Post
by pete » Tue Jan 18, 2022 7:39 pm
It's also not a direct apples - apples comparison either. There's fairly involved intricacies in design throughout the whole machine. Yes there both lathes and both cut metal. At the simple end and with everything else being equal, a heavier machine is going to be more accurate, produce better surface finishes and (generally) last longer. Mass also = rigidity, and rigidity is everything with machine tools. Look at the weight of those HLV's verses swing and distance between centers. And if I remember the specification correctly, those HLV's are guaranteed to have under 40 millionths spindle run out from the factory. From there it starts getting more complicated. For example the distance across the lathe bed way center lines verses there swing, and length of the carriage ways on those bed ways. Those two items alone when designed properly allow more stability to the components doing the actual work. And the further spread out they are the more stable and repeatable they are. The Monarch EE lathes as just one example plainly show those features were important to it's initial design. And there another lathe that's famous world wide for there accuracy. Bigger almost always means more HP, more HP with enough of that rigidity to justify the higher HP means larger depths of cut. That equals time savings and even better tool life.
It's also not just heavier and larger that are important, the machines individual parts design, durability, the built in accuracy level the factory made the machine to and multiple hundreds of other items equals what you'll get and what the machine can can physically do time after time and how long it can keep doing so. Even how the machine is initially set up in it's permanent location is very important if you expect the best accuracy it's capable of. And then there's the operators own skills and ability's. Simply owning a lathe is a lot different than actually being capable of operating one to it's full potential. That's why there's REAL machinist's and then us hobbyist's, although there are I think quite a few here who could easily be judged as both. ALL machine tools will deflect under a cut, how much is also extremely important and directly related to there design and capabilities. That's part of the heavier = better concept. Since you've owned aircraft I'll put it in that perspective, you wouldn't chose a Piper Cub for regular Atlantic or Pacific crossings. You'd want a heavier, larger, better designed and at least twin engine aircraft with a large fuel range. And you'd always want something in very good condition verses one verging on the FAA grounding it. And successfully making the trip itself has far better chances for a pilot with multiple years on multi engine aircraft verses a student pilot.
Like anything else there's always plus/minuses with every machine tool. And none are ever perfect at every task, budget, size etc no matter how well made or expensive it is. About all you can do is decide on something as close as possible to what your wanting it to do on average. And as always that inevitable budget dictates how close you can get to that ideal machine with the most accuracy. Then there's machine options. As just a single example, a full gear box with dozens of built in selections for imperial and metric threading is great. A more basic change gear lathe can sometimes be more versatile if you ever get outside what that built in gear box can do. Although there's also some that allow additional change gears between the spindle and that gear box to then allow even more changes to what those built in ratios can do. But if you refuse to ever single point threads and just use taps and dies, then the only gain is the gear box would at least allow multiple feed rates. The trade off with the more basic change gear machine is time to switch feed rates or thread pitches. At the hobby level the time is less important for most, it's still something to consider though. Unless you spend a huge amount, I honestly don't think it's possible for a more entry level person to chose a single one time purchase lathe. Needs, wants, and even project size change over the years with most ending up going larger or having more than one lathe. There's also enough I haven't mentioned that could easily fill up a War & Peace sized book.
