DC conversion on lathe.

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Torch
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Re: DC conversion on lathe.

Post by Torch »

Yes, I like the advantages of a PWM controller. But the KBMM-125 you linked to is an SCR controller, not a PWM controller. Since the motor comes with a working SCR controller, I don't understand the need to replace it with another SCR controller?
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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid »

Ooooops! I screwed up again and guess should have read a little closer! Page 1 SCR Controller. One of these days I'm going to find someone to give me adult supervision. LoL :oops:
Torch
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Re: DC conversion on lathe.

Post by Torch »

The man who doesn't make mistakes is either lying or dead. And if he's dead, there's a good chance it's because he made a mistake... ;)
rbertalotto
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Re: DC conversion on lathe.

Post by rbertalotto »

I wrote an article on this type of conversion on my web site. Do a search on the web site to find it

www.rvbprecision.com
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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid »

rbertalotto wrote:I wrote an article on this type of conversion on my web site. Do a search on the web site to find it.
http://www.rvbprecision.com
Some very nice mods there!
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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid »

I just saw an interesting mod for the lead screw. Instead of making idler gears a guy added a reversible DC motor on the right end of the lead screw. He used a 50 rpm motor and of course a DC controller. That way just take the lead screw out of gear and use the motor for fwd/rvr motor for shuttling the carriage or cutting left hand threads.
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NP317
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Re: DC conversion on lathe.

Post by NP317 »

LX Kid wrote:I just saw an interesting mod for the lead screw. Instead of making idler gears a guy added a reversible DC motor on the right end of the lead screw. He used a 50 rpm motor and of course a DC controller. That way just take the lead screw out of gear and use the motor for fwd/rvr motor for shuttling the carriage or cutting left hand threads.
Welcome to the wonderful world of Hardinge lathes!
~RN
Torch
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Re: DC conversion on lathe.

Post by Torch »

LX Kid wrote:I just saw an interesting mod for the lead screw. Instead of making idler gears a guy added a reversible DC motor on the right end of the lead screw. He used a 50 rpm motor and of course a DC controller. That way just take the lead screw out of gear and use the motor for fwd/rvr motor for shuttling the carriage or cutting left hand threads.
I think you'd need a rotary encoder and a stepper motor to synchronize the lead screw to the chuck rotation in order to cut threads. It would be a fast and easy way to change thread pitches though!
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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid »

Torch wrote:
LX Kid wrote:I just saw an interesting mod for the lead screw. Instead of making idler gears a guy added a reversible DC motor on the right end of the lead screw. He used a 50 rpm motor and of course a DC controller. That way just take the lead screw out of gear and use the motor for fwd/rvr motor for shuttling the carriage or cutting left hand threads.
I think you'd need a rotary encoder and a stepper motor to synchronize the lead screw to the chuck rotation in order to cut threads. It would be a fast and easy way to change thread pitches though!
Ahhhh yes! I see what you mean. The chuck would not be in sync with the chuck. Think I'll scrap that idea and just worry about the basics. LoL
rbertalotto
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Re: DC conversion on lathe.

Post by rbertalotto »

Powering the lead screw isn't for threading. It is to remove all gear vibration and the resulting pattern this imparts on the part being turned.

It also allows you to change the speed of the cut while under power resulting in a much better surface finish...

And a bonus is it is MUCH quieter so you can hear the scope of the ball game on the radio......

Check out my conversion here

www.rvbprecision.com
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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid »

rbertalotto wrote:Powering the lead screw isn't for threading. It is to remove all gear vibration and the resulting pattern this imparts on the part being turned.
As a novice this doesn't make sense to me. Change gears working with the speed of the lead screw determine TPI. Am I wrong here?
Torch
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Re: DC conversion on lathe.

Post by Torch »

You are correct. The change gears synchronize the speed of the chuck with the speed of the carriage travel, and hence, the TPI.

What rbertalotto refers to is when using a very, very fine "TPI" -- thousandths per revolution -- as a feed for turning. Any slight vibrations can show up as visible imperfections in the finish.
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