How to read bandsaw speed?

One thing to keep in mind with the strobe scale Poptop linked to. It will only work with the older magnetic ballast type of fluorescent. The newer electronic ballasts and the screw-in CFL bulbs run at a much higher frequency than 60 Hz. The strobe patterns will be way off. If you're going to use this method, you'll need a light source that's tied to the line frequency.

You will get some strobing with an incandescent bulb but it will be muted by the slower thermal reaction time of the filament.
 
Froneck said:
Other problem with marking the blade and checking the time if the 120" blade is running at at 10 seconds/ Revelation that means if you have a 1/2" wide mark it will wizz by in .02 seconds. Better keep your eyes open as it will zip by in a flash. A 1" wide mark will flash by in .04 seconds.

Frank
Click to expand...

I thought you might have a point Frank so I verified the procedure on my saw and it's actually pretty simple to do. I set my saw as fast as it would go and was easily able to see the blade weld as it went around. The blade length was 96" and the rotation time was 1.5 seconds (I counted 10 revs and averaged it out for greater accuracy). That works out to 320 feet per minute. I always wondered what the speed was, but never took the time to check it out.

Maybe we should start calling you Harry...as in doubting Harry? ;)

Tom
 
A siple white mark on the blade and a counter to count the laps then multiply times the overall blade length to get Inches per minute. Divide that by 12 abd you have the exact Feet per minute. You can even use a photo sensor and a timer to do that for you and output it to a 7 segment electronic display. LMK if you would like some help building the circuit or connecting it up. I'll be more than glad to put in my .02 if it will help you out.
Bob
 
I've used the method Tom described many times, and it doesn't get much easier, short of a built in speed indicator, which some of the larger saw have. There's no problem seeing the mark go by. I've marked with a Sharpie and a paint pen with good results. If the weld is visible, no additional marks are necessary.

Or just buy one of these and be done with it.

http://www.starrett.com/saws/saws-h...ssories/pocket-laser-tachometer-kit-with-case
 
:holdphone: Challenge for Frank. It takes no math. No bookwork, no googling and no homework. Just seat of the pants machine savvy.

Go mark your bandsaw blade that is on the saw with any color that you can see. Now stand so you can see the mark you made. Are you with me so far? Turn the saw on and tell us if you can see the mark as it comes around? Frank, this has been done this way long before I became a machinist. It is proven fact. There are some of us that know what we are doing.

Sorry guys, this time it got the best of me.

"Billy G" :))
 
Frank, the challenge was to you directly to try the method you said was no good. No one asked what was on your saws. You need to be thinking about what the other guys have on their saw, and solutions for their problems. It has nothing at all to do with your equipment. And I doubt that every saw you either owned or operated had the accessories you now say you have. Try, just this once, to put yourself in the other guys shoes and see how they live.
 
i use the strobe from a normal light bulb every time i turn on my sherline ( i got this off their site pic to print and all )
its a wheel printed out on paper glued to the spindle pulley and since 60 cycles never changes in the US it is dead on
and very easy to see the speed. it is the marks that look as if they stop moving, no chart required.
steve
 
oh sorry i had to add this : florescent lamps have step up transformers that increase the voltage they do not change the cycles per second so they will still work frank but a regular bulb is easier to see.
note in the schematic there is nothing to change the cycles per second just a transformer
steve

Wiring-diagram-of-Fluorescent-Tube-Light-.JPG
 
well i learned something today
i'm wrong
then my paper dial for the sherline is based on that because it matches my electronic tach for mach3
steve
 
here is a pic of one
mine is a disc on the pulley and i only use the shop lights its easy to see
steve

lathetach01.jpg
 
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