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What are factors for what "class" of lathe to buy?
- Thread starter skcncx
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S'what I'd do if I were starting from scratch again.
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Baldor upgrade is for the Chinese PM-1236, not the Taiwanese 1236T. Having done a number of VFD installs and motor replacements on the various lathes, it is not always as straight forward as one thinks. Even with the cabinet motor based lathes, they sometimes use odd motor shafts and pulleys, so like on my current lathe the brake drum is built into the pulley. I had bought a vector motor thinking it would be an easy install and I could change the pulley, but I would have to make a new pulley with brake hub. So no real benefit at the end of the day. What I have been told, is the motor on the 1236T is the same as the 1340GT, although they list the Hp ratings as different. The headstock on the 1236T is also shorter, which may further limit fitment of a replacement motor. Stock motors on the 1236T/1340GT have worked fine when used with VFD, so information is just to point out that if you plan on using a VFD (or other type of 3Ph converter) go with the stock 3Ph motor. People also downplay the issues of single phase motors effecting the surface finish, but there are reports to the contrary, there can be many contributing factors. Below is a previous post that going 3pH eliminated the issue, other means include motor isolation.
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The PM-1236T vs PM-1340GT dilemma
Very close to ordering one or the other but on the verge of a nervous breakdown trying to decide. It will be replacing a 3in1 machine that has been a pain in my --- since the day it arrived 6 years ago. Will be used at work occasionally for building small parts and for pleasure working on guns...
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1340gt surface finish problem
O.K. guys, and gals, I've tried every speed/feed combo, every carbide insert I have, every HSS tool I have, I've even put vibration isolation pads between the stand and the floor...nothing seems to work. Here's what I get... Please excuse my photography skills. You can not only SEE the...
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The short answer is, it’s not a standard IEC motor on a 1236T. The motor on my 1236T has IEC 90L foot and shaft height dimensions, but a 19mm shaft of an 80 frame instead of 24mm as a 90 frame should have. It is also about an inch shorter than a 90L, making the length conform to a 90S frame, so this is a complete bastard motor with dimensions of three different frame sizes. You also can’t get an 80 or 90s as far as I have found in 2hp, I couldn’t even find a 1.5hp in that frame size at 1,800 rpm.
There looks like there is some room in the front of the motor if you mount the pulley all the way against the shoulder, or you could use a single groove pulley since you are on a VFD and possibly save some more space. That would require modifications of the gear cover and adjusting arm, but looks possible. Anyways, there will be a good amount of customization to change this motor out, so I am glad I bought 3 phase from the factory.
Not meaning to take this thread off course but quick question for those that have converted their 1340GT to a three phase motor. Of these options, which one seems to be the easiest/best conversion? I ordered my 1340 as a single phase, but have since bit the bullet and got a RPC from American Rotary and went ahead and ordered my mill as 3 phase. I'm about 9 months into my wait on these machines so no way I'd switch my order at this point and go back to the end of the wait list. Was just wondering which motor option my be the easiest way to go if I decided to swap my lathe over too now that I have three phase power
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Other than ordering a 3-phase motor from PM, you have only a few motor options that will fit the PM-1340GT by making a few simple modifications to the mounting platform for the motor. Mark discussed this a couple of posts back, and there are several threads that discuss this process:
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Shaft diameter seems to me to be a small problem - but aligning the motor mounts and room for the motor are, of course critical. Clearly it is best to order it in 3PH and add the VFD right away, if only one can afford it.
My personal options are far easier: my 7.5HP lathe is 3PH already, with 1PH controls. My 1440 is 220 1PH 2HP, but uses a standard motor/base. The brake drum is on the driven pulley, and it uses 2 standard B belts, so my conversion is far easier.
My personal options are far easier: my 7.5HP lathe is 3PH already, with 1PH controls. My 1440 is 220 1PH 2HP, but uses a standard motor/base. The brake drum is on the driven pulley, and it uses 2 standard B belts, so my conversion is far easier.
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Other than a PM replacement, below are the only possible motors that I'm aware of, but all require modifications, nothing is a drop in replacement. I put the Baldor on my 1340 and could not be happier. Mark Jacobs (@mksj) did the controls. Some speed tests are shown here.
http://www.electricmotorwholesale.com/BALDOR-IDNM3587T/
http://www.electricmotorwholesale.com/MARATHON-Y551.html
http://www.electricmotorwholesale.com/MARATHON-Y526.html
http://www.electricmotorwholesale.com/MARATHON-E467.html