Re: Question for you guys that are tech savvy
Can you link to the motor and some info on how you mounted it?
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Good evening,
I've been using a 550w Husuper Sewing Machine servo motor on my SL for nearly 3 years now as detailed in some of my other posts.
I have nothing but praise for it, I use the lathe practically every day, both as a lathe and milling machine.
It was simplicity itself to fit and set up and is a joy to use.
regards,
David
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Re: Question for you guys that are tech savvy
Ebay has a "industrial sewing machine brushless servo motor for Consew sew machine".? It is $93, new.? It is 400-4500rpm, 600 watts.? There is an RPM indicator, buttons P, S, +, -.? It says "the positioner not included.? What is a positioner?? I do not quite understand how to control the speed for lathe use.? Turn it on and press buttons?? Is this the right motor to buy for a Unimat?? Is $93 a good deal?? Thanks for the help.
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Re: Question for you guys that are tech savvy
Good evening,
I've been using a 550w Husuper Sewing Machine servo motor on my SL for nearly 3 years now as detailed in some of my other posts.
I have nothing but praise for it, I use the lathe practically every day, both as a lathe and milling machine.
It was simplicity itself to fit and set up and is a joy to use.
regards,
David
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Re: Question for you guys that are tech savvy
That is an AC induction motor. You aren't going to be able to
vary the speed with a router speed controller. To vary the speed
of that motor you are going to need a variable frequency drive for
that.
Clues include AC and 1725 RPM, which is a multiple of line
frequency less slip.
On 7/12/23 10:05, John Hutnick wrote:
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My suggested solution is different.? You already have a motor.? If
you are using the Unimat only as a lathe, mount it on board, and
hang the motor at the back.? Buy a Harbor Freight router speed
control and use that to control the motor.? This has been
mentioned in the past here.?
Yes, DC motors operate well on a Unimat.? But you have to buy a
motor, a power supply and controller, mount it all and wire it.?
With the Harbor Freight controller, you have spent $17.99 and your
motor just plugs in.
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Re: Question for you guys that are tech savvy
Single phase AC motors that have a starting capacitor and a running capacitor are not suitable for variable speed. they also have the centrifugal clutch that will stop them dead if they drop below a set speed.?
The best motors for variable speed are three-phase AC motors, controlled via a Variable Frequency Drive (VFD) or a DC motor driven by a variable speed drive. See the two samples below.?
3-phase VFD:?
DC motor control:?
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The Marathon motor used on the Taig lathe is a poor choice for variable speed, even on a variable frequency power supply.? It has a start winding, controlled by a centrifugal switch that will turn on if the motor slows down too much.? This winding is not
designed for continuous operation, and will soon overheat.? This motor is designed to operate at a fixed speed, determined by the power frequency.? I rigged up my Taig lathe with a heavier version of the 24 volt scooter motor and pulse width modulated? control
used by several people on Unimats.? My motor is a 1/3 hp Dayton 24 volt from an estate sale, connected to a heavy power supply and the usual pwm controller.? The Dayton motor is more powerful than I need for the Taig, but is far smaller and lighter than the
original Marathon. It turns up to 4000 rpm, so I only need the slowest 3 speeds on the drive pulley. ? I think a permanent magnet field DC motor and PWM controller will give you the most bang for the buck.? There are several past threads on these conversions
for the Unimat, some giving sources for the parts required and the procedures for the conversion.?
Chuck Daldry
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Re: Question for you guys that are tech savvy
The Marathon motor used on the Taig lathe is a poor choice for variable speed, even on a variable frequency power supply.? It has a start winding, controlled by a centrifugal switch that will turn on if the motor slows down too much.? This winding is not designed for continuous operation, and will soon overheat.? This motor is designed to operate at a fixed speed, determined by the power frequency.? I rigged up my Taig lathe with a heavier version of the 24 volt scooter motor and pulse width modulated? control used by several people on Unimats.? My motor is a 1/3 hp Dayton 24 volt from an estate sale, connected to a heavy power supply and the usual pwm controller.? The Dayton motor is more powerful than I need for the Taig, but is far smaller and lighter than the original Marathon. It turns up to 4000 rpm, so I only need the slowest 3 speeds on the drive pulley. ? I think a permanent magnet field DC motor and PWM controller will give you the most bang for the buck.? There are several past threads on these conversions for the Unimat, some giving sources for the parts required and the procedures for the conversion.?
Chuck Daldry
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Re: Question for you guys that are tech savvy
You may want to consider a Consew sewing machine motor. It is a fully controllable servo motor, it comes with all the necessary controls, and it has been used on many small lathes and milling machines.?
120 bucks, price at Amazon:?
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Shop JUKI at the Amazon Arts, Crafts & Sewing store. Free Shipping on eligible items. Save on everyday low prices.
www.amazon.com
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95 bucks price at Ebay:?
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The HF controller provides enough torque to run a router.? It has been reported here in the past that it works.? So you spend $17.99 and give it a try.? If it is not satisfactory, use it for something else.
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Re: Question for you guys that are tech savvy
I'm going to offer another solution, an industrial sewing machine brushless servo motor.? I replaced the 3/4Hp motor on my drill press with a 750W servo motor and I love it - mostly.? These motors are available from 250W up to at least 750W - if not 1KW.? You get a continuous duty servo motor, you set the speed and it will hold there.? And...You get the option to run in reverse if you want to, but that might not be a good thing.
There are some Pros and Cons...
Pros:
1) Variable speed - you can adjust the parameters in the servo drive so your minimum speed is 100Rpm, and the maximum is 4500 Rpm.? (Mine doesn't like to run at 100 Rpm, the motor speed tends to oscillate.? But if I bump the minimum speed up to 300 Rpm it's rock solid.)
2) Cheap - you'll get the motor and drive for about the same price as, or less than, the motor you have listed.
3) Small size - my 1Hp servo motor is probably 1/2 the size of the motor you have listed and it's continuous duty.
Cons:
1) The speed controller that will come with the kit is designed for an INDUSTRIAL SEWING MACHINE,?it hooks up to a foot treadle.? But it can be made to work with minor modifications.? Once you move the speed controller off the neutral position it will vary the speed from the minimum speed setting to the maximum speed setting.?
2) On my setup, the display shows the motor speed to the closest 100 Rpm.? I can live with this - it's just irritating.? I know it's the display that's the issue, because I can vary the motor speed slightly and hear the pitch of the motor change, but the displayed speed does not change.? (But really, what do you expect from a $110 servo kit?)
3) The drive is set up to brake the motor to a stop - REAL quick, on the order of less than 100 milli-seconds.? This parameter is adjustable in my drive and I currently have the brake disabled.
4)?Most of these units use a Hall Effect sensor in the foot treadle to control the motor speed, this complicates replacing the speed control unit with something else. If you modify the original speed controller, you must remember to set the speed to zero when you stop the motor.? If you don't you'll get an error from the drive when you re-start it.??
There are a couple of different videos out there on YouTube that show how to replace the Hall Effect sensor with a speed control pot.??I found an article on the Home Machinist forum, at least I think that's where it was, that showed the schematic for replacing the Hall Effect sensor with a speed pot and also threw in a Run/Stop switch as a bonus.? That's the route?I took.? Now I can run at whatever speed I want, flip the switch to Stop, do whatever I need to do, flip the switch back to Run and I'm back to the same speed as before.? (I do need to remember to flip the switch to Stop before I shut off the drive or I STILL get that same error as mentioned above.)
Don
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Re: Question for you guys that are tech savvy
The HF controller provides enough torque to run a router.? It has been reported here in the past that it works.? So you spend $17.99 and give it a try.? If it is not satisfactory, use it for something else.
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Re: Question for you guys that are tech savvy
Hello:
Varying
Voltage on an AC motor is very ineffective. It is worse than
on DC. For an AC motor a Variable Frequency Drive is a better
idea, but is offered mostly for 3 phase motors.
I have
a voltage control on my Smithy lathe and at slow speeds it has
almost no torque. I did buy the "back gear" pulley set that
helps a lot.
Perhaps
a better drive would be an Arduino / motor driver / stepping
motor. You could program the Arduino to control the speed of
the stepping motor and still have full torque.
Carl.
On 7/12/2023 12:54 AM, Keith S. Angus
wrote:
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Before going too far I'd look at how the motor will fit. The usual
DC motors will fit without modifying anything, and they are not
expensive. The main reason for using the motor you have is that
you have it. It looks a bit big, it has more power than you need,
the revs are low for a Unimat, and decent speed control would
require an inverter to give variable frequency. I'd go for the
usual 24 V DC motor, which can be fitted straight on. You can now
get variable voltage power supplies, like the usual 24 V PWM
supplies, but with the speed control section built in, thus
simplifying the electrics. Can't find a link to one at the moment.
Otherwise using separate power supply and variable speed units is
not too difficult to deal with. Making a case for it all is the
biggest problem.
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Re: Question for you guys that are tech savvy
My suggested solution is different.? You already have a motor.? If you are using the Unimat only as a lathe, mount it on board, and hang the motor at the back.? Buy a Harbor Freight router speed control and use that to control the motor.? This has been mentioned in the past here.?
Yes, DC motors operate well on a Unimat.? But you have to buy a motor, a power supply and controller, mount it all and wire it.? With the Harbor Freight controller, you have spent $17.99 and your motor just plugs in.
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Re: Question for you guys that are tech savvy
Keith has helped me a lot in the past and understands what he is talking about. I don’t think I would have had the knowledge to carry this out on my own without his help.
My Unimat now purrs like a kitten!
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
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Re: Question for you guys that are tech savvy
Before going too far I'd look at how the motor will fit. The usual DC motors will fit without modifying anything, and they are not expensive. The main reason for using the motor you have is that you have it. It looks a bit big, it has more power than you need, the revs are low for a Unimat, and decent speed control would require an inverter to give variable frequency. I'd go for the usual 24 V DC motor, which can be fitted straight on. You can now get variable voltage power supplies, like the usual 24 V PWM supplies, but with the speed control section built in, thus simplifying the electrics. Can't find a link to one at the moment. Otherwise using separate power supply and variable speed units is not too difficult to deal with. Making a case for it all is the biggest problem.
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Re: Question for you guys that are tech savvy
I may be wrong here, but I thought using a DC motor w/power supply makes for easier/better speed control.?
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My u90 motor finally gave out after many years of use. So while rummaging around I found a spare 1/4 HP. 1750 rpm AC Marathon motor from my old Taig lathe that I was considering hooking up and using with the Db200. My question is regarding using
a speed controller with the motor. I found one that seems to fit my needs, would probably work with the motor and was still pretty affordable. I would like to ask if their is anything I should look out for using this combination and If it would work. Here
is the motor info and speed controller info.? Do you guys think this would be a good fit? I really would like to run a single belt and have adjustable speed on my little DB200.? Please help.
<Screenshot_20230711_231237_Samsung Internet.jpg><Screenshot_20230710_015423_Samsung Internet.jpg>
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Question for you guys that are tech savvy
My u90 motor finally gave out after many years of use. So while rummaging around I found a spare 1/4 HP. 1750 rpm AC Marathon motor from my old Taig lathe that I was considering hooking up and using with the Db200. My question is regarding using
a speed controller with the motor. I found one that seems to fit my needs, would probably work with the motor and was still pretty affordable. I would like to ask if their is anything I should look out for using this combination and If it would work. Here
is the motor info and speed controller info.? Do you guys think this would be a good fit? I really would like to run a single belt and have adjustable speed on my little DB200.? Please help.
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Re: U3 top slide accurate setting
Thanks all for the replies.
Dick, yes, I was prompted by Doug Collinge’s ‘Unimat ER-16 Collet Holder.pdf’ - he uses that method (trig) to set the angle but can measure the distance travelled easily as the normal feed is being used… I guess on the U3 I’d have to use an(other) indicator.
Carl - my mind started thinking lasers and divisions some distance away (I think you could get good precision with something like that) or even cogs for indexing - 45 teeth for the 8 degrees required for a collet holder.
Brian, many thanks for the link to that article, looks interesting.
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Re: U3 top slide accurate setting
You may wish to have a look at this project.
Fine angle adjustment for the Unimat 3 topslide
By Maurice Rhodes
Regards,
Brian.
On 11-July-2023 7:22 pm, Peter Brooks
wrote:
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Has anyone come up with a smart way of setting the angle of cut
accurately when using the U3 cross slide - the one used to cut
tapers etc?
As well as the woeful 'scale' on the slide you also have the
vagaries of tool positioning in the post.
The arrangement on the earlier lathes where the headstock could
rotate would in some ways seem to be altogether better.
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Re: U3 top slide accurate setting
Hello
Peter:
It all
depends on how accurate your setting needs to be. For turning
a Morse Taper the easy way is to set a good Morse Taper in the
lathe and indicate the compound side to match. Other angles
the best method is a Sine Bar or ground angle blocks. Using a
better protractor would be OK for many applications.
I do
agree the protractor on the compound is worthless. On my
Smithy Granite the protractor was a strip of printed aluminum
and was torn up by the locking nut. It was so bad I finally
tore it off.
Carl.
On 7/11/2023 5:22 AM, Peter Brooks
wrote:
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Has anyone come up with a smart way of setting the angle of cut
accurately when using the U3 cross slide - the one used to cut
tapers etc?
As well as the woeful 'scale' on the slide you also have the
vagaries of tool positioning in the post.
The arrangement on the earlier lathes where the headstock could
rotate would in some ways seem to be altogether better.
|
Re: U3 top slide accurate setting
Hello Peter,
I don’t own a Unimat 3, but I can tell you how I set the compound slide on my minilathe. I use a dial travel indicator to measure the amount of slope in a given distance. This method gets my setting spot on every time. You might have to use trigonometry to get the rise or fall if you don’t have it given to you. Think of it as solving for the sides of a triangle.
Dick
--
http://www.homemadetools.net/forum/?OFF-SET-tailstock-center-65965#post105972
?SMALL TURRET TOOL POST PLANS?
?LARGE TURRET TOOL POST PLANS
?MINI-LATHE CARRIAGE LOCK PLANS
?SMALL QC TOOL POST PLANS?
?QUICK CHANGE LATHE TURRET
?MINI LATHE COMPOUND PIVOT MODIFICATION
|
U3 top slide accurate setting
Has anyone come up with a smart way of setting the angle of cut accurately when using the U3 cross slide - the one used to cut tapers etc?
As well as the woeful 'scale' on the slide you also have the vagaries of tool positioning in the post.
The arrangement on the earlier lathes where the headstock could rotate would in some ways seem to be altogether better.
|
Steve Johnson
Carl
OldToolmaker
