Brushless motors

[Keith MoatParticipant @keithmoat36026]

I have a Warco super mini lathe 7 x 14 and it has a brush less motor, but it still has High and Low gears in the head stock, metal ones (and they are noisy). I've seen some mini lathes in the USA where a brush less setup has a direct drive to the spindle. Assuming I already have the correct electronics for the already fitted brush less motor, would it be possible/practical, with the correct drive pulley, spindle pulley and longer belt, to remove my High/Low gears and convert my lathe to direct drive. I understand that it will be running in the opposite direction to before, but that's a simple case of using the direction switch in the opposite way (it says "L" and "R" on mine).

P.s. is brush less one word or two ?

Regards……..Keith

[Keith MoatParticipant @keithmoat36026]

conversions

[Thor 🇳🇴Participant @thor]

Hi Keith,

I have always assumed that it was "Brushless" DC electric motors (one word), I guess someone with more knowedge of th English language will correct me.

It should be possible to bypass the gears and use a direct belt drive, the gears will give you more torque though.
There are several beltdrive modifications for the brushed minilathes, a few links:

***Link***
***Link***

***Link***

Thor

[not done it yetParticipant @notdoneityet]

One word for brushless and unless the drive is fitted to the spindle it will not be a direct drive.

It might be the same speed as the motor, depending on pulleys or gears, but I only call it a direct drive if the motor and spindle are in a direct line axially – such as many engine driven alternators where the rotating armature or field winding are affixed with a tapered shaft or flexible coupling.

One cannot change the speed of a direct drive unless the motor speed is changed. With a belt drive (indirect drive), the machine speed can be chosen by choice of two pulley sizes, a variator or a set of stepped pulleys.

[JasonBModerator @jasonb]

By only having one belt or gear ratio between motor and spindle you will not have the same speed range and if you do manage to tweak the controller to make the motor run over a larger speed range then it will be operating out of it's optimum speed range which means less torque and less cooling.

I did a simple test on a couple of mills a while ago, the two speed gearbox one could make the 100rpm cut in low range, but not in high range, the single belt brushless also stalled trying to make the cut at 100rpm and had to be run faster than the optimum speed for the cutter to stop it stalling.

Edited By JasonB on 06/05/2018 07:22:33

[Neil WyattModerator @neilwyatt]

Try and see how it goes, it should be a reversible change.

Seig brushless mini lathes don't have the gears, but have different motors and speed controllers to the Real Bull ones so the performance envelopes may be different.

Neil

[Keith MoatParticipant @keithmoat36026]

Thanks guys for the "brushless" education, I thought it was one word, but my spell checker keeps saying otherwise.

Thanks for the links Thor, my lathe is on a little bench in my garage where there's no room to strap a huge motor on the back (unless I leave the garage window open) and I'd like to keep it portable, so those are a bit OTT for me. I think the torque should be somewhere in between mt current High/Low setup, more torque than high and less than low if I'm correct.

JasonB, the speed ranges I have now are 30-800 low and 60-1800 high (top end of those ranges vary a bit) and the motor seems to want to take teeth off the drive belt rather than stall as I found out when the tool dug in once. I didn't think about cooling, my motor has a fan on the back and as the speed range should be somewhere in between my current setup I think it should cope.

Neil, great book btw, it gave me a good insight into what to expect with my new lathe, before reading it I thought these mini lathes would work great straight out of the box and your book showed how easy it is to improve them. I'll give it a go in the near future, I think Arc Euro Trade sell all the bits I need.

I think my main hobby now is tinkering with the lathe, I'm not sure if I want to turn anything really

[SamsarandaParticipant @samsaranda]

Keith, re spelling of brushless, your spellchecker is probably American in origin, their command of the English language doesn’t do many joined up words.🦅

Dave W

[SillyOldDufferModerator @sillyoldduffer]

Posted by Samsaranda on 06/05/2018 11:22:20:

Keith, re spelling of brushless, your spellchecker is probably American in origin, their command of the English language doesn’t do many joined up words.🦅

Dave W

The forum's built-in spell-checker defaults to 'American English' and I haven't found a way of permanently switching it to British English!

We spell today 'today'; during WW2, 'to-day' was the preferred form. In WW1 it was usually 'to day'. I can't get too excited about hyphens. English changes, and there are many different national versions. The effect on non-English speakers when they need to translate is famously amusing: 'English as She is Spoke' is a cracking good read.

[Keith MoatParticipant @keithmoat36026]

Thanks Dave, I have the same problem with setup and set up, I wish I'd paid more attention in English classes all those years ago.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 06/05/2018 11:37:00:

… I can't get too excited about hyphens.

.

Same here, Dave …

Hyphens are so wonderful that it's impossible to get too excited about them

… the excitement knows no bounds.

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Keith Moat on 06/05/2018 11:39:08:

Thanks Dave, I have the same problem with setup and set up, I wish I'd paid more attention in English classes all those years ago.

I wish I'd paid more attention in ALL classes at school. Day-dreaming about girls seemed far more important at the time, but I was totally wrong about them!

Can't offer much help with your mini-lathe problem. A mini-lathe with brushed motor and plastic gears is delightfully quiet, which I didn't appreciate until I replaced mine with a much bigger machine. The big lathe's permanently running cooling fans on motor and VFD make a harsh hash noise that's irritating even when the machine isn't cutting. I wear headphones!

Dave

[SillyOldDufferModerator @sillyoldduffer]

Posted by Michael Gilligan on 06/05/2018 11:46:46:

Posted by SillyOldDuffer on 06/05/2018 11:37:00:

… I can't get too excited about hyphens.

.

Same here, Dave …

Hyphens are so wonderful that it's impossible to get too excited about them

… the excitement knows no bounds.

MichaelG.

It's yet another fair cop guv! The reason is because it is no use complaining. I am insensitive to a degree to those kind of things. Please take 91 other offences into consideration during sentencing…

[Keith MoatParticipant @keithmoat36026]

I was of small stature as a schoolboy in the 60s so spent most of my time annoying, then avoiding, the class bullies. English wasn't my favourite subject, as the teacher was a hippy and had his little "crowd" of sucking up pupils, of which I wasn't one.

My lathe has all metal gears and although the lead screw gears are quiet (admittedly running at a lower speed) the head stock is very noisy. I haven't had it stripped down yet but it sounds like there may be no, or very little, lubrication in there.

[Ketan SwaliParticipant @ketanswali79440]

Posted by Keith Moat on 06/05/2018 11:12:31:

JasonB, the speed ranges I have now are 30-800 low and 60-1800 high (top end of those ranges vary a bit) and the motor seems to want to take teeth off the drive belt rather than stall as I found out when the tool dug in once. I didn't think about cooling, my motor has a fan on the back and as the speed range should be somewhere in between my current setup I think it should cope.

Neil, great book btw, it gave me a good insight into what to expect with my new lathe, before reading it I thought these mini lathes would work great straight out of the box and your book showed how easy it is to improve them. I'll give it a go in the near future, I think Arc Euro Trade sell all the bits I need.

I think my main hobby now is tinkering with the lathe, I'm not sure if I want to turn anything really

Hi Keith,

Please be careful if you are tinkering with your specific lathe. The Warco Super Mini Lathe is NOT from SIEG.

SIEGs brushless mini-lathe is belt drive, with 500w output power, without any hi/low gears.

Warcos is 450w brushless motor – but hopefully, chances are they mean input power rather than output power, in line with their traditional way of stating things. In which case, the output power is likely to be lower than 450w, and the torque is controlled more by the high lower gear arrangement – which i hope you understand.

In SIEGs case, the torque is controlled by programming of a chip on the control board. I have no idea how it is in Warcos case. In Warcos case, it suggests all metal gears,.. so basically no failsafe if you jam a tool. Hopefully you only strip a belt, rather than damage a control board. Also, this is combined with a permanent 100mm chuck as standard, balanced over a small headstock casting distance assembly. Personally, I believe that this idea is wrong, and I don't say this because ARC is a competitor.

Yes, ARC sells metal gears and 100mm chuck/backplate as optional accessories, and yes, people do buy and fit all of this, but I personally believe that these things start to make the make the machine work outside the envelope of what they were safely designed for.. slowly removing the failsafes by changing to metal everything and bigger chucks.

So, in your case, I sincerely hope that your brushless motors input power is 450w, and its output power is much lower, for safety reasons. Also, I would suggest that you avoid trying to tweak anything. In any case, if you are wanting to consider removing the hi/low gears, opting instead for direct belt drive with the existing motor, chances are that 'at a guess' that you will loose torque somewhere – at high, middle, low end, especially if the brushless motor is of lower input wattage, resulting in a lower output wattage… if that makes sense?.

Ketan at ARC.

[Keith MoatParticipant @keithmoat36026]

Thanks Ketan. My main concern with this lathe is the noise (and a very small amount of resonant vibration at certain revs) from the head stock and I thought the direct belt drive with no H/L gears may be the easiest way to get rid.

Going on your advice, I think I might strip the head stock down and check whether it's well lubricated, maybe clean and file off any sharp edges/burrs on the gears and change to angular contact ball bearings before attempting anything more "experimental", thanks.

Keith

Edited By Keith Moat on 06/05/2018 12:45:12

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