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The Pm-1440gt Has Landed

oldhank60

Active Member
Active Member
#31
I change between chucks a lot and it gets interesting supporting the 8" chucks with one arm while engaging a cam lock with the other.:eek: This is much easier. As a bonus the upper cross tubes make excellent carrying handles. :D
get a couple of 2x6 boards and make chuck holder to slide chuck up to spindle nose, it will save arms from having to manhandle chuck, and it can save rails from dropped chucks
 

jbolt

Active User
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#32
I have about 20 hours on the lathe now and find it is too low for my height at 6"1". Yesterday I made up some risers out of some 1/2" X 2" bar stock and 2' X 1/4" angle iron. I wasn't sure how flat the bottom of each stand base is so I did not weld the cross piece in to allow for any twist. The cross pieces are clamped in place with a full length piece of 1/2-13 all thread. The risers bolt to the bases through the existing threaded holes for the feet. I added two more feet to the tail-stock end. Probably did not need to but what the heck. The risers are 6" tall which is perfect for me. Next will be figuring out how to lower the foot brake. As it is now it's a little high but still usable. The dark grey Rustoleum is a pretty close match.

Stand Riser01.png Stand Riser02.png Stand Riser03.png
 

jbolt

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#34
Thanks MonkMan. Having the machine at a comfortable height makes a huge difference.

I don't think it will be too much trouble to lower the foot brake. The foot pedal is welded to a tube which fits over a stub shaft that actuates the brake. I should be able to support the pedal assembly with bearing blocks at each end and weld a blade to the back of the tube. Make a arm to fit on the actuator shaft and connect to the pedal with a tie rod.
 

MonkMan

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#35
Looks like you have it pretty much figured out, great! Please post pictures when you get it installed. Thanks
 

jbolt

Active User
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#37
I got the foot brake lowered today. Two steel stub shafts bolted to 1/4" x 3" strap bolted to the stand support the pedal assembly and act as bearings. I turned a steel sleeve to fit over the actuator shaft which uses the same bolt that held the pedal. A blade is welded to the sleeve and to the back of the pedal and connected with a tie rod. The tie rod is made from 1/2" steel hex. Most of the hex was turned off except for a 1/2" wide section for use with a wrench. The ends were drilled and tapped with 5/16-24 right and left thread for rod ends for adjustment. I set the pedal about an 1-1/2" lower than from the factory to make it more comfortable to use.

FootBrake04.png FootBrake02.png FootBrake03.png
 

GA Gyro

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#38
Curious question about brake pedals on lathes....

Can one use the brake pedal softly to modulate a slowing down of the spindle...
Or is it either no brake or quick full stop?

THX
 

MonkMan

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#39
Thanks for the pictures. Nice job, looks factory built.....something PM should offer.
 

JimDawson

Global Moderator
Staff member
Director
#40
Curious question about brake pedals on lathes....

Can one use the brake pedal softly to modulate a slowing down of the spindle...
Or is it either no brake or quick full stop?

THX
On most of the smaller lathes, the brake pedal is connected to a mechanical band brake. So yes, you can control the braking force.
 

firestopper

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#41
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

Active User
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#42
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

Active User
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#43
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.

Motor01.png Motor02.png

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.

20161002_142737.png 20161002_142745.png

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

Iron
Registered Member
#44
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

Active User
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#45
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.
 

jbolt

Active User
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#48
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.

Control Box 02.png Control Box 03.png Control Box 01.png

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.

Machine Electrical 01.png Machine Electrical 02.png

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.

Machine Control Switches 01.png Tach Display.png Tach Sensor.png

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

mksj

Active User
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#50
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
 

jbolt

Active User
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#54
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
Hi Mark,

This is all you fault you know. If you hadn't come up with all the cool features I would have blissfully went on with my single phase motor. :grin:

As for planning I had a lot of time to think about it during the long wait. I was able to get some dimensions off an Eisen lathe I thought would be close in size. It was a bit of a gamble. Working with the young engineers in the high school robotics team I have become a believer is building most things in CAD before ever cutting stock. This was no exception.

Control Enclosure CAD.png PM-1440GT CAD.png

Thanks again for all your help!

Jay
 

co1859

Active Member
Active Member
#58
Wow - Nice Lathe & sharp looking cabinet, Your Craftsmanship Is Outstanding.. - What brand name of controllers did you use in the new cabinet?
 

jbolt

Active User
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#59
Wow - Nice Lathe & sharp looking cabinet, Your Craftsmanship Is Outstanding.. - What brand name of controllers did you use in the new cabinet?
Thanks co1859!

Most everything including the cabinet came from Automation Direct. The 24vdc power supply and braking resistor were from ebay.
 

jbolt

Active User
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#60
I made good progress on the belt cover modifications today.

The mods were to extend the side to cover the belts due to the larger motor and to enlarge the area at the spindle for an outboard spider. To keep the spindle length to the spider screws as short as possible I deepend the recess around the spindle and enlarged it for clearance of the centering screws.

I used my CNC router to cut the cover and the new recessed plate. The router is not really meant to cut steel but it will do it will lots of light cuts. I used a 1/8" carbide end mill at 9200 rpm and 4 fpm. To zero the X & Y on the original spindle hole I drew a centering target in CAD and printed it on paper and then taped it over the hole. This gets me (+-) 0.01" which is good enough. I use the tip of a carbide scribe in a collet in the spindle for centering on the target.

Belt Cover01.png Belt Cover02.png Belt Cover03.png Belt Cover04.png


The new sheet metal pieces are 12 ga. steel. Here are the belt cover extension pieces ready for welding.

Belt Cover05.png


Here is the cover with the new modes welded on. The recess around the spindle is 1/2" deeper than original.

Belt Cover06.png Belt Cover07.png

By doing the mods I was also able to correct the crooked installation of the cover. Now it sits flush with the top and front of the head. Next up is prep and paint.