Electric motor for L C Mason’s Small Lathe

[Carl WalkerParticipant @carlwalker]

Hi,

I've started building the small lathe from L C Mason's book, and wondered what sort of motor I should be looking at for driving it? Nothing is mentioned in the book about powering the lathe, that I can find.

I have a 12v DC motor and speed controller I got off Ebay, of Chinese origin, for another project, not sure if it is big enough or powerful enough though, I know it revs to 3k rpm, but not sure of the power output. I may try to use that, or see if I can get something a bit bigger.

Any help in deciding what motor I should be looking for would be much appreciated!

Edited By Ricky Walker on 10/02/2021 12:58:13

[Carl WalkerParticipant @carlwalker]

[EmgeeParticipant @emgee]

Ricky

To help get more info please tell us what size the lathe is, what diameter can it turn over the bed and what is the distance between centres fitted to the spindle and tailstock ?

Emgee

Is this the lathe you are building ?

Edited By Emgee on 10/02/2021 13:22:32

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Emgee on 10/02/2021 13:12:28:

Ricky

To help get more info please tell us what size the lathe is, what diameter can it turn over the bed and what is the distance between centres fitted to the spindle and tailstock ?

Emgee

.

For preliminary info. … See the fourth post on this old thread: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=56802

MichaelG.

[Trevor Drabble 1Participant @trevordrabble1]

Ricky , Believe the Cowells and small Sieg machines use 125 W – 150 W motors . Hope this helps . Trevor.

[Cornish JackParticipant @cornishjack]

Still have the part complete bits from an attempted build some 30+ years ago. I intended to use a Parvalux, which, from memory, was around 100 watts. I based it on the Unimat 3, which I still have, but was a bit concerned that the plain bearings might have needed slightly more. I would have thought that Parvalux would still have something suitable in their range.

rgds

Bill

[IanTParticipant @iant]

Ricky, I have a small lathe (similar to a Super Adept) and used a small fractional HP AC motor that I already possessed for it. If I was looking for a small motor now though, I'd probably fit one of these 200W nominal (it's probably about 150W output) brushed DC motors.

I have the same motor (but with the original variable speed control PCB) on my Cowells drill and it works very well. I'm sure it would do so on your small lathe too when combined with the pulleys. You don't really need a very large motor but your (12V DC) one may not be quite enough.

200W DC Motor & Controller

Regards,

IanT

Edited By IanT on 10/02/2021 14:07:39

[HollowpointParticipant @hollowpoint]

I don't know if you should take my advice because I keep blowing things up lol. ..but there are several routes you could go:

If you aren't bothered about reversing the direction of the lathe or controlling the speed then a simple small AC motor would be fine. Something like 100w or more. 230v 1450rpm

Another option is a 12v or 24v DC motor with a matching power supply, If you go this route I would try to find something over 150w as you can easily stall the motor at low speeds. The ampage is the thing to watch here. (low volts=high amp)

A third option is a 90v or 180v DC motor and a KBIC style DC drive board. Again 100w or more. This would be my preferred option since the drive board compensates for the load by increasing the voltage and you get good torque.

Lastly you have the option of a small 3ph motor and a VFD. This is probably the best solution but also the most expensive by a considerable margin.

[Carl WalkerParticipant @carlwalker]

Posted by Emgee on 10/02/2021 13:12:28:

Ricky

To help get more info please tell us what size the lathe is, what diameter can it turn over the bed and what is the distance between centres fitted to the spindle and tailstock ?

Hi EmGee

That is indeed the book, I am building my lathe from. The specs for the lathe as designed are:

Centre height:1-3/4"

Distance between centres: 8"

Max swing on faceplate: 4" dia.

Max swing over saddle:1-7/8" Dia.

I am planning on making a few changes, eg 6mm threads instead of 1/4" Whitworth, and plan on making a set of module 1 change gears instead of 20 DP in the original – I may need to use Module 1.2 or so for the back gears, to get closer to the original 20 DP gears. I still have to work out the gears needed. I'll be making all my own gears, I have a Warco Mini Lathe, and a Clarke CM10 Mill/drill for machining the parts with.

Thanks to everyone who has replied so far, you've given me a lot to think about

Ricky

Is this the lathe you are building ?

[edited: image of L C Mason book, "Building a Small Lathe"]

Edited By Emgee on 10/02/2021 13:22:32

[IanTParticipant @iant]

If you do purchase one of the 200W DC motors Ricky (and have a 3D Printer) I can supply a simple SCAD script to print a suitable 'saddle' for it.

Regards,

IanT

[Former MemberParticipant @formermember12892]

[This posting has been removed]

[BazyleParticipant @bazyle]

How about an industrial sewing machine motor? Some come with variable speed. A domestic one probably wouldn't be enough.

[Pete.Participant @pete-2]

Trevor Drabble, is that boat in your icon the one filmed by Mr Crispin at a model engineering show?

Did you build this?

Apologies to the op for interruption of his question.

I agree with Bazyle, there are some interesting sewing machine motor kits on ebay with motor, speed controller etc.

[Carl WalkerParticipant @carlwalker]

Thanks to all who have replied, I have now bookmarked that 200w motor and controller, I should be able to buy it in a week or so. My next decision is as to what size to make the mandrel nose. The original drawings call for a 1/2" BSF thread, but I'm thinking I may go for the Unimat 3 nose size, it depends on what chucks are available at what price. It will be a while before I get that far, so I have plenty of time to look into it

Cheers

Ricky

[Former MemberParticipant @formermember12892]

[This posting has been removed]

[John BaronParticipant @johnbaron31275]

Hi Ricky, Guys,

An excellent source of small induction motors is the scrap yard ! I've salvaged many "Shower Pumps" that have seized up pumps but the motors have all been OK. The hot side pump usually leaks and lime scale build up causes them to seize. Very occasionally water migrates into the bearings, but they are common, cheap and easy to replace.

I've salvaged motors from 175 watts (1/4 Hp) right up to 900 watts, (just over 1.2 Hp). All have been two pole motors (2880 rpm). There are some that are universal brush motors, but you don't always find that out until you pull it apart. I tend to take those back to the scrappy after I've salvaged the useful bronze parts.

[Colin HeseltineParticipant @colinheseltine48622]

John,

Which country are you in. Certainly where I live (UK – Midlands) you cannot go into scrapyards and have a ferret around like we used to do 50 years ago. H&S has seen to that. I spent hours climbing into cars stacked two or three high to find bits for cars I was working on.

Colin

[John BaronParticipant @johnbaron31275]

Hi Colin,

So do I ! I'm in North Yorkshire. I do have access to s couple of scrapyards around here and I did used to have access to one in Birmingham which unfortunately seems to have closed down and the land is currently being sold.

But I do agree that it is becoming harder to find places that will let you wander around them. One that I go to will put stuff on one side for me if I let him know what I'm after. There was an old lathe in there a few days ago. I expect that it went into the cast iron scrap pile.

[Author]

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