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[4]

PM-1236T arrives after difficult journey

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Meta Key

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My recently ordered PM-1236T is in place!

Here are the before and after pictures:
IMG_2537.jpg
IMG_2715.jpg

The poor thing had a difficult journey from Taiwan to Pittsburgh and, finally, to Montana.. The crate arrived with some obvious and some not yet obvious damage. It is a mystery to me how the freight companies can inflict such damage on something so well crated.
IMG_2590.jpg
IMG_2591.jpg

One of the steel straps holding the boxes on top of the crate was completely missing and the other was loose. When I took this box off the top look what I found on the underneath (protected side) of the box.
IMG_2597.jpg

Inside the damaged box was the right cabinet base. Quite a bit of missing paint from the door in particular and some from the cabinet itself.
IMG_2609.jpg

I decided to put the base together. I'll deal with the paint damage later. Here it is, in it's designated spot in the shop:
IMG_2611.jpg


Then, I started to disassemble the crate itself. Uh-Oh! Check out the upper edge of the back splash. More missing paint.
IMG_2622.jpg

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While removing the shrink wrap I also noticed that the pallet had made a hard landing at some point. That protruding bolt is very bent and the pallet is also "field modified". The view from the rear:
IMG_2641.jpg

IMG_2643.jpg

And, from the front:
IMG_2647.jpg

A quick check with PM and I'm assured they'll take care of anything that needs taking care of. That's really good news!

Assembly continues..
IMG_2669.jpg

OH, but wait! I'm in the middle of a kayaking adventure. This is Montana and summers are short so we have to take advantage of them. Work on the lathe will continue after more of this:
IMG_2673.jpg

OK, back from vacation. Everyone survived the ordeal! Now back to the PM-1236T project.

Here it is, all cleaned up and in place. Hard to tell if this picture or the prior is more beautiful!
IMG_2716.jpg

Wired it up to 240 VAC and plugged it in. The power light lights. The work light lights. Flipped the spindle motor control lever and N O T H I N G ....

OH NO!

Verified the 240 VAC (actually about 232 VAC at the outlet).
Verified the 240 VAC inside the electrical box on the back of the lathe.
Verified that I had all switches properly positioned at startup.
Still no joy.

So, I break out the schematic from the manual and start tracing things out. The first thing I notice is that the relay is NOT pulling in under any circumstances. OK, I pull the relay and connect 24 VDC to it's coil and it pulls in. So, the relay is OK. Then I connect a VOM to the relay socket coil contacts. No volts, under any circumstances. Hmmm...

The wiring box is pretty compact and I needed to label the cables so I could start to figure out what was going on. Or, more accurately, what was not going on..

I traced out the cables and printed up some labels to make my life easier.
IMG_2700.jpg

At about this point, the wife walks into the shop to see how things are going. She notices a lot of covers off the lathe, switch panel hanging out, and me with a VOM in hand and a discouraged look on my face. I get the raised eyebrow look of "five thousand dollars and it doesn't even work?!" but she says, "Maybe I'll check back later...." and leaves the area. Heh..

Looking at the schematic I thought the wiring through the motor control switches was the most likely candidate for failure so I removed wires 3 and 6 from the motor control cable and measured continuity when the spindle control lever was in the neutral position and an open circuit when in either forward or reverse mode. Which is proper. OK, that's not the problem.

Then, I thought the motor overload relay might be faulty. I measured continuity from wire 2 on the terminal block to pin 12 on the relay. Continuity, which went away when I pulled out the reset lever on the overload relay. OK, that's not the problem.

While tracing out where all the cables go I noticed that there was a cable going to an interlock of some sort mounted on the headstock. But, that's not on the schematic. I started tracing out the wiring to see where that interlock was in the circuit.
IMG_2699.jpg

Sure enough, the undocumented headstock mounted interlock is in the critical path -- if it's not actuated then the spindle motor will not run although the lights light up indicating you have power to the machine. I pulled the headstock cover off and examined the interlock itself and the metal actuator that is mounted to the cover. It looked good so I re-assembled the headstock cover. Still, no joy. I then started to slowly remove the headstock cover and was surprised to see that the actuator and the interlock don't line up and the actuator is sitting just above the interlock switch -- about 1/4" too high!

You can barely see the actuator through the crack between the headstock and the headstock cover while you're removing the cover but it's quite clearly visible. It should be inside the interlock and NOT visible. DOH!

A quick look at the actuator made me think maybe the installer had put it on downside up. I reversed it and that didn't help. Now the actuator was interfering with the switch mechanism and still not entering the slot to activate the interlock.

The interlock switch itself is screwed into tapped holes in the headstock and its position is not adjustable. The actuator is screwed into the headstock cover and not really adjustable either. Here's where the actuator is mounted inside the headstock cover.
IMG_2709.jpg

My current solution is to remove the actuator from it's mounting bracket and insert it into the interlock (thus, defeating the interlock) and replacing the headstock cover. I'm not sure I care about having an interlock here.. Must be an OSHA thing or something.

The good news is that now the spindle motor runs!!!

OH NO! After about a minute of run-time I see little bits of motor drive belt residue accumulating on the chip pan underneath the headstock. Well, I'll look into that this afternoon when I get back from running errands...

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Attachments

81husky

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#2
Your pallet and box looked a lot like my 1340GT did when I got mine. Disappointing to see how poorly handled my lathe was, but so far, I haven't been able to trace any problems to the damaged crate. I removed the cover switch when I rewired my lathe for the VFD. Seems like overkill for anybody with a brain.
 

wrmiller

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#3
The factory belts have been known to shred themselves fairly quickly. Most of us have changed them out shortly after receiving their lathe.

I don't have the numbers handy, but someone else will likely know them. :)
 

markba633csi

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#4
Good job troubleshooting the electrical issue- Looks like the lathe survived the hard knocks pretty well
They sure are nice looking when they are new :)
mark
 

MarkDavis

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#6
The crate on my 12-28 was beat up when it arrived this spring.

I would say the roughed up crates are due the fork lift drivers employing the braille method.
 

Meta Key

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The factory belts have been known to shred themselves fairly quickly. Most of us have changed them out shortly after receiving their lathe.

I don't have the numbers handy, but someone else will likely know them. :)
This afternoon I had a look at the drive belt system. I found that the motor pulley was 0.035 inches away from being in line with the headstock pulley. Doesn't sound like much but the two pulleys are very close together -- it's a short span. So, I adjusted the motor pulley on the shaft to get the two pulleys in line with each other.

I also discovered that the motor is not mounted square to the headstock. Measuring across the face of the motor pulley I find that it is 0.024" off from one side to the other relative to the plane of the headstock pulley. Not sure that's enough to worry about. I am seeing less residue from the belt..

I also note that the far end (non-pulley end) of the motor is pressing up hard against the end of the back splash. In fact, I could barely get the belt to move onto the slow pulley set due to interference from the back splash. It seems like a belt about 1" longer would go a long way toward fixing that problem. The back splash makes a really effective sounding board, greatly magnifying the vibration noise from the motor..

I'll take another look at that tomorrow.

Meantime, I've started running through the speeds and feeds for the break-in.

Oh, and I changed the wiring so that the rotation of the spindle matches the rotation of the spindle switch shaft. It came wired so that moving the lever UP had the spindle turning normally and moving the lever down ran the spindle in reverse. It seemed counter intuitive to me so I reversed it. The manual suggests changing the wiring at the end of the motor switch shaft but I found it much simpler to reverse the wiring inside the electrical box on the back of the headstock. Now, moving the lever down makes the spindle rotate normally and flipping it up reverse. You'd probably need to be standing in front of the machine for any of that to make sense. It seems much more intuitive now -- but that's probably just me. ;-)

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Meta Key

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The crate on my 12-28 was beat up when it arrived this spring.

I would say the roughed up crates are due the fork lift drivers employing the braille method.
Boy, howdy! It's like they play fork lift soccer with these things!

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.LMS.

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#9
zmotorsports has the belt part numbers on his thread.
 

Meta Key

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Your pallet and box looked a lot like my 1340GT did when I got mine. Disappointing to see how poorly handled my lathe was, but so far, I haven't been able to trace any problems to the damaged crate. I removed the cover switch when I rewired my lathe for the VFD. Seems like overkill for anybody with a brain.
I agree! I'm perfectly happy with my solution. Plus, if I ever decide to mount a tach sensor there are already two threaded holes in the headstock for mounting something and a cable running into the electrical box. It's a no-brainer!

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Meta Key

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#12
Good job troubleshooting the electrical issue- Looks like the lathe survived the hard knocks pretty well
They sure are nice looking when they are new :)
mark
It was good to dig into the electrics a little. Now I'm familiar with the system and that never hurts. I started a schematic that reflects the actual point to point wiring which was very helpful. I may finish that diagram one of these days..

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