Bootstrap Drill Press

Introduction
Humans are wobbly structures without a built-in ability to hold tools at fixed angles and position. Any machine tool will increase the accuracy of the work produced by holding the tool bit and workpiece positions more accurately. A drill press makes accurate holes by guiding a rotating drill bit in a straight, usually vertical, line down towards a table. A frame holds the position of the drill guide and table so they do not move while drilling. The table provides methods of clamping the workpiece in place while being drilled. Various jigs allow holding round or other odd shapes, and positioning the workpiece a known distance from it's end to the drill bit. Besides making holes, other bits such as a sanding drum let you do other tasks.

This bootstrap drill press converts a hand held electric drill into a press by adding the guide, frame, and table. It is an intermediate tool between hand held power tools, and commercial drill presses or the OSE industrial grade press. The bootstrapping concept is to use the tools you have to make better tools. This press will be less expensive than buying a press of similar capacity, and also gives some practice with a relatively simple project before trying a more challenging one.

Design
The design is based on the Instructables Drill Press. Alternate/modified versions can be made based on available tools and materials, and some suggestions will be given below. The key parts are:


 * A rigid frame which maintains the drill bit vertical under operating load. In this instance the cast iron pipe serves as the frame.


 * A guide rail which controls vertical movement of the drill in a straight line. An aluminum angle sandwich is used as the guide in this design.

Overall dimensions can be modified to fit what hand held drill you have available and what drilling tasks you expect to do. The prototype was made as a portable unit for bench top use, but it can be made into a stationary version by installing it into a table. I used wood for most of the remaining parts besides the frame and guide rail simply because I had some available already.

Assembly Time
This project will take about 10-15 hours to complete, including shopping for supplies. It will tend to take longer if you do not have a permanent place to work and have to put things away periodically.

Cost
The prototype cost me $45 (SouthEast USA) for pipe, angle, and screws and bolts. I already had the electric drill (~ $70) and scrap plywood and lumber (~ $10), which would be extra if you don't. An equivalent commercial drill press of the same capacity is in the $170-200 range, so the main savings is if you already have a hand drill and want the flexibility to keep using it separately.

Tools Needed

 * Some kind of workbench - Working on the floor is uncomfortable. A raised work surface is more comfortable and allows clearance for clamps. Two sawhorses straddled by a few 36 or 48 mm thick boards (2 inch nominal US) is sufficient for this project.


 * Electric circular saw - With the addition of clamps and a straight edged object this can cut relatively straight lines, which are all that are required for this project. This could be done with a hand saw or jig saw, but it will be slower and less accurate.


 * Electric hand drill - This will be used both to build the drill press, and serve as the motor to run the press once built. It is designed be removable so you can still use the hand drill on it's own. Since the power of the motor will limit the capacity of the drill for making large or deep holes, a more powerful motor is better if you have a choice.  The drill should have a speed lock button so you do not have to keep holding the trigger to keep it running. Secondarily, the maximum opening of the chuck in the drill will limit the size bits you can use.  If it does not come with it, also get a set of twist drill bits (the most common type) in various sizes up to 6 mm (1/4 inch).  If you expect to drill a lot of metal, get bits which are harder than "high speed steel", which is the least expensive and most common type, otherwise they will wear out fairly quickly.


 * Measuring square - Needed to mark lines at right angles for cutting and measuring, and for checking the drill is perpendicular to the table. There are several types available (combination, framing, rafter).  Any of them will do for this project.  Always test your tools.  You can test the squareness of your square by placing it against a known straight edge, marking a right angle line with a pencil or pen, then flipping the square over along the straight edge and seeing if the line you drew and the edge of the square are parallel.


 * Ruler or Tape Measure - Needed to measure dimensions. A large measuring square, such as used for house framing may suffice for this project, but a tape measure is also highly useful.


 * Bar Clamps - To hold things while drilling, cutting, or gluing. At least two, 60 cm (24 inch) long is a good size.  Other types of clamps will also work if they are large enough.

Supplies Needed

 * 19mm (3/4 inch) Plywood - You will need one or more pieces large enough to cut the following. Preferably use solid core plywood with relatively smooth surfaces.


 * Table - 1 piece at least 40x60 cm (15x24) inches. If you keep the table small, the press can be portable or put away.  If you make it larger, it can handle larger items without extension tables.
 * Guide Plate - 1 piece about 25x25 cm (10x10 inches) - this will be adjusted to fit the guide rails, so cut it a bit oversize and trim to fit after.
 * Drill Mount - 1 piece about 23x30 cm (9x12 inches) - size will need to be large enough to hold the drill firmly without too much overhang.
 * Misc small pieces - for mounting drill, clamping, etc.


 * 36-48x133 mm (2x6 inch nominal) Lumber - 1 piece the length+width of your table + 15 cm (6 inches). This will be cut into one ~15 cm square block to anchor the pipe, then the remainder ripped in half lengthwise to make pairs, and cut to pieces which will frame under the table, but 2.5 cm (1 inch) smaller. This will give the table an overhang to clamp items you are drilling. The framing will keep the table from bending and also raise it so clamps can be used, and when the drill bits penetrate the workpiece there is someplace for the cuttings to go, and they do not damage whatever the drill press is sitting on.


 * 3.75 cm (1.5 inch) Threaded Cast Iron Pipe - The diameter is the inside measurement. This is used to build a right-angled frame to hold the guide plate and drill mount perpendicular to each other without bending.  You can substitute other materials for this task, but the key requirement is that it can be attached firmly to the plywood at either end, and hold the 90 degree angle, without any wobble. The entire point of a drill press is to hold the drill bit perpendicular to the table, so any wobble defeats that purpose. This size is not commonly available at consumer hardware stores, so you may need to go to a plumbing supply specialty store.  The pipe diameter should be considered a minimum.


 * 30 cm (12 inch) Nipple - 1 piece. A nipple is a straight length of pipe threaded on the outside at both ends. This will determine the maximum height the drill can reach above the table.
 * 20 cm (8 inch) Nipple - 1 piece. This will determine the overhang from drill bit to vertical pipe, and thus the maximum distance a hole can be from the nearest edge of the workpiece.
 * 90 degree Elbow - 1 piece. This will be threaded on the inside at both ends, and be used to connect the two nipples.
 * Flange - 2 pieces. This is a wide end piece with holes for screws or bolts.  It will be threaded on the inside, and go on the far ends of the nipples, to connect to the table and guide plate.


 * 1.5 x 12 x 19 mm (1/16 x 1/2 x 3/4 inch Aluminum Angle - At least 120 cm (4 ft) length. This is used to make the guide rails which the drill mount slides up and down along.


 * Screws, Bolts, and Glue - for putting everything together. I mostly used what I already had, but the actual parts count is as follows:


 * 64 mm (2 1/2 inch) Flat Head Phillips Exterior Screws - 12 pieces - Used to fasten the table to supporting frame under it.
 * 6x75 mm (1/4-20x3) Flat Head Machine Bolts with Nuts - 4 pieces - Used to fasten pipe flange to table and anchor block underneath.
 * 6x38 mm (1/4-20x1-1/2) Flat Head Machine Bolts with Nuts - 4 pieces - Used to fasten guide plate to other pipe flange.
 * 6 mm (1/4 inch) Inside Diameter Flat Washers - 8 pieces - To distribute the pressure from the above nuts to the wood so the wood fibers do not get crushed.


 * Optional Items - You can reinforce the table surface with a metal plate, as long as it is perfectly flat. You can also coat all the exposed wood with polyurethane (after staining if you want).  This will reduce accidental damage, and make it easier to clean up if you use cutting oils when drilling metal.