micro lathe from scratch - maybe

[zeeprogrammer]

Some of you may remember my question on collet variety...here's the rest of the story.
I've been talking to a buddy of mine at work and we're thinking (thinking! mind you) of making a very small lathe.
It's not to make precision parts but should be capable of turning a variety of material for very simple parts.

Plastics
Wood
Perhaps some metals like aluminum or brass (but probably not steel or more difficult metals).

Maybe incorporating only a 3-jaw chuck. No bigger than a 2".

Stepper driven Y and X. Just a carriage and cross slide.

No tail stock.
The bed ways may be rod (like from a printer).
No ability to run material through the chuck.
12V driven motor.

Your thoughts on this are welcome. Whether positive or negative.

I think the HP on my mini-lathe is 1/3HP or maybe bigger.
I think we're talking something smaller here. What do you think is required? Any suggestions for a motor?

We're talking objects no longer than an inch...maybe up to 3.
I'm figuring accuracy will be forgiving. We're not talking about building engine parts.

Let's see where this goes. If anywhere.

Some project ideas...if this helps...

Pens (a stretch I think)
Miniature bowls, vases, canisters, candleabras, etc.

I know all of this can be done with a mini-lathe. But part of this is being able to build our (your) own itty-bitty lathe.
If you have stories of this being done (or tried) before...that will be interesting too.

So what have you got?
"You're an idiot" is acceptable. Just never call me "hey you".

[steamer]

Why not?    I built a mill when I didn't have money, but I had a lot of scrap.   It worked very well and I made a lot of engine parts for my launch engine on that mill.




Have at it.

Dave

[Johnb]

Take a look at "Building a small lathe" by LC Mason. This describes something of the size you're looking for, but is a full featured little lathe. For building a small lathe from scratch using just hand tools and itself, article by Don Gordon in Model Engineer, I think back in the late 80s. He was a fascinating guy to chat to on the SMEE stand at the ME exhibition. Mind you, his lathe was treadle powered!

[fcheslop]

http://modelengineeringwebsite.com/lathe_build.html

[stevehuckss396]

I think it's a great idea. Look into an RC electric motor to drive your spindle. They are small and put out a ton of power.

[Firebird]

Hi

I think its a great idea and one I have had myself so i will follow along. My Myford is a great lathe but it lacks speed and is a bit cumbersome for small stuff.

I made a high speed headstock for the Myford which is belt driven from the original headstock (I'll dig out some photos if it helps) I used an R8 to 2MT adapter for the spindle, probably too big for the sort of thing you have in mind here but maybe a 1MT adapter would be a suitable spindle?

If you look back through some of my posts you will find the power drive I have fitted  to the leadscrew of the Myford and the Z axis on my X1 mill. Both these mods use 12 volt windscreen wiper motors. Both have variable speed, controlled by a PWM (pulse width modulator). They are plenty powerful enough and easily sourced. The speed wouldn't be high enough as they are geared down via a worm gear but that could be removed. Some years back I built a little electric truck for my daughter and now my grand daugter drives it, its powered by a car radiator fan motor.

You mentioned using the rods from printers. another good source of beautifully ground straight bar comes from the piston rods of car shock absorbers. The front shockers can be up to 20mm dia.

Hope this helps

cheers

Rich

[Arbalest]

I've thought of this a well. Given the availability of things like ball screws, linear guides and module rack and pinion gears etc it should not be too challenging for many folks. Personally I'd still have a hollow spindle and a tailstock but that's just me. It will be very interesting to see what you come up with.

[zeeprogrammer]

Thanks for the support.
Nice mill Dave. I bet you were happy with that.
John, I'll have to get a hold of Mason's book. It looks interesting.
Thanks for the link Frazer. Very helpful and gave me some additional thoughts.
I hadn't thought about RC motors Steve. I took a quick look. Looks like I have to dig a little deeper for specs.
Nice to see you Rich. Being in a windowless basement I think of your shop once in a while. I did wonder about wiper motors. I'll dig into those more too.
Thanks Arbalest. The chuck I'm thinking about may obviate the possibility of a hollow spindle but I do need to keep it in mind. The tailstock is another story. In my first post I'd said 'no tailstock' but I'm going to keep it a possibility.

The links to the small lathes are very helpful. Still too big but very useful.

Yes the idea is for 'anyone' to be able to put one of these together with, ideally, no machining. Off-the-shelf parts as much as possible. A 3D printer may be helpful to make some parts. My buddy at work has one. He's a mechie engineer and a pro at SolidWorks.

Big concerns of course. Rigidity for one. How to get the chuck square to the bed. How to mount the chuck for that matter.
I've been thinking about that 2" chuck from Harbor Freight but it's not clear to me how to mount it. It uses a T1 (IIRC) that I believe is removable.

Thanks. Any/all thoughts are welcome.

Again...this may go nowhere. Much depends on whether my buddy at work stays involved. (He started it!). But it's fun noodling this.

[steamer]

Zee....The RC car motors are unbelievable.    My son's truck has a brushless DC motor.  It can draw 100 amps @ 7.4 Volts continuous.  More in short bursts.

It turns at 50000 rpm.    This motor is TAME compared to some....Not a bad approach actually.   I recall we had a member at the other place that made a really nice spindle using a RC motor as a drive motor.


Dave


PS....the car weighs almost 5 pounds....

<a href="https://www.youtube.com/watch?v=7uGGRpLmItc" target="_blank">http://www.youtube.com/watch?v=7uGGRpLmItc</a>
 

[zeeprogrammer]

Thanks Dave. I did see that video on another thread. Pretty cool.

I'm liking the RC motor idea for a number of reasons. Variety, easy-to-obtain, relatively cheap, easy to control.

[b.lindsey]

I will be looking forward to seeing where this goes Zee. I suspect we have all had similar ideas at one time or another, good on you for taking a stab at actually doing it!!

Bill

[zeeprogrammer]

Thanks Bill.

Yeah this is bad news. I think I'm getting hooked by it.
Seems I can't stop thinking on it. Started some doodling.

But many of my projects have started this way. 

[dieselpilot]

I considered doing something much like this, but with more precision in mind. I Ebayed a 5C headstock made by Dunham Tool and a pair of 6" linear slides with lead screws. The plan was to take a piece of structural steel C channel and mount the components to build up a lathe. I'm sure it would have worked, but didn't progress because I didn't have a mill large enough to do the work. Then I decided a conversion of some kind would be better. I almost bought a Hardinge HSL locally without a carriage. Eventually, I found an Emco Compact 6 CNC minus control.

If the project is mainly about making the lathe, then go for it. If the end goal is to have something with some capability you may reconsider. Right now I'm rebuilding a small CNC lathe to meet my needs, but they are probably different than yours. The Emco Compact 5 CNC are fairly common and can be had ready to run.

While RC motors are powerful, it comes at high speed. Think about the reduction required to get the speed you want. Electronic speed control works, but also limits torque unless the motor is much bigger than required. I would source a small 120VDC motor and use a KB or other SCR type control that runs right off the mains. You will have a power supply for the steppers anyway so you could run the spindle on the same 24VDC or whatever you run the steppers from, just make sure you have enough current available.

[fcheslop]

Why not just print the whole lathe bed 
Try glass reinforced material.Im just playing about with a cube that has mitre gears so when you turn one corner the others rotate .All printed Not all my work but fun.
Will do some pics if you are interested.
Just a thought why not 3D scan the mini lathe reduce it by what ever and print it 

[zeeprogrammer]

dieselpilot...good thoughts about the RC motor. I do figure some reduction may be needed regardless of motor but I have more learning to do.

Yes...this is somewhat related to 3D FFF/FFD printers. Similar concepts to some extent. So the idea is that the whole thing is powered by a PC power supply. 12V then is what I want to drive the motor with.

frazer...all the 3D FFF/FFD printers I've come across use ABS (mostly) and some PLA. What glass reinforced material are you talking about?

Sure...I'd like to see some pics.