The Pm-1440gt Has Landed

[Firestopper]

Very nice job on the riser and brake bar relocation. Great design!

On the question on braking, some also use drum brakes with controlled braking as well.

 

[jbolt]

This lathe has a drum brake. When the foot pedal is depressed it also triggers a switch to kill the motor. It brakes really fast with an 8" chuck from full speed so I'm not sure how much fine control there is.

Thanks for the pictures. Nice job, looks factory built.....something PM should offer.

Thanks MonkMan.

Machine height is a personal preference so in the end I think it is up to the user to make any height adjustments. Probably not much of a market for risers and foot brake lowering kits.

I will say the specs say the spindle center line from floor is approximately 47". Mine with the leveling feet on is only 43". Had it actually been 47" I probably would have not made the risers. Now it is at 49" which is perfect with a mat in front of the lathe.

 

[jbolt]

Now that the foot brake is done I started on the VFD conversion. Finding a 3HP motor that would fit was a PITA. The factory 2HP single phase and 3HP 3 phase share the same size housing. Not sure how that works but whatever. The only 3HP motor I could find with the same factory frame size was a 3600 rpm motor. The 1800 rpm motor of the same series was much longer and would not fit. I managed to find a 3HP 1800 rpm inverter duty TENV Marathon motor that is short enough but it has a larger circumference. The new motor has a 1.125" shaft vs. the 24mm factory motor so I had to get a new sheave from Gates.

The factory motor mount would not work with the size and configuration of the new motor plus it is a pain to adjust so I fabricated a mount out of 1/2 steel plate. I basically made a large hinge. The pivot part of the hinge is made from 5/8" rod drilled out for a 5/16" hinge pin. The motor is supported/adjusted with two tie rods similar to what I did for the foot brake. Takes just a few minutes to change the belt now, seconds to adjust.

Because of the larger diameter motor it now interferes with the belt cover so that will need to be modified. I was planning on modifying it anyway to add a spider the the rear of the spindle.

 

[dr.diesel]

I am a few clicks from ordering one of these as well, thanks for all the info and picts!

Can you comment on the quality, being manufactured in Taiwan, is it noticeably better? Fit and finish, gear wine, manufacturing debris in any of the gear boxes, etc?

 

[jbolt]

I am a few clicks from ordering one of these as well, thanks for all the info and picts!

Can you comment on the quality, being manufactured in Taiwan, is it noticeably better? Fit and finish, gear wine, manufacturing debris in any of the gear boxes, etc?

It is a gear head lathe so it does make some noise but not something that drives me crazy. I can carry on a conversation with someone while it is running and not have to speak loudly.

The spindle run out is less than on the specs. Mine is under a tenth of a thou when cold. When warmed up I can measure the error tolerance in the spindle bearings. The Castings on the bed appear to be very high quality. I love the D1-5 spindle and the 2" bore. All the handles and levers work smooth from the get-go. I pulled the top of the head off and found no grit. I have not checked the other gear boxes. The only "fit" issues I had were the splash guard was installed incorrectly and the belt cover does not line up well at the top of the head-stock. Something is out of square, head-stock or cover. The stand is rock solid.

I have about 50 hours on the lathe now and it has meet all my expectations on performance. The only thing it does not do quite as well as my old lathe that was a belt drive is I don't get the mirror finish in aluminum. It is close but I suspect it is the gear head or single phase motor. I will know more once I complete the 3 phase conversion. I didn't like doing a lot of steel on my old lathe but it is a joy to do on this one.

 

[dr.diesel]

Thanks Jay, just placed my order for one! Appreciate the info once again.

 

[jbolt]

Thanks Jay, just placed my order for one! Appreciate the info once again.

Excellent! Hopefully they will be in stock soon.

 

[jbolt]

Okay the VFD conversion is mostly done!

First a huge thanks to Mark (mksj) for the design and for answering all my questions. You are the man!

I did a few things differently than others. My original intent was to use the existing electrical space for the electrical components and mount the VFD inside the base but everything was too tight for my liking. I also like to use breakers instead of fuses so I can turn things on-off for service or troubleshooting. Most everything is mounted in a 24" x 16" x 8" Nema 1 cabinet mounted to the side of the machine. The cabinet is mounted to the machine base with hinges so it can swing open to access under the base to service the brake components and limit switch. The enclosure has a 110v pancake fan that draws air across the VFD. It is mounted adjacent to the VFD and above the braking resistor. The fan always operates when the machine is turned on.

Some of the factory wiring was too short to pull into the new cabinet so I used the existing terminal block to extend the wires. I also kept the original transformer to power the machine lights and DRO.

Most machines have the transformer powered all the time but I prefer to have the machine completely powered off when not in use so I added a 35A contactor and switch to turn the machine power on. I also put the coolant pump on a 110v contactor and switch.
I still need to make the labels for the switches but on the top row from left to right is the "Speed Pot", "2-Stage Braking Switch", "FWD/REV Toggle", and "Proximity Sensor Bi-Pass Switch". There is only enough room for four switches on the head so I mounted the other switches in the base. From left to right is the "Main Power Switch", "Coolant Switch", "Light Switch", and "E-Stop". I still need to make the mount for the proximity sensor (hanging off the lever). I mounted the tachometer to the bottom of the DRO and made a bracket for the hall effect sensor. The magnet is temporarily mounted with electricians tape. The will get permanently mounted to the rear spider.

Next is to modify the belt cover for the outboard spider and to clear the new motor.

 

[dieselshadow]

Holy cow! What a nice install. Very clean and professional. Extremely well done sir!

 

[mksj]

Hi Jay,
Very nice and professional install, glad you like the control system design. You can see you put a lot of thought and planning into modifying this lathe to fit your needs. Well done!
Mark