Thread: Newbee saying G'day, and question about upgrading lathe motor with a bigger one...

Hi all,

Jeez I'm glad to have stumbled across this forum, and to see people from places I actually know!

I am mainly into metal work (lathe and mill), but have found a lot of good (and friendly) advice on this site, even in the woodworking forums, so ten points to everyone and keep it up - I'll definately be sticking around! I tell you what, nothing beats the typical Australian 'tongue in cheek' humour I have read in some of the posts on this site - laughed myself silly a few times!

As the title said I also have a question, hopefully someone can give me a straight answer. I have tried a number of other forum sites, however with me having only 'normal' intelligence, I have struggled a bit to comprehend some of the answers I received. Nothing against those people who are able to provide a full techincal answer, but sometimes need to remind themselves that if the person who asked the question could understand the technical answer given, they probably wouldn't have needed to ask the question in the first place! Anyway.....

Question is..I have a small metal lathe that currently has a 150watt motor (yes I know is small but suprisingly good), however like any red-blooded male, the time has come for more power

The solution....

Does anyone see any problems with fitting up the motor and pulley system from a drill press? I can get an old 6 speed drill press with a 350watt rated motor, with rpms that range from 500 to 2800, though most of my work would be done around the 1500 rpm mark. In my mind this seems like a good and practical idea, but then again.. so does taking a new Ferrari out on a test drive...and 'forgetting' to take it back...so you see my dilemma!

Any opinions, suggestions and advice greatly appreciated.

Thanks.

Colin

Hi. Welcome to the forum.

Sorry, but don't know anything about lathes - just didn't want you to feel that you were being ignored.

You'll find that the speeds defined by your new motor may not be bang on with what the lathe spindle is being driven at, however you'll be able to see that straight away and work around it. Apart from that, I can't see any reason for it not to work, provided it's all installed and modified to work correctly. Oh and welcome to the forum, too.

Welcome aboard, You can do anything provided it will physically fit, the only issue is as already pointed out maintaing the current speeds that are already there, the way to do this is by varying the size of the pulley you attach to your motor to drive the sytem, example if the current motor turns at 1500 rpm and has a 4 inch pulley and your fitting a 2500rpm motor then youll have to put a smaller pulley on, it can be worked out quite easily, this will maintain you system speeds but will increase your torque. I went the other way I had 3 phase motors in my mill and my lathe, but I didnt want the expense of 3 phase power fitted, so I removed the three phase motors and fitted single phase units and adapted new pulleys to maintain the same speeds. Dont worry about screw feeds ect there all mechanically locked but you dont want to set your lathe on say 150rpm and it actually turns at 600rpm. I hope this makes sense. Ps you can pick up pulleys of all sizes at most metal merchants or alternatively machine up your own prior to changing the motor
Steve

Thanks guys,

Paws, thanks for the welcome! Didn't feel ignored but I'm used to it anyway, happens all the time at home!

I am putting the lathe on it's own custom bench, so I will make plenty of room to mount the new motor with a screw type adjustment for tension(probably make up a box from perspex or thin sheet alloy to cover it to keep the chips out as well). Also making a complete enclosure for the 'business end' of the machine to keep it all enclosed. The lathe is fully cnc'd so for most of the work I can put the cover down to contain the chips.

Article99 - As far as the pulleys go, I was also looking to use the pulleys from the drill press spindle, 'grafted' on to the lathe spindle. I'm not overly concerned about knowing the exact rpms, for my hobby use near enough is good enough, and as you mentioned, I'll easily work around this - worse case if I need other pulleys I also have a mate with a $250,000 room sized cnc machining centre who can make up pretty much anything - awesome machine - talk about 'tool' envy!!!. I'm sure out of 6 ratios I'll find one that suits for 99% of my work though. Would need to spend a bit of time ensuring everything was in good alignment, vibration free etc, but yeah, I didn't see any reason why not.....
does this mean the Ferrari test drive is a go'er too then.......

I would imagine the speed range mentioned for the drill press would be for the spindle (don't really know the actual motor's rpm) which is a pretty good range for the lathe.

Simso, I actually don't use the screw feed with the beast being cnc'd, so of no concern there. Interesting comments on the 3 phase motors, as a lot of previous advice I got was to fit a 3 phase motor, an inverter, and variable speed control! Not a bad suggestion I guess but that combination would more than likely be more expensive than the actual lathe by the time it was complete! I'm not afraid to spend a few bucks on on mods of real benefit, but why do that if I can find a near enough solution for next to nothing!

Is it too simplistic to assume that if my current motor has 150 watts of power, and the drill press has 350 watts, it will be that proportional amount more powerful, or are there other ratings I should look at first (amps etc)?.

Thanks again, been a great help so far!

Colin

Nope you got it right dude. Rpm is always a factor with these units, because as I said before you dont want a motor that spins to fast becasue it defeats the purpose of doing it, watts is volts x amps, so if your running 240 volts then the amps for the 150 watt unit are 0.62amps and the 350 watt unit is a 1.45 amp unit, you still are gonna have to take very light cuts at this sort of power range my lathe runs at 10amps or 2400watts. CNC lathe very nice, I have my own cnc router so I know where your coming from. Have actually contemplated buying a cheap 1metre long lathe just to convert to cnc so that way I can do my own tapers ect, still might, but rod over here is going to do his shortly so I may just ask him to do the bits as I need them. My lathe I wont convert I use it by hand way to much. If you go the three phase option the motor is cheaper than a single phase unit, but 400 for three phase minimum into your shed plus speed controls ect, starts getting exy
Steve

As far as the motor speeds go, if they have the same number of poles, they will be the same speed( if they are both single phase motors) You have probably already checked that, but I didn't see it mentioned, so I thought I'd pipe in, just in case.

3 phase motor, an inverter, and variable speed control

That's actually not such a dumb idea. You could jack that into your NC software and make the spindle variable speed. (When cutting on the face of the job, the software speeds up and slows down the spindle so your surface cutting speed remains constant, no matter what diameter of the job the cutting tool is on.)

To better explain that...

http://www.youtube.com/watch?v=ghF7njMgZgs
http://www.youtube.com/watch?v=jfAR5M9vW0c&NR

Notice how you can hear the spindle changing speeds along the different diameters as it turns the chess piece? That's the variable cutting speed thinger. Very nifty, very handy. Also means your cutting tool inserts last a shiteload longer.

Oh and yes, you'll want to ensure it's as vibration free as possible. Apart from the noise from a rattly motor driving you up the wall, the vibes will run right through to the slides and your cutting insert, which'll screw up accuracy and eventually chip the edges of the insert over time.

Thanks for all the replies!

Article99, Would be nice to hook up to the nc program but being a bit of a tight-a*s I just could not justify the expense (the drill press is under $50 bucks and was kind of a 'what if' moment!), would also be great for threading! If the lathe was bigger I would probably go down that path, but as it's only for small scale production of small scale parts (95% of my parts only have a total diameter of 10mm to 20mm), is just kind of a hobby that got out of control! Very cool links, I've seen the chess piece one before, could watch stuff like that all day!

Sterob, yep , both single phase motors - thanks for the input. All info gratefully accepted.

Bottom line.... by the sound of it is definately doable, after double checking, the pulley speeds do range from 600 to 2800 (at the spindle) so that's fine (as said before I will use the complete drill press pulley assembly from the motor to the spindle), I get more power (350 watts vs 150 watts at the moment). Just have to ensure all is in good alignment, motor mounts are solid, and we should be good to go.

Simso, 2400watts, wow, you must be able to take some serious meat off each pass! The parts I make are small scale in alloy and brass so even with light cuts each part is completed fairly quickly. I did the CNC conversion myself (I like a challenge), bought the steppers, built the driver boards then learned manual Gcode programming (still a long way to go though), but is kinda cool being able to press 'play' and have the machine churn out part after part, all exactly the same! I'm also buying a small milling machine in the next week or two and will do the cnc conversion on that as well, should be good. Did you build the cnc router?

Thanks again for all the input. To throw another question into the pot, would it be possible / feasible to add some kind of electronic variable speed control to the thing so I won't need to change pulleys at all? I've already resigned myself to the fact that I'll just live with the pulley arrangement, but if anyone know of a cheap(ish) solution, very interested to hear.

Thanks again.

Colin

Yeh you can power regulators of ebay, and they will work just fine
Nah 2400 watts is nothing I still manage to stall it every now and then
Steve

Coming in at this stage of the conversation I am now curious what lathe you are actually talking about I have a Taig Lathe and a Hercus. The Taig is small and whole groups talk endlessly about them.If yours is a Taig the Australian Agent is here in Canberra.It is difficult to discuss generalities and a pic would cover many words. Regards Peter

Yes I did build the router myself as well, rodm "local member" helped with the knowledge required to do it". Pictures say more than words so here you go
Steve

Welcome Colin,

It takes a while for people to read the forum sometimes,
so don,t feel left out.
I know little but the basics of lathe work,but I a willing to learn.

Grahame

Hi All,

Long post.

Ok, I've attached a pic of my lathe, have something soft under you as you see it cos you will probably hit the floor laughing! I'm sure the original manufacturers didn't have this in mind when they made it!

Excuse the mess though, I'm in the middle of a run of parts.

To justify: I'm a mild mannered pen pusher by day (insurance of all things), but have always been into large scale model cars (1/12 , 1/8 Pocher etc), but instead of spending a huge amount to begin with on a lathe that I may or may not (not being the key word) get along with, I decided to go one of the $500 C1 micro's to test the water. Before this I had no training or experience in lathes (didn't even get to use the beat up wood lathe in high school!),

This lathe itself, straight out of the box, again from my limited experience, was pretty good (or at least I was happy with it). I have owned it now for about 9 months, and as my experience has grown, I've become more sympathetic towards its capabilities and limitations. As you can see there are a few non standard mods (caliper for DRO etc), and I have spent a fair amount of time ensuring everything is square and tight, and runs like a charm now that everything has 'bedded in'. Having no previous experience, I thought it was important to learn to use the machine manually first so I fitted calipers as DRO's to the x and y axis. Once I got the hang of it, fitted up the CNC bits about 4 months ago, have removed the y caliper, just have to do the other. As with most things, the steppers were fitted up, 'temporarily' with bits of pine as brackets (well, they're still there....well..you guys know how it goes)

When I do the drill press motor conversion I will remove the 'gear' cover on the left hand side of the machine, and make another box to cover it all. The lathe will also get a dedicated bench with allor drip tra and splashback, with perspex hood.

Now I've go the hang of it, I want a little more power out of this machine, but in the next 6 months will also be looking to get a larger unit (Hafco or something similar). Will be looking for best option up to about $1300. Obviously for my parts I don't need a long bed.

I have also attached a pic of the production run I'm in the middle of, to give you an idea - this is the largest part I turn on the lathe. They are the brake drums for the 1/8 Pocher Alfa Romeo. I supply these to www.scaledetails.com along with a few other parts, bottom line here is my lathe, tooling, cnc conversion etc has all paid for itself, and I'm actually in front with it (the wife is happy)! This run of parts will pay for the milling machine!

Simso, very nice work on the router (that kangaroo looks awesome). So a power regulator would do the job for variable speed control then? Good to see the obligatory sound system in there with the lathe! I used to run a Kenwood car headunit with a pair of 6x9's and 10 stacker cd, until I needed the power supply for the CNC conversion! Now just have the dodgy 20 year old clock radio.

Grahame, thanks for the welcome, to give a little advice myself, just have a go, from doing that I've certainly learned what NOT to do! If I can offer any assistance please feel free to ask.

Penpal, what size machines do you have (interested in any opinions that may help my future purchase), what do you turn, what is your opinion?

Thanks all.

Colin

Hey thats a cute lathe and Im not taking the out of you. A mate of mine had the exact same unit,being cnc'd certainly exopands its horizons dramatically, theoretically theres not much you couldnt do on it because with the cnc you can vary the depth of cuts for maximum tool usage and control. Well done, are you using ballscrews,allthread or acme
Steve