Don Busby's Musical Box Comb Making

For information about mechanical musical instruments, see the web site of the Musical Box Society of Great Britain www.mbsgb.org.uk

Shot	Description	Notes	Photo
1	Model B-Super	a. Tool rack at tailstock end b. Lathe is set up as per shot 4 c. Home-made jig for milling/notching/slotting/slitting Box combs is in 2 parts: i. cross slide part  ii. vice part d. cutting fluid is draining off
2	Comb-making Jig (normal shot)	a. cross slide part extends to slit just behind 3x M4 screws b. vice part is bolted to the moving part of vice and travels over fixed jaw c. 3 holes (tapped M4) in the middle MS bar (2 pop marks) set a work piece at 2° 57' to the lathe bed for slotting as shown in shot 6 d. the slit (groove) in the back clamping angle (to the right of the M4 screws) is for passage of slitting saw blades
3	Comb-making Jig (Oblique shot)	a.b.c.d as above e. compare position of vice part with that in shot 4
4	Fly cutter for shaping tips of comb teeth (notching)	a. Home made ex blank end arbor and 3/16" sq HSS tool bit b. Spare tool bit sits on blank work piece c. Tips of teeth have already been milled down to 0.5mm thickness prior to fly cutting 'V' notches between teeth d. three passes with tool lengths of 6/8/10mm
5	Fly cutting the first 'V' notch (notching)	a. 25 more to go after this - each sub-comb is made as 25 full teeth with ½ a tooth at each end these ½'s are cut off after slitting (as per shot 7) b. the 3/32" work piece is set on a 1/32" support plate which has been pre-notched
6	Preparing to slot the angled groove	a. work piece is set at 2° 57' to the lathe bed on a plain 3/32" support plate.  The support plate extends beyond the notched tooth tips.  This allows use of the dial gauge to check depth of slot b. see also shots 10 & 11
7	The end of a slitting run	a. cutting fluid has been wiped off for clarity b. lathe is always fully cleaned each day c. ½ teeth have not yet been cut off d. blade used is 80x22x0.5mm (with inner bore slot)
8	Full comb (5 sub-combs) on sounding board for tuning checks	a. 125 teeth in all - mounted on brass flat by M6 screws b. M4 holes are retained for further lathe work
9	Underside of the comb as attached to the brass flat	a. further development work is to be carried out.
10	Checking depth of angled slot	a. Depth of slot checked frequently towards end of operation b. see also shot 6
11	Curving the roots of the teeth	a. the end mill shown in shot 6 has been replaced by a ball nose mill
12	The notched/slotted comb (underside up)	a. the picture shows 5 sub-combs - the lathe jig is only big enough to make one sub-comb (72.5mm wide) at a time
13	The notched comb before slotting and slitting (underside up)	a. as 12a b. notching is described in shots 4 and 5
14	Top side of comb after slitting	as for shot 12
15/16/17	Jig for drilling damper wire holes (utilizes part of comb making Jig - with additions)	a. holes 0.5/0.6/0.7mm diameter are drilled into the ends of comb teeth b. brass bars clamp teeth down c. 1.6 Dia brass guides with i.d. holes 0.5/0.6/0.7 fit over drill bits d. brass guide enters 1.6dia holes in brass clamping bar to steer drill bit e. drill bit is extended from 0.5 to 3mm in length, gradually between drillings to enter 1mm into tooth 'land' f. brass 'leaves' on top of jig hold teeth at correct centres whilst drilling
18	Tool rack (home-made)	a. lathe tools are ready at hand b. wooden slot fits over lip of lathe tray
19-24	Comb-making jig in various states of dis-assembly to show its components and principles of operations on it	a. shot 20 shows reverse side (not seen on other shots) with adjustable clamping device for holding tooth tips down - mainly to prevent vibration during slitting saw operations b. shot 24 down to Chester's rotary vice
25/26	Pillar drill and jig for shaping and sharpening fly cutter tools for notching	a. notching is described at shots 4 & 5 b. carborundum wheel for roughing down c. diamond 'cup' for finishing and sharpening d. MS flats (shot 26) are moved to right side as bit is turned over