Lathe speeds

[Dave Harding]

The electrics on my lathe failed recently and I had to get a new inverter from Haydocks. This has been fitted now and the lathe is working.

My question relates to the lathe speeds which seem to be different compared with the previous setup.

Is there any way I can check what the actual new speeds are?

Thanks.

Dave

[Duncan A]

If the inverter has a motor speed readout, you can calculate the lathe spindle speed from: motor speed times motor pulley diameter divided by spindle pulley diameter.

Alternatively, there are a number of cheap iPhone and Android tachometer apps which strobe the flash to give a speed indication.

eBay has a cheap digital tacho which may do the trick if you don't mind spending £15.
http://www.ebay.co.uk/itm/like/141266596309?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&rlsatarget=&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

Or just blag a digital tacho and a bit of reflective tape from a mate in your local garage or engineering works!

Duncan

[Dave Harding]

Thanks Duncan. I don't mind £15 so will consider all your options.

I never really thought about whether the settings on the lathe dial was accurate before, whether the knob pointing to 1000 revs actually gave 1000 revs, but the new situation has made me think about it.

Thanks again,

Dave

[Lazurus]

Is the exact speed of the spindle an issue, I just go by is the speed right for the job at hand to give the best finish in safety. My lathe also has speeds marked but I have never taken any notice...... now I might have to.... OCD.

[GBF]

Is the exact speed of the spindle an issue, I just go by is the speed right for the job at hand to give the best finish in safety. My lathe also has speeds marked but I have never taken any notice...... now I might have to.... OCD.

Absolutely  I don't think I ever look at the speed read out it is more important to start at a low speed and turn it up to what is safe.

Regards George

[bodrighywood]

Must agree that speed is important, what the speed is isn't. I couldn't tell you what speeds I am using at any given moment. Turn down before switching on and pick up as you go along as necessary, better too slow than too fast IMHO.

Pete

[Dave Harding]

Thanks for comments. I am turning quite happily without knowing the speed of the spindle, just using the ' the if it feels right it is right' method.

The obvious slower speed I now get just made me think "have the stated speeds ever been accurate". Guess I'll never know!!

[bodrighywood]

Speed on a lathe depends on what you are turning, the stability of the lathe etc so as George says always start with the lathe turned down tghen increase. Too slow is better than too fast. If you have a lathe where speed changing means having to change the belt it is tempting not to bother but when you find a lump flying past you at speed or worse stopping in the middle of your face you will wish you had. So far it hasbn't happemeed to me but I know of people it has and it ain't worth the minute or two to change speed. Always worried me a little that some of the cheaper small lathes have a bottom speed of about 700rpm which IMHO is far too fast for some off centre things or when starting up between centres with softer woods. 

Pete