Hi All!
these things came into the shop quite a while ago and it bugs me that i don’t know how to use them or what they are called. I can’t find anything on the starrett site. The tips are triangular carbide and the scale seems to count revolutions of the tip . The way it is weighted allows the scale to hang down while the tip rotates. I guessing that they work on a metal lathe somehow?
Thanks Tai
Replies
Their revolution counters. You insert the tip into a shaft and count the revs for a fixed time period like 15 seconds. RPM is thesn 4 times the count (using 15seconds as the time)
Tai,
When you need one of those guys they are invaluable. I used mine not to long ago to figure out the blade speed of my new old bandsaw. Any job where you are trying to get a certain RPM by changing pulley sizes can be made easier by these. Old Starrett tools are starting to get collecters attention, so their value will probably just keep going up. Nice find.
Thanks for the replies! I've actually NEEDED these things now that I know what they are for. I wish i'd posted before. I'm gonna go measure something!
Aloha Tai
Starrett makes three accessories that you might want for your speed indicator. Two of them are rubber tips that fit on the end of the spindle. One tip is pointed to fit in the center hole found on a lot of shafts, the second tip is flat on the end for shafts without a center hole. In most applications the rubber tips work better than the metal one, because they won't slip and throw off the accuracy.
The third accessory is a metal disk about 2 inches in diameter with a rubber tire on its rim. The disk has a circumference of 6 inches. Place the rim against something like a bandsaw blade and divide the rpm's reading by 2 and you have the blade speed in feet per minute. The easiest way to buy them is to go directly to Starrett. They're on line at Starrett.com.
John W.
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