There is value in digital readout.....but, if you don't have it, then what?

Discussion in 'Woodturning Discussion Forum' started by odie, Oct 9, 2017.

  1. odie

    odie

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    Many of us are constantly starting and stopping our lathes, and those who have digital rpm readout, have most likely discovered that knowing exactly what rpm produces the least vibration, is a real boon to getting the cleanest finish cut possible.

    I have many things that can, and do vibrate on my headstock.....and watching for the vibration, along with feeling for it with my fingertips, I can fine tune the rpm to the best possible rpm at any phase of the turning in it's progression to completion.
    IMG_3263_LI.jpg

    However, I do NOT have digital readout. In recent times, I've been using a little rare earth magnet with a colored dot applied to it. This magnet can be placed anywhere around the circumference of the potentiometer and I can align a designated point on the potentiometer knob with it. Works great! I can start and stop the lathe multiple times, and always quickly return to the best rpm without having to go through the time consuming process of finding the best rpm.
    IMG_3261 (2).JPG
    The rare earth magnet in a different location here:
    IMG_3262 (2).JPG

    -----odie----- :D
     
    Last edited: Oct 9, 2017
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  2. Zach LaPerriere

    Zach LaPerriere

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    Odie, I think you have it figured out and aren't missing much. In my experience at least, the best speed for vibration changes with each bowl. I've grown accustomed to looking at the tachometer, but it's just a reference.

    Where I get the most of seeing the RPMs is sanding, just as a reminder of where to start and to slow down as I progress upward in grits. This is fairly intuitive without a tach, but sometimes I notice I'll put the lathe on a little too fast.

    I do think the a tach really helps beginners, because they haven't developed the feel of things.
     
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  3. odie

    odie

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    You are absolutely right, Zach.......and besides the fact that each bowl has it's own best speed, and beginners, with use of the digital readout, have a reference that can be a valuable asset, but becomes more intuitive with experience.......each bowl can, and often times does change best vibration speeds as you remove wood. (We have to keep that in mind, and adjust as necessary......this is another advantage to having all those "visual" indicators of vibration I have on my headstock.)

    I usually don't care all that much while roughing......but, when I'm doing the 2nd turning, after the seasoning has taken place, the best rpm for vibration free (or the least vibration possible) can be a very critical factor in how much sanding needs to be done. :D

    -----odie-----
     
    Last edited: Oct 9, 2017
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  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    I don’t have Digital readout. I use the dial on my lathe as a gross adjustment.
    Each piece needs to be fine tuned for speed. For out of balance pieces it is finding a speed High enough to allow efficient removal of wood yet low enough to eliminate excessive vibration.

    I know to dial just below 3 on belt 2 for a good sanding speed.
     
    Last edited: Oct 9, 2017
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  5. Richard Coers

    Richard Coers

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    I've been turning for 32 years, never had a digital readout. Both big lathes I have had use a seperate on/off switch from the speed control. Never needed to know the speed, probably never will. I'm surprised you needed to label that stop paddle. Seems intuitive that is what it is, surprised you have to read what that paddle does each time, LOL.
     
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  6. odie

    odie

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    I know you're just kidding, Richard! :D

    ......just went over 35 years turning myself! :p

    It's not a matter of need, the paddle is labeled just as most things in my shop are. It's more habit than anything else......and, I don't even look for the stop paddle......just intuitively know where it is, and hit it without looking.;)

    -----odie-----
     
  7. Mike Brazeau

    Mike Brazeau

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    I borrowed a laser tach from a fellow guild member about ten years ago and put together a spreadsheet for the three belt positions on my 2436 and about six dial settings for each position. Have it taped inside a cabinet door and if someone wants to know what the actual speed is, I can tell them approximately what it is. Otherwise it is what I am comfortable with and used to doing. Do not miss not having a DR.
     
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  8. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Knowing a numerical value just clutters valuable storage space in your head and doesn't give you any advantage when it comes to tuning out vibration. You still have to go through the same exercise that you now do to find the optimum spot where the vibration is at a minimum. And, furthermore that continually changes as wood is removed and the mass balance of the piece is changing. Eventually, if there is still any residual resonance it usually is so small that it can easily be tuned out with just a small speed change.
     
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  9. Bob Mezzatesta

    Bob Mezzatesta

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    I think it's a bit like power windows and locks and heated seats. The older I get the more standard they become. I do find the tach useful when drilling to dial in the appropriate speed for the particular drill.
     
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  10. hockenbery

    hockenbery AAW Advisor Staff Member

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    How did it compare to the RPMx100 numbers around the speed control dial?
     
  11. john lucas

    john lucas

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    I've never had a read out on any of my lathes. Don't need it. MY 3520A does have a random number and you can look up the speeds on a chart. I only did that one time so when people ask me what speed I turn such and such at I can give them a rough answer. It's a lot less obnoxious than saying "I turn at what ever speed I feel is necessary". Which is true but sounds kind of smart assy.
     
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  12. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I've seen a few demonstrators who, when asked that question, took the time to explain why speed isn't as important as looking for other things such as lathe shaking, wood fluttering, or changes in sound from the piece of wood.
     
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  13. Doug Rasmussen

    Doug Rasmussen

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    Grizzly uses Delta VFD's. A local turner was throwing his out after Grizzly replaced it because of a misdiagnosed problem. He gave it to me along with the readout module. With some hassle I was able to get the VFD working. Delta pre-programs them at the factory and password protects the settings. Even Grizzly doesn't know the password. The factory settings disable the VFD keypad and limit speed to 120hz (actually not a bad idea to protect the lathe user).

    It wouldn't surprise me if Delta sells the readout as an option in case anyone wants it.. It's powered off the VFD and uses a pickup on the spindle to display actual rpm instead of the theoretical rpm based on the hz setting.
     
  14. Fred Belknap

    Fred Belknap

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    I never had a lathe without a DRO, so I am use to using it. I fined it very useful when I have a bowl on a vacuum chuck, I like to keep the speed around 500rpm , I guess I could guess at the speed but it's there so why not use it.
     
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  15. Tom Albrecht

    Tom Albrecht

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    This sounds a bit like "Been there, done that."

    That said, my first three or four lathes didn't have an rpm "readout", as is probably true for anybody here who's over 60, and started turning in high school. It is also true for loads of pro turners who've made loads of sales of fine art turnings done without the readout.

    I had it on my previous Oneway, but can't say I ever really looked at it. Then when I got my American Beauty I thought I better get a readout adapter, Feh-- why?
    I am sorry if I sound like a snob, I'm really not. OD really has it all worked out by feel, and I'm sure he doesn't really need that red magnet dot-- shite, look at the marvelous stuff he's posted here.

    I can see the value for instruction purposes, but honestly, every time I have had a piece break up or disintegrate (Both times-Ha Ha) I knew I was pushing the limits. I knew, because there is a sonic sense and feel that comes from having "Been there, done that".
     
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  16. robo hippy

    robo hippy

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    I never had a read out, so never developed the need for one. I did develop the feel for what I am turning, and how things are cutting. Fundamental in most martial arts as well. Just pay attention to the wood and your tools.

    robo hippy
     
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  17. Emiliano Achaval

    Emiliano Achaval

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    Never felt the need to know the speed, ever. Then I started chasing threads, lol. After doing so many boxes I'm starting not to be so worry about speed, even doing some without even checking, you develop a feel for it ...
     
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  18. john lucas

    john lucas

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    Emiliano that is the first time I started using the readout. I was struggling with thread chasing and wondered if I was using the proper speed so I looked up the number in my chart. Only helped a little because I guess I had the speed turned down far enough to begin with.
     
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  19. hockenbery

    hockenbery AAW Advisor Staff Member

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    Alan Batty told me to chase threads slow the lathe down until I could see the threads on the spindle.
    Don’t know what speed it is but it works.
     
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  20. Mike Brazeau

    Mike Brazeau

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    Al, here is a screen print of the speed chart. My 2436 is a 3 HP manufactured at the beginning of 2004.
    Oneway Speeds.jpg
     
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