# G0602 Spindle Pulleys



## adlerJ (Apr 28, 2021)

Hey everyone! So I recently acquired a G0602 and tooling for a decent price. I am very new to lathes, this is my first one. Anyways, the previous owner installed his own motor as the original died on him and he had this on hand. Though I am going to be installing my own motor and VFD setup more in the stock location. I was more concerned on the pulley side on things. The middle pulley set is not there, and it is just running from the motor pulley up to the spindle. He used it this way obviously, but I would like some advice if I should order a replacement pulley or just run it without the middle pulley with the vfd.

Thanks for your help!


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## pacifica (Apr 28, 2021)

adlerJ said:


> Hey everyone! So I recently acquired a G0602 and tooling for a decent price. I am very new to lathes, this is my first one. Anyways, the previous owner installed his own motor as the original died on him and he had this on hand. Though I am going to be installing my own motor and VFD setup more in the stock location. I was more concerned on the pulley side on things. The middle pulley set is not there, and it is just running from the motor pulley up to the spindle. He used it this way obviously, but I would like some advice if I should order a replacement pulley or just run it without the middle pulley with the vfd.
> 
> Thanks for your help!


Seems like the more direct the better. I have several direct drive machines and they are smoooth.
With a vfd the pulley sizes are extremely important so you get the full range of speeds using the vfd.
Also I can't stress enough using machined and balanced pulleys with a cogged gates belt( i prefer very  slightly loose).


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## RJSakowski (Apr 28, 2021)

I have a G0602 and I definitely favor keeping the full pulley set.  Many who do the VFD conversion elominate the intermediate pulley, relying on the VFD to provide the lower speeds.  My position on this is that reducing the speed with pulleys also increases torque proportionally.  Most VFD setups suffer from lack of low end torque. 

It is a simple fact that torque is the product of horsepower and speed.  Horsepower is fixed by the amount of power the motor can accept so reducing speed means a reduction in torque.  The stock 602 has a 1 hp motor and a low range spindle  speed of 150 rpm, it has a pulley ratio of 11.5 and 35 lb-ft., less losses.  A 1 hp 1725 motor with VFD operating without the benefit of the intermediate pulley and on the low range would have a pulley ratio of 2.4 and if the VFD dropped the spindle speed down to 150 rpm, the available torque would be 1.5 lb-ft., again less the losses.

I am in the final stages of converting my 602 to a 2.5 hp dc motor with a variable speed drive.  I have an encoder on my drive with a feedback loop that senses a decrease in speed with increased load allowing full power to be applied if necessary to maintain speed. which will provide me with an estimated 36 lb-ft of torque in the low pulley setting with spindle speeds as low as 15 rpm. 

In the high pulley setting, my spindle speed will have more tha doubled that of the stock setup at 5600 rpm.  This is due to a motor running over 4000 rpm.


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## adlerJ (Apr 28, 2021)

RJSakowski said:


> I have a G0602 and I definitely favor keeping the full pulley set.  Many who do the VFD conversion elominate the intermediate pulley, relying on the VFD to provide the lower speeds.  My position on this is that reducing the speed with pulleys also increases torque proportionally.  Most VFD setups suffer from lack of low end torque.
> 
> It is a simple fact that torque is the product of horsepower and speed.  Horsepower is fixed by the amount of power the motor can accept so reducing speed means a reduction in torque.  The stock 602 has a 1 hp motor and a low range spindle  speed of 150 rpm, it has a pulley ratio of 11.5 and 35 lb-ft., less losses.  A 1 hp 1725 motor with VFD operating without the benefit of the intermediate pulley and on the low range would have a pulley ratio of 2.4 and if the VFD dropped the spindle speed down to 150 rpm, the available torque would be 1.5 lb-ft., again less the losses.
> 
> ...


Awesome! I figured as much, but knowing nothing of lathes I thought I would ask! I have a 1hp motor that I was planning on using to drive it. I will look for replacement pulleys! I am also planning on installing encoder and other goodies as well. Would a bigger motor be something you recommend?

Thank you!


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## CCCerakote (Jun 25, 2022)

RJSakowski said:


> I have a G0602 and I definitely favor keeping the full pulley set.  Many who do the VFD conversion elominate the intermediate pulley, relying on the VFD to provide the lower speeds.  My position on this is that reducing the speed with pulleys also increases torque proportionally.  Most VFD setups suffer from lack of low end torque.
> 
> It is a simple fact that torque is the product of horsepower and speed.  Horsepower is fixed by the amount of power the motor can accept so reducing speed means a reduction in torque.  The stock 602 has a 1 hp motor and a low range spindle  speed of 150 rpm, it has a pulley ratio of 11.5 and 35 lb-ft., less losses.  A 1 hp 1725 motor with VFD operating without the benefit of the intermediate pulley and on the low range would have a pulley ratio of 2.4 and if the VFD dropped the spindle speed down to 150 rpm, the available torque would be 1.5 lb-ft., again less the losses.
> 
> ...


Which motor did you pick? Im in the process of trying to pick a motor and was going to go 1.5 hp but now thinking about your 2.5 route?


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## RJSakowski (Jun 25, 2022)

CCCerakote said:


> Which motor did you pick? Im in the process of trying to pick a motor and was going to go 1.5 hp but now thinking about your 2.5 route?



I bought my motor from surpluscenter.com.  Their item no. 103037, model M-217250.

edit: It appears that they no longer sell that motor. https://www.surpluscenter.com/shop.axd/Search?keywords=treadmill+motor


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## woodchucker (Jun 25, 2022)

being in md, you might be close enough to https://cgsurplus.com/


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## CCCerakote (Jun 25, 2022)

Was the encoder something you added or comes on a specific motor or controller? Sorry this is new to me and I was sold on vfd until I read your post.. lol thanks again


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