fine tuning rpm for least vibration.......

[Odie]

Scott Brandstetter's post on vibration reminded me of something that I thought I'd pass along. This is a discovery I made quite by accident a few years ago. On top of my lathe's headstock, you'll see a magnetic base with a 3-piece adjustable arm. There is some green tape on the arm sections. This is two magnetic bases used for attaching a dial indicator, which I've combined to be used for attaching a laser pointer for another purpose. In the past, I've used my fingers on the lathe bedways to determine the least vibration by fine tuning spindle rpm. I noticed this 3-piece adjustable arm vibrate with much more sensitivity than I could detect with my fingers, so I'm now using it every time.

Fine tuning for vibration is a crucial element in accomplishing some very difficult and critical finishing cuts to the highest possible degree of integrity.

At one time, I tried to improve on the concept, by making a thin antennae wire like affair vertical to the headstock, but found that the 3-section magnetic base was the better indicator of very small and almost undetectable vibrations.

If anyone is interested in the original purpose of the laser pointer, let me know......but I'll have to take photos to show it.

ooc

 

[Bill Boehme]

I have a goose neck LED lamp that serves a similar function, but I find that it is necessary to take its shaking with a grain of salt. While the lamp goose neck is stiff, it isn't absolutely rigid which means that it will have a resonance determined by its own mass, spring constant, and damping that may or may not be a good indicator of how much the lathe with its spinning mass are shaking. Because of this, I use a sanity check to make sure that it isn't just the lamp that is shaking. Even if I can't feel the lathe shaking I often dial the speed back a bit just to stop the lamp from shaking.

 

[Bill Boehme]

BTW, as everybody knows, the purpose of a laser pointer is to entertain the cat.

 

[robo hippy]

I use the lamp as an indicator as well. If the lathe is vibrating, so are your cuts and the piece you are turning. While in coarse roughing cuts, it isn't critical, with very thin pieces if you want anything approaching uniform wall thickness, you have to have 0 vibration.

robo hippy

 

[Odie]

BTW, as everybody knows, the purpose of a laser pointer is to entertain the cat.

....and the dogs! 😀

I use the lamp as an indicator as well. If the lathe is vibrating, so are your cuts and the piece you are turning. While in coarse roughing cuts, it isn't critical, with very thin pieces if you want anything approaching uniform wall thickness, you have to have 0 vibration.

robo hippy

Yes, very true, Robo Hippy.......roughing cuts aren't as critical, but finishing cuts most definitely are!

ooc

 

[Fred Belknap]

I'm also curious about the piece of wood attached with a lot of tape to the arms of the light.😕

 

[Odie]

I'm also curious about the piece of wood attached with a lot of tape to the arms of the light.😕

I'm not sure I'm willing to divulge that highly secret invention of mine, Fred.......😀





Heh,heh,heh......just kidding! I do a lot of adjusting of the three lamps mounted on top and backside of the headstock, and those pieces of wood taped to the lamp arms are nothing more than a way to help me make quick adjustments a little easier for my hands......🙂

ooc