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GEAR HOBBING MACHINERY (Hobbers), For Bevel, Helical, Spur & Worm Gears

Illinois #76, hob lead checking machine, #12861

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Illinois #76, hob lead checking machine, #12861
Illinois No. 76 Hob Lead Checking Machine
Stock# 12861

In the hobbing process it is essential to know the accuracy of the hob when new, and also after each sharpening.

A hob has three elements, which must be right ½

These are:

Profile of hob teeth ½.

Lead of thread in hob ½.

Concentrically ½.

No matter how accurate the tooth profiles are, if they do not fall in the true helical path of the thread, or if the lead of the thread is either short or long, the gear tooth contour produced will be violently affected.

The effect of imperfect lead in a hob on gear tooth contour may be readily understood when it is recognized that ordinarily one revolution of a single thread hob produces, or finishes, one gear tooth complete.

It is not only necessary that new hobs have accurate lead but it is of utmost importance that the original accuracy of the lead is not impaired by repeated sharpening.

The Illinois Hob Lead Checking Machine No. 76 is designed to permit rapid checking of a quantity of hobs. Master Lead screws are used for each pitch and hob diameter.

These Master Screw are made to within .0002 in 6 inches of lead.

The hob being mounted integral with the Master Screw will register any deviation from true helical path as the cutting edges pass by the indicator.

The indicator head may be placed in either right or left hand position by merely swinging it around its pivot screw. This permits immediate contact with either the right or left hand side of the hob tooth.

An auxiliary indicator may be placed on the front indicator arm for checking diameter run out.

The machine is made to be operated by hand or by motor mounted within its base as desired.

Length ½ ½ ½ ½ ½ ½20 inches Weight ½ ½ ½ ½ ½90 pounds
Width ½ ½ ½ ½ ½ ½.10 inches Boxed ½ ½ ½ ½ ½132 pounds

Height ½ ½ ½ ½ ½ ½15 inches


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