Variable speed rpm speeds

RB72

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I have a HF 7 x 12 mini lathe and a HF mini mill which both have a variable speed dial. Does anyone know if you set the dial to the mid point if you are actually turning at half the max rpm for that high or low speed. Trying to guesstimate rpm. Maybe someone that has attached a tach would know. Otherwise how do you all set the speed by material, etc. Just by feel and how it is cutting.
 
if you really want to know the exact rpm, you will need a photo tach. others here have stated that the listed rpm's are seldom correct. . .
then again, trial and error of cutting seems to suffice in most cases. little "blue" c-shaped shavings seem to be the preferred outcome.

then again, what do I know . . . . :think1:
 
When I setup VS on my lathe, I got a tachomater (handheld) to get a ballpark idea of speeds at certain positions of the dial + belt settings. after initial use - that was the last time I used that thing. I pretty much go by feel and try to find the sweet spot for each project as it goes. after a while once you are used to working certain materials over and over again you get the idea.
 
Is the hand held you have one of the inexpensive $10 - $20 ones I see on ebay, etc. If so do they work ok. Had not thought about that option.
 
I have one of those $20 ebay tachs and it's fine. It comes with strips of reflective tape. I put a 1/2" square piece on all the chuck backs and can spot-check if needed (which isn't all that often) and this works fine for me... It gives about the same results as a friction-type mechanical tach I happen to have but is a pain to use.


Ray


Is the hand held you have one of the inexpensive $10 - $20 ones I see on ebay, etc. If so do they work ok. Had not thought about that option.
 
I have both I like the digital that works with reflective tape. I bought mine at HF. I can't remember what I paid for it but I remember it was cheap and on sale. I also used a 20 percent coupon. Like the others I don't tend to use it a lot but it is nice to have when you need it. The are also useful on lawn equipment to set up the carburetor speed.
 
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