ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Bevel Pinion with a No. 6 Cutter, Filed at the Small End (Brown & Sharpe 1911)
The same 12-tooth, 8-pitch pinion as Brown & Sharpe's worked example, but cut the way their own shop did it: with a No. 6 cutter instead of the No. 8 they sell for it, cut to the right thickness at the large end, then filed well round at the small end. They did this only for a 12-tooth pinion running with a gear two or three times its size.
Source: Brown & Sharpe, Practical Treatise on Gearing (1911), Fig. 23 example, Part I ch. IX–X, Part II ch. III and the set-over table p. 58. The blank sizes are our arithmetic with their rules; the steel and bore are ours. Picture: their Fig. 23.
Advanced
1 day
Instructions
1
1
Work out and turn the blank
Work out and turn the blank
Pitch diameter 12 ÷ 8 = 1.500 in. Angle of edge 26° 34′ and angle of face 59° 11′ (Brown & Sharpe's figures for every 12 and 24 tooth pair). Diameter increment = cos 26° 34′ × 0.250 = 0.224 in, so turn the steel blank to 1.72 in outside diameter. Face ½ in long. Try both angles with a protractor against the end of the hub.
Materials for this step:
Mild Steel Bar1 length for one blankTools needed:
Metal Lathe
Lathe Cutting Tool
Protractor
Micrometer2
2
Choose the cutter
Choose the cutter
Twice the back cone radius × 8 comes to about 13, which would call for a No. 8, but take a No. 6, 8-pitch bevel gear cutter (17 to 20 teeth), as Brown & Sharpe's own shop did for this pinion. Measure its thickness Tc at the pitch line, 0.145 in from its tip.
Tools needed:
Bevel Gear Cutter
Gear Tooth Vernier Caliper3
3
Set the head at 22° 18′
Set the head at 22° 18′
Apex distance = sec 26° 34′ × 1.5 = 1.677 in. Angle increment: tan = sin 26° 34′ ÷ 6, giving 4° 16′. Set the dividing head to the cutting angle 26° 34′ − 4° 16′ = 22° 18′ and index 12 spaces. Depth at the large end 0.270 in.
Tools needed:
Milling Machine
Dividing HeadBevel Gear Cutter4
4
Set over and cut one side
Set over and cut one side
Apex distance ÷ face = 3.35; we take the nearest column, 3¼, where a No. 6 cutter has the factor .318. Set-over = Tc ÷ 2 − .318 ÷ 8 = Tc ÷ 2 − 0.040 in. Set off centre by that amount, take up backlash, and cut round all 12 spaces.
Tools needed:
Milling MachineDividing HeadBevel Gear Cutter5
5
Set over the other way and trim
Set over the other way and trim
Set over the same amount the other side, line the cutter up with the space at the small end, take a trial cut, and rotate toward the cutter until the tooth is right at the faces of the large end: 0.196 in at the pitch line (0.138 in at the small end). Check with the gear tooth vernier, then cut round.
Tools needed:
Milling MachineDividing HeadBevel Gear CutterGear Tooth Vernier Caliper6
6
File the small ends
File the small ends
The No. 6 cuts the tooth sides with a longer curve than the No. 8, so expect considerable filing: round the teeth over at the small ends, without filing them thinner at the pitch line.
Tools needed:
Fine FileMaterials
1- 1 length for one blankPlaceholder
This blueprint makes
Related Blueprints
These blueprints share knowledge with this one — techniques, materials, or principles that connect them in the learning graph.
CC0 Public Domain
This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.
Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.