Supping up the mini lathe

Re: Supping up the mini lathe *LINK*

Fred in NC

>I did a conversion. I mounted my DC motor inside a cabinet I built for the lathe. I had to get a new pulley (from Jet Tools) because it had to be bored out slightly to fit the 5/8" shaft in the new motor, and I wanted to keep the original pulley mouted in the original motor that came with the lathe. I also bought a new longer belt from Aarubco Rubber Co.

From what is in the market right now, you might

want to contact Surplus Sales (no affiliation). They have a couple very nice DC controllers, at $60 or less, and suitable surplus DC motors to go with it.

Some of these DC motors are rated at much higher HP than you would consider adequate. The motor I use in my Jet Mini is rated at 1.5 HP. Remember, if you run a motor rated at 130 VDC from a 90 VDC controller you will only get about 1 HP.

Remember that controllers such as the Minarik (highly recommended) from Surplus Center are rated at one amperage as they come from the factory, and a much higher amperage if you add additional heat sinking. Mounting the controller on a larger metal plate, with air circulation in the back will increase the amperage rating.

Hope this helps. Feel free to ask questions, there are several others in this forum who have done the conversion.




Surplus Center

Re: Supping up the mini lathe

Don Henthorn

>I made the same conversion except that I placed the motor at the endo f the lathe.






This converter came with a circuit board and a potentiometer which needed to be mounted in a home made box. It wasn't a hard job and the difference in the performance of the lathe is weel worth it.

Re: Supping up the mini lathe

Lan Brady

>Another question, instead of an answer. How about a used tread mill motor and controler. Would that work?

Lan

Re: Supping up the mini lathe

Don Henthorn

>The motors that Fred and I used are surplus treadmill motors. However the controllers for treadmills require some different features because of their use and unless you have an electronics garu as a friend it might be difficult to figure out how to disable the features you don't need. As an example, when the treadmill is turned off the speed goes back to zero, not a feature you want on a lathe.

Re: Supping up the mini lathe

Danny Wells

>I did it with a 1 HP AC motor. The thing about going with AC is that the motor has to be 230 volt 3 phase in order to get the variable speed and reverse. I used a Penta KB power inverter that will accept 115 volt or 230 volt single phase input. It converts the input to 230 volt 3 phase. I love it. The wiring was not difficult. Other than using the AC rather than DC, my set up is very similar to Freds.

My photo files are too large for an upload. However I have written an article on how to do this and would be glad to e-mail it to you with photos if you would like.

Re: Supping up the mini lathe

Dan Lanicek in TX

>Don,

So you used one of those circuit boards? Do they have a on/off switch and speed knob on them? All the pics I've seen of them are at an angle that I can't tell.

Re: Supping up the mini lathe

Dan Lanicek in TX

>Fred,

How did you bore out the pulley?

Also, how feasible is it to replace the pulley on the spindle? I was thinking of replacing it with a standard V-belt pulley so that I could use a standard pulley on the motor as well.

Thanks for the info,

Dan

Re: Supping up the mini lathe

Dan Lanicek in TX

>Danny, I would love to get a copy of that article.

Thank you,

Dan

Danny, I would appreciate a copy also! Thanks

Clem Wixted

>

Re: Supping up the mini lathe

Fred in NC

>The motor pulley in the Jet Mini is aluminum in a metric size, and almost 5/8". I just used a 5/8" drill bit and carefully drilled it out.

I bought a new pulley from Jet Tools. The motor that came with the Jet is still in place, pulley and all. A change of belt is all I need to use the old motor. I did this for two reasons:

1. I can unbolt the lathe from the cabinet and take it with me.

2. I have a spare motor ready to go.

A copy for me too please

John Trant (Baltimore/DC area)

>I would like a copy if you are able to send it via email. Drop the 2 for email(i.e., boxesandbowls@comcast.net)

Thanks!

John

Re: Supping up the mini lathe

Arch

>Hi Dan, I think that getting in over your head depends on why you want to make the conversion. If you like to tinker, have the tools and the know-how to enjoy this facet of the hobby (that takes time away from the the lathe) then adding VS is feasible and a good project. I don't think increased HP is needed. Overall, it's less expensive and better turning technique to use gentle cuts and a loose belt. I suspect that most of the successful conversions were made by competent people who enjoy tinkering and took advatage of a one-time Vega bargain.

OTOH, if you are converting a minilathe to VS yourself, primarily to save money, I think you should consider selling your lathe and buying a used or even new VS minilathe. Make up the difference from things you know how to do (sell something, overtime etc.) and spend your time turning on your lathe instead of working on it.

I don't mean this as condescending or rain on your parade. I've made projects for lathes as well as on lathes, but I've not always been glad I did. :)

Good luck in whatever you decide to do and let us know the outcome.

Best, Arch

Re: Danny, me too. TIA

Arch

>

Re: Supping up the mini lathe

Kudzu

>Excellent timing on this. I just bought a lathe with no motor. I have a 1P motor laying around I was planing on using. But I keep thinking about just buying a DC motor or a 3Ph AC motor. I just am not sure of which way to go. Any advantages of one over the other? Cost?

U can use a single phase AV motor too *LINK*

Kudzu

>Decided to ring my Electrician buddy up and ask him about this. He worked in an industrial setting and is extremely sharp on this stuff. I was asking him about DC motors, 3 phase motors etc what was the best option..

After explaining to him I was looking for variable speed on a lathe and that I had a a single phase motor laying around he told me I could buy a motor controller at Grainger that would work with it. I didn't need to buy another motor. A quick search I found Dart brand 1.5 HP controllers for around $150-$175. Pricey but cheaper than going out and buying a new motor and controller.

So if you have enough HP on your lathe and would like Variable Speed looks like it is not that hard nor 'too' costly to do. Looks my my new/old lathe with be variable speed!

On the link look at the bottom of the page for Dart Controllers.


Dart controllers at Grainger

Why are these not used routinely?

John Trant (Baltimore/DC area)

>Why would the lathe companies opt for 3 phase motors opposed to the more common single phase motors? My guess is that 1-phase motors will loose power at low rpms unlike 3-phase motors.

Does anyone know the pro and cons of using this controller with a single phase motor?

John

Re: Supping up the mini lathe

Don Henthorn

>Arch, I would have to disagree with you on getting the variable spped. The only advantage to the VS is that you don't have to move the belt, which you don't have to do very often anyway. The variable speed is handicapped by the same speed range that the nonVS has, so the only advantage is con venience. The advantage of the conversion is that the speed can be varied from 0 rpm to the top speed the lathe normally has whether VS or nonVS. I have found the low speeds to be a great advantage in sanding and finishing and is also helpful if a piece is badly out of balance. This particular controller has an extra circuit that maintains the torque at the lower end.

Re: Why are these not used routinely?

Don Henthorn

>From what I understand, John, you are right about loss of torque at the lower speeds for most converters. The ones that Fred and I used have an extra circuit which keeps the torque up at lower speeds.

Re: Why are these not used routinely?

Kudzu

>I think you onto something and the cost of the controller!! I am digging a bit deeper into this and still have some questions about these and how they work Not much information on the web that is not aimed at industrial uses.

One thing he did tell me was that HP did not stay constant. Is that not the case with a 3 phase and a converter?

Why are these not used routinely?

Dennis J. Gooding

>I am an electrical engineeer although not a specialist in AC motors. I would offer the following observations: Most large single-phase motors are capacitor-start motors. They operate as a two-phase motor until reaching a speed near their final speed (slightly below synchronous speed for the power frequency for which they are designed). At that point, a switch operated by centrifucal force reconfigures the motor to operate as a single-phase motor. These motors use a capacitor during start-up to produce the second phase, which ideally lags the phase of the suppied power by 90 degrees. There are at least two problems with trying to use the motor with a line frequency much less than the design frequency (to obtain a lower speed). First, the centrifugal switch will not actuate to change to the single-phase mode. Second, at the lower supply frequency, the phase shift produced by the capacitor will be much less than 90 degrees and the starting torque produced by the motor will be much less than at the design frequency. At some point, the motor will fail to produce useful torque. Dennis

Re: Why are these not used routinely?

John Trant (Baltimore/WashDC)

>One thing he did tell me was that HP did not stay constant. Is that not the case with a 3 phase and a converter?

My 3-phase 2 HP AC motor has plenty of torque at the low end unlike my VS 1.5 HP DC motor. The advertised advantage of variable frequency controllers on a 3-phase motor is that they maintain torque at low RPMs. I do not know the power curve verses rpm but I have not stalled out my 3-phase motor at low rpm which I cannot say for my DC motor.

John

Re: Supping up the mini lathe

Bruce Wiseman

>me too please.

Re: Supping up the mini lathe - LINK - *LINK*

Colin Spencer

>Dan

I upgraded a Record lathe using a 3 phase motor and controller. The details are at the link below.

Colin


Record Lathe Upgrade

Learned some more on this

Kudzu

>These controllers will not work with a capacitor start moto that we so typically have. Sorry about the misinformation.