New Lathe

[wrmiller]

Seems like putting a good VFD on a geared machine would offer the advantages of both. I'm still leery of Chinese electronic controls. So I wouldn't want a machine that relied on them to remain functional over many years. One thing that would be really nice, putting an additional gears on the quick change gear box that converted the lead screw to metric.

My 1340GT is a geared head with a VFD. The soft start, slow jog, and electronic braking are a big plus. Also, the lathe motor is 3-phase, so that means smoother running (less ISV) than a single-phase motor giving me mirror bright finishes if I do everything else correctly and no 'printing'. The variable speed really lets me fine tune the finish cuts.

I also have, courtesy of mksj, a electronic stop function that allows me to blind ID thread without having to disengage the threading lever or worry about crashing my tool in the part. It really helps as I don't do blind ID threading very often and I can get a bit tense while doing so.

I can run a geared head lathe just fine. I can even run it without a DRO on it. But I don't want to if I can help it.

 

[Dabbler]

here's my 2 cents on the lathe and VFD, etc....

1440 is a very nice size and it is unlikely you will outgrow it. It will have all the horsepower you will practically need.

I wouldn't worry too much about the low speed torque problem. Unless you are doing a lot of work with HSS cutters on pretty large diameters, you will seldom need really slow speeds, except for threading - and - you'd better not be taking deep cuts while threading! So it isn't too big a deal. I can see a problem threading a 2" 8 tpi thread and needing to slow it down, but then I'd thread away from the chuck (in reverse, with an inverted tool) using carbide, and then rev it to about 200-250 anyway. so no real problem.

 

[Larry42]

then I'd thread away from the chuck (in reverse, with an inverted tool)

That is by far the easiest, fastest way to thread. I'm going to assume you also plunge straight in W/O all the fooling around with 29+-.

I also have, courtesy of mksj, a electronic stop function that allows me to blind ID thread without having to disengage the threading lever

That sounds interesting, tell me more.

 

[wrmiller]

That sounds interesting, tell me more.

When I bought my 1340, mksj was making harnesses and control panels to support a vfd and to convert the controls to low voltage. He also wired up some extra features that took advantage of the vfd.

On my setup, he gave me a multi-stage braking feature (3 sec, 1 sec, and 3 sec/1 sec w/micro stop), that worked with the stock micro-stop that he had modified with a precision micro switch and harness. Quite repeatable.

When threading, I set up the lathe and micro-stop to do a 1 sec stop in the relief area I cut where I want to stop threading. Once I begin threading, the lathe will stop in the relief area, I back out the threading tool, hit the bypass switch and run the lathe in reverse back to the starting position. Once there, I dial in the new DOC (I thread straight in) and engage the forward lever. I only use the fwd/rev lever on the carriage, the cross slide dial, and the bypass switch (bypasses the micro switch so the lathe can run in reverse) on my control panel.

Rinse repeat. I don't disengage the threading lever until I'm done.

I mostly use this on blind ID threading as I can get a bit tense when doing those.

 

[starr256]

If I might present a slightly different take. Given that one has no experience with machining, is not engaged in an apprenticeship program and has no clear idea what to make, try a smaller less powerful new lathe with a good warranty and support. Unless there is a an experienced machinist in the house who owes you a lot of money and is willing to hold your hand, you are going to screw up. Some screw ups are going to mean redoing a part, and some are going to be rather startling and potentially dangerous. The larger lathes are powerful and less forgiving of mistakes. Once experience is gained and tooling acquired, you can always trade up to a bigger machine. If this makes sense, you might consider the PM1030V with DRO (DRO is a must from my prospective). I do recommend Blondihacks video on small lathes.