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Dragons_fire
05-22-2010, 07:53 PM
Here is what i have been working on for the last 3 weeks. Its not finished yet, but its in a running state so now i just need to finish up some of the details.

http://i163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/P1000529.jpg

It is my first attempt at cnc, and i think it went fairly well. I learned a LOT, and enjoyed the time in the shop. My original plan with it was for making pens, wine stoppers, and chess sets. It's meant for wood and plastic, although i will try it with some aluminum at some point.

http://i163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/P1000532.jpg

So for the specs, its got a 1/5HP spindle motor, that overheats and may not work but has lots of power and enough rpm. The steppers are 36oz/in unipolar that are driven by L297s drivers and ULN2803 Darlington arrays. They are 12V steppers that i am running at 12V, so that could be why its a little slow. Although, my leadscrews are 32tpi brass rods, so that could have something to do with the speed. The spindle bearings are cheap 40mmx3/4" ball bearings, and they dont seem to have any play in them yet, and are fairly smooth running.

http://i163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/P1000531.jpg

So as for work left to do, my Y-axis stepper is held on with c-clamps at the moment, the 12V power supply i wanted to use isnt any good, so im going to switch to another one i have laying here. I want to add limit switches to both axis, handwheels to the back of the steppers, and I really need to do something about the #35 chain drive for the spindle. I havent had much luck finding belts that small, although i havent looked too much.

Then when all that stuff is done, i would like to clean it all up and maybe anodize it all.

And here is a picture of the second part i made on it. Its a chess pawn that comes as a sample with EMC2.

http://i163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/P1000528.jpg

Dragons_fire
05-22-2010, 07:55 PM
I forgot to mention in the last post, the pawn was just a piece of pine 2x4, so thats why it tore out on the thin parts.

And here is a video, its big so be warned!

http://i163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/th_P1000514.jpg (http://s163.photobucket.com/albums/t305/dragons_fire_photo/CNC%20Lathe/?action=view&current=P1000514.flv)

Ken_Shea
05-22-2010, 08:10 PM
Let me be the first to say, that is absolutely fantastic!
Well done.

Was a little surprised to see a chain drive, that is not a criticism, just an observation.

All in 3 weeks is a record as far as I seem to ever recall reading.

Ken

doctor demo
05-22-2010, 09:40 PM
Interesting to say the least.I can't tell from the pictures and I have not tried the video, but I am curious about the bed and saddle details. Are the rods the only aligning mechanisms or does the bed do more than take up the vertical load from the carriage?

Steve

Dragons_fire
05-22-2010, 09:50 PM
The chain was laying around, so it got put to use here.. its overkill and really noisy, so im hoping to get some pulleys and a v-blet to replace it with.

The rods are 3/8" O1, and the carriage has 4 bronze bushings in it that slide on the rods. there is some flex in the rods, in the middle of the travel, but not enough to affect anything im planning on doing with it.

at the moment, the longest thing i plan on making on it is pens. with the length of the bed, i can get almost 3 pens at once, so i might end up shortening it so i can still fit two on, but it should stiffen things up a bit.

Your Old Dog
05-23-2010, 06:07 AM
Great job! Keep in mind that those who turn wood frequently turn it green and frequently soak it in a solution that escapes my mind at the moment. Projects are kept in plastic bags until finished and then dried slowly in plastic bags with a few small holes in them to insure slow drying. Some guys use microwave ovens to dry wood.

dr pepper
05-23-2010, 06:25 AM
Interesting project.
Some steppers will double step, that would give you a traverse speed.

dvbydt
05-23-2010, 09:42 AM
Great project!
A 32tpi leadscrew with a 200 steps per rev stepper, gives you a resolution of 0.00016 ins. You dont need that for wood and plastic, so you can at least double the pitch of the leadscrews.
But now you are now hooked into the CNC world:D . Next comes bipolar drives, ballscrews and microstepping Gecko drives.
Good luck and please keep posting your progress.

IanR

Mcgyver
05-23-2010, 09:46 AM
way to go, very nice project.

Dragons_fire
05-23-2010, 10:30 AM
Thanks for the nice comments.

The 32TPI leadscrews were used becasue im using fairly small steppers. I may try going to a courser pitch at some point, but its a hobby machine so speed isnt a big deal at yet!

I cut one more pawn last night, and it takes about 8 minutes. the motor was almost 200*F after the 8 minutes and was just measured by touching the probe of my multimeter temp sensor against the outside can of the motor.
Even the chain gets really warm, it has a slight bit of play in it, but maybe i have it too tight.

I also used nylon tubing as my motor to leadscrew couplers, and it works good, but thats the only thing holding the screws now, so i need to also come up with a bearing system to suppot the screws and hold them from moving.

RancherBill
05-23-2010, 11:00 AM
That's a great project.

Using available materials is the way to go on proof of concept machines. I hope you do your Mark II version, it will also be great.

Two random thoughts,

1: Get rid of the clamps. The people from the micro-cracking thread might wander over and highjack your nice build thread. :D :D

2: When you get around to anodizing I know a professional anodizer that works out of his home that would definitely exceed your expectations. He has been in business for 30+ years.

tyrone shewlaces
05-23-2010, 11:12 AM
Cool !
My only criticism would be that there appears to be a couple places where swarf will collect easily and be a little hassle, but that can be addressed when and if it ever becomes a problem.

I'll throw out an idea too just for future pondering.
There was an HSM article about a hundred years ago where a guy made a little lathe and used a cheap 5C spin indexer for the spindle. It seemed to be a great idea to me at the time and I still can't think of any negatives for it on a light lathe.
(Picture of what I'm talking about)
http://www.travers.com/images/Items/250x250/69-102-682.jpg

It looks like you made the spindle and headstock from scratch so if you wanted to add 5C collet capability to the lathe, I think you could pick up one of those cheap 5C spin indexers (I think they were around $20 at the time, but probably still pretty cheap these days) and easily modify it to work if that would appeal to you. Personally, I really like being able to use collets in the lathe and 5C is a pretty good way to go.

Good job. Congrats and kudos on you.

p.s. You could always make your own 5C spindle too for the cost of a piece of stock. It's just a taper on the nose of an otherwise cylindrical bore, plus a little key pin in the middle. "Deluxe" would be hardened and ground, but that's not necessary at all. Probably only last 10 or 15 years before it wears to the point of needing attention, hehe.