Estimating chuck speeds

[LouStule]

20 Bucks on Ebay, LCD display with a magnet and sensor.
Use this on my Lathes and Mill, all have VFD'S.
Easy.

I found it. It looks like a perfect solution. Thanks!

Found what? Do you have a link?

There are actually several (mostly from China) Easy search.

[LouStule]

Welll according to the pictures you posted of your lathe in the other thread you HAVE a speed chart!! With standard pulley setup those lathes went from 28 to 2000 spindle RPMs. 2 ranges of motor to countershaft and 4 on the spindle plus backgear.

Thanks. I mis-posted. I was actually talking about the spindle speed on my mill. Thanks everyone for the great info on this board.

[John Evans]

Thanks. I mis-posted. I was actually talking about the spindle speed on my mill. Thanks everyone for the great info on this board.

AH ! yes that do make a difference ! LOL Those no contact Tac's work great have used one for years.

[neanderman]

Look at the Motor Nameplate it shows the RPM most likely 95% x Line frequency X 60 / No of Pole pairs (either 1 or 2)
Typically 1750 RPM

Then measure the pulley diameters or gear ratios.

Just bear in mind, with v-belts, the ratio formula is not direct -- do an internet search on "v belt pulley ratio calculator".

Otherwise, Mario covered it. It's all math, and can be calculated.

[armscor 1]

I just glued a neodeom miniature magnet on the top of the final drive pulley and set the hall effect sensor in close proximity and works great, it has an inbuilt led which flashes everytime the magnet passes the sensor to indicate it is functioning. Great for VFD.