Can you give a bit more info such as

Depth of cut on each pass, speed of feed and rpm, any cutting fluid?

2, 3 or 4 flute cutter and make? sharp?

Is the quill locked, is the axis that is not moving locked?

My X3 did need the quill bearing preload adjusted as the nut was actually loose on arrivalbut not needed touching again in over siz years

J

Quill play is seen as rather unusual by most people, but it is perfectly acceptable behaviour for two consenting adults – just don't bring it up at a dinner party unless you know your hosts very well indeed.

Aunty Stub.

Even on a big solid mill 7mm is too great a depth of cut for a full width cut with a 6mm mill, even in aluminium. The sideways force pulling the cutter off line will be very high.

It's probably the toolbit bending, and the forces generated by this may have loosened the spindle bearings or headstock gibs. Try a 2mm DOC and make sure the table gibs are snug too.

Neil

7mm is way too deep causing you to have to feed very slowly. Try about 1/5 to 1/4 of that and feed faster.

A 4 flute cutter is not ideal for slots as there is a tendancy for the cutter to move sideways, Ideally you want a 2-flute cutter often known as a slot drill for obvious reasons.

J

.

Nigel,

I agree with most of what you said; but must just mention that there is a useful integer between two and four

Three flute cutters are very versatile.

MichaelG.

And a 12mm cutter is going to be a LOT stiffer than a 6mm…

Neil

Unless its a centre cutting 4-flute design in which case you can plunge and ramp with them bit like the one on the right that I was using at the weekend.

Alan,

Not sure if yours is a Super X2/Super X2 Plus, as not from ARC. Regardless, your post seems to suggest that you have low or limited experience of using a small size milling machine. At ARC, we come across this/similar issue about once a month. By the time a matter such as this is raised, the machine has been 'shagged', because of lack of experience. Many of us go through this hard learning process, especially if we do not have access to the words of wisdom being expressed on this thread by the experienced users, or if we think that we are cleverer then them.

I too have gone through this process – on an SX3…videos on our website on that page, being an example…where I forgot to lock down certain axis before milling/drilling, too fast speeds and feeds resulting in poor finish, and respective axis becoming loose. End result – shake rattle and role – machine shagged – get a bollacking from our experienced engineer who ends up having to re-adjust gib screws…

Now that you are in this state for sure, as suggested by others, adjust/lighten gib screws, check/adjust spindle locking nut/s (depending on if it is a SIEG two nuts/non-SIEG – one nut with grub screw). Before your next milling exercise, lock non-moving X or Y axis – normally the screw with/without handle to be found in the middle of all gib adjusting grub screws. If you have a SX2/SX2P, lock in the three pronged handle which moves the head up and down on the rack, fine feed the cutter to the depth of cut you need, and then lock the Z axis gib onto the dovetail of the column, using screw with/without handle to be found in the middle of all gib adjusting grub screws. The idea is to get maximum rigidity before you start milling.

Generally, for aluminium, do consider two flute slot centre cutting endmills, ideally a cutter which does not have a coating (I dont know the technical reason why). If not available, most centre cutting end mills – with/without coating will do, giving variable results based on depth of cut, spindle speed, feed rate, with/without coolant, and grade of material being cut. Oh yes, it does help to have a sharp cutter.

The best way to figure this out is to experiment, but generally, start with about 0.5mm to 1mm depth of cut, and a spindle speed between 2000 to 2500rpm, spread some coolant/WD40/paraffin on the area being cut. Then start feeding the cutter into the aluminium and listen to cutter, feel the machine for vibration, and reduce the speed of spindle, and speed of feed, if necessary. If happy, experiment up to a maximum of 2mm dept of cut. You are unlikely to get anywhere with a 7mm depth of cut in one pass.

BIGGEST MISTAKE I have seen/hear every time is expectation for 'small mills' to behave like a big mill/Bridgeport with higher depths of cut, feed and speed. This really gets me annoyed at first, but then I have to remember that the user probably does not have any experience of using a small mill, or this is the users first experience of using any mill. This is OK, if the user is accommodating about his lack of experience, but difficult to consider if they start going up the 'I AM so and so with X years of using a milling machine over Y number of hours (usually a big machine or a CNC machine!) ' route or 'not fit for purpose' route. We come across both types

Good Luck, Ketan.

The problem of cutters pulling to one side happens all the way up to the largest of machines. Slots should be milled as mentioned earlier with smaller tools and finished to size cutting one face only.

I worked for several years a machine bigger than my garage and never cut a clean slot in one go no matter how big the cutter. When you are using "hobby" mills, although they look pretty tough, the structure can flex under heavy loads so the;

0.1mm quill play + tool deflection + machine deflection

will account for the rough shape and finish of your slots. Once you accept the problem, working around it becomes the norm.

Trevor