The Pm-1440gt Has Landed

[oregontripper]

I hope nobody minds bringing this up top? Can't imagine reading this thread and not wanting a PM1440GT! Great stuff!

 

[7milesup]

I hope nobody minds bringing this up top? Can't imagine reading this thread and not wanting a PM1440GT! Great stuff!

I know right?!

 

[mkbuildit]

waaahhhaaHA! I finally ran some customer parts today. What a huge difference. I parted off a bunch of 2" 6061 stock. Something I could not even think about on my old lathe. An ISCAR parting tool with a drizzle of kerosene went through it like butter. Will be even better with the VFD conversion and variable speed.

Here are some parts I have permission to post pictures of. I make a couple a dozen a year for a local shop. Their smallest manual lathe has a 24" chuck on it so they farm out this kind of stuff. Made from 3/8" 7075. The long skinny part is 0.187" dia with a tolerance of +0.0 -0.0005". The short fat end is a 0.25"bearing fit with the same tolerance. The long skinny part is about 2" long and has to be cut in a single pass. I used to scrap about 30% on my old lathe. I did these in about a third the time it used to take on my old lathe with no scrapped parts. Awesome!

View attachment 135847


I also made up a chuck cradle. I had always meant to make one for my old lathe but never did. A must with the heavier 8" chucks. Made from 3/8" poly and 1" aluminum tube with press in star threaded inserts.

I know right?!

I just read this entire thread. I cannot wait to get my VFD installed and have my 1440 running now!

 

[Beantown]

Are there laws against resurrecting 7 year old threads? If so, lock me up. With my PM-1440GT on the way, I can tell you this was one of the most useful threads I've read so far. Especially the wiring diagram. It filled in so many gaps for me. Made me realize that I don't want to do the basic VFD wiring. I'm going to put in the work to research and convert to DC for my control circuits. It will be worth the extra time and I really want that proximity stop!

Thank you for sharing your build. It's impressive!

 

[jbolt]

Wow, crazy to think it has been 7 years since I started this thread. I'm glad some are still finding it useful.

There are some other really great VFD conversion threads that are more up to date than this one that keep the new electronics within the stand.

The proximity stop is really cool but I never use it. I learned various threading techniques from back in my machine shop days in the 80's and those serve me well.

 

[Beantown]

Wow, crazy to think it has been 7 years since I started this thread. I'm glad some are still finding it useful.

There are some other really great VFD conversion threads that are more up to date than this one that keep the new electronics within the stand.

The proximity stop is really cool but I never use it. I learned various threading techniques from back in my machine shop days in the 80's and those serve me well.

Ha! Yea, I've been reading all of the VFD threads trying to understand the various circuits. I'm much better in DC and microcontrollers. I can read code and understand that logic far easier than these AC spaghetti balls of wire, switches, and relays! lol

Since I'm jumping into this will zero machining skill, I imagine the proximity stop will prevent me from doing a lot of dum!

 

[jbolt]

Ha! Yea, I've been reading all of the VFD threads trying to understand the various circuits. I'm much better in DC and microcontrollers. I can read code and understand that logic far easier than these AC spaghetti balls of wire, switches, and relays! lol

Since I'm jumping into this will zero machining skill, I imagine the proximity stop will prevent me from doing a lot of dum!

I'm no electronics wiz so it really isn't that difficult. You will have no trouble once you get into it.

Just remember, crashing a tool is a valuable learning experience.

Now once having had a boss who was deadly accurate across the shop with a box wrench took that learning experience to a whole nother level. (Ah, the good ole days... LOL!)

Congrats on the lathe. You will enjoy it.

 

[tomxl650]

I have been looking for many used vs new lathes between 1340 and 1440. I came down to 3 brands Sharp, Arca, and PM1340GT & PM1340GT. prices/warranty/customer service/sales/manuals. I have decided to go with PM 1440GT it is probably more machines than I need for the time being. Any suggestion?

 

[B2]

Hi @Beantown

Ha! Yea, I've been reading all of the VFD threads trying to understand the various circuits. I'm much better in DC and microcontrollers. I can read code and understand that logic far easier than these AC spaghetti balls of wire, switches, and relays! lol

I have the PM1440GT. I got rid of of the mechanical relays when doing my VFD conversion via using solid state circuits. I even added extra features like a spindle rotation counter. I really like it and I do use the proximity stop even when I am not threading. It is also a safety feature to prevent crashing the spindle/chuck. My conversion is perhaps over documented as to the details and I think this scares some folks off, but if you know a little electronics you can follow the solid state operation. Also, I managed to get the entire conversion into the back of the lathe where I had removed the relays etc. I even got my home made the ebrake resistor in there. I also managed to add all the feature switches, displays etc to the front panel..... so there are no NO extra external boxes / cabinets hanging off of the lathe. The detailed descriptions is noted as "PM 1440GT Part 2 VFDDescription...". I did make some addition/improvements after this initial posting and for the most part posted them later. "Part 1" tells you how the original factory wiring circuits work(ed). I even included parts lists, but some of these links may be out of date by now. Here is where you can find my docs.

VFD conversion using solid state electronic components.

By the way, I built my circuits with simple circuit boards and wire. There is another HM member who is now working to make a PC circuit board for my conversion. He has a 1340 rather than a 1440GT, but the VFDs are the same so the functionality is pretty much the same.

If you have questions or need help just give me a shout.

Dave L.

 

[Beantown]

By the way, I built my circuits with simple circuit boards and wire. There is another HM member who is now working to make a PC circuit board for my conversion. He has a 1340 rather than a 1440GT, but the VFDs are the same so the functionality is pretty much the same.

If you have questions or need help just give me a shout.

Dave L.

That is quite interesting. Did you use a microprocessor or discrete logic ICs? Solid state relay or transistors? If you have any pictures or a schematic you would be willing to share that would be awesome. I wanted to do a microprocessor, but after reading about how noisey VFDs were I didn't think it would be very reliable. ICs should be much less sensitive.

I think that it the golden ticket with Mark's DC control conversions. The components he uses appear to be impervious to EMI and they are super reliable.

Either way, I like to learn and read about all options.