Milling on a Lathe

Evening all,

My attempts at milling on the myford 3'' 1/8'' are pretty poor! I do not have a vertical milling vice, my attempts using V blocks, clamping with T nuts and milling horizontally have been poor. Would this be the factor? If for example I try to mill a 1/4'' slot in ally I get a gouge in the lower of the slot feeding in with the cross and visa versa feeding out. The fly cutter I machined is fine horizontally end mills however just gouge.

Tin hats on

David.

Aluminium can sometimes be better done on the back gear. less heat

Everything needs to be properly adjusted to do decent milling on a lathe, no slop anywhere

(You should really get a milling slide, it makes things easier)

Edited By Ady1 on 11/09/2015 00:30:15

And locking all the slides not in use is essential. Good solid locks, not just nipping up a couple of the gib screws.

Is the ally free-machining alloy? Some of the low grade alloys and straight aluminum can be very sticky to machine.

That may be my problem it was just flat bar bought at my local metal supplier so unknown it is gummy to machine though. I do have some marine ally mostly broken bits off the various boats we'v owned over the years my gave that a try just to see the results. I realised locking everything off is a must but milling on the cross slide horizontally means i need all of my movements. Milling vice would be the way forward, just asking though I'm going to finish all the odd jobs on the machine I have, sell it and buy something bigger which I will invest in a milling vice for.

Thanks David.

Are you using a four flute end mill or a two flute slot drill? If you use the four flute variety to mill a slot there is a sideways force created by the front of the cutter that deflects it if the set-up isn't sufficiently rigid and causes the side of the cutter to dig in.

If it is a sticky material try lubricating it with paraffin.

Russell.

Sounds like your cross slide is way too loose to me. This might be due to uneven wear. If so it will be difficult to do anything about it.

John

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Hi David, I've just started experimenting with milling on a small lathe (sc3) and I have found a carriage lock to be almost mandatory. I use an mt3 collet and draw bar to hold the end mills but the home made fly cutter goes in the chuck.
My set up requires really sharp cutters for best results. Light cuts only, but a reasonable finish can be obtained.
All gibs are a hair on the tight side when milling.
I also bought a vertical slide, I modified it to sit better over the cross slide instead of hanging in space. I try to keep the work as far over the saddle as I can so there is a column effect. The vertical slide gives much better results when that too is locked.

> but milling on the cross slide horizontally means i need all of my movements

You still only use one movement to make the cut.

Neil

Sorry, I do lock off the carriage, My problem is with the cross slide. When I feed in, the cross slide gets pulled in the direction of cut in jerks, I imagine that it's the back lash in my machines cross slide. I shall film and post. I hope you understand my explanation Neil.

David.

Greetings David,

Try to feed the workpiece against the direction of cut to prevent "grab".

A good book on this subject is "Milling Operations in the Lathe" by Tubal Cain. Workshop Practice Series number 5.

Gordon.

Hi David,

It sounds as if you are "climb milling" which does exactly as you describe, pulls the work into the tool and jerks unless you have a lead screw with no backlash. Try feeding in the opposite direction which is "conventional milling". This will only apply a load to one side of the nut on the screw and should eliminate the jerk.

Paul.