|
Hi All
I have a unimat SL that works fine but is just a bit too small.
I was thinking about the Unimat PC but the motors are under-powered.
Is it a big job to change the motor for a 24v DC, has anybody done it?
Thanks
|
no great hassle to change out, you just need the 24V motor and a power supply, i added a speed controller too, then its just mount the motor (i mounted mine further away which gives me more room around the lathe) and make up a new belt to length.
------ Original Message ------
Sent: 01/03/2020 14:58:41
Subject: [Unimat] Unimat PC motor
Hi All
I have a unimat SL that works fine but is just a bit too small.
I was thinking about the Unimat PC but the motors are under-powered.
Is it a big job to change the motor for a 24v DC, has anybody done it?
Thanks
|
Thanks Peter.
Did the mod need any special machining to mount the motor any further away?
I don't suppose you have any photos do you?
|
no the motor i had was just fixed to the base board i have on the lathe, and then i joined a polyethelene belt to the right length.  
------ Original Message ------
Sent: 01/03/2020 16:23:04
Subject: Re: [Unimat] Unimat PC motor
Thanks Peter.
Did the mod need any special machining to mount the motor any further away?
I don't suppose you have any photos do you?
|
I intend to replace the motor on mine soon. I searched for a long time before I came to the conclusion you can't get a more powerful motor that fits in the hole for the original one, unless you go to RC model motors. They claim phenomenal power in a small space, but don't last long. However, in this application they would run well below rated power, so they might last a bit longer. I have never been able to get enough information on a possible motor and a driver all together to know what to buy. It's a bit frustrating as the RC crowd work in strange units, of LIPO cells and Kv figures. Some proper data on power, current, torque and voltage would be useful, preferably with some performance curves.
I have got a powerful brushless DC motor and driver that should eat the job, but it will need to be fitted outside the casing, roughly where the power supply is at the moment. That will mean redoing the belts. I will make pulleys for plain belts, as the toothed belts are so noisy. I'm also looking to see if I can devise a proper back gear for low speeds. I used to work with a mill that had it built into the final pulley, but that was a bit bigger than the Basic lathe. The motor runs up to 12000 revs, so I would gear it for that as the maximum speed. Allow for a 2:1 range on the speed control and have a second pulley for half speed, maybe another one after that, then back gear for really low revs. Then the aim is to put modern NC onto it.
It might take a bit of doing - it might never get done!
Keith
|
Hi Peter.
Thanks for the photos.
It looks a nice setup. Is that a Unimat 3?
|
yes its a unimat 3, i have had it from new back in the 1970's its been loved and used then sat for years and is now back being loved and used.
------ Original Message ------
Sent: 01/03/2020 18:56:13
Subject: Re: [Unimat] Unimat PC motor
Hi Peter.
Thanks for the photos.
It looks a nice setup. Is that a Unimat 3?
|
Hi Keith
Thanks for the reply.
What is the actual size is the motor that comes with the Unimat PC.
I was thinking of putting a 24v DC motor is as they are very popular, but if they are too big it's a no-go.
|
??? ??? Keith, I share your frustration in trying to get data on
the R/C model motors. They seem to operate in some non SI
universe. Should you succeed in ferreting out the specs please
share it.? Baffled Bill in Boulder!
On 3/1/20 11:39 AM, Keith S. Angus via
Groups.Io wrote:
toggle quoted message
Show quoted text
I intend to replace the motor on mine soon. I searched for a long
time before I came to the conclusion you can't get a more powerful
motor that fits in the hole for the original one, unless you go to
RC model motors. They claim phenomenal power in a small space, but
don't last long. However, in this application they would run well
below rated power, so they might last a bit longer. I have never
been able to get enough information on a possible motor and a
driver all together to know what to buy. It's a bit frustrating as
the RC crowd work in strange units, of LIPO cells and Kv figures.
Some proper data on power, current, torque and voltage would be
useful, preferably with some performance curves.
|
Good to hear it's been used. My Unimat SL looked like it had never been used when I got it last year. It must be older than your 3.
|
OP has a PC. A little more difficult to re-motor because of the way the motor attaches.
-----Original Message-----
From: Peter ashby via Groups.Io <aescinga.pgen@...>
To: Unimat < [email protected]>
Sent: Sun, Mar 1, 2020 12:46 pm
Subject: Re: [Unimat] Unimat PC motor
no the motor i had was just fixed to the base board i have on the lathe, and then i joined a polyethelene belt to the right length.  
------ Original Message ------
Sent: 01/03/2020 16:23:04
Subject: Re: [Unimat] Unimat PC motor
Thanks Peter.
Did the mod need any special machining to mount the motor any further away?
I don't suppose you have any photos do you?
|
The standard motor is 48 mm diameter. The holes it fits through are not much bigger, 52 mm I think, and there is not much scope to open them up. Once the motor gets much bigger their is nowhere to put it except outside the headstock. I should mention that I know where to find a suitable motor, but I think it costs too much. Maxon do a range of motors at 45 mm diameter, 12, 18, 24, 36 & 48 V, max revs from about 5000 to about 10000, but they cost over ?500 and need a separate drive circuit which I think costs another ?70. Say ?600 for the pair. Then the motor has a large terminal box on the end but I think it would just about fit. The 250 W version would fit better in a sense, in that it is longer, but unless such a motor turns up in someone's junk box it's all a bit academic.
I did find a website which gave some motor details in sensible numbers, but then I could see no way to relate a suitable drive to the motors. Unfortunately our local RC shop, which used to be large and comprehensive, has turned to mainly mail order. I'm sure they have something on the shelf that would do the job, but they no longer chat to customers over the counter.
Years ago someone here said he had successfully used an RC motor on a Unimat, I think a DB/SL, but never gave details of what he had used. It's all a bit frustrating.
Keith
|
Used my UniPCs? to make tools and parts from steel, titanium, brass as well as POM and other plastic materials since the Uni came out. Both, the manual and CNC have still their original motors
Found soon if you think the motor is to weak you are working with a wrong tool, a tool not sharp enough, the speed or chisel angle is not right..
Before mounting a more powerful motor think twice - there are parts in your lathe not built for.
Seen by the age of the UniPC the risk of ruining the plastic gears ..of course you can replace them by metal..
Regards, Lui
Zitat von "Keith? S. Angus via Groups.Io" <ksangus@...>:
> The standard motor is 48 mm diameter. The holes it fits through are not much bigger, 52 mm I think, and there is not much scope to open them up. Once the motor gets much bigger their is nowhere to put it except outside the headstock.
|
On Sun, Mar 1, 2020 at 11:16 PM, luifri@... wrote:
Found soon if you think the motor is to weak you are working with a wrong tool, a tool not sharp enough, the speed or chisel angle is not right..
Before mounting a more powerful motor think twice - there are parts in your lathe not built for.
Seen by the age of the UniPC the risk of ruining the plastic gears ..of course you can replace them by metal..
Regards, Lui
?
I know what you mean and I have already advised other people not to go mad and fit huge motors to little lathes. The standard Basic/PC motor is 40 W, and is generally thought to be too weak. The DB/SL and U3 use motors of about 90 W, and my old SL was fine with a 130 W DC motor, so I'm sure the Basic can take something a bit more powerful. The problem with the PC is that the stepper motors are very weak as well and could not deal with deeper cuts - in that sense they match the main motor. By fitting a more powerful main motor it will be possible to fit more modern, and stronger, stepper motors for the computer control and remove metal faster. I'm sure the structure of the lathe will be strong enough to take it, but I will be careful anyway. I'm used to these small lathes, so I don't think I will have a problem. The plastic gears are not so easy to replace with metal or anything else - they are 0.75 Mod, which is uncommon. I have only found one supplier who lists them as available, although I'm sure I could find someone to make them to order, at a high price. However, if I convert to NC I would hope to find a CNC programme which includes thread cutting, so the gears would not be needed. Also the only gears I have are the set for cutting inch (tpi) threads, and I only use metric. Since it is difficult to get the gears I don't think I will ever use any! Keith
|
I have a DC motor control rated at 90 volt input. ?I have not found a reasonably priced motor to pair it with. Most likely a treadmill motor would work but they are expensive on EBay.
Dick
|
here in Cleveland we have HGR a resale place from lathes to pieces. I have both the controllers for my SB 10H and others I can reduce my speed to 5 revs, but you better get one rater more than you AC one I ended putting on a 2 HP motor to replace my 3/4hp on on the 10. Dave
toggle quoted message
Show quoted text
I have a DC motor control rated at 90 volt input. ?I have not found a reasonably priced motor to pair it with. Most likely a treadmill motor would work but they are expensive on EBay.
Dick
|
Look at motors for invalid/elderly scooters. They're mostly 24 VDC, compact, and quite powerful. They can push a 300 lb person up a hill!
Hi Keith
Thanks for the reply.
What is the actual size is the motor that comes with the Unimat PC.
I was thinking of putting a 24v DC motor is as they are very popular, but if they are too big it's a no-go.
|
|
|
On Mon, Mar 2, 2020 at 06:46 PM, OldToolmaker wrote:
I have a DC motor control rated at 90 volt input. ?I have not found a reasonably priced motor to pair it with. Most likely a treadmill motor would work but they are expensive on EBay.
The voltage doesn't matter - it's the power that counts. I reckon for the DB/SL and U3 about 100 to 150 watts is fine. I wouldn't go for more. The treadmill motors I see on Ebay are much higher power, inconveniently high voltage and too high on price. The typical 24 V scooter motors like Ebay item 174101982818 is very suitable. 24 volts is easy to work with, the motor fits in the available space (both DB/SL & U3), 120 watt is all the power you need and it's affordable. Keith
|
??? "Be careful what you wish for...You may get it!"?? A
professional machinist friend scored a 10 HP industrial lathe at a
good price. Set it up in his garage with a rotary converter and
started working. Was horrified when he got his first bill. Set it
up running and went to see the meter spin as a blur! Sold the
machine to an industrial user!??? ??? Bill in Boulder CO USA
On 3/2/20 4:15 PM, Keith S. Angus via
Groups.Io wrote:
toggle quoted message
Show quoted text
On Mon, Mar 2, 2020 at 06:46 PM, OldToolmaker wrote:
I have a DC motor control rated at 90 volt input. ?I
have not found a reasonably priced motor to pair it with. Most
likely a treadmill motor would work but they are expensive on
EBay.
The voltage doesn't matter - it's the power that counts. I reckon
for the DB/SL and U3 about 100 to 150 watts is fine. I wouldn't go
for more. The treadmill motors I see on Ebay are much higher
power, inconveniently high voltage and too high on price. The
typical 24 V scooter motors like Ebay item 174101982818 is very
suitable. 24 volts is easy to work with, the motor fits in the
available space (both DB/SL & U3), 120 watt is all the power
you need and it's affordable.
Keith
|
Les Orton
OldToolmaker
firefite Roenigk