[dfro]

Hello everyone,
I want to see if I can make a metalworking manual/cnc lathe. For many years I have wanted a metalworking lathe, but the cost of a quality machine has stopped me every time. I have looked at all the cheap imports that I can afford, and I cannot bring myself to buy one. I want a beautiful precision instrument that is within my abilities to maintain and adapt to my needs as they develop. And I feel the skill and abilities I gain in building my own machines will be worth it.

This website and the projects of various members have greatly inspired me. So, here is where I am so far in my past attempts and in my current thinking on this project.

I have read the Dave Gingery series, and I began my version of his lathe project in fits and starts. I made the lathe bed and ways using a square 2 x 2 steel tube filled with cement that had a 1/4" plate screwed and jb welded to it. I learned how to cast aluminum and made a headstock and feet for the bed. The project stopped when I could not get the headstock moving on the ways smoothly.

Next, I got a 52" Atlas lathe bed on ebay for 20 bucks. The shipping cost more than the bed. This I sand blasted and repainted and then I had the ways reground. The company that ground the ways did not have the ability to grind the underside of the ways, so I began studying scraping. I purchased "Machine Tool Reconditioning" by Connelly, I got a 24 x 18 surface plate and I made my own carbide tipped scrapers.

I was going to then piece together the lathe with parts from other Atlases, but while trying Atlas machines, I realized they did not have the weight and tolerances I was looking for. They were all really worn out.

So, I started looking at old SB 9 and 10 inchers again recently, but the decent looking ones are out of my price range and I do not trust buying one without the thought that I would have it reground and reconditioned. This is an expensive proposition.

So I figure, if I am going to go to all the trouble of rebuilding old machines or rebuilding new, low quality imports, why not start from scratch. In the process, I can also make my lathe more modular, so that upgrading any component is not very hard. DIY makes sense also, because in my various projects I do not need thread cutting ability until I have cnc working. So, I will be happy without all of the split nuts and power feeds and quick change gears. Turning two cairrage handles if fine until I have the steppers hooked up.

Today, I have gotten a lot of ideas studying the various threads on this site and I would like to run them buy anyone who is interested in helping me.

1. I was thinking I could still use the Atlas 52" lathe bed I have. The tops of the ways are ground flat (I do not know how flat, however). Being old, I assume all of the twist has settled out of the casting. I could buy Thompson-type guide rails and attach them to the ways by drilling and tapping holes in the ways. The carraige and tailstock would attach to plates that attach to the Thompson bearings.

2. I have noticed that a lot of builders are starting with the mini-mill and mini-lathe headstocks that Little Machine Shop sells. I like that idea. I am wondering if the mini-mill and the mini-lathe headstocks have the same dimensions for the bearings, because I would like the get the mini-mill headstock and the base casting it attaches to. These two castings I could then bolt to a plate that bolts to the Atlas bed where the original headstock is screwed down. The v groove that is ground in the mini-lathe headstock in also not necessary. Could I get the mini-mill and swap in the mini-lathe spindle? Does anybody know?

3. I am thinking that I could push the mini-lathe/mill headstock, spindle, and bearings to handle a 9 or 10 inch swing as long as I do not take huge cuts. The lathe bed is designed for the 12" Atlas, I think. Any thoughts on this?

4. I could clamp the tailstock along the ways by pushing a gib tight against the outside surface of the original Atlas bed ways. A type of apron could hang down and one or two set screws could be tightened by hand. I don't think this would torque the Thompson guides and bearings too much.

5. I could power the spindle with a timing belt and pulley. I will have to learn which one to get. I am not sure what motor I will use to power it. Any suggestions would be great. It looks like a lot of people are finding tread mill motors and speed controllers.

As, I get further along I will show some drawings, I am also learning to use Rhino 3D.

Thanks

[vishnu]

Hi,

I am also in the same position. After all the reading and data collection from CNCZONE and other sites i have planned to by a small manual lathe. I plan to start my conversion as follows.

1. Convert the Two axis into Servo driven system.

2. Convert the Spindle to a DC drive with VFD

3. Design a Automatic tool Changer

Yes its good to start from a old machine because lot a time will be saved on the mechanical part. Its better to check the if you are on the right path with a 100% error free accurate machine thats what is called a CNC.....?

My first plan was to start right from scratch using a 30 or 45 Deg slant bed. But when i started to plan the time could well be over 3 months for the mechanical part as i have to do all by myself. As i was in a dilema i came across many threads in the forum regarding converting a old lathe/Mill in CNC machine. Then an Idea Struck me the cost of my brand new lathe with 6" chuck will be arould $1000 Dollars without tooling. Thats pretty cheap that building one. Donot try to start with a Stepper as they are not accurate and a waste of money. Go for a Servo no second thought. I plan Gecko drives or Uli servo driver With Mach3

I estimate you can finish the project in approx. 45 days if you go with the old machine else it could take 4-6 months of your precious time if you dont have a helping hand.

Well i will be begining from scratch with the purchase of my lathe next Week.

Please share you ideas.

Regards,

Vishnu

[dfro]

I am planning to use my Atlas 52" lathe bed, an import mini-lathe headstock, a mini-mill cast riser block, and a mini-lathe tailstock. I will then use lots of adapter plates to mount it all to the lathe bed and the THK or Thompson linear guides and bushings. I think this approach will get me off to a good start without needing to weld and bolt up everything from scratch.

I am interested in having a modular approach, where I am not stuck because I do not have a South Bend part that no one is making any more, for example. It is cool to see in this forum how people are continually upgrading and expanding their machines to fit new needs. I want to first succeed in getting a manual lathe working. Then, I can use it to make the cnc parts and make a cnc router mill.

I think the flat ground Atlas ways are a good stable flatness reference point upon which to add the linear guides. I know that drilling and tapping the ways will destroy the lathe bed for any other purpose. But, it is not a big loss at $20 if it doen't work out.

My main concern so far is to finding a way to clamp down the tailstock, without torquing the linear guides and bearings too much.

Vishnu, I will consider your idea of only using servo motors.

I will share some drawings and pictures soon.

[acondit]

How about mounting your linear rails toward the outside edges of the ways and having the tailstock ride on the inside edges of the ways not on the linear rails? Then use a standard type tailstock clamp to lock it in place.

Alan

[S_J_H]

dfro, My concern is such a long bed and the mini lathe headstock. It is much to small to handle 50" long parts.
I think I would consider shortening the lathe bed some and it will be cheaper to build with shorter rails. But yeah, the flat ways of the Atlas would be a good surface to start from.
A mini mill dc motor is a pretty good match for the mini lathe head stock. Several dc drives you could choose from. Or a 1/2 hp 3ph with vfd might be a nice choice.
I just milled off the dovetail on my mini lathe headstock base as well as on the mini mill riser base. Messy cast iron but it machines real easy and nice.
I totally disagree with above opinion on steppers.

Steve

[dfro]

acondit, your suggestion is worth pondering. So far, my thinking is to have some apron type pieces drape down off of the plate that connects the tailstock to the guide bearings. These would drape down over the outside surfaces of the bed ways. I could then have a couple of set screws on both sides which would tighten some brass gibs into the ways and secure the tailstock/plate/bearings structure. I figure that if I am tightening it from both sides I will balance out some of the torque on both guide rails. I will draw a sketch in Rhino soon.

S_J_H, I hear you about the bed being too long. I would have to be careful about what machining I did. But, I could use the whole bed for turning wood and plastic, probably. I could mount a dremel and a carbide bur bit to the carriage and turn some pretty sweet braids and posts. For the metal turning, I would stay within 18", maybe. (?) Any other suggestions on what I could make the headstock out of? If you have looked at an Atlas 12" lathe, I am sure you noticed how little metal is in the headstock. These Chinese 7x headstocks look pretty beefy. I have tried to follow how people are beefing up the bearings in other forum threads, but I have to study the subject of bearings quite a bit more. Again a modular approach, where I am not tied to any one companies parts is appealing to me.

Thanks

[dfro]

It seems a nice addition to the lathe would be to have the headstock set up so that it could operate two ways. It could be a normal free running, fast spinning lathe headstock for normal turning and threading operations, or it could be set up like a 4th axis. Then I could do more complex machining like spirals, braids, and flutes. It could also be used as an indexing head and cut gears. Hell, it could turn a replica of the 'Venus de Milo' for that matter.

I would just have to figure out a way to change belts to engage or disengage the different motors.

A brushless dc motor would be very cool to try for the free running headstock motor. I have done a little PIC and AVR programming, and I have looked into this a little for some other projects. Maybe a lot of people are doing this already on their mills and lathes.

[S_J_H]

dfro, yes I think the mini lathe headstock could probably handle long parts made of woods and plastics, especially with a live tool. I am to "metal" minded at times.

Well the mini lathe head stock is pretty inexpensive, it's cast iron and simple to fit a belt drive to. For a small hobby machine it's not bad at all. You can also fit tapered rollers into the mini lathe headstock.

You could also try a 9x20 headstock. Very similar to the mini lathe but larger with tapered rollers and probably more expensive. Drawback is the spindle has a screw on chuck.They both have MT3 spindle tapers.


Make your own of course, I think that is only realistic if you have larger machines or access to them.
Anyhow, go for it! Sounds like a great project.
Steve

[dfro]

S_J_H, where could I get a 9x20 headstock and tailstock? That sounds like a good option - more metal would be good. Could you tell me which tapered bearings you are talking about. I would not mind improving the bearings as long as they do not cost $200 per pair - like I have heard some people mention on other threads.

I could get a SB 9" headstock and tailstock on ebay, but I am worried about the spindle, bearings and tailstock ram being worn out.

I could cast or fabricate a headstock from scratch, but I don't want to do that again, for now.

I cast a pretty nice little Gingery-style headstock, but I ran out of steam on that project. I will show some pics of it soon. I might make it into a cnc indexing head or something later.

Two questions: what kind of forces can linear bearings withstand? Are they used on production cnc lathe's?

[dfro]

Grizzly sells parts for the 9x20 at: http://www.grizzly.com/products/G4000

The total cost of the headstock parts I need and a complete tailstock is ~ $450. Ouch!

I think starting with the 7x headstock and tailstock is the best option. I can learn and make my mistakes on a smaller, less expensive setup and then maybe later upgrade to something bigger.

[acondit]

dfro,

What about buying a complete HF 8x12? They sell for $539 and you can now have them shipped to your local store. That way you'll have the spindle, motor, controller and chuck as well as the tailstock.

Alan

[dfro]

Alan,

I have thought about your advice and I looked at your website, also. Nice website.

I am considering this senario.

I will buy a Grizzly 9 x 19 lathe. Having a manual lathe and my Jet benchtop mill always 'on line' keeps me moving on all of my projects.

With these machines, I will build the cnc lathe I have been talking about and I will build a gantry mill. I am also interested in replacing the Jet mill, which has a round column and a lot of slop in the table, with a homemade cnc mill that uses a square column. Or i will buying a square column cnc mill.

I have heard the saying 'the perfect is the enemy of the good'. I fall into perfectionism easily. With these manual machines, I can build better machines and keep my other projects 'on line'.

What do you think? Also, how do you like you Grizzly 9x19? I like your idea of adding more rigidity to the compound rest with a four bolt clamp.

[S_J_H]

dfro,
I have a grizzly 9x19. I have done many mods to it. Some mild some wild. Have a look here-
http://s109.photobucket.com/albums/n...ods/?start=all

It's a nice lathe to use in it's current state.

I easily could have cnc'd it but I wanted to have both a manual and a cnc lathe.
I did consider a 8x14 or 8x12 for CNC. But after cnc'ing 2 small mills with dovetail ways I really wanted to test the waters with a scratch built machine and linear rails. So far I am very happy with my decision as the build is going well.
Steve

[dfro]

Steve,

Your photos are really inspiring. So, you have the Grizzly G4000, correct? Did you completely take apart your 9x19 machine and paint it grey? I am very interested in what you did to the tailstock ram, too. Did you machine a part that screws into the back of the existing ram?

Your diy cnc lathe build is the main inspiration for my cnc lathe design. I just will be starting with an Atlas lathe bed instead of making the bed out of steel plate. Could you tell me what type of linear rails and bearings you are using and where you got them? I will check your thread again to see if you have already shared this info.

What are your plans for a tailstock? You might want to consider securing the tailstock in the way I am thinking - tighten some gibs to the outside surface of the steel bars that the rails are attached to. Just and idea. I will get some cad pics up soon.

While saving up for the G4000 (and clearing up a spot for it in my small shop), I will get busy drawing up the cnc lathe. I will also start planning my gantry mill.

Any other advice you may have on the 9x19 table top lathes will be greatly appreciated. Thanks, Alan and Steve for helping me with my game plan.

Dave

[dfro]

Steve,

Is that a Grizzly G0619 mill I see in the background of some of your cnc lathe pics?

How do you like it?

I would like to replace my Jet round column benchtop mill with a square column mill.

[S_J_H]

Dfro,

Two questions: what kind of forces can linear bearings withstand? Are they used on production cnc lathe's?

Oh these things are trick! They can handle forces in any direction and quite a bit! Take a look at the manufactures specs for exact numbers.
Yes they are used on production machines. Here is a nice little article about them-
http://www.cncmagazine.com/vol6thru8...-LinrGuide.htm
I am using Hiwin brand rails/blocks and I bought them from www.automation4less.com.

As for the 9x19, yes it is a Grizzly G4000. I just painted it grey.
The tailstock ram was made by welding an attachment to it. But you could probably do it simpler with a screw on attachment.
It's a very very good mod IMO. Saves so much time having a lever feed. I also am into mini engine building. The tailstock can now be used effectively to hone cyls with a nice cross hatch.

I have the standard X3 (Grizzly G0463)
It's cnc'd now. Great little mill, Here's my cnc thread on it-
http://www.cnczone.com/forums/showthread.php?t=24983

My plans for the tailstock on my cnc lathe is to mount a mini lathe tailstock on a plate and use 2 rail blocks for it to ride the long axis rails. A pillar with a 7/16" thru bolt will drop down to the bed surface. The bolt will firmly lock it into place to any of the tapped holes in the bed. The pillar will be adjustable in length( only need a few thousands of an inch adjustabilty) to allow for flatness variance on the bed surface and precisely allow the tail stock to be bolted in position on the rails without brinneling the rails or bearings.

I am interetested in seeing your castings. I would like to learn metal casting in the future.
Steve

[dfro]

Steve,

I tried to download some images of my diy lathe #1, but the image size is too great. I will have to figure out how to reduce them.

I also did some sketches in Rhino of my tailstock plate idea. IMHNO (in my humble newbie opinion), this might be a better approach than what you are considering. The gibs tighten down with four threaded knobs. It is very easy and convenient to loosen, move, and retighten the plate/tailstock assembly. I think you will get very weary of unscrewing, realigning, and rescrewing down your tailstock assembly to the treaded holes you have on your design. Also, I think the locking leverage would be better with my design. There might be some flex in the aprons, though. Any, comments are welcome. This is just how I am thinking of doing the tailstock, so far.





Here is another idea: A vertical steel plate could run down the middle
The clamping knobs could be in front and behind the tailstock base that is clamped to the tailstock plate. These would then push the gib into the lathe bed to lock the tailstock assembly in place. The only problem is this eats up a lot of distance on the ways, reducing it's distance between centers. There could also be problems with the plate flexing up, also.



Please, let me know what you think.

I am also considering buying the slightly bigger Grizzly G0602 10x22 lathe.
I like that it has a 1" bore instead of the 9 x 19's 3/4". I am not sure though about the knobs that are used to change the gears, though. I will have to study the schematic to see how it works. Maybe the 9 x 19 would be better, since it is sold by so many different vendors. Parts would be easier to find if anything needed to be replaced.

Your mill conversion thread is very inspiring, and your resonance damper device is pure genius!! Could the holes be loosely filled with bb's or buckshot?

Dave

[dfro]

Photos of diy lathe #1:

Patterns:



Headstock, countershaft, lathe bed:





The bottom of the headstock:



I decided to put some old-school curves in the feet:





I filled the lathe bed's square steel tube with Commercial Grade Quikrete Fast-set Non-shrink Grout with a piece of rebar going down the middle.

I also used Bondo where the castings shrunk from the sand a little. I was going to paint it all green like the countershaft.

As I said before, I am going to move on to diy lathe attempt #2. What I plan to try with this lathe bed is to make it into a scraping reference plate. I will attach handles where I screwed in the feet. I have heard the advice that steel is not a good substance for making scraping references, because it twists as you take material off. Granite makes a great reference. So, I figure maybe by adding the non-shrinking grout, some of solid properties of stone will be gained. I figure it is worth a try. For almost no money, and some elbow grease, I could have a 36" flat reference to use in scraping mill and lathe ways. It has already been ground, so it is close to flat already.

Comments very welcome,

Dave

[S_J_H]

Dave,
Your method for the tailstock lock looks good. I would use the side clamp version. I think my idea will work very well though so I'll stick with it since the bed is already tapped. I'm using a 7/16" bolt which can create some serious clamping pressure!
Realistically the little tailstock will be the weakest link, not either of our clamping methods. I don't plan on doing a lot of tailstock supported work so unscrewing a bolt to position it won't be any bother to me.

I would probably go with the 10x22 lathe. It looks better made and heavier than the 9x19.
Thanks for the kind words on my mill and damper.
The dampers work ridiculously good. I can't say if bb's or lead shot would work as well. One thing is for certain. Resonance is gone completely.

I like your pics of DIY lathe#1. I see a nice machine as a possibilty there..
But I guess a nice long flat reference surface would be very nice to have as well.

Steve

[dfro]

Steve,

Thanks for the comments and advice.

In the future I would like to try the lost foam casting method. It really simplifies a lot of things. I like this primer on diy lost foam casting:

http://www.buildyouridea.com/foundry...oam_howto.html

I would like to build a cnc foam cutter. It could be a good first cnc project, since the mechanical parts do not have to be very rigid and the steppers can be small. It could be a good place to work out all of the electronics and software for the first time, too.