OT - Tachometer for milling machine

[burninbriar]

Just want to show the antique tac I just got for my antique BP milling machine. Since I have a VFD I need some way of knowing how fast it turns at the various frequencies. I've heard you can figure it out by dividing the belt speed (marked on the machine) by the hertz but I can't figure out how to get the VFD to show the operating frequency. I'm sure there is probably some way, but the book is really confusing.
Anyway, although I already have a tac for it, I could not resist this one when I saw it. It has 3 speed ranges, 500, 1000 and 5000 RPM. Its made by American. Really my style.
Check out the pics.

[monte55]

I just love old meters, dials, etc. I love brass dial cases and beveled glass.

[N20Silverado]

You must have an old VFD. The one I set up last week has motor rpm setting. You tell it what speed motor it is and then when it runs it will tell you how fast the motor is turning. Although that is good information, it is useless if you can't do the math in your head for the tool speed. Looks like your tac will fit your needs perfectly.

[Burnt hands]

tach for milling machine

Pete,

Harbor Freight has a digital tach with optical sensor so no contact is needed.

Just got one and am having fun measuring everything I can stick a piece of reflective tape on.

Here is info.

www.harborfreight.com


PHOTO SENSOR TACHOMETER

Take accurate RPM measurements without wiring--without even touching object. Infrared beam detects RPM. Includes reflective tape. Runs on 4 AA batteries, not included.

* RPM range: 2.5 - 99,000
* Digital touch
* Stores last minimum and maximum reading
* Auto-zero adjustment
* +/- 0.05% accuracy
* 5 digit LCD display
* Includes case

ITEM 41727-5VGA

$56.99

[dandimand]

ditto on the digi tach I bought one for my mill to set the rpm for tapping .

[burninbriar]

You must have an old VFD. The one I set up last week has motor rpm setting. You tell it what speed motor it is and then when it runs it will tell you how fast the motor is turning. Although that is good information, it is useless if you can't do the math in your head for the tool speed. Looks like your tac will fit your needs perfectly.

My VFD was used, and free. It didn't work when I got it but it turned out that the faceplate was knocked out of whack and just refitting it took care of the problem.
Its an Allen-Bradley PowerFlex 4. I got the manual for it but it seems to be over my head. I got it figured out enough to get it programmed for general use but thats about it. Even if I figure it out, I would probably forget it by the next time I use it, thats why I just went with a tackometer.

Pete,

Harbor Freight has a digital tach with optical sensor so no contact is needed.

Just got one and am having fun measuring everything I can stick a piece of reflective tape on.


$56.99

I thought about a digital, but I don't get in the shop as much as I would like dew to health reasons so I did not want to get something that would let me down with a dead battery when I go to use it.
The HH Sticht I think is really accurate but I really like the antiquated stuff.
Like you, measuring everything you can stick reflective tape to, I was having a ball with the old American tachometer.

[SNUNEZ]

rpm

fabricator here rrying to mill
I need help with speeds and feeds is there a book easy to understand or is there a rule of thumb? I can use?

[NickP]

Kool!

Nice piece. I haven't seen one of those in some time.

[burninbriar]

fabricator here rrying to mill
I need help with speeds and feeds is there a book easy to understand or is there a rule of thumb? I can use?

Practical Machinist is a good forum.
http://www.practicalmachinist.com/vb...3;t=006781;p=0

Here is a good book from a link from them. Its a pretty big down load.
http://www.bbssystem.com/manuals/Lathe-Tutorial.pdf

The attachment I included is a chart to convert RPM of various Dia. to FPM.
I have another chart for FPM on different materials with different cutting tools but I have to try to find it. I have a copy glued to the VFD door in the shop but I should have a copy here some where.