I would like advice regarding drilling small holes in aluminum parts with the mpcnc, how you would do it, e.g. if you have holes that are 3-4mm size.
I am using dw660 which can take 1/8 and 1/4 inch shank bits. The 1/8 inch diameter end mill is of course 3.175mm, bigger than desired 3mm hole size.
I am thinking the best way to drill holes would be to use a drill press rather than the mpcnc for the actual hole drilling and just use the mpcnc to mark where the holes should be.
I am thinking to try putting some blue painters tape on top of the part and use drill in Estlcam with a V tip bit to take a shallow depth just take the tape off to locate the center point of holes, then switch to regular end mill cut out part along external perimeter with mpcnc, use punch to make impression where tape was removed and use drill press and drill hole to size desired.
If you have confronted this problem before, what did you do?
I should also mention, I bought some smaller endmills on amazon that have 1/8 shank and using “hole” function in Estlcam with one of those I tried didn’t work well to carve out the holes with the precision desired.
You can use a smaller bit (I have a 1/16th) but plunging is not easy in metal with smaller bits. Marking and using a drill press is probably what I would do, maybe a vbit and a 0.3mm depth or so, just to give a nice place to punch or drill from.
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Or be okay with a slightly larger hole. 0.175mm is well within the normal tolerances I use.
I’m brand new here and have been lurking reading up on stuff before I dive in, but I feel I might have a decent suggestion. Although, I don’t have a machine yet and haven’t used one so this may be way off.
Would it be possible to chuck up a center drill and then just plunge down a mm or two and make an accurate spot for each hole, then finish drilling the holes the correct diameter at the drill press after the rest of the part is machined? Here’s a center drill size chart:
If the chuck will hold it, you can usually chuck up a 1/16" bit so that only a tiny amount is sticking out. Makes it much less likely to break if you do it this way.
We all have broken end mills, one of the diamond cutting wheels on a dremel will cut carbide. Probably wouldn’t take too long to fashion a spot drill. Just cut the flutes off, then cut a cone on the end, and cut that in half-ish.