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PM1440GT change gear problem

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bpctcb

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I ran into a problem with my new PM1440GT lathe while trying to set it up to cut metric threads. I needed a 1.0 pitch so I installed the change gear 28 in the upper location to mesh with the 120 gear. I couldn't get the gears to mesh properly.

I observed that the 127 gear was now contacting the collar on the shaft next to the 28 upper change gear. The only way I could gain enough clearance was to completely remove the offending collar. But I can't run the machine with the collar removed because the 28 gear has nothing to keep it from sliding on the keyed shaft with the collar removed.

The only solution I can think of is to make a shortened key that only fits under the upper change gear and make a reduced diameter collar that doesn't have a key under it.

Has anyone else had this problem while trying to use change gear 28?
Can any PM1440GT owner tell me what I am doing wrong or think of a better solution?

I sent an email to PM to see what they say.

BP
 

SamI

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Would it be possible to simply turn the collar down slightly rather than make one with a shorter key (although I see no reason that wouldn't work)? You could make a mandrel in the lathe and press fit the collar onto it which should allow you to turn it down.
 

Bob Korves

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Don't modify anything until you get some advise from other users of that specific machine. You can also call Matt and talk to him about it.
 

jbolt

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Don't modify anything. It has been a while since I cut metric threads but I recall I have to swap the position of the spacer and gear on the shaft or some combination to make it work. I can take a look this evening and verify what needs to be swapped if you haven't figured it out by then.
 

bpctcb

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jbolt, thanks for posing that pdf. I haven't seen that before and it's way more detailed than my owners manual.

PM replied that I needed the upper change gear 28 meshed with the 127 gear also.

What is aggravating is that the diagram in my owners manual shows the upper and lower change gears meshing with the 120 gear for all metric pitches. It never occurred to me that my owners manual was wrong. I was making my gear changes based on the owners manual.

I went out to my shop and looked at the diagram on my machine. The diagram on the machine has the upper change gear meshing with the large 127 gear for metric pitches.

BP
 
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jbolt

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You must have one of the first production run lathes like I do?

I sent Matt a list of inconsistencies in the factory manual of which most were addressed in the manual they published later.

There is also another error on the inch thread chart on the lathe where a PX lever combo should be RX. Matt had the factory fix that and he sent me an updated panel but the new panel was longer with different bolt spacing so I updated my panel with a sharpie.
 

bpctcb

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jbolt, I revised my above post.

I bought my lathe just last November; manufacture date is 8-2018 IIRC. The diagram on my lathe does show the correct gear placement. I think I will trash my paper owners manual and stick to the pdf manual.

BP
 

jbolt

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Yeah the factory manual is a little sketchy. I don't know why they still include it and not just send it with the manual PM has made.

At least you have it dialed in now. Have fun threading!
 

Bob Korves

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I suggest you print out the pdf and put a copy in the shop by the machine. That is what I do. Sometimes companies and pdf's go away, and computer file copies also go away, leaving you high and dry if you have not downloaded it and printed it.
 

dpb

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You must have one of the first production run lathes like I do?

I sent Matt a list of inconsistencies in the factory manual of which most were addressed in the manual they published later.

There is also another error on the inch thread chart on the lathe where a PX lever combo should be RX. Matt had the factory fix that and he sent me an updated panel but the new panel was longer with different bolt spacing so I updated my panel with a sharpie.
Is the entire PX column with the 11.5 tpi thread incorrect? Column should be RX?
 

jbolt

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Is the entire PX column with the 11.5 tpi thread incorrect? Column should be RX?
That's the one. PM's manual is still not correct. I'm assuming the the new lathes have the correct badge?

Photo of a thread chart off an Eisen lathe with the same gearbox.

Thread-Feed-Chart.jpg

Thread chart on my lathe.

pm1440gt thread chart.jpg
 

dpb

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Mine is only 6 months or so newer than yours. Has the same incorrect thread chart.
 

bpctcb

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Mine has the correct RX in the 11.5 column. But it shows the large gears as 109 & 103 instead of 127 & 120. Doesn't matter much I suppose as I didn't receive any extra large gears to swap out.

I had my wife print out the pdf of the better manual. I am going to put it in page protecters then stick it in a 3 ring binder.

BPCCA67A02-785C-45A7-BD9C-F5C8EC2A603E.jpeg
 
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