Depends on your milling machine, you don't want to take too heavy a cut with the smaller ones, motors and controllers can go pop! I would probably do this in 3 cuts but my machine is fairly heavy with no fragile electronics. If the cutter is cutting without making horrible noises then it should be OK. A squirt of oil helps. Harold Halls book on milling is worth getting if you don't already have it. Don't worry too much about weather you are doing it 'properly', time isn't too important for hobby work, it's the result that counts.

Dave

?how do you cut 6mm deep in a 4mm bar ?

It’s usually easier to cut slots with slot drills rather than endmills unless you want a slot open at one end. Endmills as you have probably found will not bore a hole as the cutting face does not include the middle third of the end.

Edited By Frances IoM on 05/05/2016 23:05:49

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Frances,

I think the picture that Rod posted answers that ^^^

MichaelG.

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Edit: You beat me to it, Rod.

Edited By Michael Gilligan on 05/05/2016 23:12:42

Hi Rod,

I'm relatively new to machining and have a Warco WM-16 milling machine which I think is the same size or maybe just a little larger than the X2P. It has a 2MT spindle and 750W motor.

For a long time I've been using end mills and the occasional 2-flute slot drill from kit inherited from my Dad and have always taken very cautious milling cuts.

I noticed Jason.B mention the other day about trying out a roughing endmill from ARC and I've always wondered what these were like so I bought a 10mm HSS-AL 4flute and I have to say I am amazed at how much more metal I felt comfortable removing in a single pass, this was tried on EN3B mild steel to make some T-nuts. It also feels different when winding the axes, seems to have more feedback through the winding handles.

I would highly recommend anyone new to hobby machining to invest in at least one roughing endmill as it turns what can be a tedious exercise into an enjoyable step in making something on smaller milling machines. Wish I'd done this sooner.

Ed.

Edited By Ed Duffner on 06/05/2016 06:20:22

Ah! I see – I generally browse with images turned off and have to explicitly allow any redirects (avoid many problems including blocking the all too many trackers) thus I hadn’t realised you had published a photo hosted from your own site

On the vertical mill I'd cut the slot in two or three passes with a 6mm cutter. On the horizontal mill straight through in one pass.

With these small cuts you are unlikely to be power limited, even on a small mill. I'd concur with JasonB; the biggest mistake is pussyfooting around with feedrates. Slower isn't better, it just rubs the cutter and squeals or chatters.

Andrew

Rod,

I just tried the cut you made with a 6mm 4 flute ripper cutter on my old style x2 (the one with the tilting column).

Went through in one pass, 6mm deep without any significant complaining.

Regards,

Dan

Although the rougher/ripper may go through in one pass if the work needs a good finish you will have to go through with a normal cutter to clean up the edge so choose your cutter diameters accordingly to allow for a finishing cut.

Have a look about 2/3rds down this page where I'm milling the cylinder as you can see the rougher in action and the finish it leaves compared to a 3 flute "normal" cutter

The metal you show looks like 'black' steel as used for welding structures. This helps to explain the burrs you noted. I have found inclusions of slag in such material – visible strands about the size of a pencil lead. This is no problem for welders (who tend to cut with shears or angle grinders), but it can wear cutters quickly.

You might get a better finish and longer tool life if you seek out 'free-cutting bright mild steel'.

Cheers, Tim