Milling in lathe?

[Perko7Participant @perko7]

After much indecision i finally took the plunge and made up some collets to fit in the 3-jaw following advice in various links from this thread. Made from MS bar, turned and bored in situ, position of No1 chuck jaw marked with centre-pop, removed from chuck and slots cut with hacksaw, back into chuck with endmill inserted, tightened chuck, switched on and held my breath – needn't have worried, worked well despite the overhangs, ran true, and didn't come loose so happy chap now. Can't take deep or fast cuts but that wasn't the objective. Photos below:

Apologies to the purists.

Geoff P.

[mick70Participant @mick70]

http://www.model-engineer.co.uk/news/article/free-plan-cross-vice-to-vertical-slide/22255

hoping to get this done at club over winter whilst engines aren't running.

[Harold Hall 1Participant @haroldhall1]

Thanks Thor for giving my Lathe's Milling Head a mention. I did a few weeks back place on YouTube a video showing it being used, a link to it can be found here

I do also have on my website an article about milling on the lathe, plus nine lathe only projects, the best place to look for these is on this page of my index

Harold

[MWParticipant @mw27036]

Posted by Michael Gilligan on 25/09/2016 12:21:10:

Posted by Nick Hulme on 25/09/2016 12:11:40:

Michael,

I'm fully aware that the concavity is tiny, and I know why this was done, but this still equates to out of tram, the beauty of a mill is that you can tram it for visually perfect results where the paths of large cutters overlap, I assume from your attitude to this feature that you're also relaxed about tramming your mill

Nick

.

Nick,

My 'mill' is a BCA Mk.III and is [to within my measurement capability] perfectly aligned when I insert the dowel.

There is no need, or facility, to 'tram' it.

MichaelG.

The sherline Mill has a similar alignment dowel on it's earlier fixed head model, You can get a universal mill that doesn't have one but clearly this isn't an unusual set up.

Most machines would be aligned by the factory anyway, it isn't a good idea to change it if you don't have to, and odds are they have much better measuring equipment and jigs and expertise designed to deal with the problem anyway.

Michael W

[Perko7Participant @perko7]

An update:

After a few passes, the work-piece started to come loose. Tightened the clamp bolts but ended up stripping one, and not with excessive force either. Had a look, they are simple thin square nuts that fit into the wider part of the tee-slots. Only 2.5mm thick so with M5 threads there were barely three full threads engaged. Tried to get spares from the supplier, you guessed it – none available. Tried to get something similar, but no luck, so ended up making 'proper' tee-nuts to fit. Took a bit of sawing and filing but now have 4 tee-nuts that are a snug fit and have ample thread for tightening the clamps. Anyone else buying the 'Toolmaster L275 mini vertical mill slide' would be wise to make up some tee-nuts to suit before doing anything else.

Geoff P.

[HopperParticipant @hopper]

Well done. You are well on the way now! You would probably find you can take deeper and faster cuts if you push that cutter as far back into the chuck as you can, cutting overhang to a minimum. Also, mounting the vertical slide directly on to the cross slide would eliminate a bit of flex too, assuming you have a graduated handwheel on the main leadscrew to measure the depth of cut that way.

[Perko7Participant @perko7]

Thanks Hopper, will need to modify collets a bit as grip is not enough when pushed hard. Cutter rotates in collet before belt drive slips, not ideal but at least a good safety feature. I'll extend the slots so the cutter can go further in, which will also provide more grip.

There are tee-slots on the cross-slide but not enough room to mount the vertical slide without removing the topslide. What i have done is move the vertical slide back to the central tee-slot on the topslide which makes it a bit more secure. There's a bit of movement but as long as i take up the slack before each pass it works ok.

Graduated handwheels? – i wish. Not really standard fittings for a 90-year old machine. I know i could update it, but it belonged to my late grandfather and i'd like to keep it as original as possible. Usually measure by 'number of handwheel spokes' or by position of knob. All leadscrews are 10 tpi (topslide, cross slide and main carriage) so 1/4 turn is about 0.6mm or 25thou which seems to be well within lathe capacity. Happy to go slow and easy on the old girl.

Will post comments elsewhere on experience of climb milling versus traditional as it's not quite the same on a lathe as in a milling machine.

[PaulRParticipant @paulr]

I have no experience of milling in the lathe (although I aim to get some as my 'new' ML10 came with a vertical slide!) but wouldn't it make more sense for Geoff's workpiece to be mounted flat (parallel to the surface of the slide) and the end mill used in the way for which it was designed ie cutting on the side rather than the end? Guidance welcome as I'd rather avoid unnecessary changing of trousers 😀

[MuzzerParticipant @muzzer]

I would tend to agree with you, Paul.You'll get a better finish and won't wear out the corner of the cutter (and thus trash it) so quickly. To avoid the need to wear fresh or rubber pants, you'd want to use "conventional" milling rather than "climb" milling, as there is likely to be a fair bit of spring and backlash with this kind of setup. As you say, this is an ideal opportunity to reorientate the work accordingly – it isn't always possible.

Murray

[EmgeeParticipant @emgee]

Geoff, my tip would be to place a piece of flat material between your workpiece and the bottom vice jaw to add support to the overhang from the vice jaw, it doesn't have to be exactly the same width as the work. When cutting move the workpiece into the cutter from front of the lathe so cutting forces try to push the plate down onto the additional support. It may have been said already but best to lock any slides other than that used to traverse when cutting.

The alternative method of using the side of the cutter would mean longer setting up time because of clamping on packing and aligning the job so the cut is on the correct line. Murray has mentioned already the importance of using conventional milling, climb milling could lead to the work being snatched from the vice.

Emgee

Edited typo

Edited By Emgee on 22/11/2016 16:57:16

[Perko7Participant @perko7]

Thanks Emgee. Locking the slides is not really an option as i'm relying on the cross slide to move the work past the cutter. Also the only way of locking the slides on my machine is by tightening the gibs until you can't move the slide, not the best solution i think.

Thanks also PaulR and and Muzzer, I didn't think about mounting it the other way. Would certainly have reduced some of the backlash/spring, but multiple passes at the same setting also resolved that.

I tried both conventional and climb milling, conventional was best for removal of material without clenching various body parts, but climb gave better finish for the last pass as long as it was very fine cut and feed otherwise it would snatch at the workpiece and also the swarf would get carried over into the path of the cutter causing interruption to the cut.

Still, i'm happy with the outcome even if some pieces aren't exhibition standard. At least they'll be hidden from view on the assembled loco.

[Ian S CParticipant @iansc]

By locking the slides, meaning lock all except the one in use, and have that one tightened a little.

Ian S C

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