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Precision and Commercial Gears, Assemblies, and Differentials

Spur Gears

Commercial and Precision Spur Gears

Spur Gears

Spur Gears have straight teeth and are usually mounted on parallel shafts. They are the simplest in design and the most widely used. External spur gears are the most common, having their teeth cut on the outside surface, also available are internal spur gears and rack and pinion gears. Spur gears can be found in instruments and control systems.
Precision Anti-Backlash Gears

Anti-Backlash Gears

Anti-Backlash Gears are used in precision applications where little or no backlash is required. SDP/SI's fine pitch anti-backlash gears are designed using Stainless Steel Springs for tensioning and are available in clamp, pin or Fairloc® hub styles. Many types of gears can feature the anti-backlash attribute, the most common being spur gears.

Precision Bevel Gears

Bevel Gears

For intersecting shafts, Bevel Gears offer a good means of transmitting motion and power. Most transmissions occur at right angles, but the shaft angle can be any value. Ratios up to 4:1 are common, although higher ratios are possible as well. The pitch surface of mating bevel gears is cone shaped.

Miniature Bevel Gear with Fairloc Hub


Precision Fairloc® Bevel Gears

AGMA 10 1/4 Bore, Precision Matched Sets, 20° Pressure Angle

MATERIAL: 303 Stainless Steel, 2024-T4 or T351 Aluminum Alloy, anodized before cutting.

SPECIFICATIONS: Socket Head Cap Screw Supplied. Fairloc® hubs require controlled shaft tolerances. Suggested clearance fit between the bore and the shaft is .0001/.0008. Available on special order: Teeth not listed, different pitch, bore size, passivation. Sold as a Set

 Precision Gear - Shaft / Hub Clamps

Shaft/Hub Clamps for Split Hub Gears and Pulleys

Shaft/Hub Clamps are designed to hold split hub gears and pulleys to the shaft in many applications. Precision and commercial grade clamps are available in one and two piece balanced construction and reduced clearance radius types. Screw-type shaft/hub clamps are offered for shafts as small as 1/16". All our clamps allow easy adjustment and removal of the gear or pulley on the shaft.

Precision Cluster Gears

Cluster Gears

Cluster Gears are a unit of spur gears of various diameters mounted on a shaft. Gears assembled in this arrangement are most often used in gearboxes for a variety of applications, including automotive.

Precision Composite Gears

Composite Spur Gears

SDP/SI offers a wide variety of gear types and materials, including Composite Gears. Composite gears are non-metallic gears cast around a knurled metal core. These lightweight gears can run at high speeds without lubrication while reducing noise, vibration and shock. They are corrosion and chemical resistant and do not absorb moisture. Composite gears can replace Stainless Steel gears in applications where high torque is required.

Precision Differentials


Our design, engineering and manufacturing expertise is not limited to precision gears, but includes custom gearboxes, planetary gearheads and differentials. Our precision gears and gear assemblies meet the critical tolerances and functionality that the aerospace, defense and medical industries demand.

Precision Differential End Gears

Differential End Gears

SDP/SI builds small Stainless Steel differentials in the following pitches: 96, 72, 64, 48 and are available as standard catalog items. Differential End Gears, Stainless Steel or Anodized Aluminum, will be assembled, free of charge, to differentials when ordered at the same time. 10 arc minutes maximum backlash between end gears.

Commercial and Precision Gear and Dial Clamps

Gear and Dial Hubs

Precision Stainless Steel Gear and Dial Hubs are available in three hub types: clamp, pin and Fairloc®. The Fairloc® hub requires controlled shaft tolerances; suggested clearance fit between the bore and the shaft is .0001/.0008. An anodized aluminum pin type gear hub is also available for use with stamped or molded hubless gears or disc and drum dials.

Commercial and Precision Gear Blanks

Gear Blanks - Nonmetallic

SDP/SI manufactures a variety of gear types, including spur gears and internal gears. When making a spur gear the gear teeth are cut on the outside of a gear blank while internal gears are made by cutting gear teeth on the inside diameter of a gear blank. SDP/SI offers gear blanks as well as standard gears that are available in a wide range of teeth, bore sizes and pitches.

Helical Gears

Helical Gears

Helical Gears differ from spur gears in that its teeth are twisted along a helical path in the axial direction. It resembles the spur gear in the plane of rotation, but in the axial direction it is as if there were a series of staggered spur gears. This design brings forth a number of different features relative to the spur gear, two of the most important being:

1) Tooth strength is improved because of the elongated helical wrap-around tooth base support.
2) contact ratio is increased due to the axial tooth overlap.

Helical gears thus tend to have greater load-carrying capacity than spur gears of the same size.

Internal Blanks

Internal Gears

A special feature of spur and helical gears is their capability of being made in an internal form, in which an Internal Gear mates with an ordinary external gear. This offers considerable versatility in the design of planetary gear trains and miscellaneous instrument packages. Advantages of an internal gear are the following:

1) Well suited to compact design since the center distance is less than for external gears.
2) A high contact ratio is possible.
3) Good surface endurance due to a convex profile surface working against a concave surface.

Precision Miter Gears

Miter Gears

Miter Gears are a type of bevel gear designed to work in pairs. A miter gear set has a 1:1 ratio, identical dimensions and number of teeth. Miter gear sets are found in applications where input and output rotational speed of the drives does not vary but direction changes.

Commercial Pinion Wire and Spur Gear Stock

Pinions, Pinion Shafts, & Pinion Wire

SDP/SI Pinion Wire is extruded and can be used to make spur gears when a stock gear is not available. Available in brass and steel in the following pitches: 64, 48, 44, 32 and 24 (Modules 0.4, 0.5, and 0.8), 14–1/2° and 20° pressure angle. Pinion wire is offered in 1, 3, and 5 foot lengths as a standard catalog item. Other lengths are available on request. Steel Spur Gear Stock is also offered in pitches: 48, 32, 24 and 20 (Modules 0.8 and 1) and is used to make spur gears.

Precision Racks

Rack & Joining Gauges

Precision Racks are the straight or flat portion of a [rack and pinion] gear system, the pinion being the round gear. Teeth are cut into the rack that meshes with the pinion resulting in smooth, precise linear motion.





Splines Internal and External

Splines Internal & External

Precision Worms


Worms - Worms and Worm Gears work as a pair, rotating on shafts at 90°. Worm meshes are characterized by high velocity ratios. Also, they offer the advantage of the higher load capacity associated with their line contact in contrast to the point of contact of the crossed-helical mesh.

Precision Worm Gears

Worm Gears

Worm Gears - Worms and Worm Gears work as a pair, rotating on shafts at 90°. Worm meshes are characterized by high velocity ratios. Also, they offer the advantage of the higher load capacity associated with their line contact in contrast to the point of contact of the crossed-helical mesh.

Spur Gears

SDP/SI is a well-known manufacturer of high precision standard and custom gears for a wide range of applications. Our fine to medium pitch gears are manufactured for some of the most demanding customers in the aerospace, defense, and medical industries of today.

SDP/SI applies strict quality control throughout the entire manufacturing cycle. Comprehensive engineering experience enables us to offer the additional services of design review and / or value engineering toward the goal of manufacturing efficiency. An on-site Class 10000 clean room is used for testing, assembly and packaging. NADCAP and customer approved facilities are used for casting, heat-treating, plating, and painting. We can machine in many materials including aluminum, brass, bronze, steel alloys, stainless steel and titanium.

Inch Gears

AGMA 12, 10, 9, and 8
Available Pitches: 120 thru 16
Pressure Angles: 20° and 14.5°

Metric Gears

ISO 12, 10, 9, and 8
Available Modules: 120 thru 16
Pressure Angles: 20° and 14.5°

SDP/SI specializes in plastic gears. Molded and machined plastic gears are offered in both inch and metric sizes. A wide assortment of various configurations, number of teeth and sizes are available. Standard catalog items include spur gears, gear racks, bevel gears, miter gears, flexiracks and pinions, and worm gear sets. If a standard component does not meet your needs, modifications or customized parts can be designed, engineered and manufactured to your exact requirements.

Elements of Metric Gear Technology Download:
Elements of Metric Gear Technology
How to achieve optimum performance in a Miniature Gear Train
INTECH POWER-CORE™ Gear Information
View Custom & Secondary Operations View Shafts and Shaft Accessories Learn more about Fairloc® Learn more about Shaftloc®

Spur Gears Composite Spur Gears Hardened Inch Spur Gears 120 Pitch Inch Spur Gears 96 Pitch Inch Spur Gears 80 Pitch Inch Spur Gears 72 Pitch Inch Spur Gears 64 Pitch Inch Spur Gears 48 Pitch Inch Spur Gears 32 Pitch Inch Spur Gears 24 & 16 Pitch Inch Spur Gears Spur Gear Stock Ground Metric Spur Gears Modules 0.4 & 0.5 Metric Spur Gears Modules 0.7 & 0.75 Metric Spur Gears Module 0.8 Metric Spur Gears Module 1 Metric Spur Gears Modules 1.25 & 1.5 Metric Spur Gears Module 2 Metric Spur Gears Module 2.5 Metric Spur Gears Module 3 Metric Spur Gears Anti-Backlash Gears Bevel & Miter Gears Shaft / Hub Clamps
for Split Hub Gears & Pulleys
Cluster Gears Differentials Differential End Gears Gear & Dial Hubs Gear Blanks Helical Gears Internal Gears Pinions: Shafts & Wire Racks & Joining Gauges Ratchets Pawls Splines Internal & External - Inch Splines Internal & External - Metric Worms Worm Gears Secondary Services

Our sister division, QBC, offers monitoring and maintenance tools for power transmission components.

Shaft and pulley alignment equipment: Use alignment computers and lasers to accurately align shafts and pulleys in different types of industrial machinery..
Attain Fast and Accurate Pulley Alignment
Get tools that are easy to use:

  • Horizontally mounted machines, including gearboxes
  • Vertical/Flange mounted machines such as pumps, motors and gearboxes

BETEX Impact 33 Fitting Tool Set: For safe, precise and quick mounting of bearings, bushings, sealing rings, cam wheels and pulleys the use of an Impact fitting tool set is an absolute necessity.
Safely Mount Pulleys without Damaging the Shaft
Use safe, environmentally friendly and energy efficient tools to mount bearings and other drive components:

  • Impact Fitting Tools to avoid unnecessary damage and premature failure

Bearing Monitor: Our VibChecker is another tool that is specific to measuring vibration frequency in bearings.
Monitor Vibration and Noise Levels for Best Machine Performance
Regularly scheduled monitoring of drive train conditions can prevent machinery downtime and costly repairs. Easy to use, multi-functional, hand-held tools are available to:
  • Measure shock pulses and machine temperature
  • Monitor irregular machine sounds
  • Vibration measurement

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