel the spot and then checking that spot on the drive belts (part that is then on the motor drive pulley) you might find a wear spot in the sides of the belts that makes the belt jump once per revolution when it passes the drive pulley.
> 
> Parting can be intimidating, but to slow sfpm can be a bigger problem than to fast as far as the grabbing.



I just happen to have a new belt.  The reviews I'd read said the stock belt was pretty much junk, so I picked up a new belt just in case.  I'll try swapping it out and see if it makes a difference.


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## 18w (Apr 26, 2015)

Coug67 said:


> Michael, I appreciate the advice.  My stock was about 2.75" with a 1.625" center bore.  I'm still REALLY new on all this.  I've been reading and watching all the videos I can.  I was very careful to square up the parting tool to the end of the stock.  Sounds like a little more aggressive feed and speed may be the trick.



And don't spare the lubricant! WD 40 works well on aluminum as do other products. I like Relton A-9 for parting aluminum and use WD for milling. 

Darrell


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## coolidge (Apr 26, 2015)

Coug67 said:


> I just happen to have a new belt.  The reviews I'd read said the stock belt was pretty much junk, so I picked up a new belt just in case.  I'll try swapping it out and see if it makes a difference.



Have you tried a link belt? You can buy link belts at Harbor Freight, note they are made in Europe not China. I measured vibration on my G4003G with a test indicator and there was a considerable reduction in vibration with the link belt vs BOTH the China factory belt AND a Made in USA NAPA variable cog belt.


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## Doubleeboy (Apr 26, 2015)

Coug67,   If you are new to machining you may want to limit your parting adventures in stock larger than 1.5 inches for a while, get the feel of it, try slightly different grinds on your parting tool if HSS.  I say this guardedly lest some newbie takes it as recommendation to part with tool off center, but...... sometimes dropping the tool just a little, I mean a few thousandths, not a lot, can help the tool start cutting quicker and not rub, if your feed is half decent say .010 or quicker you start to cut as soon as your tool touches workpiece, with a quick feed you motor right thru .  When parting I always have my hand on crossfeed lever.  If it does not start cutting nicely , starts squealing, or seems to be fighting the tool, I stop feeding , back out, turn spindle off and figure out what was wrong.     I frequently dismount work from lathe, take it to saw and cut off then return to lathe for finish facing cut, to avoid the drama of parting large work.

You can also part half way thru, back out , move over a few thou and go at it again, now giving your tool some side clearance for chips to easily exit the cut.


michael


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## coolidge (Apr 26, 2015)

You can also just hack it off on the band saw then face the cut edge, most times I have to face a part off anyway.


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## tomh (Apr 27, 2015)

cougar
You most likely did more damage to your shorts than the lathe.  So don't be to hard on yourself.   On most lathes that I have seen & repaired from crashes, the damage was to the compound, often in the form of cracks or snapped off completely and very rarely to the spindle or the gears. 
Parting  can be very tough on a lathe and your nerves, so I would follow the advise above and remove the part  and cut off the wast on a saw  and then face to finish.
Tomh


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## barrydc1 (Apr 27, 2015)

You should put a 2" dia round 8" bar of aluminum in the chuck without tailstock suppport and make two "dumbells" or rims on it by turning out the area in between for about 6" and on the ends.  Then run a cut for diameter on each of the close and far rims and measure for as close as possible diameter and see if you displaced your headstock.  That happened to me after I crashed my ball turner into the spinning chuck.  There are lots of articles here on that kind of alignment test, and you really need to do that now or at least after you diagnose your tick!


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## JayBob (Apr 27, 2015)

My old chuck would make a ticking noise at slow speeds.  It took me a while, but I figured out it was the pinions for tightening/loosening the chuck.  They had a good amount of slop to them, and would click every time they came below center.  Wasn't noticeable at higher speeds, my guess, due to the centrifugal force present, keeping them still.


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## planeflyer21 (Apr 27, 2015)

JayBob said:


> My old chuck would make a ticking noise at slow speeds.  It took me a while, but I figured out it was the pinions for tightening/loosening the chuck.  They had a good amount of slop to them, and would click every time they came below center.  Wasn't noticeable at higher speeds, my guess, due to the centrifugal force present, keeping them still.



Interesting how ticking can be so many things.

On my Granite I was getting an annoying ticking...couldn't find it.  One day I heard a metallic "clink", shut it down and looked in the cabinet.  A key had worked itself loose on a pulley, due to a set screw slowly backing out.  Spent a few hours going over all the set screws with Loc-Tite and reset that one key.

Check various set screws, as well as the mentioned chuck.  I sprung one of those too once.


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## tmarks11 (Apr 27, 2015)

I am a BIG fan of carbide cut-off tools.  HSS works great for other applications, but the indexible carbide bits are great... especially because they are made with relief cut into them (cutting edge is wider than the support blade) so they don't bind.   The clamp-type are the best (has a physical bolt to hold them in place).

Here is what I use: Iscar Do-grip DGTR.  The shape of the supporting structure makes it more stable than a typical slender blade, so it won't chatter as badly.  It fits in a normal #1 or #2 QCTP holder.  You can find them relatively cheap on eBay ($50-60) for the tool holder.  It will part up to 1.4", beyond that I have to use hss blade.






http://www.iscar.com/eCatalog/Family.aspx?fnum=557&mapp=TG&app=52&GFSTYP=m


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## Coug67 (May 1, 2015)

I'm 99% sure it's the low input gear.  It only happens when that gear is engaged, and even then only on two teeth in particular.  I can just barely feel it when I rock back and forth while those teeth are meshed.  The rest of the rotation is butter smooth.   I can't see any visible damage to the teeth, but it wouldn't take much to distort them enough to where they didn't engage perfectly with the spindle gear.  I put a DTI on the chuck and runout seems ok.  The chuck has a slightly tight spot about halfway in when tightening the jaws.  The jaw alignment seems alright, but must have damaged the scroll when the piece got wedged out.  Was planning to replace it a little while down the road anyway.  Guess it'll just be a little sooner than I expected.

I have a carbide cutoff tool almost identical to that Iscar, but it wasn't deep enough to do the parting I needed.  I'm pretty sure I know where I messed up.  The quick change parting holder I have is slotted big enough to perfectly fit a 7/8" tall parting blade, but it puts the wedge clamp way forward on the  holder.  That allowed the back end to pivot and be kicked to the side when the tool grabbed a little.  Kicking to the side just made the tool grab harder.  Vicious circle until it kicked out far enough to get into the chuck.  I wasn't particularly happy with the way the parting blade fit in the holder, but (mostly due to inexperience) I assumed that was the way it was supposed to fit.  I should have gone with my original gut -- or at least asked someone.  If I use that particular holder again, I'll use a much narrower height blade that will allow the wedge to snug back closer to the center of the holder.  That should keep the front and back from being able to wiggle and throw off the alignment.  More than likely I just won't use it anymore.  I'm thinking very seriously of ordering the Arthur Warner indexable parting holder for grooving (cylinder fins and such).  For everything else, I'll use the bandsaw for cutoffs as suggested. 

As many have said, I'm just thankful I didn't get hurt.  There are about a thousand ways it could have gone that would have easily led to a trip to the hospital.  I don't want to be the old guy someday who has to explain why he's missing a finger or two.  Even  more, I don't want to be the one who does something so stupid that he doesn't get to be an old guy.  Lesson learned.  Look forward to tapping  into the experience here.  Just hope that next time it's for advice _before_ I do something stupid.

Jason


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## brav65 (May 1, 2015)

If all looks good turn up the music and get back to work. Just remember the first scratch is always the worst.  These are well built tools that are meant to be used.  I know that she is your baby, but don't beat yourself up. Take a look at some of the re-builds on here to see machines that have been abused yet can still be brought back to life.  Every mistake is an opportunity to learn what not to do.  I am just glad you did not get hurt. Those mistakes are the ones we truly remember.  I have a finger that is a little shorter than it should be from a mistake that I have never made again.  Smile and enjoy your new lathe!


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## GA Gyro (May 3, 2015)

brav65 said:


> If all looks good turn up the music and get back to work. Just remember the first scratch is always the worst.  These are well built tools that are meant to be used.  I know that she is your baby, but don't beat yourself up. Take a look at some of the re-builds on here to see machines that have been abused yet can still be brought back to life.  Every mistake is an opportunity to learn what not to do.  I am just glad you did not get hurt. Those mistakes are the ones we truly remember.  I have a finger that is a little shorter than it should be from a mistake that I have never made again.  Smile and enjoy your new lathe!



IMO this is good advise.  The first bump or scratch hurts the most... yet these are indeed well built machine tools which will perform well through their service life... even with a few bumps.  

Kinda like the first scratch on a new car... easy to fix, but hurts.


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