Milling with a drill press

[joed1]

Hi ! I was reading a post about one guy who was considering making a drilling guide similar to the one that CNC offers (the one with a bunch of 1/8" holes in it, which allows milling with a drill press), and you had advised him that all he needs to do is drill within your guide plates. I was thinking of that myself. I was looking at the CNC site instructions for using the milling plate (with the 30-something little holes in it), and I was thinking "why can't I just do a bunch of 1/8-inch holes free-hand (maybe use a straight-edge rule and a fine marker or punch), then drill them out with the 3/8" and 1/2" drills as per the rest of the instructions? So, this is how people are doing this? What about doing the drill-milling freehand also, using the top plates as a guide? I know it's probably trickier than using an XY table, but if you're only doing one, could this work? What size and type end mills would you recommend for doing it this way, and what other considerations should I be aware of? Thanks!

[joed1]

Can anybody who has done an 80% receiver with a drill press respond with some guidance for a first-timer?

[Nathan]

There has been thousands of people who have done 80%'s with drill press's. I am going to let them answer some of your specifics.

[Nathan]

If you are using the Tactical Machining jig, you must mount the jig in a good vice that holds it straight up and down. Make sure you set the depth so that you do not drill to deep in each of the two pockets that you will be milling out. Drill out each corner of the fire control and rear lug mount area to within 1/16" of the proper depth, use a 1/4" drill or slightly smaller. Each hole should be drilled with the fixture firmly in a vice. It will take some time to keep moving the vice but it is worth it to have a good part when you are done. Once all of the corners are drilled to within 1/16" of the correct depth, drill rows of holes between these holes as close as you can to the previous hole without breaking into it. If you break into the hole next to one already drilled, it will go into that hole and not straight down. If you do this accidentally, skip it and continue until you have as much as you can drilled out of the pocket.

When you are done drilling, vacuum up all of the chips (You should do this as you go anyway.) Replace the drill bit with a two flute 3/8" end mill. A 2 flute end mill can "Plunge" or be able to drill straight down, many 4 flute end mills cant plunge.

Re set your depth so you go to the correct finished depth. Use the end mill to "Drill out" the metal between the holes you drilled. Do not cut into the jig or touch it with the end mill or your finished product will be out of spec (But would still work unless you cut through the side or something).

When you finish cutting out off of the metal in the pocket, see if the trigger hammer and upper will fit in the finished pocket. If it is to tight, use a dremmel tool and the 1/2" sanding drums to open up the pocket and smooth out any thing that remains.

It is like making a wooden duck, you take wood and remove anything that does not look like a duck. In this case you use the jig to guide what needs to be milled out, the dremmel will remove the small metal left between the drilled holes. If you dont have a dremmel, use the drill press and the dremmel sanding drum on it at high speed but be aware that he drill head may fall off if you press hard sideways on it. Never side mill with a drill press, the head will fall off since it is only held on by a taper. If it falls off it will roll and can cut you and your receiver up.

[Bernie333]

Refernce milling with a drill press...youstated that it is "only held on by a taper pin"....WHAT is only held on with a taper pin? Is there a remedy? Are lyou talking about the drill's chuck?

[minuteman]

Yes, ..... Your drill press chuck has a taper that is jammed up into the drill press spindle. This is essentially a friction fit. Remember a drill press uses vertical force to plunge the drill bit into the material. Sideward pressure on the chuck can cause it to come out of the spindle. You can use an end mill in a drill press if you take care and take very light finishing cuts.

[rmcduffee]

I have succesfully milled a 80% lower with just a drill press (a Craftsman that is at least 60 years old). As described above most of the material was removed by drilling and then the mill bit was used to clean up and finish. I purchased a cross-slide vise from Harbor Freight to emulate the X, Y axis of a real vertical mill. I always went slowly and tried not to side load the bit excessively.

[roaries7]

Is there a minimum horsepower a drill press should have to mill the lower? I currently only have a benchtop press and am in the process of looking for an affordable floor standing one.

[Nathan]

Honestly if you are looking for a good drill press, stop.

Look for mills. They will cost just a tad more then a good drill press and be a heck of a lot more useful. Heck we bought a used full sized bridgeport one time for $750. I have even seen better deals. Evena new mini mill you can normally find for less then $500.

[roaries7]

Yes, that's what I'm finding. (Sorry for the noob move and not searching first)

Wanted at least 1hp and for a little more money, a mill can be had instead of a drill press.