Tipe machining gear biasanya merupakan faktor penentuan proses machining, dikategorikan berdasarkan ukuran gear, konfigurasi integral seksionnya, jumlah yang

diperlukan, akurasi yg diperlukan, rasio gear-pinion, harga.

Dalam industri, perlakuan panas yang paling banyak digunakan untuk gear adalah carburasi dan hardening. Keduanya memberikan daya densitas yang tinggi.

Carburasi gear memberikan resistansi panas yang tinggi dengan menggabungkan jenis proses hardening lainnya. Gear dengan proses ini mampu menerima beban kejut dengan baik.

Spur, Helical, and Bevel Gears. The lubricationrequirements of spur, helical, straightbevel,and spiral-bevel gears are essentially thesame. For this class of gears, the magnitudes ofthe loads and sliding speeds are similar, andrequirements for viscosity and antiscuff properties

are virtually identical. Many industrial spurand helical gear units are lubricated with rust andoxidation inhibited (R & O) mineral oils. Thelow-viscosity R & O oils, commonly called turbineoils, are used in many high-speed gear unitswhere the gear tooth loads are relatively low.Mineral oils without antiscuff additives are suitablefor high-speed lightly loaded gears wherethe high entraining velocity of the gear teethdevelops thick EHD oil films. In these cases, themost important property of the lubricant is viscosity.Antiscuff/EP additives are unnecessarybecause the gear teeth are separated, eliminatingmetal-to-metal contact and the scuffing mode of

failure. Slower speed gears, especially carburizedgears, tend to be more heavily loaded. Thesegears generally require higher viscosity lubricantswith antiscuff additives.Hypoid gears, such as those used for automotiveaxles, are especially prone to scuffingbecause they are heavily loaded and have highsliding velocities. For these reasons, hypoidgear oils have the higher concentrations of antiscuffadditives.For critical applications, the contact temperatureshould be calculated with Blok’s equation(see Eq 1) (Ref 15) and compared to the scuffingtemperature of the lubricant. This quantitativemethod is effective for selecting a lubricant

with adequate scuffing resistance.