Introduction: Poor Man's Milling Machine for Wood (for Making Cat Doors, Sliding Bevels and Other Cool Stuff).
This is my second "tool" instructable. The first one is about a "show" piece: Although I use it all the time, its functionality alone cannot in any way justify the amount of time invested in making it (I could buy a similarly useful tool for a few euros). Only the joy of owning, holding and using a quality tool justifies it.
This instructable is the exact opposite: no looks, just pure, unadulterated usability. Also, where the previous one was very complicated, this one consists mostly of bolting together shop-bought parts.
It is also related to my first tool instructable, in that the tool described here was extensively used in making the other one.
For detail work in wood, there are cases where nothing beats a milling machine. The problem is that milling machines are very expensive - way beyond the budget of most amateurs. The solution is to assemble one from discrete parts. You will not get the full features of the real thing, but it will still be adequate for a large range of uses.
Note: I have added a new instructable, with the improved version I built recently. If you found this one interesting, make sure to check the improved version too.
The main components of my milling machine are:
A high-quality drill stand. I use a proxxon BFB2000 (or here). I have used cheap drill stands in the past and found they not even worth the metal they are made from. I advise against their use. The cost of the proxxon from most online sellers is around 200 euros, including postage to my home (your mileage may vary, as always). If you are patient, you may find on e-bay a used or refurbished one for half as much. Please do not confuse it with other proxxon models which, although generally similar, will not fit a tool with a 43mm neck.
A cross vice. Mine is similar to this one(see note at the end of this step).You may get a better deal on e-bay.
A router with a 43mm neck. Several years ago, the market was flooded with ultra-cheap routers with a 43mm neck (the neck size is important, because 43mm is the standard size of a power drill, so these routers fit the drill stand like a charm).Nowadays it is much more difficult to find them. You can look for one of the following:
But please make sure their voltage matches the mains voltage in your country. Alternatively, if you have patience, you can look for a used Bosch POF500A or POF52 (again, check the voltage before buying). I use a Bosch POF52 which I got used from e-bay for close to nothing and am quite happy with it.
You will also need:
A piece of thin plywood (around 6mm will do), 10X15cm (4"X6") used to prevent the base of the cross vice from marring the base of the drill stand. If you don't have an appropriate piece of plywood at hand, a piece of veneer will do.
2 carriage bolts, M8X40 with their nuts for attaching the cross vice to the drill stand
2 M8 hex nuts, fully threaded, with washers and nuts (winged nuts are preferable), for attaching the milling machine to your workbench. The length of the bolts will depend on the thickness of your workbench top - around 70mm+the thickness of your workbench.
A bench grinder for shaping the carriage bolts into T-bolts
A power drill with an 9 mm bit for wood
A wrench for the nuts of the carriage bolts
Finally, for the bonus build at step xxx, you will need:
A piece of thick plywood, 28X14 cm.
A piece of thick plywood, 20X3 cm
A piece of hardwood, 28X2.5X2.5 cm
Two wood screws
Some wood glue
Two bolts, M6X85, with washers and (preferably winged) nuts.
Note: If you buy from Amazon using the links I provided, I will get a small commission. I hope it is obvious that this does not influence my recommendations.
Step 1: Gather Your Supplies
When you have everything at hand, you are ready to start making your milling machine.
Step 2: Make the T-bolts
This is the only part of this build where you actually make something! (except for the angle grinding jig at the end of this instructable).
For some reason, my camera adamantly refused to focus correctly in these pictures, but I hope you 'll get the point: grind two flats on opposite sides of the head of each carriage bolt, until the bolts slide easily in the t-slots of the drill stand.
Step 3: Assemble the Milling Machine
Start by placing the plywood on top of the drill stand base. At first my sense of geometry directed me to place it parallel to the base edges, but I found out that in this way the column interfered with the movement of the cross vice. I ended up with a placement like that shown in the first picture.
Place the cross-vice on top of the plywood. Adjust the position so that two of the screw "holes" (they are actually half-holes) coincide with the slots.
Slide the t-bolts (with the nuts on) into the appropriate slots. You need one bolt on each side of the cross vice for stability.
Tighten the screws with the wrench.
The drill stand base has two holes for attaching to a benchtop. Mark the benchtop from these and make two 9mm holes with the power drill. Pass the hex bolts (head side up) through the holes in the stand base, then through the benchtop holes. Add the washers and nuts from below the benchtop and tighten them.
Remove the router from its base, then insert its neck in the drill stand's holding ring. Make sure it is well seated, then tighten the bolt and nut that keep it locked in place.
Step 4: Enjoy Your Milling Machine
Your milling machine is now ready to use. The depth scale will enable you to make cuts of a specific depth. Using the handwheels, you can move your workpiece to a specific position with a high level of accuracy. You can also use them to make accurate straight cuts.
One of the problems I fount with this machine is that, when I want to rout a slot, I can only do it in one of two directions: either parallel or perpendicular to the vice jaws.
I have had the need for oblique cuts, so I made a jig that is the object of the next step.
Step 5: Bonus Build: Angle Milling Jig.
To make this jig, join the base to the small slat with glue and screws. Then make matching holes in the base and hardwood piece (make one hole in each piece, pass the bolt through, then with the two pieces thus joined together make the second pair of holes which will necessarily match).
To use the jig, grip the base slat in the vice jaws, grip the workpiece between the base piece and hardwood jaw, adjust the angle and tighten the winged nuts. See details in the second picture and an example in the third and fourth ones.
The fourth picture shows what this jig is all about: making slots and holes at an angle to the workpiece sides.
You can see more examples of the use of the milling machine in my sliding bevel instructable.
Step 6: Teaser: a Kitty Door in a Door
This, of course, is my cat's door. But as Kipling said, that’s another story...
Except for the fact that I would probably never have made it without my milling machine and the angle milling jig. It isn't that I couldn't make it otherwise. Just that it would have taken me a lifetime and a half...
Participated in the
Build a Tool Contest