Pm-1340gt Crash -- Now What?

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
 
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!
 
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.
 
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.
Click to expand...

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.
 
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.

557.gif

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

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.
 
You must log in or register to reply here.
Back
Top