What's a speed indicator used for?

[pebbleworm]

It's like taking the pulse of the machine. If you have a variable speed motor with no tachometer it really is helpful in zeroing in speeds and feeds. At least for someone who has no claims to being a professional machinist. If you are dealing with this stuff all day, every day you would have a sense for it.

 

[mixdenny]

They still sell them, they are pretty much unchanged in 100 years. The earlier ones are collectible, here is part of my collection. Dennis

 

[The Liberal Arts Garage]

You're Mostly right- most useful in o.h. Belt days. The high- tech guy had a horse
timing watch in a hunting case. Gave mine away as a curiosity. ........BLJHB

 

[4GSR]

I bought one new in 1978 to use to set the analog tachometers to the motor RPM's on DC motors back then. The photocell ones they had back then cost over $1000 bucks! Company was too cheap to buy one. Now, I have one that that is electronic digital, still photocell, but much smaller scale, that I only paid about $35 bucks for. The Starrett one was half of my paycheck back then, a whopping $75! Something like that. I still have it, too.

 

[gi_984]

I actually picked up one off Craigslist for $20. I'll eventually get around to checking the actual speeds on some of my machines at different settings.