A drill vice is not rigid enough for milling.
Milling is effectively a series of interrupted cuts, the work need to be held securely.
Aligning the vice along the table, with a clock can be a time consuming task, so I made an alignment tool.
Look at the first photo in my albums (Dated 18/11/2020 )
The only parts requiring any precision are the bottom end of the pillars. they need to,be a really snug fit in the T slots (If they are not, the fixture will not align the vice very accurately )
The "cross bar" needs to be fixed to the pillars so that it is positively located and cannot move.
The trick is that having assembled the complete "goalpost" on the mill table, you take a light cut along the cross bar. In that way, when you clamp the fixed jaw of the vice to it, it will be against a face that is that followed by a cutter.
The only other things that need to be made are two T nuts, and two studs to clamp the whole device into mplace.
I used a couple of long M8 bolts that were waiting "To come in handy", but for another smaller vice, I used some M8 studding and flanged nuts.
Alignment time is less than 5 minutes, compared to possibly 20 minutes of winding to and fro, tapping to align,and probably getting very frustrated.
Using mine, and checking with a clock, the vice is usually within 0.001" (0.025 mm) over the 100 mm length of the jaws.
If your mill is decently trammed, you should be able to produce a part where the thickness varies by almost nothing.. A set of parallels, will help where the work is shallower than the vice jaws, and needs to be packed up to protrude above the top of the jaws by a distance slightly more than the final depth of cut.
You are generating a surface by moving the workpiece under the cutter, rather than forming it.
(As a guide, using HSS end mills, your fed rate should not exceed 0.002" (0.050 mm ) per tooth. So you will need to work out how fast, or slow, from speed of rotation and number of flutes.
It is a hobby machine, with limited power, and rigidity, do do not expect to remove metal at the rate which a powerful heavy industrial machine can. Overloading the machine will cause wear, at a minimum, or damage to motor, or gears as a worst case. Having said that, don't let the cutter idle on the work. That can can cause the cutter to rub,and overheat, which will ultimately blunt it.
HTH
Just spotted a 100 mm vice in the "For sale" section.
Howard
Edited By Howard Lewis on 24/06/2022 01:28:08