One milling operation that is really cool is indexed cutting. With an indexing arrangement you can cut hexs for wrenches to fit stuff or truly accurate flats on two sides for this. I recently took an hour to make my own autococker valve tool rather than go to the store or mail away for one. The simple 5C collet indexer was the key to this project. Without it I would not have any way to cut the accurately sized hex that was needed. A typical quick indexer that is good for down to 1 degree increments is shown here....
5c Spin indexer http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3
Those are the basics for tooling to get you started. As you work with these and want to get into doing more you can make up your own special fixtures and devise ways of making multiple cuts to achieve shapes you couldn't get otherwise.
A big part of any machine of this sort is that you will spend as much and in many cases more on the tooling and accessories as you will on the machine. Many folks would say twice as much on the tooling and accessories is the rule. For this reason it makes a lot of sense to not just jump into a milling machine because you're bored. This is a hobby all it's own that deserves the proper attention. With a bit of care the machine and much of the tooling will last for your whole life. So take the time to consider this and shop intelligiently instead of buying a machine that you can afford but just barely.
OK, let's look at some of the machines out there and discuss them based on the information we've seen so far. Most of these are pictures copied from the websites of the suppliers in the links shown in the very last section.
I should start this by stating that I have not used any of the machines noted below but I have used machines in different size ranges and have gotten a feel for what is possible and practical on each size range in terms of cutters and chattering. On the other hand sizing up the dimensions on the tables and vertical clearance is pretty much a given. My tooling is the same size as your tooling will be so when I suggest that you need such and such amount of room it's based on what I found for myself in the past.
And a last note before we get to the machines. Any of the machines out of China or India will need to be stripped down, checked for sand or cutting swarf and then cleaned and reassembled. My lathe came with enough casting sand or grinding dust in the places where only oil should be that I feel it would have acted like grinding compound and ruined the machines in short order. So definetly take the time to break them down pretty much completely and clean and lube them before putting together.
With the very low cost of this one and others like it I'm sure it's the first thing many of you will look at. However you'll quickly find that you will run out of room in the work area once you start adding in cutter holders (MT2, very hard or impossible to find), vise, workpiece, etc. Any special arrangements will be very hard to accomadate. And I suspect that the small skinny size of the vertical column will lead to a lot of chatter in all but the smallest cutters used in softer materials. All in all not a machine for paintball scale work using paintball scale tooling. I'm sure some of you can make it work for some jobs but it'll always be a compromise and many cuts will not be possible due to the machine's limitations in size and mass. Definetly not recommended for paintball work.
At first glance this machine seems to fill the needs for a small but useable paintball milling machine. The table is a minimal but not far off size, the table travels are great and the table to spindle distance is workable if not great. The problem is that the head shaft is based on the micro lathe and it is small. Too small to take larger end mill shanks of 1/2 inch diameter. Which is likely just fine since the shaft would probably flex and chatter like a magpie at the loads. So while this would work you'll be limited to 3/8 shank cutters and smaller mill diameters and will need to sort of worry your way through any larger jobs or anything at all involving machining steel. It'll likely work OK as a hobby machine in aluminium and plastics but any work in steel will require very light cuts and LOTS of patience. This machine definetly would be on the very bottom of my list of acceptable models. If I'm all wet on any of this and any owners of these machines want to chime in I'd be happy to be told otherwise.
Harbour Freight and Grizzly Tools both have this same machine but in different colors. It's the Sieg X2 machine that you can find info on at this link...
This is the absolute rock bottom minimum machine that I think is capable of doing paintball gun projects. It's table size is slightly under the minimum but not by much. Table travel is 9inches on the X and 4 inches on the Y axis. So it won't be enough to run the whole length of a body in one go in some cases. The table to spindle distance isn't given on the sites I looked at but it appears to be about 10 inches. Again that's a rock bottom minimum in my books. Weight of the machine is listed on the Sieg site at 110 lbs. That's about minimum to absorb the milling vibrations from even lighter cuts. Finally the table movement is handled by lead screws that are 16 tpi so the graduations on the smallish dials are done to 62.5 thousandths. If you're working by the numbers you'll need to watch for that oddball half thou when crossing the zero mark. Same with the vertical travel.
I'm neutral on this machine. It is probably big enough but it is definetly the minimum size of machine I'd suggest. If you get it and find that it's not very happy working on paintball guns then don't come crying to me.
Here's a link to a very detailed writeup on this machine......
I see that the author mentions about a lot of lost movement in the vertical travel fine control. This is typical of the styles that use a worm drive to the big crank. My own mill uses the same style of drive and has the same lost travel and vague motion. I got around this by adding a 1 inch travel dial guage to my quil and rely on that for readouts of depth when I need them. One day I'm going to clamp on a 6 inch travel caliper instead so I don't have any issues with the depth of travel.
This is a far better machine for paintball milling. It's the next size up the scale with both Harbour Frieght and Grizzly having versions but in different colors. The table is a much better size, the X travel is enough to deal with one long full length body cut. The machine is heavy enough to not complain with any sort of reasonable cutting operation and the table to spindle distance is large enough to deal with most setups. As a machine shop hobbyist this is not a machine that you will outgrow unless you move on to much larger projects. It's not cheap but it'll do the job for you for years to come. This machine is the Sieg S3 that is sold under some different names. There's a review site link shown below and appears to be a dedicated user group for support. All in all a very nice hobby tabletop milling machine. This one I feel very safe in recomending.
Review of a Sieg midi-mill http://www.mini-lathe.com/X3_mill/Sx3rvw/SX3-4.htm
Another option. It's roughly the same specs as the G0463 shown above but it's a little heavier, has a little more table to spindle but has a drill press column rather than a big square rigid pillar. I think I like the G0463 a little better. Also the G0463 is overall slightly smaller. In this close comparison the factors the G0463 has going for it outweigh the slightly greater mass and slightly larger table to spindle specs.
This is actually the same machine that I have in my own shop. Mine is an earlier form of it with a metal cover up top but the specs are all the same and I recognize the castings. I can state that it is capable of doing some fairly heavy hobby style cuts even in steel and has proven to be a good machine for me. It still has it's share of design problems that I'm slowly upgrading to deal with. If I was doing it all over again I'd go for the S3/G0463 machine as it would suit my needs just fine.
Now here's a powerhouse. This thing could mill your whole gun to shavings in one pass and not even break a sweat. It'll run on 110 but you'll probably want to set it up with a 20 amp circuit and heavier guage wire. If you need to do much heavier jobs where it'll be working harder I'd recommend you set it up for 220volts. It's easily got enough table size and travel to handle anything paintball related and has more than enough table to spindle distance for anything paintball related.
Part 4 of 3 coming below...