Gunsmithing 1or 3 phase for lathe,mill

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PCR

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Oct 28, 2006
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tempe, az
#1
I'm getting ready to purchase a lathe & mill for gunsmithing work and need to decide on single phase or 3 phase. I know there is an extra expense for 3 phase for the rotary converter.

I'm looking at the Jet 1440W lathe and a Jet mill in the 2-3,000# range.

My question: Is it worth the additional expense to buy 3 phase equipment. I will need an electrician to run power to the equipment either way.

Thanks,
Brad
 
#2
Re: 1or 3 phase for lathe,mill

Go with a single phase motor on all your shop equipment and you can't go wrong. For the small shop or hobby machinist, the additional monthly cost of power company three phase is prohibitive. There are more prospective customers out there for a used single phase machine than for three phase machines.

However, a simple conversion of a three phase motor into a rotary phase converter using the same hook up as your kitchen range or dryer (220V)is economical if you can pick up a salvaged three phase motor for a "near free" price. I have been using one for more than ten years on my SBL 13.
 
#3
Re: 1or 3 phase for lathe,mill

I too will suggest going with a phase converter, for a few reasons. It is very easy to do, it works fantastically, and it opens your options.

I say this, because for up here where we are, used 3 phase equipment is more plentiful and generally 'cheaper' than single phase, because of the "limited customer base" of 3 phase supply.

So the difference is substantial, once you have the converter. And with one in particular, two machines can be running off of one phase converter AT THE SAME TIME. You just have to start the "higher horsepower" one first.

Hope that helps.
 
#5
Re: 1or 3 phase for lathe,mill

the phase converter is the way to go, I just hooked up my gunsmiths(I am an electrician) and he has 4 machines on it, 5hp lathe, 1hp vert mil 1/2 horizontal mill, and a little tool grinder. As long as you get one that can handle the start up of your largest motor and is rated for all the combined horsepower you can run many many machines on it. He is a three man shop were no more than 2 machine run at a time. SO it work greats for them. If it is just you then you can lose with the phase converter. If you plan on running a bunch of machines and having a bunch of smiths in your shop then 3ph service is the way to go.
 
#6
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body">I too will suggest going with a phase converter, for a few reasons. It is very easy to do, it works fantastically, and it opens your options.

</div></div>

+1.... my converter cost me about $150 and my time to build it, works great...
 
#7
Re: 1or 3 phase for lathe,mill

There are two types of converters, a static version that just through electronics powers that 4th leg, or a rotary that actually generates it, the rotary is more money but works as good as having the 3 phase piped into your shop, you can also usually find deals on 3 phase equipment at sales because the average homeowner doesn't want to deal with the problem. I built a new garage a few years ago, had a rotary converter wired to feed several outlets in the shop, put in a remote switch and when I need one of those machines I go push the start button on the wall use the machine then turn it off. Food for thought.
 
#8
Re: 1or 3 phase for lathe,mill

I purchased my lathe (3 phase) and used a VFD or variable frequency drive on it. For one piece of equipment a VFD is a good solution as long as the HP is reasonable.

Static phase converters work but you will loose motor HP. I think it kicks the motor running and then pulses on two legs hence the power loss.

Rotary phase converters give you that 3rd leg and can run multiple machines if you don't mind the noise.

My lathe was in great shape at a good price so the VFD add on with a simple drum switch was a perfect solution. VFD's can be had on flea-bay for cheap if your watching. My Mitsubishi was $80 new for a 4 or5 HP model.
 
#9
Re: 1or 3 phase for lathe,mill

Good conversation, as I too have a similar question(s), not meant to hijack the thread. When y'all are talking about 3 phase, are you talking 440v? Will these converters power a 440v 3 phase off residential wiring?

Reason I'm asking is I had a Bader Grinder given to me a while back. This is what a lot of pro knife makers are using to grind their wares. The problem is that this grinder came with a 440V 3 phase 5hp motor. The logical place I have to hook it up is here at home in the basement, obviously I don't have the juice to do it.

Thought maybe going "amish" with it out in a shed I have with a through the wall driveshaft and a gasoline engine. Doable, but the gas engine/pillow block bearings/shaft would run me more than what some of you are talking on these "converters".

It goes without saying I'd rather have it downstairs in the basement hooked up to electric where the rest of my shop stuff is at. I've priced new 220v motors with the same size shaft but they're cost prohibitive right now.

Anyone with the expert knowledge who can help me resolve this problem with the motor I have, and do it inexpensively, can have a custom knife of their choosing at a tremendous discount, maybe even gratis if this thing will fly good enough/cheap enough.

Right now I'm building knives "by hand" at a whopping $1.60 an hour for the time and materials I have in 'em. Which means not a lot of knives are getting made very fast. If I can reduce the time to increase the profit y'all will see me enter the market pronto, website and all. Been told my knives are on par with Ingram and the rest, so it interests me greatly to go professional. Currently designing my own tactical profile which will likely go over well here on the hide.

First dude with the right know-how to coach me through this electrical problem via PM gets the deal..........

Just one example I've built recently, a little skinner in D2.
HPIM2638.jpg
 
#10
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Good conversation, as I too have a similar question(s), not meant to hijack the thread. When y'all are talking about 3 phase, are you talking 440v? Will these converters power a 440v 3 phase off residential wiring?

Reason I'm asking is I had a Bader Grinder given to me a while back. This is what a lot of pro knife makers are using to grind their wares. The problem is that this grinder came with a 440V 3 phase 5hp motor. The logical place I have to hook it up is here at home in the basement, obviously I don't have the juice to do it.

Thought maybe going "amish" with it out in a shed I have with a through the wall driveshaft and a gasoline engine. Doable, but the gas engine/pillow block bearings/shaft would run me more than what some of you are talking on these "converters".

It goes without saying I'd rather have it downstairs in the basement hooked up to electric where the rest of my shop stuff is at. I've priced new 220v motors with the same size shaft but they're cost prohibitive right now.

Anyone with the expert knowledge who can help me resolve this problem with the motor I have, and do it inexpensively, can have a custom knife of their choosing at a tremendous discount, maybe even gratis if this thing will fly good enough/cheap enough.

Right now I'm building knives "by hand" at a whopping $1.60 an hour for the time and materials I have in 'em. Which means not a lot of knives are getting made very fast. If I can reduce the time to increase the profit y'all will see me enter the market pronto, website and all. Been told my knives are on par with Ingram and the rest, so it interests me greatly to go professional. Currently designing my own tactical profile which will likely go over well here on the hide.

First dude with the right know-how to coach me through this electrical problem via PM gets the deal..........

Just one example I've built recently, a little skinner in D2.
HPIM2638.jpg
</div></div>



For your application I am assuming your house is 220 AC so you would need a step up transformer to get the correct voltage to feed in / out of a VFD. VFD's are great if the HP is small and for a single machine. Unfortunately a replacement motor might be less cost wise unless you get the transformer or VFD on the cheap.
 
#12
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Good conversation, as I too have a similar question(s), not meant to hijack the thread. When y'all are talking about 3 phase, are you talking 440v? Will these converters power a 440v 3 phase off residential wiring?

Reason I'm asking is I had a Bader Grinder given to me a while back. This is what a lot of pro knife makers are using to grind their wares. The problem is that this grinder came with a 440V 3 phase 5hp motor. The logical place I have to hook it up is here at home in the basement, obviously I don't have the juice to do it.

Thought maybe going "amish" with it out in a shed I have with a through the wall driveshaft and a gasoline engine. Doable, but the gas engine/pillow block bearings/shaft would run me more than what some of you are talking on these "converters".

It goes without saying I'd rather have it downstairs in the basement hooked up to electric where the rest of my shop stuff is at. I've priced new 220v motors with the same size shaft but they're cost prohibitive right now.

Anyone with the expert knowledge who can help me resolve this problem with the motor I have, and do it inexpensively, can have a custom knife of their choosing at a tremendous discount, maybe even gratis if this thing will fly good enough/cheap enough.

Right now I'm building knives "by hand" at a whopping $1.60 an hour for the time and materials I have in 'em. Which means not a lot of knives are getting made very fast. If I can reduce the time to increase the profit y'all will see me enter the market pronto, website and all. Been told my knives are on par with Ingram and the rest, so it interests me greatly to go professional. Currently designing my own tactical profile which will likely go over well here on the hide.

First dude with the right know-how to coach me through this electrical problem via PM gets the deal..........

Just one example I've built recently, a little skinner in D2.
HPIM2638.jpg
</div></div>
Many of the Baldor buffers were split voltage 220/440 check to see if you can change the leads on the motor to run on low voltage or post a picture of the motor tag
 
#13
Re: 1or 3 phase for lathe,mill

First to your question, just get the single phase equipment if you DO NOT already have 3 phase supplied to your location.

Second, used 3 phase is the way to go for the best bang for your buck. Not to mention I would rather have a 15 yr old Clausing Colchester then a brand new Jet.


But as others have stated, you will need some sort of power generation device if you don't have 3 phase power. If you want to have lines run to your locale, I was told by my power company a minimum of $50,000.00 a mile ( for 3 phase).

And actually there are 3 types of converters. Digital, which in my opinion is the best, is kinda pricey, aprox. 3k for a 20 or 30 amp model. These actually rectify and re-generate via IGBT's the legs. Then you have static converters, which the very basic models merely use a capacitor used to get your motor running, then pull the cap. out of the ciruit and run your equipment on the 2 legs of single phase provided (VFD's fall in this category, although you are able to manipulate the output). VFD's are relatively affordable, depending on how fancy you get, and the size. If you figure $125.00/Hp, that should get you in the ball park (you can spend A LOT more). Then you have rotary converters, they are the motor setups that are very common and have a lot of DIY stuff out there. The only problem is like previously stated, noise, heat, and efficiency. Capacitors are used to bring the 3rd (or generated) leg up to balance the voltages on 3rd leg with the other 2 supplied legs, at a certain load.

There are pro's and cons to rotary and static converters if you delve into the operation of each, where the digital claims pure sinusoidal AC output, voltage and current balanced to less than 3% (IIRC) across all legs under all loads. Which is better than your utility company is required to hold. But they are expensive.

I guess your budget is going to dictate where you draw the line, as well as any future plans, and electrical distribution method you prefer (IE: VFD or static goes on the machine, rotary and digital converter can be run into a distribution panel, then to your machines.)
 
#15
Re: 1or 3 phase for lathe,mill

Many of lathes, made in america are 3 phase, but the quality and precision that they were made with are second to none.

They can be had for some pretty decent prices if you take your time and look around.The slightly older (1960's)Models

They are superior quality than any of the China lathes you will find today. The precision in which they were made allow them to run far smoother and the weight helps that also.

I'm a retired Gunsmith and have run man types of lathes, an older American made lathe in good condition runs 5 times smoother than a China lathe, this is very important as smoothness of cut and precision of cut is so important to doing the best Gunsmithing work.

Yes, you will need a converter, rotery or new electronic, just make sure it has far more capacity than what is needed.

You will be far ahead getting a good american made lathe. At least look at several, hear and feel them run, you will see a big differece. A good Bridgeport is going to be the best mill you will find.
Since CNC has come out, prices for non CNC have dropped. I know of people who have got older american lathes and mills just for moving them as many shops have switched to CNC.
Take a good machinest with you to check out the equipment.

This is the most important pieces of equipment that anyone who Gunsmith's need, do not scrimp and go for the best quality, you will turn out quality work, smooth cuts with precision.
If you have equipment that is only so-so, you will have more waste and your work will show the difference.

Take the time to look, there are also used equipment suppliers that buy and sell older equipment, but check with large machine shops, talk to machinests, you may get hooked up for just freight charges. It may cost $500. to $1000. to have shipped, but if you find a shipping company and tell them you'll wait until they have a truck in the area, you can save a lot.
You will need to rent a forklift the day the shipment arrives to take the equipment off the truck.

Really give this some thought, I know what I speak of from experience.

My Best, John K
 
#16
Re: 1or 3 phase for lathe,mill

I was in your shoes back a year and a half ago... 1 phase or 3, Chi-com or US??? My decision:

Old-time dial machines are going for pennies on the dollar right now. Everyone wants digital, cnc, xyz.

I picked up a 16" SB lathe and standard J head Bridgeport from I guy I know, North of me by 3 hours. The stuff needed a little TLC, but after only a short time, they were ready to go.

One thing for sure: Studying the design, the parts diagrams, the replacement parts, the history of the manufacture, all of it, really impressed upon me that I'd just bought a couple of machines for life.

Many folks have told me that the Chi-com stuff is OK for a home shop machinist, but the production guys will use it for 5 years, depreciate it, and sell it for scrap. The off-shore machines just don't last like the old ones from the US do.

As for the phase thing: I built a rotary phase converter from virtual scratch. There's a lot of info on the web. All you need to do is have a rudimentary understanding of electricity, wiring and how a phase converter works. From there, it's almost gravy. Don't be afraid of it, unless you know nothing about flowing electrons. In that case, buy a static, buy a rotary, buy a digital, or buy single phase.

My 9" SB is single phase. Works fine, but it's a smaller lathe, made for smaller cuts.

Bottom line question to you: What do you want to do with these machines?
 
#17
Re: 1or 3 phase for lathe,mill

So if I was going to play around with a lathe and learn how to cut chambers in my own rifles don't I need a lathe with a large ID headstock so I can run the barrel through. Most of the older lathes I have found are small ID. What should I look for.
 
#18
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Good conversation, as I too have a similar question(s), not meant to hijack the thread. When y'all are talking about 3 phase, are you talking 440v? Will these converters power a 440v 3 phase off residential wiring?

Reason I'm asking is I had a Bader Grinder given to me a while back. This is what a lot of pro knife makers are using to grind their wares. The problem is that this grinder came with a 440V 3 phase 5hp motor. The logical place I have to hook it up is here at home in the basement, obviously I don't have the juice to do it.

Thought maybe going "amish" with it out in a shed I have with a through the wall driveshaft and a gasoline engine. Doable, but the gas engine/pillow block bearings/shaft would run me more than what some of you are talking on these "converters".

It goes without saying I'd rather have it downstairs in the basement hooked up to electric where the rest of my shop stuff is at. I've priced new 220v motors with the same size shaft but they're cost prohibitive right now.

Anyone with the expert knowledge who can help me resolve this problem with the motor I have, and do it inexpensively, can have a custom knife of their choosing at a tremendous discount, maybe even gratis if this thing will fly good enough/cheap enough.

Right now I'm building knives "by hand" at a whopping $1.60 an hour for the time and materials I have in 'em. Which means not a lot of knives are getting made very fast. If I can reduce the time to increase the profit y'all will see me enter the market pronto, website and all. Been told my knives are on par with Ingram and the rest, so it interests me greatly to go professional. Currently designing my own tactical profile which will likely go over well here on the hide.

First dude with the right know-how to coach me through this electrical problem via PM gets the deal..........

Just one example I've built recently, a little skinner in D2.
HPIM2638.jpg
</div></div>

Quick hint gratis: I have remanufactured a fair amount of old equipment and even built a few pieces of specialized equipment to spec from scratch. Take a picture of the motor nameplate. Many common 3p motors will be 240/460 capable by switching leads wired into the motor. If the motor will take multiple voltages then the only likely remaining issue is control voltage to the motor starter. If the motor is only 460 then your choices are limited; as posted previously a transformer (plus a phase converter) is cost prohibitive. You may find a VFD capable of this but it will also be moderately expensive. If you have a dual voltage motor and a manual motor starter then your prospects are looking better. Take a picture and post it; I'll shoot you straight.
 
#19
Re: 1or 3 phase for lathe,mill

To The OP, single to three phase conversions are doable. It is not difficult to do this but it can be expensive if you are hiring out your electrical. The benefit to cost ratio goes up if you have multiple pieces of 3 phase equipment. The benefit to cost ratio also improves if you are able to acquire quality used 3p equipment vs. new. If you are purchasing all new equipment then you best bang per $ is likely to purchase equipment based upon your currently available power supply. I am currently using a 3hp knee mill and 3 hp "mother of all belt grinders" run off of single to 3 phase conversion. Rotary phase converters are king but a static phase converter wired to a dummy start 3p motor can work well also. Lots of options out there and lots of info about "how to do this" on the web. Good luck with whatever you choose.
 
#20
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coues103</div><div class="ubbcode-body">3 phase all the way i even know where a phase converter is here in the valley if you are interested</div></div>

Thanks, I'll keep that in mind. And thanks everyone for the info.
 
#21
Re: 1or 3 phase for lathe,mill

im a liscenced electrician and i have seen alot of these"add a phase" converter will shorten the life of your motor, i would personally go with the single phase lathe, it wont be as efficent but i think it would be easier and cheaper on you in the long run
 
#22
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: customgun1</div><div class="ubbcode-body">im a liscenced electrician and i have seen alot of these<span style="font-weight: bold">"add a phase" converter will shorten the life of your motor,</span> i would personally go with the single phase lathe, it wont be as efficent but i think it would be easier and cheaper on you in the long run </div></div>
Can you say what the mechanism is that shortens the life of a 3-phase motor when run by a good quality <span style="font-weight: bold">Rotary Phase Converter</span>, NOT a solid state (Static) converter?

Thanks,
Mark
 
#23
Re: 1or 3 phase for lathe,mill

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: customgun1</div><div class="ubbcode-body">im a liscenced electrician and i have seen alot of these"add a phase" converter will shorten the life of your motor, i would personally go with the single phase lathe, it wont be as efficient but i think it would be easier and cheaper on you in the long run </div></div>

I too would like to hear more specific detailed information about this assertion as my personal experience has been markedly different. Lets face it either a poor installation or inferior equipment will never be good for single or three phase equipment. I do not believe that a properly sized and installed phase converter can harm anything. Some newer CNC equipment may be fussy on the controls side when using a phase converter that is not specially set up for this task. It should be expected that there will be less energy efficiency and some loss of net output power at the motor shaft with a converter. I have seen a lot of equipment with a lot of cumulative hours that have had no problems whatsoever. I will be the first to say that phase converters are less than ideal for "true production" where equipment runs continuous for 8+ hours a shift, particularly if being used at the top of the power rating. I also venture to say that not many gun shops keep the equipment that busy; those that do likely run true three phase power and have better equipment to begin with.
 
#24
Re: 1or 3 phase for lathe,mill

I put together my own rotary converter with no electrical experience it was easy. It is a 20hp and i think you could do it for about 500.00 or 600.00 bucks. All i do is flip a switch and i could run several machines at once. If you go with a static you might not be able to use the same one and share it with other machines. They have to be rated for the same hp range then they might not last because they are not made for extended use. If you need guidance call 660-651-8895
 
#27
Re: 1or 3 phase for lathe,mill

I ended up buying a 15HP rotary converter from AmericanRotary.com.

Thanks everyone for your contributions. I learned a lot from this thread and feel that I made a great choice for my 3-phase equipment.
 
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