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Thread: Get me over the hump

  1. #71
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    I have a variable speed 12" x 28" metal lathe. It has a full complement of change gears to let me cut threads, and two sets of pulleys for the belt between the variable speed motor and the gear box. I believe it is 1.5 HP but couldn't find that in my paperwork. I only use the low speed belt, which gives it a range of 0 to 750 rpm. I am very pleased with this lathe, and it has ample power at very low speeds. I can't speak for when it is in "High Range, with the other belt moved over to the other set of pulleys which give me the 750 to 1500 rpm speed range, as I never use it.---Brian Rupnow
    Brian Rupnow

  2. #72
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    Quote Originally Posted by brian Rupnow View Post
    I only use the low speed belt, which gives it a range of 0 to 750 rpm. I am very pleased with this lathe, and it has ample power at very low speeds.
    that makes some sense - the two different pulley sizes is itself a mechanical speed control in that you are not covering the whole range electronically.
    .

  3. #73
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    Re McGyver's post #58: "Geoff, that nice looking shop is far too clean. Sign of a troubled mind I'd say"

    He He. I took that photo just after my annual cleanup prior to a visit of the Model Club executive. It sure doesn't look like that now!!!

    Re ulav8r's comment in post #60: "The problem with a tool cabinet as a stand is twofold: 1. It is not rigid enough tp stop vibration/resonance 2. There is little toe/knee room to allow you to stand up straight while using the machine. If you have to lean over to operate it, it will be rough on your back."

    Agree, but the top on mine protrudes 3" from the drawers and the lathe's center-line is 11" from the front. I just checked and the front of my shoes are 3" in front of the cabinet face. The table top surface is 37" above the floor. Never once had a complaint from my back.

    I have no vibration issues. Perhaps the huge amount of tooling/accessories stored in the drawers and cupboard help in that regard.

    Geoff

  4. #74
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    None of us can truthfully tell the OP that he will not be satisfied with such a machine. We do not know what he will end up using it for, nor what he expects. He may think it is the best thing ever.

    We CAN give our opinions, tempered by experience. My opinion from what I have gathered looking over the manual, is that there are two major issues I see with the PM 1127.

    One is the very wide range of the variable speed, strongly suggesting a rather weak performance at low speeds. We see that demonstrated with a minilathe in This Old Tony's video. It's worth noting that the minilathe has a motor that is fully 1/3 as powerful as this one, yet that small machine was stalled to a stop by a cut that most people would consider a light cut on a small workpiece (0.020" on a 1.5" workpiece). A considerably larger machine would be expected to make bigger cuts on larger work. My own lathe , with a smaller motor, will make that cut easily.
    Given that the motor is 3x more powerful, and the speed range is roughly half, one might predict that the stalling cut for the PM machine would be a cut of 0.030" to 0.040" on a workpiece of 6" or so diameter. Certainly better, but not what can be done with any similar size machine that has a back gear.

    The other issue is the "fake QC box". The machine has to be regarded as a change gear machine. At $3000 or so, I would expect to find a real QC box, doing a useful range of threads and feeds without requiring a change of gears. I own a change gear machine, and I have come to regard that as a real nuisance. While one may not cut many threads, with the PM machine, every change of feed likely requires a change of gears. You will use a lot more feeds than you will ever cut threads, in all likelihood. Both are made a problem by that design.

    To me, those factors make it not worth that sort of money when similar machines with all the features wanted, and more, can be had used for half that. And many of the used machines are more recent machines of asian manufacture, so this is not a bigot talking about "old American iron" here.

    What we know is that it MUST lose power at low speeds due to the drive type. That is simple physics and cannot be avoided.

    Now we have a person who uses a machine of the general type, and who finds no problem. So far so good.

    It may be that the OP would also find no issue. I assume that Mr Rupnow works with things up to half the swing of the machine or so. The OP as I recall has a car hobby. Cars are bigger than model engines, and so are their parts. It is reasonable to warn the OP that he may find a disappointment if he has cause to work with parts that would not fit on a minilathe.

    It is true that carbide wants higher speeds, where a variable speed motor produces more power. It is equally true that the same cut at a higher speed requires more power, so the net result is somewhat of a wash, the power increase is used up in the speed increase, so the cut possible is likely not increased.
    Last edited by J Tiers; 01-11-2019 at 11:02 AM.
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  5. #75
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    Quote Originally Posted by J Tiers View Post

    The other issue is the "fake QC box". The machine has to be regarded as a change gear machine. At $3000 or so, I would expect to find a real QC box, doing a useful range of threads and feeds without requiring a change of gears. I own a change gear machine, and I have come to regard that as a real nuisance. While one may not cut many threads, with the PM machine, every change of feed likely requires a change of gears. You will use a lot more feeds than you will ever cut threads, in all likelihood. Both are made a problem by that design.
    .
    Feature-vise the grizzly G4003(G) looks like lot more lathe than PM 1127 for roughly same money. ie. gearhead with 70 to 1400rpm range and full blown quick change threading gearbox.

    Used old iron can be great but somewhat rare and/or pricy in the most wanted "garage lathe" sizes (10 to 13" swing, 30-40 inches between CC)
    Last edited by MattiJ; 01-11-2019 at 11:32 AM.

  6. #76
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    The Grizzly G4003 is certainly an even better option than the PM 1127, if the price is not a deterrent. It ticks all the boxes for power, size and has a stand included.

  7. #77
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    But now we're moving up to a whole other level. It's indeed a great machine. I'm not going to argue at all since it's the size I've got But it may be a lot more "involvement" than lowlyslow wants to dive into just yet.

    From what Brian was nice enough to come on and post I'm going to suggest that there's "theory" and then there's "first hand experience". And I'm not so proud as to admit that I can go off the deep end now and then. And with that in mind I'd say that the Brian's first hand experience counts for more than my own hand wringing. Clearly even if not perfect the variable speed machines are at least usable to a good degree for that size of lathe. And it would certainly keep lowlyslow's initial entry price down to where it's a touch less shocking to his heart....

  8. #78
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    Quote Originally Posted by BCRider View Post
    But now we're moving up to a whole other level. It's indeed a great machine. I'm not going to argue at all since it's the size I've got But it may be a lot more "involvement" than lowlyslow wants to dive into just yet.
    You know how these threads go.
    Beginner asks about x*y lathe and we are arguing about various models, merits and different sizes of lathes until we come to agreement that You really need at least 4 different size lathes from 6" bore 65000lbs Kransnoyarsk metal kombinat behemoth to swiss watchmakers lathe.

  9. #79
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    I know what you mean. Remember Cennad's thread asking about a lathe for his closet size shop? It only took one page before suggestions for lathes that would not even fit into his available room were being made.....

  10. #80
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    Michigan
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    So the OP is in Virginia. That makes a huge difference. He should have quite a lot of options for great lathes not very far away.

    Yes Virginia, there is a Santa Clausing.

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