looking at getting a cross slide vise for my tabletop drill press for light milling. The drill press is harbor freight grade, as will be the cross slide. The extent of the milling i will do with this will be 3/16 slots x 1/2" long though 1/10" thick aluminum, so it should be a fairly light load. Will I be able to accomplish what I want with the hardware I have/can purchase?
If you have one of the cheesy drills with the threaded on chuck instead of the taper mounted chuck, you are ahead of the game. If there are any tapers at all, between the spindle and the cutter, the side loads will cause the cuck to pop off, usually at the worst possible time.
Aside from that, there is not much headroom on that drill press.
It is a sub-optimal solution, and you would be FAR better off to get mill/drill unit and do away with the drill press, and use the mill/drill as your primary drill.
You REALLY want anything with a drawbar to hold an endmill, in order that the side loads don't cause the holder to drop out.
================ Generally speaking this is not a good idea, but more than likely you can get away with this FOR THIS APPLICATION AS DESCRIBED. It won't be quick, and it won't be very accurate, but its better than a file.
One of the keys is to keep everything tight, such as retightening the chuck every few minutes. Your major problem is that neither the chuck, its MT attachment to the quill, and the drill press bearings were designed for side [milling] loads. An Asian designed/manufactured drill press that is built down to a price will have even less safety factor than the older American iron, and these were marginal at best in this regard.
I suggest that you use the drill press as a drill press to plunge cut as much material as possible from your slot using a center cutting 3/16 end mill, leaving a "scalloped" edge on both sides of the slot and then go back and clean up the sides using a [light] side milling cut.
NOTE: a 3/16 end mill is [almost] certain to cut a slot wider than 3/16, how much more depends on how loose the particular quill and bearings are. So you may have to use a 1/8 end mill and shift from side to side to get a clean edge 3/16 wide slot.
It is vital, given the backlash/slop inherent in this setup, that you use only conventional milling where feed direction is opposite the rotation of the cutter. "Climb" milling, where the cutter wants to "pull" the material in will almost surely cause tool to "grab" the work, take too big a bite, ruin the work, snap the end mill, and cause the operator to change their fruit-of-the-looms.
Also be advised that some aluminum machines about like Bazooka Bubble Gum. Extrusions are particularly prone to this. This is a good application for WD-40 as a coolant/lubricant. Don't use too much, apply it to the top of the end mill next to the chuck so it will run down as you cut.
Tool wear will be concentrated on the tips of the end-mill, so when side milling use the upper portion of the end mill flutes if you can.
Use two flute end mills on aluminum. If you use a 1/8 end mill to generate a 3/16 slot you might try a 3 flute as this avoids the "cogging" action of having both flutes engage and release at the same time. Use the less expensive M2 end mills. The more expensive cobalt and carbide end mills are for much higher speeds and much more rigid machines than your drill press, and as these are more brittle, they will be much more likely to break. FWIW -- I have found Wholesale Tool to be a good source of economnical endmills. for some examples click on
Wear safety glasses, and be aware that the chuck could come loose at any time. Put some guards in place. Keep your hands away from the cutter as much as possible. Run everything as slow as possible. Take your time. Listen to the machine.
All I can add is that the X-Y corss slide vises that I have seen at Harbor Frieght have LOTS of slop (backlash). If nothing else goes wrong, this slop will drive you nuts. If the end mill digs in anywhere, it can pull the vise to the "other" limit of the backlash and dig an unwanted gouge out. If you plan carefully for this and if you can truly lock one axis, you may have a change. I used to do light milling in my Craftsman drill press using a Palmgren X-Y table. It worked out pretty well, but the chuck, which does have a taper, also has a threaded collar that pulls the chuck up tight and NEVER comes loose. I never even had trouble with the end mill pulling out of the chuck, which is another insidious problem. I suppose I was taking such light cuts (1/8" end mill into annealed tool steel)that it didn't pull out. The problem with this is (if it happens) is that the end mill sneaks out a few thou at a pass, so your cut is deeper at one end than the other.
I have seen the "Micro" mill on sale at HF for as little as $250. Maybe it was a floor model?
"Cogging" action? You've got me on that one, George. Unless you are talking about the inability of an end mill with three or more flutes to cut a slot to size. A two flute mill would be fine. 'Splain yourself, please.