Milling on a lathe

[ttabbal]

So, in my thread about beginner projects a lot of mill projects are creeping in. I don't mind that, it's nice to get ideas, but now I want to mill things.

So I know the attachments are not rigid enough to do heavy milling. I'm thinking little slots, keyways, etc.. Mostly aluminum, small cuts on steel I'm sure will come up. I ran across this Grizzly adapter...

http://www.grizzly.com/products/Milling-Attachment-for-G4000/T10721

It's small so it will keep me honest, and the hole spacing looks like it might well bolt up to my PM 1127 cross slide. I'd likely need to make or buy some T-nuts, and perhaps buy or build something to clamp work to the table. Along with something to hold a mill cutter and a couple cutters.

 

[Mitch Alsup]

Issues::

1) I have a similar adapter for my Taig mini (or micro) lathe::
1.a) it is difficult to hold things well enough to mill <accurately>
1.b) the milling performance is <best I can say> slow
1.c) it is hard to see what you are milling
1.d) I did mill some slots in 6061 Al for a telescope I built 19 years ago
........just about the only use that thing ever got.

As to 1.b: I can use a hacksaw and a file at a faster rate than I can mill in the Taig--which was very frustrating

But give it a try, as the cost is "not that much".

I ended up with a real lathe (G4003G) and a real Mill (G0730).

 

[ttabbal]

Yeah, I'd love a real mill. That's not happening anytime soon. I could swing the parts to try the adapter. I could wait a bit and get a mini mill, but even those start around $700. And at that point you get close to a decent benchtop mill for a little more and so on..

 

[cg285]

my grandfather built his shop and house in 1923. he put this lathe in the basement of the house. he had a machine shop/auto repair business until 1986 when he died. as a teenager i saw he had a bridgeport mill and i asked him what did he do before that for milling. he looked at me like i was an idiot and said "well the .... lathe of course" he never ceased to amaze me on what he could produce. point is a lot can be done on the lathe

 

[TTD]

Hi ttabbal,
I started out (as I’m sure most here have) pretty much exactly like you…a few little (useful) projects on the lathe to get familiar with both machine & process/order of operations. And, like you, it wasn’t very long before I realized that I NEEDED a milling machine. I couldn’t (& still can’t) afford a proper milling machine, so a milling attachment for the lathe was my only option, knowing full well going in of its limitations.

The problem I found with most, if not all, “store-bought” milling attachments (& even most of the home-brewed ones I looked at while researching) is they tend to place your work piece waayyyy out past the crosslide, making for a chatter-inducing, non-rigid setup, not to mention drastically reducing your workspace (especially when working parallel with lathe axis).

My solution for this was to make my own milling attachment for my little 7x12 lathe that would hopefully remedy the problems noted above. I won’t clutter up your thread with a bunch of pics of my setup, but here is a link to the build if you are interested:
https://www.hobby-machinist.com/threads/milling-attachment-for-my-7x12-mini-lathe.37410/#post-405613
…and first project using attachment (indicator holders):
https://www.hobby-machinist.com/thr...ct-with-milling-attachment.37673/#post-322506

Since that original build post, I have used the attachment on everything from Delrin/Acetal to 4130 CrMoly tubing & everything in between with no problems. Still have to be mindful of your setups, DOC, machine’s ability etc, etc.., but it works good!

Hope this helps rather than confuse your decision more!

 

[British Steel]

Like TTD I improvised until I bought a milling machine - I mounted the topslide (compound) from my lathe on a large webbed angle plate, then mounted that on the cross-slide (blessed with T slots), made a long T nut for the topslide's toolpost mount to bolt a small vice to. This gave me about 10x5" of x and y travel (and i could use the cross-feed for powered x-axis) and, with the tailstock brought up to support was *reasonably* rigid.
I used (1/16" steps) collets in the spindle, which limited me to 7/8" shanks, plenty big enough with everything flapping around!

I mostly used that setup to cut short keyways etc., worked pretty well.

Dave H. (the other one)

 

[ttabbal]

Thanks for posting the details of your design @TTD. I thought it seemed like hanging it off the side of the cross slide would introduce flex where one would not want any. I figured the idea was to allow for travel of the work below the cross slide plane. But the stickout plus a vise mounted on there could get excessive. I suspected that clamping the work directly to the table of the commercial unit might help, but then setup becomes a bit more tiresome.

I don't think that the unit I linked would mount parallel to the ways. That's a design consideration I didn't think of. I could see it being useful though. If I used an angle plate that allowed for the bolts to be in a square pattern, I could mount it in any 90 degree orientation. I see some that use a rotating base, but I suspect that's another flex point and I think I'd rather avoid that for now.

I'm not in a huge hurry. I don't have any milling cutters or a way to hold them other than the lathe chuck. And I keep reading that it's not a good idea to do that. An MT5 end mill holder isn't terribly expensive, add some all-thread for a drawbar and it should be pretty sturdy. Or there's always a collet chuck, which I already have reasons to want. Though it does push the price up a fair bit and I'd need collets.

 

[ttabbal]

I decided to pick up the Grizzly adapter. It fits, parallel to the ways. So I can have the table face me or away from me, but not toward the chuck. I'm thinking of building an adapter to mate it to the lathe so I can face it whatever way I want to.

The idea right now is to buy/make some t-slot bolts/nuts to hold a piece of plate steel down to the cross slide in a square pattern so I can rotate it, and have a bolt pattern that fits the milling adapter. I'm thinking about 1" A36 with a ground finish. Any reason that might not be thick enough? Then perhaps adding a spacer and building a solid mount for my tool post for those times the compound is too flexy.

 

[ttabbal]

So I've been tossing options around and think I have most things ready to mess with. I ran into a question I thought would be good here.

Many people use mills for drilling. Many are advertised as drill/mills, the smaller ones anyway. If I wanted to drill in this setup, perhaps on a flat workpiece, could I use my tailstock drill chuck in the headstock with the proper MT5/3 adapter? I know end mills need to be positively held with a drawbar in that configuration. Do drills? I've never seen people mention it, but that might be because it's too nutty for most people to think about in the first place.

This is partly because my drill press has so much flex that I almost need more travel than my 1" indicators have to measure it. But mostly because now that I thought of it I almost have to try it, if only to see that I hate it. But I want to make sure I'm not likely to break equipment or people doing it. And yes, I'm planning to get a decent drill press or mill or both.

 

[mikey]

If I wanted to drill in this setup, perhaps on a flat workpiece, could I use my tailstock drill chuck in the headstock with the proper MT5/3 adapter? I know end mills need to be positively held with a drawbar in that configuration. Do drills? I've never seen people mention it, but that might be because it's too nutty for most people to think about in the first place.

This is partly because my drill press has so much flex that I almost need more travel than my 1" indicators have to measure it. But mostly because now that I thought of it I almost have to try it, if only to see that I hate it. But I want to make sure I'm not likely to break equipment or people doing it. And yes, I'm planning to get a decent drill press or mill or both.

Sure, you can use your drill chuck on your lathe with the proper adapters. Do what you need to do to get the job done - just don't damage your nice new lathe. By the way, I vote for a new mill and a good used drill press.