Variable Speed Motor for Taig Lathe?

[Danuzzo]

Let me preface this thread by saying that I know very little about electronics. However, I want to modify my Taig lathe by replacing the AC motor with one that I can use a reduced speed. The lowest spindle speed on the stock Taig is around 525 rpm. I have seen that many have converted to a DC motor with variable speed. Also many have used a Sherline motor and controller. I like the Sherline idea; but, I don't like the price, about $380.00 with shipping.

I am looking (and have searched the web) without success for a less expensive alternative that I could just basically just drop in as far as the electronics are concerned. I just don't know what to buy as far as a separate motor and compatible controller. Any info in this regard would be greatly appreciated.

 

[djc]

A motor and controller off an industrial sewing machine could be a good fit. These are available from overseas sellers at a good price.

What you would have to look at is how to control the speed - the standard foot control used on a sewing machine would not be suitable. In this sense, there are no electronics involved, just a re-engineering of the mechanical part of the speed control. You would also need to make the motor pulley compatible with the Taig pulley.

A small three phase motor and VFD could be an option, but is less plug-and-play than above. The physical wiring is simple, but you have to decide if programming (consisting of setting multiple parameters of) the VFD fits comfortably in your skill set.

 

[timo_gross]

Let me preface this thread by saying that I know very little about electronics. However, I want to modify my Taig lathe by replacing the AC motor with one that I can use a reduced speed. The lowest spindle speed on the stock Taig is around 525 rpm. I have seen that many have converted to a DC motor with variable speed. Also many have used a Sherline motor and controller. I like the Sherline idea; but, I don't like the price, about $380.00 with shipping.

I am looking (and have searched the web) without success for a less expensive alternative that I could just basically just drop in as far as the electronics are concerned. I just don't know what to buy as far as a separate motor and compatible controller. Any info in this regard would be greatly appreciated.

How much power does the old motor have? What rpm range? I bought the drill press with a 3-phase motor and put a 2nd hand VFD on it. (can be adjusted with a knob now, and it can run in reverse) *VFD runs from a single phase outlet*

Some sewing machine motors seem to come with a control box and knob for speed control. (look for Sewing machine servo motor.) Seems it requires a 220V input to the thing (single phase) and claims 200 - 6000 rpm.

 

[ShopShoe]

I remember someone made a simple speed reducer by using a countershaft system. Basically, a shaft with two additional stock TAIG pulleys was made so that the motor could drive the countershaft with one set of cone-pulley belt speed adjustments, then the other end of the countershaft used another pulley and belt to drive the lathe spindle, providing another set of speed adjustments. This is similar to Blue Heeler's posting on "Transmissions":

https://www.homemodelenginemachinis...de-for-model-engines-ball-bearing-hint.36337/

A quick, maybe temporary solution that might get you started.

Meanwhile, a quick google will get lots of links to approaches to variable-speed motors. Try "TAIG lathe speed....." combinations.

--ShopShoe

 

[Steamchick]

I fitted the sewing machine option son by Timo Gros above. Very easy conversion. Simple wiring, just plug it in and go! There are motor spindle options so I selected the spindle for my original motor spindle. Easy to swap over.
Speed and power are much better than the previous brush motor option. More torque at lower speeds.
The best I found and works well
K2

 

[Danuzzo]

How much power does the old motor have? What rpm range? I bought the drill press with a 3-phase motor and put a 2nd hand VFD on it. (can be adjusted with a knob now, and it can run in reverse) *VFD runs from a single phase outlet*

... ...

Current motor (no pun intended) is 1/4 H.P. Rpm is 1725. That picture you posted interests me. I would need 110 (120) volt however. The Taig lathe needs very little H.P. to run.

 

[Danuzzo]

I remember someone made a simple speed reducer by using a countershaft system. Basically, a shaft with two additional stock TAIG pulleys was made so that the motor could drive the countershaft with one set of cone-pulley belt speed adjustments, then the other end of the countershaft used another pulley and belt to drive the lathe spindle, providing another set of speed adjustments. This is similar to Blue Heeler's posting on "Transmissions":
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--ShopShoe

I saw something like that for a Taig somewhere. Maybe YouTube. I like the idea.

 

[clockworkcheval]

Hi Danuzzo, on my TAIG I mounted a 300 Watt 24 Volt DC motor of nominal 6.000 rpm. It was originally intended for a robot-actuator. With the DC controller and the original pulley set I get a rpm range from about 20 rpm to 20.000 rpm. The high revs are useful for drilling holes well
under 1 mm diameter. for The motor is mounted on a simple hinge. The TAIG itself is mounted on a length of U-beam that also contains the controller.

 

[djc]

I would need 110 (120) volt however.

Plenty available on AliExpress.

https://www.aliexpress.com/w/wholesale-110v-brushless-servo.html

Shaft size seems to be 15mm, so you would need to check if a standard Taig pulley would accommodate that.

 

[Danuzzo]

Plenty available on AliExpress.
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Shaft size seems to be 15mm, so you would need to check if a standard Taig pulley would accommodate that.

Thank you for the link. Looks like I should be able to find something there. As to size of shaft, I think the Taig is 5/8" which is a little larger than the 15mm; but, I should be able to make an adapter.

 

[Danuzzo]

I found one on Amazon. Looks just like the one Timo showed. Here is the link: https://www.amazon.com/XXSTAR-Controller-Drilling-Woodworking-Machine/dp/B0CMV558SD

It goes down to 200rpm. Anyone know what the torque would be like at this rpm? Anyone using one of these?

Edit: With the 200rpm, what kind of spindle speed would get using the Taig pulley that gives me around 525 spindle rpm? Is there a formula for this calculation? The current motor runs at 1725 rpm.

 

[timo_gross]

I found one on Amazon. Looks just like the one Timo showed. Here is the link: https://www.amazon.com/XXSTAR-Controller-Drilling-Woodworking-Machine/dp/B0CMV558SD

It goes down to 200rpm. Anyone know what the torque would be like at this rpm? Anyone using one of these?

Edit: With the 200rpm, what kind of spindle speed would get using the Taig pulley that gives me around 525 spindle rpm? Is there a formula for this calculation? The current motor runs at 1725 rpm.

Roughly the diameter ratio. Or 525 rpm / 1725 * 200 = 61 rpm. (ballpark) no idea what torque comes out of this. (depends on motor) In doubt I would adjust pulley diameters.

 

[Toymaker]

Does your current Taig motor motor have brushes? If yes, than it's most likely a "Universal" motor and will happily run on AC or DC, and there are many variable DC motor drivers available.
If your Taig motor is strictly AC, (likely an induction motor) than considering it's low power needs, you might be able to use a light dimmer as a speed control.

Good luck with whatever you decide.

 

[djc]

In doubt I would adjust pulley diameters.

There is a torque figure quoted in the link provided by Danuzzo.

Please consider the picture above from clockworkcheval. The pulleys shown are standard Taig items. The smallest diameter is not far removed from the shaft inside it meaning it might not be practical to make this smaller.

Hence, in order to produce any further speed reduction, the driven pulley on the lathe spindle would need to be increased. Making a 6-step pulley as shown is not an easy task.

 

[Steamchick]

You could always mount an intermediate shaft with double idler pulley, giving you - say - a 2:1 or 3:1 reduction?
My Unimat SL3 does that successfully:

This view is after I re-motored to a DC brush motor (inside the original housing) and simple variable "speed" (Voltage) AC. power supply, and bridge rectifier.. With the gearing from the motor, I have better torque than previously, at all speeds.
K2

 

[stanstocker]

Let me preface this thread by saying that I know very little about electronics. However, I want to modify my Taig lathe by replacing the AC motor with one that I can use a reduced speed. The lowest spindle speed on the stock Taig is around 525 rpm. I have seen that many have converted to a DC motor with variable speed. Also many have used a Sherline motor and controller. I like the Sherline idea; but, I don't like the price, about $380.00 with shipping.

I am looking (and have searched the web) without success for a less expensive alternative that I could just basically just drop in as far as the electronics are concerned. I just don't know what to buy as far as a separate motor and compatible controller. Any info in this regard would be greatly appreciated.

I used this:

https://www.pennstateind.com/store/TCLVSKIT2.html?Category_Code=assorted-lathe-accessories

You will need to bore out the Taig pulley that mounts on the motor which will eliminate the smallest step(s). A simple aluminum 2/4 X 1 1/4 bar was mounted to the baseboard perpendicular to the axis of the lathe and the motor mounting plate was secured with a single bolt. A large washer plus a Belleville washer allows the motor to pivot firmly enough not to move in use but to allow easy belt changes. It's probably been 12+ years since I made this mod and while still doing clock work the lathe was used anywhere from seconds to hours almost every day.

Be aware that unlike the Sherline, this motor has no zero speed with the power on. When the switch is turned on the machine starts to run. Having both Sherline and Taig, the Sherline is a wee bit smoother in speed control and regulation, but not to the point that I ever considered spending the additional money to replace this motor with a Sherline motor and controller. FWIW, the Sherline motor controller is a readily available KBIC controller, this motor has what I believe is a clone of the same controller, but mine at least is not a true KBIC board.

I never found a need for very low speed on the Taig, although it might be nice if you like to run in taps or run does without hand cranking.

 

[Danuzzo]

Roughly the diameter ratio. Or 525 rpm / 1725 * 200 = 61 rpm. (ballpark) no idea what torque comes out of this. (depends on motor) In doubt I would adjust pulley diameters.

Thanks. You made it very simple to grasp. I would imagine the torque of the motor would not be great at 200 rpm, but I don't think I will need to go that low. To get 100 rpm at the spindle, the motor rpm would need to be approximately 350 giving me around 105 rpm at spindle. The motor torque would probably be a bit better at 350 rpm.

 

[Danuzzo]

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I never found a need for very low speed on the Taig, although it might be nice if you like to run in taps or run does without hand cranking.

I want a lower speed with some torque because I do machine steel on the lathe. Diameter is usually less than 1". I turned the C.I. piston of my current Webster build on the Taig, and I would have liked to lap the piston on the Taig, but I think the speed would have been too fast. I also think that I may have been able to machine the Webster steel cylinder with the Taig with lower speed and more torque. Actually, I may have been able to do it in it's current state. It's not that I don't have a bigger lathe. I just like to challenge my capabilities (somewhat limited) and the capabilities of the Taig. By the way, I regard the little Taig as very capable within its size limitations.

Thanks for the link. I do like the Penn State set-up. How is the torque at around 350 rpm?