PM-1340GT 13"x40" Ultra Precision Lathe

Pondrocket44

Pondrocket44

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I'm currently on the hunt for a lathe to add to my garage shop. I came across the 1340GT I have interest in this machine my question for single point threading to a shoulder this machines spec is showing spindle speeds of min 90 and max 1800 with speed adjustments configured as stepped from 90,135,205,205,308,475,335,505,770,780,1160,1800. My main question it to all the threading professionals out there is this machines configuration for threading considered low, medium or high. I'm no threading expert but would like to know all opinions on this machine for threading purposes. I'm headed to Quality Machine Tools in a few weeks from now to check out this lathe.

Thanks
 
To me, 90 rpm is a bit high for threading to a shoulder unless the machine has an automatic stop (don't think this one does)
60 (or lower) would be better. You might consider a variable speed lathe
 
I have the 1236T, which is slightly smaller, but otherwise identical. 90 rpm is on the higher side for threading, especially if you are threading course threads. Many of us chose the 3 phase motor option and added a VFD, so we can go slower than that. A VFD also opens up the opportunity to use Mark Jacobs’ proximity stop so you can stop really fast when threading to a shoulder. Search on Mark’s user name @mksj and you will find a lot of information on it.
 
I converted my PM-1340GT to a VFD drive to attain lower RPM for threading. Several others here have done the same. II also replaced the motor with a vector rated Baldor unit which provides for a wider range of speeds while maintaining a flatter torque curve, and have a single position pulley/belt, so no need to change belt positions. This implementation includes the Mark Jacobs proximity stop setup for threading into a blind hole or shoulder. Details on these upgrades are discussed in the following thread and you can see the low-speed test results here:
davidpbest

Thread 'PM1340 - the Best & Jacobs Full Custom Edition'

34168602201_b6c3e2a878_o.jpg


It’s been several months since I took delivery of, and posted about my PM1340 lathe. It's time for an update since I’m nearing completion of what started as a straight forward VFD conversion project, and then took on a life of it’s own and led to a substantial customization of the stock PM1340 lathe.

I’m forever grateful to Mark Jacobs in particular for his thoughtful advice, council and helpful suggestions, and especially for the new electronics control package he developed to my specifications. Without Mark’s fine contribution, this project would never have...
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I have a 1340Gt, great lathe for the home shop.
Threading to a shoulder is always a challenge on a manual lathe without some way to automatically stop the spindle in a precise manner, mechanically or electronically. You can go the slow speed fast reflex method but it still limits how close you get to the shoulder. Fortunately there is a great option for this lathe - an e-stop using a VFD. Look here: MKSJ link to e-stop
I have this setup and I can routinely thread to a shoulder @ 500 RPM and consistently stop @ + 0.005 in. That works for both outside and inside threading. A VFD and e-stop adds so much versatility to this lathe I could not work without it. Yes it cost $, yes it requires some knowledge to get it installed but the payoff is well worth it. There is a wealth of knowledgeable people here that can help with MKSJ being the guru on this. He has also build VFD + e-stop setups for many people so you can buy one ready to install if you want.
 
On a lathe I usually recommend you go with a 3 phase motor, as it is less susceptible to failure, gives more speed flexibility and can result in a better surface finish. What I call the basic VFD install for the 1236T/1340GT is quite straight forward ( does not require removing the existing control system, just rewiring) and can be done for around $500 with the GS20 VFD, or with the GA500 about $700. The 1236T/1340GT significantly benefits going to a 3 phase motor and adding a VFD, as you can change the speed dynamically, you get controlled acceleration and you get very quick predictable braking (usually ~1second). These significantly add to threading/turning to a fixed point. As far as threading, many individuals thread away from the chuck, but with a VFD you can thread either direction in a very controlled fashion. I had previously made complete replacement VFD control systems for the 1236T/1340GT with electronic stopping that permitted threading up to 500 RPM, but no longer do so. I am only doing some one off turnkey type VFD systems for forum members that I have worked with in the past/friends.

On threading, usually the faster you thread, it improves the finish and less likely to work hardened/chatter in some difficult to turn metals like SS. I recommend using lay-down inserts like those from Carmex, Top Notch system from Kennametal, or some individuals have used the Aloris threading insert system. I can provide more details and/or get yourself a copy of David Best's book on indexable lathe tooling which is a great primer outlining the lathe indexable tooling. I also use the cross slide for threading as opposed to the compound, never had any issues with the 1340GT doing so, and for the electronic stopping you always end up at the same stopping position. At slower threading speeds thee may be some advantage to using the compound.
mksj

Thread 'Pm1340gt Lathe Basic Vfd Control Conversion Using The Stock Control Board And Switches'

Many individuals buy the PM1340GT lathe as a 3 phase machine with the intent to convert it over to a VFD system, the usual VFD that is used is the Hitachi WJ200-015SF. Unfortunately the conversion often requires a somewhat complex and costly conversion process to optimize many of the VFD functions. In many cases the machines may sit for many months if one is not familiar with how to do the conversion. I normally do these builds/conversions for other individuals, and have shared this information in this forum, but it is somewhat involved and very time consuming.

I normally do not...
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Introduction to Indexable Tooling for the Metal Lathe: A User Guide: Best, David P.: 9798753874993: Amazon.com: Books

Introduction to Indexable Tooling for the Metal Lathe: A User Guide [Best, David P.] on Amazon.com. *FREE* shipping on qualifying offers. Introduction to Indexable Tooling for the Metal Lathe: A User Guide
www.amazon.com

If you do go three phase with a VFD, you can follow the basic install instructions, these days I have switched my recommendations for VFD's to the Yaskawa GA500 series (GA50UB010ABA) or the Automation Direct GS20 series (GS21-22P0). The install is similar but the JOG is easier to setup as there are two separate inputs, I can provide parameters for either of these VFD's and some basic guidance if you decide to go the VFD route.
control-concepts.myshopify.com

GA50UB010ABA - 3 HP, 9.6 Amps, Normal Duty, 2 HP, 8 Amps, 240 VAC, Heavy Duty, Single-Phase, IP20/Protected Chassis

Yaskawa - GA500 AC Microdrive - GA50UB001ABA - 1/16 HP, 1.2 Amps, Normal Duty, .17 HP, 0.8 Amps, 240 VAC, Single-Phase, IP20/Protected Chassis
control-concepts.myshopify.com
 
mksj said:
On a lathe I usually recommend you go with a 3 phase motor, as it is less susceptible to failure, gives more speed flexibility and can result in a better surface finish. What I call the basic VFD install for the 1236T/1340GT is quite straight forward ( does not require removing the existing control system, just rewiring) and can be done for around $500 with the GS20 VFD, or with the GA500 about $700. The 1236T/1340GT significantly benefits going to a 3 phase motor and adding a VFD, as you can change the speed dynamically, you get controlled acceleration and you get very quick predictable braking (usually ~1second). These significantly add to threading/turning to a fixed point. As far as threading, many individuals thread away from the chuck, but with a VFD you can thread either direction in a very controlled fashion. I had previously made complete replacement VFD control systems for the 1236T/1340GT with electronic stopping that permitted threading up to 500 RPM, but no longer do so. I am only doing some one off turnkey type VFD systems for forum members that I have worked with in the past/friends.

On threading, usually the faster you thread, it improves the finish and less likely to work hardened/chatter in some difficult to turn metals like SS. I recommend using lay-down inserts like those from Carmex, Top Notch system from Kennametal, or some individuals have used the Aloris threading insert system. I can provide more details and/or get yourself a copy of David Best's book on indexable lathe tooling which is a great primer outlining the lathe indexable tooling. I also use the cross slide for threading as opposed to the compound, never had any issues with the 1340GT doing so, and for the electronic stopping you always end up at the same stopping position. At slower threading speeds thee may be some advantage to using the compound.
mksj

Thread 'Pm1340gt Lathe Basic Vfd Control Conversion Using The Stock Control Board And Switches'

Many individuals buy the PM1340GT lathe as a 3 phase machine with the intent to convert it over to a VFD system, the usual VFD that is used is the Hitachi WJ200-015SF. Unfortunately the conversion often requires a somewhat complex and costly conversion process to optimize many of the VFD functions. In many cases the machines may sit for many months if one is not familiar with how to do the conversion. I normally do these builds/conversions for other individuals, and have shared this information in this forum, but it is somewhat involved and very time consuming.

I normally do not...
  • Like
  • Love

Introduction to Indexable Tooling for the Metal Lathe: A User Guide: Best, David P.: 9798753874993: Amazon.com: Books

Introduction to Indexable Tooling for the Metal Lathe: A User Guide [Best, David P.] on Amazon.com. *FREE* shipping on qualifying offers. Introduction to Indexable Tooling for the Metal Lathe: A User Guide
www.amazon.com

If you do go three phase with a VFD, you can follow the basic install instructions, these days I have switched my recommendations for VFD's to the Yaskawa GA500 series (GA50UB010ABA) or the Automation Direct GS20 series (GS21-22P0). The install is similar but the JOG is easier to setup as there are two separate inputs, I can provide parameters for either of these VFD's and some basic guidance if you decide to go the VFD route.
control-concepts.myshopify.com

GA50UB010ABA - 3 HP, 9.6 Amps, Normal Duty, 2 HP, 8 Amps, 240 VAC, Heavy Duty, Single-Phase, IP20/Protected Chassis

Yaskawa - GA500 AC Microdrive - GA50UB001ABA - 1/16 HP, 1.2 Amps, Normal Duty, .17 HP, 0.8 Amps, 240 VAC, Single-Phase, IP20/Protected Chassis
control-concepts.myshopify.com
Click to expand...
mksj

Thanks for the reply I feel much better now I know there is a conversion option to get a VFD added to the machine. I was already planning on a 3 phase motor. My Bridgeport is 3 phase and I run a rotary converter on it, my question will the rotary converter work on this PM-1340 or do i need to get its own converter? I would imagine with the VFD conversion the warranty on the units motor is void. Any how one I get closer mid next year on pulling the trigger I'll post my updates. Are there pictures or a video on the finished conversion process. Let me know if & when your available for a phone call. Thanks
 
RPC can be used for both machines and would be fine to start out with, but the PM-1340GT benefits significantly from the addition of the VFD and it address your concerns about low speed threading. The other benefit is you can run the VFD from say 20-100 Hz and there would be no belt changes for low/high speed pulley settings. You basically flip the motor pulley and run the large motor pulley to the large headstock pulley which splits the default difference between the two default belt speeds. My understanding is that PM will still cover the lathe under warranty including the motor, but contact them to verify. I would guess the majority of 1236T/1340GT lathe owners that buy the 3 phase version use VFD's, and there are far more problems with the single phase motors vs. the 3 phase. I have done numerous VFD installs on these lathes and yet to have seen a 3 phase motor fail over many years.

As mentioned I no longer build VFD systems for these lathes, but I had a 1340GT for many years as well as numerous VFD installs on them and can provide some suggestion if/when you get to the point you are going to purchase one. You can PM me and we can take it off line and talk directly. There will most likely be significant price increases in future machine shipments due to increased tariffs and shipping costs once current stock is sold.
 
Thanks to all for above replies. I am headed to PM tomorrow from Michigan to check out the PM-1340 I will have a few questions for them and hopefully all will get answered and my decision to buy one will get upgraded.
 
Pondrocket44 said:
Thanks to all for above replies. I am headed to PM tomorrow from Michigan to check out the PM-1340 I will have a few questions for them and hopefully all will get answered and my decision to buy one will get upgraded.
Click to expand...
I just have mine today, but I am in Dallas far from you
 
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