Carnes-Miller Gear manufactures spur gears utilizing either the hobbing or shaping process. Part attributes contribute to the process selection. These attributes might include the location of the gear in relation to other features, limited cutter clearance, or the face width of the gear. Machine tool work envelopes are also a factor to be considered. Often times it is not an either or, but what is most cost effective. CMG has practical experience in making this determination.
Spur Gear capabilities:
- Shaped: maximum 20in/500mm diameter with 5in/127mm face
- Hobbed: maximum 16in/400mm diameter
- AGMA 10 on shaped and hobbed gears
- AGMA 13 on ground spur gears
- Profile tooth grind up to 15.75in/400mm in diameter
- Geared or pinion shafts can be ground up to 26in/660mm in length
Carnes-Miller Gear operates in the medium size tooth pitch range from 3DP to 32DP or .5 MOD to 10 MOD respectively.
Enlarged Pinions and Reduced Gears
Pinions with a small number of teeth sometimes require an enlarged diameter, consequently a sufficient increase in the diameter, increases the root diameter and helps prevent the undercut which weakens the pinion. Similarly, the outside diameter of the mating gear can be reduced by the same amount. This balances the gear modifications and the standard center distances and pitch diameters do not change. The result is a design that does not change and a stronger pinion.
Stub Tooth Gears
The Fellows Stub Tooth has an addendum and dedendum shorter than the conventional full-depth tooth. The diametral pitch is expressed as a fraction. The numerator determines the pitch diameter and tooth thickness whereas the denominator determines the addendum, dedendum, depth and clearance of the tooth. CMG has experience in the stub tooth design. tooth.
Internal Spur Gears
Internal spur gears, also known as ring gears, have teeth on the inside of the blank. CMG can shape up to 20in/500mm pitch diameters and 5in/127mm face width on internal parts. Because of the nature of the hobbing process, internal gears cannot be hobbed.
Cluster gears are a series or cluster of gears on a shaft or gear blank. Frequently there are relationships between these gears. Examples would include timing between the different clusters of teeth, or a timing of a tooth to a keyway. CMG can maintain specific relationships between features because we have full CNC shaping and hobbing capabilities.