[handlewanker]

Hi....half th4 size???.....it must have a bigger shank size to hold in a collet then?

On the rule of 4D for stick out you would have to have a very small collet nut to even see the cutter......touch down for Z zero would be a microscopic exercise.....that's coming into the field or watchmaking.

I have some drills that have 3mm shanks but .025mm actual drill diam size on the end, but the actual drill end part is only 10mm long.

I once had to drill jet holes for a model aero engine carburettor, and the drill was made from a piece of piano wire in the form of a spear point.

First you make your drill...... then you make a brass sleeve..... then you drill the sleeve with the drill........ then you press the drill into the sleeve........ then you Locktite it in.......then you drill your job.

I tried holding small drills in pin chucks but the run out was more than the drill diam.

If you fix the drill into a longer brass body and then mount it in a small 4 jaw chuck you can dial the drill up to get it to run true and machine the shank up to the chuck jaws which gives you a drill that will run true.

Small diam HSS drills can be silver soldered into bigger diam steel bodies quite easily......feeding them into the work is another experience.
Ian.

[A_Camera]

The shank diameter is of course much larger, all the ones I use have 1/8" shanks. I used a few twist drills which are 0.8mm but even most of the small drills I use have 1/8" shanks.

[handlewanker]

Hi....that makes sense for tool holding.....just one collet.

BTW....have you ever tried to sharpen a 1mm drill bit?

I made a Wishbone type drill sharpener to sharpen drill bits from 0mm to 5mm diam, using a diamond honing block for the abrasive.

You need a 10 X watch makers loupe to see the results, but now I have a USB microscope on the go to do small tool refurbishing and examining..... and measuring too.
Ian.

[robobass]

Old thread, but first, how deep are you cutting? Why are you buying stock from HD? You can get better alloys online for cheaper. I would never try to dry-cut 6061 with a high speed spindle. I don't know what it is called in North America, but I use "Al Cu Mg Pb - F34/37 EN AW-2007" which has lead content making "dry-cut-able". I run passes no deeper than .5mm at around 350mm/min. Carbide is good, but TIALN or TICN is probably the best for this. More expensive than HSS per endmill, but orders of magnitude cheaper per job. I mostly cut brass dry with both TICN and Carbide. Some of my endmills last for years.

[louieatienza]

Old thread, but first, how deep are you cutting? Why are you buying stock from HD? You can get better alloys online for cheaper. I would never try to dry-cut 6061 with a high speed spindle. I don't know what it is called in North America, but I use "Al Cu Mg Pb - F34/37 EN AW-2007" which has lead content making "dry-cut-able". I run passes no deeper than .5mm at around 350mm/min. Carbide is good, but TIALN or TICN is probably the best for this. More expensive than HSS per endmill, but orders of magnitude cheaper per job. I mostly cut brass dry with both TICN and Carbide. Some of my endmills last for years.

TiAlN and TiCN refer to the coatings; they are both essentially used on carbide endmills. There really is no set speed or depth-of-cut as it all depends on your machine's power and rigidity. Also 6061 is the easier alloy to machine. The big-box-store alloy is likely 6063 or worse 3003. Basically the harder the alloy the easier to machine. I find the 7000 series fairly easy, including the cast stuff (Mic6.)

I probably would not use TiAlN coating with aluminum, since the coating actually has aluminum in it (hence the Al) and is really used for very hard machining.

[robobass]

Right. I meant that I use TICN coated HSS-E ball ends, which seem to cut smoother. I use uncoated carbide straight mills.

[LeeWay]

There are special coatings used for aluminum, but your sharpest bits will be uncoated HSS. They are not really stronger than carbide, but are more forgiving on a less than solid machine.
Especially given the size. Single flute bits are great and do not tend to lift the material when using, but for cutting aluminum, you really need to shear the chips. It needs to be chips and not clumps and fluid can certainly help with that.
Knowing the grade of material is a must as well.
I was shipped 6063 material when I ordered 6061. While I could still machine the parts in my mill, the parts were really sloppy looking and left a lot of deburring chores. Feed and speed needed to be much different than for 6061.
The tapped threads would tend to cross thread easily too. Nasty stuff.