Building a Celtic (wire strings) or folk (nylon strings) harp from scratch, using purchased blueprints, is a challenging but rewarding project for the advanced to experienced woodworker. However, even those with only basic woodworking skills and limited access to tools can build a beautiful harp with the help of a purchased harp kit. Experts can cut out all the pieces themselves, and novices can assemble and finish the already cut and pre-drilled wooden parts.
On clear, blemish-free lumber stock, trace harp parts, following the harp blueprint plans. Using a band saw or a table saw, cut out harp parts. (This step is unnecessary if you're building your harp from a kit: The parts will be pre-cut.)
Following the blueprints, mark the locations for the tuning pegs and the harp pins, the string holes in the sound board, and for the side dado slots in the right and back sides of the sound box parts, if any. Then, using a drill press, drill holes for the tuning pegs and harp pins, and the string holes in the sound board, taking care to adhere to blueprint specifications about the placement and the depth of the holes. Using a router, carefully cut the dado slots into the right and back sides of the box. (This step is unnecessary if you're using a kit: The parts will be pre-drilled and pre-cut.)
Secure the neck joint using wood glue. Allow the glue to dry.
Glue the sides and top of the sound box, then allow the glue to dry. Insert the back panel by fitting it into the slots in the sound box sides or nailing it in place, as instructed by the blueprints or kit instructions, and do the same with the sound board. Fit the base onto the bottom of the pillar, glue and secure to the bottom of the sound box with four wood screws.
Fit the neck and pillar to the sound box. The strings will hold these parts together, so don't glue or nail either joint.
Stain the entire harp except the sound board, following the instructions provided on the can of wood stain. Wipe off excess stain using a soft cloth. Allow the stain to dry for 24 hours. Apply varnish to the entire piece using a paint brush and following instructions on the can. Allow the varnish to dry completely before you continue to the next step. (Depending on humidity, this can take up to two days.)
Install the tuning pegs and guide pins into the holes drilled to receive them. You'll need to use a screwdriver to twist them into place.
Insert the brass eyelets into the holes drilled into the sound board.
Knot one end of each harp string, and secure the knot with a cyanoacrylate-based fast-acting adhesive. Following the blueprint or kit instructions for which colours and sizes of strings to use in which order, thread the harp strings through the back of the sound box, through the eyelets and through the eye in each corresponding tuning peg. Tighten each threaded peg, using the tuning wrench, just enough to wind up enough of the slack in the string to keep it out of the way while you thread the next string onto the harp.
Adjust each string so that it fits in the grove in the guide pin, then raise or lower the guide pin until the string height meets the specifications in the blueprints or harp kit instructions.
Using an electronic tuner to verify the pitch and the tuning wrench to tighten or loosen each string, tune the harp.
At first, your new harp will need to be retuned many times a day. This is because the strings continue to stretch and the harp adjusts. After about 20 tunings, it will settle in, but will still need to be tuned frequently. If you're not a musician, you may wish to ask the assistance of a musician friend to properly tune your harp, at least at first. A trained ear is necessary for tuning accuracy.
Don't attempt to create your own blueprints for a harp, even if you are an experienced woodworker. The strings exert so much pressure on the structure of the harp that it can collapse or split, and it takes calculation and experience to design a structure that will be strong enough to withstand the string tension and yet still respond with a musical sound.