Holding an end mill in the chuck, good or bad idea?

Think think, your older Myford may have dovetail slides but the beds of the newer Myfords are square. Yer don't need to get into the realms of dovetails. Yea, I got them and sic blether and a'that ( Rabbi Burn's Night ye ken) ye can get away with a creative thinking.

Creative thinking is that you might only need a traverse of 25MM or an inch. That's a 2 inch- yes TWO inch cutter sweep and this size will probably have our lathe jumping out the shed and up the road.

Erm , Before i become like the fufu bird roughly what size and depth of cut are you trying to do
For those that dont know the legend of the fufu bird, It ran round in ever decreasing circles until it disappeared up its own backside.
If you get a bit of heavy duty angle iron and the mentioned fly cutter or a solid block fly cut square you could mount the compound vertical that way you get a freeby if wobbly vertical slide

Joe Pie has one answer -

[ame]https://www.youtube.com/watch?v=gCUkJydSmdA&t=301s[/ame]

- Nick

the simple answer to your original question is YES
For the home model machinist its do and make do
There are small problems most have been mentioned
However in my view,making a sleeve is a waste of time
it will not improve any runout problem,a 3 jaw chuck with min runout
would be best and i would not envisage the tool coming loose
The next best option is to make a MT2 to er collet chuck or buy
if available. The best option is to buy a mini mill then you have a lathe and a mill and not a combo. My thoughts

Firstly Nick, yes Joe has an answer which is where my earlier post stems from with regards to a sleeve with three cuts bored out.
Frazer that I've seen also, however that video is what sparked the question, an angle plate mounted to the cross slide with the top slide bolted to it giving Z axis. However a clamp of some sort would still need to be made to hold the workpiece, which would require some degree of milling a block of steel mounted to the top slide that was mounted to the angle plate ect.
Norm I remember your lesson that the workpiece could be turned 180 in the clamps and you could machine the same length on the cross slide again, by packing. However a single pass will produce a far more accurate result if everything is true and failed in, I doubt I have the ability to reset my lathe a second time to a 0.0005" accuracy.
Baz I can see the advantage of having separate machines, in mainly cost saving, but also by combining, some versatility of a machine is lost. Cost (with me, a missus and five kids and a fish especially) is always an important consideration.

My thought was to be able to mill slots and internal reliefs into flat surfaces, only around 5mm at most (I think). Also to mill the webs of cranks At the desired angle.

If you want to use the 3-jaw with no run out you'd need to bore soft jaws.

I would say go for it. Especially if you only have a couple thousands of runout with the 3 jaw. Just remember you lose a lot of rigidity milling on the lathe in general.

Some of the issues people are talking about with their slots being too big may not be coming from tool runout, but from rigidity issues. Even on my bridgeports at work if I put a slot into a part the endmill will pull towards the climb side of the cutter(the smaller end mills especially). This makes the slot slightly bigger because the end mill is walking some from being pulled in one direction. This will only get worse with a less rigid setup. So if you take light cuts and use a smaller end mill to at least clear out most of the stock before putting the full size cutter in you should have good results.

Not a good idea to hold an end mill directly in a lathe chuck as it does not grip well enough (both surfaces being so hard) plus the inaccuracy of the chuck. I got around this by making a couple of collets out of mild steel rod/bar. Turn down the outside to about 4 to 5mm larger than the diameter of the end mill, then bore out to the exact diameter of the end mill. Centre-pop the outside adjacent jaw No 1 so you always put it back in the same place. Remove, and using whatever means at your disposal cut three slots along the rod/bar at 120 degree spacing for the full depth of the bored-out part, making sure they are midway between the location of the chuck jaws. De-bur, and when you put it back in the chuck in the right position it should be able to grip an end mill quite well and it should run true. Not as tight a grip as a proper collet, but adequate for the normally light cuts possible when milling in the lathe.

Jon you have a few choices concerning this but all will either need a deeper pocket or time to make tooling its that simple
A simple vertical slide set up is usable yep its cruddy ,wobbly and causes loads of swearing as well as a stiff neck trying to see whats going on and as rightly mentioned slots tend to be oversize due to the total lack of rgidity
When I first started playing with these machines I spent more time making tooling than making toys its a simple fact you either make it or buy it but if you make it then you learn
Just get an old MT1 drill cut the drill off and make a simple holder if you are that worried or do that thing Im not familiar with buy one
The crank web and many other thing including slots for simpler engines canbe done with that old fashioned tool that saves heating the workshop a file
cheers

Hi J, if you have to do milling operations on the lathe it is best to use a vertical slide attached to the crosslide, either use a vice mounted on the vert slide or by fixing parts direct to the vert sllde using the tee slots.
Vertical slides are available that allow the job to be swivelled to an angle with the lathe axis, this is certainly an advantage on some jobs but you do need to ensure the unit cannot move under cutting forces.
Using the normal 3jSC chuck to hold the milling cutters is not the best method but if you take sensible size cuts and always keep the cutters sharp all should be OK.
If you try to "climb mill" the cutter WILL move out of the chuck and spoil the work.
If you use screwed shank end mills provided there is enough length you can lock 2 nuts at the end and when fitted to the chuck bring the nut surface onto the back of the chuck jaws, this will reduce the risk of the cutter working out of the chuck.

It is best to observe the usual rule of locking slides that are not being used for making the cut, pay attention to using the best speed and feed for the material being cut.
Although milling on the lathe is not ideal if a milling machine is not available there is no choice.
Many works of art have been created that way but it will of course be a learning process perhaps with tears on occasions.

Marcus

so for slot milling or keyway milling as well as cross drilling in the lathe I use this little tool to hold the roundstock and use the 3 jaw to hold the end mill or drill. I think I got this idea from tubalcain videos but I couldn't find the video so maybe it was from someone else. but it works great for quick and dirty keyways and cross drill.
just bolt it down to the compound where my tool post bolt is already sticking out, run it up to the face of the chuck to square it. sinch down the bolt and then instert round stock and clamp it in the v and your off and running.
it might not be accurate to split a hair, but its plenty accurate for a cross hole for a tommy bar or a key way for a pully shaft or something. quick and easy.

in the photo the v looks all chewed up, its really just leftover glue from where I didn't have room to use clamps so I glued the part in, I need to scrape or wirebrush all that off.

I'm still taking the contrarian position to the responses to this original post. It's much better to have separate machines dedicated to their tasks than to constantly be setting up a combo machine. Milling especially requires that the work piece travel parallel and square to the cutter so jigs and set up are required only to tear it all down when the lathe is required.

Switching back and forth is a nuisance for me that easily justifies the cost of separate machines. When I need to mill, I step up to the mill. When I need to turn I step up to the lathe and when I need to drill the press is aways available and ready.

Sure you can accomplish multiple tasks with only one basic machine and the creative challenge sounds like something that all of us have tried but in the end having separate machines are way better, in my opinion.

One problem about holding a milling cutter in the 3 jaw chuck hasn't been mentioned:
Jon. I believe you own an ML4 which is quite elderly and 'well used'. The chucks that you received with it are probably elderly and well used and quite possibly there is some bell-mouthing to the ends of the chuck jaws, either from holding work in the end of the jaws or general wear and tear in the jaw slides.

So, although it is possible to hold the cutter directly in the jaws, your original idea of making an improvised collet will be the best and safest way. Ensure your improvised collet is the full length of the jaws to minimise any walking out. Another safety addition to be considered is to grind a small flat on the shank of the cutter and use a grub screw in the collet to bear on the flat.

Dave
The Emerald Isle

Hi Jon, Guys,

One comment that I will make to Dave's post is if you are going to go down the road of making a collet, putting a lip on both ends will prevent the collet from walking out of the jaws. Weldon put a flat on their cutters, so a small flat ground on the side with a securing grub screw will increase security of the cutter.

Now I did mention that I had made a dovetail slide some time ago, pre mill era, and said that if I could find it I would take some pictures of it. Well here it is:

It was intended as a practice piece, I learnt a lot from doing this... I'm glad I bought a mill Today I wouldn't dream of using the lathe to mill.



This first picture shows the flycut surface. One of the first tries, at this time I think I was struggling to get the cutter ground properly. You will notice that the surface gets progressively better as I learnt.



That slot was cleaned up with a file and the insert done the same way. If I remember correctly, I used super glue to hold it in place while I drilled, countersunk and threaded the hole. 2BA I think.



This picture clearly shows the brass 2BA pinch screw and the 2BA leadscrew along with the brass nut and 1mm cross drilled pin.



A horrible close up, out of focus picture.



Here you can clearly see the surface of the dovetails.





These last two pictures show how sharp the edges ended up. The work piece was clamped to the cross slide using packings to lift things up to working hight and a small angle plate to make sure that each cut was at 90' to each other. The cutter was clamped using the four jaw to hold square tools with the end ground to get the 45' degree edge.

I would have taken pictures of the tools that I made, but I no longer have them, probably reground to do other jobs.

Anyway I hope that helps.

Well my milling question may be void soon anyway as I have been offered one of these
http://www.lathes.co.uk/amolco/

Although it is designed for the ML7, or as a stand alone unit, the person who's offered me it has said that he will do the machining on the foot to allow it to fit my ML4 and most likely make some dovetail clamps to help lock it solid on the lathe bed.

One very happy Jon

Baron thanks for the photos of your efforts.

JCSteam said:

Although it is designed for the ML7, or as a stand alone unit, the person who's offered me it has said that he will do the machining on the foot to allow it to fit my ML4 and most likely make some dovetail clamps to help lock it solid on the lathe bed.

Click to expand...

ML7 to ML4?????? Should be an interesting saga err topic:hDe:

Cheers



N

Yes I'm thinking a new foot may be required then save the one on it for when there's an upgrade. 😀

Though if your offered a horse you wouldn't look how long it's teeth are.just plain rude

One more thought.... consider making this gift milling attachment a stand alone machine. The column does not look too rigid and the play in the lathe carriage will cause all sorts of milling problems if you try climb milling by mistake. Squaring a vice to the milling cutter could also be an issue. With a stand alone machine you can take the time to make it as rigid and precise as possible.

My last input for your consideration.

Look into Military Auctions... in the 70’s I picked up a manual Bridgeport and a Moriseki lathe for $600 each that were not run out...

My first milling work was on the Myford Super 7 using an angle plate with just less than half a Cross Slide Vice bolted to it to give a single axis slide and a drilled and tapped tooling plate bolted on the front. I held end mills in the older roughing 3 jaw chuck and the setup allowed me to make some useful parts.
I moved on to an L. W. Staines Milling Attachment, having good X-Y in the horizontal plane made enough of a difference to make me want a vertical mill.
The Amolco should work nicely until you feel the need for a separate mill ;-)

- Nick