V. H. Fixtures
Vertical Hammer Hanging Fixtures
Concept: Use carefully prepared samples and precision fixtures to achieve factory-quality results.
Overview: The Sample Hammer Gluing Fixture enables precise control of both rake & bore angles on samples for use in setting up the Vertical Hammer Hanging Fixture fences. With hammers in compressed alignment, the fences will faithfully reproduce the angles of the samples. For the tenor section, where the bore angle changes smoothly from note to note, a dial is calibrated to the data measured directly from samples & the piano string angle to give you a custom result.
Use of original hammers or samples: If the original hammers are found to have usable clearance, consistent blow distance & acceptable rake angles it is very easy to reference & record the data onto the Hammer Boring Fixture. After the hammers are all drilled, select the end hammers for the bass section to make samples.
Directions:
Set-up of the Sample Hammer Gluing Fixture:
Using the original hammer sample, set the cursor to the center of the moulding; set the half-round fence along side of the hammer shank & lock the toggle to secure the boring angle. The fixture is now set for gluing the new hammer and shank. For the bass section, the same setting will ensure an identical pair used to set the Vertical Hammer Hanging Fixture fences. Take care to let the glue tack and hold before gluing the next sample. When you have both new samples for a section, you are ready to install them.
Set-up of the Vertical Hammer Hanging Fixture:
These new samples are installed against the L.H. block and temporary R.H. angle bracket. With the hammers between the samples lined up together on the bench measure the distance and duplicate that same distance between the samples on the fixture. The rake angle fence is then set to the samples. Bore angle is set and recorded on the sliding fence block.
The samples are then removed as well as the temporary angle bracket and all the hammers for the section are placed in the fixture. Care is used to keep the hammers tight against the back of the angle bracket and perpendicular to it. When it is loaded, the screw clamp block is used to press the hammers together to hold them in place.
Gluing begins on the R.H. side of the fixture for the bass hammers to allow the shank to rest on the sliding fence rod by gravity. The rod is removed and replaced on the right side of its support shaft for clearance (opposite for the remaining two sections). Use of an 1⁄8" x 6" dowel or rod to place a thin film of glue on the inside walls of the hole works well with a carefully controlled amount on the end of the shank. Too much glue on the walls of the hole will cause problems in getting the shank to bottom in the hole and will reduce the strength of this critical joint.
For the tenor section, the hammer bore angle is recorded with a tick mark on the top of the sliding fence block. Record the hammer # of the first note that has a 0° bore angle with a tick mark also. Between these two marks, the length of the arc is measured and divided up. A piece of paper ½" x 3" or so can be used to hold against the curve and transfer the two tick marks to this paper, then use a digital caliper to sub-divide into usable reference points to aid in making a smooth transition to 0°.
