Introduction: Improved Poor Man's Milling Machine for Wood (for Wooden USB Sticks, Bookmarks and Other Unbelievably Cool Stuff)
Several years ago, I assembled my "poor man's milling machine for wood". I will hereafter call that one "the old milling machine". Over the years it has served me well, but the time has come to make a newer and better one. I now invite you to meet the "new milling machine".
The main culprit for the problems of the old milling machine was the cross vice. Although it worked, it had several limitations:
- Poor construction: The obvious design choice here would be to use 4 thrust bearings, two at each point of contact of the movement screws with the body of the cross vice. To reduce cost, these were skipped. I had modified this early on, so it was no longer a problem.
- Limited length of travel: The length of travel of the old machine was 14.5X12 cm and not all of this was always usable. When I had to mill a longer feature, as was often the case, I had to do this stepwise: Mill part of the feature, reposition the workpiece in the clamp, mill some more and repeat until the feature was complete. Although it worked, this approach was less than optimal.
- Movement only in parallel and perpendicular directions (to the edge of the workpiece): This is due to the fact that the vice was integrated with the X-Y table without the possibility of rotation. I could work around this limitation with the use of jigs (e.g. see the angle milling jig in step five of this instructable) but again this was not optimal.
- Not perfectly rigid: This had to do with the short length of the trapezoidal slider. Even with the adjustment screws fine-tuned, the cross vice displayed noticeable horizontal racking.
A few months ago, I decided it was time to upgrade. I looked around for a suitable replacement for the cross vice and found the following candidate in e-bay: 450 x 170 mm Table Milling Machine Table de Travail de Fraisage pour Perçage. Please note that this link may become outdated soon, but as long as this item is in production, I would expect you to be able to find it using some of these words as search terms in e-bay. At the time these lines are written, there are several sellers on e-bay who offer the exact same milling table at similar prices. The seller from whom I bought mine is not bad - the tool arrived without problems, except from the mediocre packaging (which is not the seller's responsibility). On the other hand, he is not the best e-bay seller I 've ever seen: He doesn't leave feedback (even though I left positive feedback for him), he doesn't reply to questions (in the days of automatic translation, the fact that he probably can't read and write English is hardly an excuse). More important than the seller, however, is the product itself. At around 30 Kg, it is as sturdy as one could wish. After adjusting the gib screws, it slides smoothly, with virtually no racking. The handwheels were placed separately in the box and one of them would not fit its axle. Shaving a few mils on the lathe solved the problem. Overall, I find it is great value for money. I hoped it would be well built and it exceeded my expectations. Again, it is not perfect, but at this price one couldn't expect it to be. My sole remaining gripe has to do with the scales on the handwheels, which are very superficially engraved (a future project?)
Step 1: Design Base
In the previous incarnation of this machine, I had attached the cross-vice on top of the drill stand base. This is how it is designed to work. With the new milling table, however, using the same approach would severely limit the travel in the Y direction and thus partially defeat the purpose of the upgrade.
So for the new machine, I decided to attach both the drill stand and the milling table on a separate base. I decided to make the new base from plywood, for its stability and workability.
Using a scrap piece of plywood, I placed on top of it the drill stand and the milling table. Turning the front handwheel, I moved the table all the way to the back. I then moved the drill stand so that its column touched the table. With this positioning the column was as close to the milling table as is possible without interfering with its movement. This allows me to make the most of the milling table's capabilities.
I then marked the positions of the mounting holes from the drill stand and the milling table onto the scrap plywood piece, removed the drill stand and milling machine and measured the positions of the holes. With this information, I proceeded to make a CAD drawing of the base.
Step 2: Build Base
I wanted the base to be as rigid as possible, so I laminated two 50X55 cm pieces of 20 mm plywood. The resulting 40 mm plywood was sufficiently rigid. I then veneered the base with teak veneer (I like the mechanical properties of plywood but not its look). I won't dwell on the veneering process too much here, as it is not functionally necessary and I plan to make a separate instructable on veneering in the near future anyway (I will link it here when it is ready).
When the veneering was complete, I applied several coats of polyurethane varnish. This is not my finish of choice for teak - I only use it when durability is of paramount importance and this was one such case.
Finally I transferred the hole positions from the CAD diagram to the base and drilled the holes. I made the front pair of holes in the drill press. The other holes were too far from the edges for my drill press, so I made them with a hand drill, trying to make them as straight as possible. Finally, I turned the base upside-down and enlarged the bottom of the holes (which was now the top) using a router with a 25 mm bit. If I just held the router by hand, it would tend to "dance around" and make a mess. To avoid this, after placing it into position I placed a long piece of wood over the router base and clamped it from both sides. Then I turned on the router and slowly lowered it until I had reached the required depth. Then I moved it to the next hole and repeated the process until I had enlarged all 4 holes.
Step 3: Gather Your Supplies
With the base complete, it is time to gather the components and tools in order to assemble the machine.
The base I built in the previous step.
The milling table. See the introduction for details.
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 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):
Trend T4EK or T4ELK (as always, you can look for better deals elsewhere)
Alternatively, if you have patience, you can look for a used Bosch POF500A or POF52 (again, check the voltage before buying) on e-bay. I use a Bosch POF52 which I got used from e-bay for close to nothing and am quite happy with it.
A drill press vice like this one.
Several bolts and nuts. The ones I used are as follows:
2 pcs M10X40 carriage bolts with washers and nuts: I converted those to t-bolts and used them to attach the vice to the milling table.
2 pcs M8X80 hex bolts with washers and 4 nuts, to hold the drill stand securely onto the base.
4 pcs M10X60 bolts with washers and nuts, to hold the milling table onto the base.
Aside from the tools used in step 2 to build the base, the only things you 'll need are
A ratchet and set of sockets like this one or a set of wrenches matching the bolts and nuts.
A bench grinder like this one: used to convert the carriage bolts into t-bolts.
Note: If you buy from Amazon or Banggood using the links I provided, I will get a small commission. This does not influence in any way my recommendations.
Step 4: Make the T-bolts
The milling table came with two t-bolts. I prefer to attach the vice to the table with 4 bolts, so I had to make an extra two. For this, I started with two M10X40 carriage bolts. The only thing I needed to do was to grind two flats on opposite sides of the head of each carriage bolt, until the bolts could slide easily in the t-slots of the milling table.
Step 5: Assemble the Milling Machine
With all components ready, it was time to assemble the machine.
I started by placing the M8X80 bolts in their positions, securing them with one nut each and tightening those nuts. I placed a piece of scrap wood under the base, so I could reach underneath while I attached the milling table. Then I placed the milling table on the base in its approximate position, pushed the bolts from the underside of the base through the holes in the base and the milling table and placed the washers and nuts on top, without tightening them. After placing all four bolts and nuts, I registered the front of the milling table with that of the base and tightened the nuts.
I lowered the drill stand into position behind the milling table, guided by the bolts. After making sure that its back side was flush with that of the base, I placed and tightened the second pair of nuts.
I placed the router in the mounting bracket and tightened the retaining bolt.
I placed the 4 t-bolts (two that came with the milling table and two I made in step 4) into the t-slots. With the bolts positioned, I placed the vice on the milling table, added the washers and nuts, aligned the back of the vice with that of the milling table and slightly tightened the nuts. After making sure the vice sides were perfectly aligned with the X-direction of the milling table, I tightened the nuts fully.
To check the alignment of the vice with the table, I placed a straight piece of wood into the vice, tightened the jaws, then moved the table all the way to the right and back sides. I then lowered the router (which had a straight bit on) and moved the table to the front until the bit just barely touched the wood. Then I raised the router, moved the table all the way to the left and lowered the router again. The bit was just 0.5mm or so closer to the wood, so I had to fine tune the vice position and check again until I was satisfied with the alignment.
Step 6: Bonus Improvement #1: X and Y Scales
Having completed the assembly of the new milling machine, I started making improvements. Those are extra steps that use additional tools.
The first improvement was to add scales for the X and Y dimensions. I was planning to attach with spray adhesive two of the paper rulers which IKEA and Leroy Merlin shops offer to their customers. When I tried to do this, however, I found out that the spray adhesive can I had was dead (it's been many years since I last used it). So I decided to use, for the time being, the leftovers from a metal self-adhesive ruler strip. These come in sizes starting from 1m - much more than is usually needed. In my case, I had used a 40cm piece in my bandsaw and had two leftover pieces. The disadvantage, of course, is that they don't start at the zero mark, but in practice I believe I will only use these to measure differences in position (I would rarely start a cut at exactly the zero point, even if it was in the scale).
I started by cleaning the surfaces where the ruler strip would be applied with acetone. I then cut the two pieces of ruler strip with a pair of scissors, removed the backing and carefully applied them onto the milling table. To complete each scale, I made a mark on the matching surface with a permanent marker.
I have ordered two new ruler strips. When they arrive, I will replace the ones I have placed. In the meanwhile I have used those and find them a nice addition.
Step 7: Bonus Improvement #2: Wooden Vice Jaw Liners
The provided metal lining pieces are adequate for metalworking, but they would mar a wooden piece. I had the same problem with the old milling machine, and worked around it by using a piece of paper to soften the grip. The thing is, with the old machine this was the least of my problems. Now that I have a machine I am happy with, it made sense to invest a little time for some improvements, so I decided to make a pair of wooden jaw liners.
I started with a piece of iroko wood around 2.5 X 2.5 X 30 cm (1" x 1" x 12") that was hanging around waiting for an occasion to make itself useful. I gripped it in the vice and marked the length I wanted the jaw liners to be (around 2cm longer than the jaws). I then cut two pieces with my bandsaw.
I then gripped the two pieces in the vice and used the milling machine to flatten what would become the top, right and left-hand sides of the jaw liners.
With the liners held securely in the vice, I used a marking knife to transfer the jaw positions into the liners. I rotated the liners and cut a recess.
I removed the screws holding the metal liners into place, removed the metal liners and used them to mark the screw hole positions in the wooden liners with a brad point drill bit.
I made the holes for the screws with a drill press, then used a countersink bit to enlarge the "Front" of the holes for the screw heads. Then I placed the jaw liners into position, screwed them on and proceeded to mill their front surfaces to make they would be completely square.
With the shaping of the jaw liners complete, I gave them a final sanding and screwed them into position. I can now use my milling machine without fear of marring my workpieces!!!
Step 8: Future Improvements
There are several further improvements I plan to make:
- Improve the markings on the handwheels: Ideally, the handwheels would have vernier scales. Far from it, they only have rudimentary markings. I plan to improve this, possibly in several stages. Provisional time frame: 1-2 months.
- Improve the vertical depth scale: It is difficult to get sub-millimeter accuracy using the vertical depth scale alone. I plan to investigate replacing the mechanism with a more accurate one. Provisional timeframe: 3-6 months.
Participated in the