Chinese milling adapters for a mini lathe

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Bogstandard:
I think your major problem is taking things a little too far. That vertical slide is a mighty big lump to have on such a small bed, but should still be able to be used, after a fashion.

Many years ago, when money was really tight and small machinery, like hobby mills, just weren't available, a vertical slide was the only real way of getting some semblance of milling done in a home workshop, and during it's time, people managed to perfect it's use and some marvellous creations were produced using them.

But like everything else in the machining world, you have to get to learn to use it correctly. Whatever is relevent to a milling machine must be used with this attachment. Rigidity of the workpiece and a full understanding of the complexities of milling cutters and their uses. Just sticking a cutter into a collet chuck and hacking away at a lump of metal held in the vertical slide will be doomed to failure. Climb milling is usually the first stumbling block, followed by attempting to take too heavy a cut or too fast a feed. Climb milling is easily solved, DON'T DO IT, as to the others, that is a matter of yourself learning how far you can push the limits of the attachments before you start to get unsatisfactory results. With a milling machine, you might be able to take a 50 thou cut, but using a vertical slide, you might find you can only take 2 thou, it all depends on rigidity and setup.

So play about with it a little longer and find both it's and your limitations, and maybe you will find a way for yourself to get good results, but on no account will it ever be as easy or as fast as using a true milling machine.

Bogs

DavidA:
maybecnc,

...Lathe cross slides aren't usually truly square to the lathe bed ..

So how do you manage to take a square cut across the face of anything if your cross slide isn't square to the centre line of the lathe ?

I would have thought that the first thing needed when setting up the lathe is to attain this squareness.

Dave.

maybecnc:

--- Quote from: DavidA on March 22, 2011, 08:05:16 AM ---So how do you manage to take a square cut across the face of anything if your cross slide isn't square to the centre line of the lathe ?

--- End quote ---

Dave, on lathes you don't and you shouldn't expect it to work that way. If you check lathe specs, even Hardinge say it is not truly square. On the cheap Chinese ones the error may be :scratch: is a bit bigger so the problem is increased.
To mill square on a lathe there is the need to use the DTI to check part alignment for cutting on each face. Many times I do a first cut just to check how far it is from square and then realign the part to finish the job.

The reason to mill on a lathe always feeding the cross slide from back to front is to ensure the milling cutter will be cutting to side. If feeding cross slide front to back the end mill is forced to remove metal at the front of the end mill, and then it is easy to see the end mill bending as you feed cross slide. And it will wear end mills on a flash.

Anyway, perfect results shouldn't be expected milling on a lathe. But if one has the trouble to improve lathe fittings until he gets very reasonable / good results milling on a lathe, then he gets a heck of a good lathe that will make quite good lathe work.

Jose

lordedmond:
Its not that the slides are not square

when a lathe is set up correctly the cross slide is set up to face slightly concave by about a tenth ,they do that to ensure the face cannot be convex ,
but in practice it would make no difference in milling, I have built two loco's using that very same setup , ok it was on a ML7 but is was still a vertical leaning curve with cutter walk outs into the bargain

But it did work had to shuffle the rods along to mill the entire length

Stuart

look like you posted as I was typing

DavidA:
Jose,

Can't say that I agree with you entirely. I would expect (and get ) my old lathe to track square to less than 0.0005" across the face plate. And also checked with a dial guage. Maybe that's not dead square, but it's close enough and the lathe is about 50 year old.
If your trying to square the end of, say, a bit of 50 X 10 mm bar by clamping it on the cross slide then I was always told that you get the edge facing you to run true to the lathe centre line then you can clean up the end with an end mill using the cross slide. If your cross slide isn't somewhere near, then the end won't be square.

My concern was that you must also be accepting this error when you are facing off a job in the chucks.

If it works for you, then ok. Just me being picky. :D

Dave.

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