Improvements in Banjoes.
Year: 1889

page_text: Date of Application, 19th Dec., 1889
Complete Specification Left, 18th Sept., 1890-Accepted, 18th Oct., 1890
PROVISIONAL SPECIFICATION.
Improvements in Banjoes.
ALFRED JOHN BORROW 17 Colville Place, Charlotte Street Fitzroy Square, W.C.
London, Organ Builder, do hereby declare the nature of this invention to be as
follows:-
A hollow rim banjo constructed of thin wood under this principle.
There are rims produced 2 inches in width, one 2 inches smaller in diameter than
the other. We now place one rim inside the other, thereby forming the outside and
inside rims, and a circular and parallel channel.
We then fix 2 circular rings to the top and bottom of the channel, wide enough
to span from one rim to the other, thereby completing a circular hollow rim, 24 inches
in depth and 2 inches in width. Holes are now bored on the top and the inside of
the rim, and more holes added if the tone requires them. The advantages of this is
its bold and mellow tone, not the harshness which the metal banjo produces, but still
retaining its sharp tone, also containing that depth of tone which surpasses any other
banjo.
The dimensions vary to suit the size of banjo.
COMPLETE SPECIFICATION.
Improvements in Banjoes.
ALFRED JOHN BORROW Organ Builder 17 Colville Place Charlotte Street Fitzroy
Square, W. do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The object of this invention is to produce a "hollow rim" for the banjo, to consist
of several combinations as hereinafter stated, to obtain a powerful, mellow and clear
tone, expelling the harsh note that the metal banjo produces, also the dull tone of the
ordinary wood rim banjo.
In order that my invention may he fully understood and carried into practice I
now describe the same with reference to the accompanying drawings or designs, in
which similar letters indicate corresponding parts, in all the figures.
Figure 1 is a section of a circular block or mould, round which the banjo rim is
constructed. The rim is shown in course of construction on the block (half size).
The designs are on a scale of 12 inches to the foot, or full size, except Figures 1. 2
& 3 which are on a scale of half size or 6 inches to the foot.
Figure 2 is a plan or profile of rim when finished and taken off the block or mould.
The portion of the arm or handle (marked L) that passes the rim, is inserted to shew
the position of the rim more plainly (as seen from the top side of rim).
Figure 3. This a section view of Figure 2 when finished, which enables the reader
to see the interior or hollow of rim.
Figure 4 is a pattern of a "lap or feather edged joint," shewing how one piece of
wood dies out of the other at the joint. This class of joint is used in construction
where the two ends of a band lap over one another to complete the circle.
Figure 5 is a profile of a rib or sixth part of a circle to obtain the necessary depth
of hollow as seen in Figure 1., also in Figure 2. (marked F).
Figure 6 is a profile (marked A) and section (marked B) of bridges made of bard
wood to support the outside band against the "1 screws and brackets."
The bridges
are also seen in the other drawings (marked J). The "s screws and brackets" are
described in Figures 8 and 9.

page_text: Figure 7 is a section of rim with all fixings attached and shewing the interior of
same, the dotted lines indicate the position of the arm or handle.
Figure 8 is a profile (marked A) and section (marked B) of "bracket" with screws
and nut, this combination receives and regulates the strain of the parchment and
shields the banjo rim from bruises and from unnecessary connection with the player.
Figure 9 is a profile of bottom end of leaf or hook of "bracket."
Figure 10 is a section of a larger size rim shewing the interior or hollow thereof,
adopted to gain a more powerful tone, which can be strengthened by a further
increase of depth.
Figure 11 is a section of rim which can be adapted for an instrument of smaller
dimensions.
DESCRIPTION IN DETAIL, AND A PRACTICAL MANNER TO MANUFACTURE SAME.
In constructing a "hollow rim" I use old and seasoned wood, & Salisbury glue,
and linseed oil combined for glueing the joints, and finish the rim with a. special
varnish that is used for musical instruments generally.
Figure 1. The section of a circular block or mould (marked A) made of wood.
On both sides of the block I screw a metal ring (marked B). A necessary number of
holes are drilled on the side and top flanges of rings. The holes that are in the top
flange are "
tapped" to fit the "thread" on the thumb screws (marked C). Tho
other holes are for fixing the rings to the block by means of the ordinary screws as
shewn holding metal rings in Fig. 1. These thumb screws which pass through the
metal plates (marked D) act as cramps for the joints.
Having described the block and fixings I now proceed in the first stage of con-
structing a banjo rim 11 inches in diameter with a hollow 14 inches in depth and
radiating from 1 inches to 1 inches in width.
Stage 1. Stretch a layer of paper round the edge of block (marked A) allowing the
two ends on meeting to lap, then glue them together on the block, this is to prevent
the block from adhering to the rim.
Stage 2. Obtain a piece of Swiss pine 2 feet long, 14 inches wide & of an inch in
thickness, steamed and bent into a circle to fit the block. When dry bevel one end
of the band to a feather edge. Then start at the feather edged end by fixing it with
cramps to the block. On completing the circle, glue and fix the two ends together
forming a sort of splice, (shewn in Figure 4) this forms the inside band of rim
(marked E). When the joint or splice is dry take the cramps off and fix the block
by the centre on a lathe and turn the band circular, smooth & to the thickness shewn
in drawings (marked E).
Stage 3. Obtain 12 ribs of Swiss pine (as shewn in Fig. 1 marked F) and also in
(Figure 5). Glue and fix six on each edge of band (E) which they are made
to fit.
A plan of these ribs are shewn in position (Figure 2 marked F) which, now forms
a part of the rim. When dry turn the ribs to the required gauge of diameter.
Stage 4. Obtain a strip of Swiss pine 3 ft. 6 inches long, 24 inches wide and of
an inch in thickness. Then bevel one end to a feather edge, steam and bend it, (same
as the band marked E) next cut off two strips of an inch wide, fix and glue them
round the edges of rim. These strips or bands (as shewn in Fig. 1 and other
drawings marked G.) are to strengthen the ribs at the butt joints.
When dry remove the cramps, and by means of the lathe "pare" the interior of
the rim level and clean, leaving no ridges or surface matter. Then fix small "glue
blocks" (marked H Figure 1) round the interior of rim to support the joints. Next
bore sounding holes (marked I Figures 1, 2 & 7) on the top of rim or sounding
board. These holes are not limited in number or size.
The rim is now built to the required depth or hollow, which only requires the band
(marked K) to be fixed, which forms the outside band that has to support a number
of regulating " screws " and "brackets" (marked O. P. Q & R Figures 7. 8 & 9)
that hold the parchment. This band is not strong enough for the purpose alone, so I
strengthen it by means of small bridges (see Fig. 6 profile A & section B) which are

page_text: inserted in the rim (before fixing the band marked K) exactly where I intend a
"bracket" to be placed. There will be 20 brackets which will require 20 bridges as
shewn in drawings (marked J). Having fixed & glued these bridges proceed in
fixing the band (K).`
Stage 5. Obtain a piece of sycamore or any fancy wood 3 ft. 7 in. long, 24 inches
wide & of an inch in thickness. Work this strip of wood through the same process
as previously described, then glue and fix it in position on the rim, at the same time
do not allow any glue or surface matter to be inside the rim or hollow as it injures
the tone. When dry remove the cramps and turn the rim into shape on the lathe.
The shape and thickness thereof is shewn in the drawings of the finished rims, then
veneer the bottom side (F) with a fancy or inlaid wood veneer to match the outside
band (K). This completes the construction of the "hollow rim."
Before varnishing the rim insert the arm or handle (marked L in Figures 2. 3
&7) which can be passed through the banjo rim & fixed in the ordinary manner as
shewn in drawing, or it can be inserted half way through the rim & glued to ensure
firmness.
Figure 7 shews the part of rim with fixings that holds the parchment when
stretched over the top or sounding board of rim.
N. and M. are the ordinary metal bands that are used for stretching the parchment
which is regulated by the ordinary screw (0) and the nut (P).
Q. is the improved bracket that receives the screw and nut. The reason for not
using the ordinary bracket, is that it would have to be fixed on the outside rim where
the strain is not direct. The consequence would be that they would either pull out
or split the rim, their not being sufficient substance of wood to hold them.
It will be seen that the "improved bracket" (Q) hooks on the bottom of the rim where
it is fixed by the screw (R). This system brings all the strain of the parchment on
the bottom edge of the rim, which is supported by the bridges inside (J). This class
of bracket is made of brass or silver which forms a shield and an ornament to the rim
(further described in Fig. 8 profile and section A and B) also (Fig. 9 showing the
ornamental leaf that forms the claw or hook of bracket).
Figure 10 is a facsimile of Figure 7 but in construction make a deeper rim or
hollow as shewn in drawing. The reason for making rim deeper is to gain more
power. This extra power is caused through the sounding board (F) which is directly
under the vellum, being deeper than the 2 inch rim (see F. Fig. 7) and therefore
repels the sound to a greater extent as it passes through the vellum.
Sounding holes are bored in the top of rim or sounding board, similar to
Figures 2. 3 and 7 (marked I) to allow an amount of sound to pass into the hollow of
rim, which being equivalent in proportion to the sounding boards and has the same
tone as the smaller hollow, with the addition of extra power. These deep hollow rims
are best suited for concert banjoes.
Figure 11 is a facsimile of Figure 7 but in construction has a narrow rim or
hollow.
In this rim I prefer the sounding holes on the inside (E). Holes can also be made
in the sounding board, if required.
33
All the "hollow rims as stated herein can be applied to any size banjo.
The sounding holes regulate tone of instrument & therefore are made accordingly.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
1 claim is
1. An improvement in banjoes in the shape of an "hollow rim" made of wood
which causes a more powerful and mellow tone than the ordinary instruments.
DAL: 10th ... of Santambon 1800
ALFRED JOHN BORROW