Autonopedia

A

A shoulder on a seed harrow tine has a parallel round shank without a square tenon.

Only a very slight reduction in section is needed to form a shoulder.

Neither fullering nor swaging is necessary as the drawing down can be done by hammering the bar on the flat of the anvil and using the rounded edge of the anvil to form the shoulder.

B

Next drive the reduced portion of the tine into the countersunk side of the small round hole in the bolster.

Withdraw the tine, reverse the bolster so that the square edged holes are uppermost, and drive the tine into the same hole.

This completes the shoulder and forms the upset.

The special bolster used for forming the shoulders on tines is described in Chapter 2 and shown in Figs. 24 and 25.

C

This is the seed harrow tine as forged.

The rounded pin, which will be threaded, continues right up to the shoulder without a square tenon.

D

Medium and heavy tines have a square tenon between the shoulder and the threaded portion.

More reduction is required on these tines and the drawing down should be started over the bick of the anvil and completed on the flat, leaving both the tenon and the pin square.

E

To square and upset the shoulder take a NEAR WELDING heat and drive the tine into the square hole in the bolster.

The pin, which is to be threaded, must now be rounded on the face of the anvil to the required size.

It is then driven into the special round hole in the bolster; this will form the shoulder between the pin and the tenon and leave the tenon the required length.

F

Here a medium harrow tine is shown in three stages:
(1) cut and marked,
(2) the pin and tenon formed,
(3) the tine pointed and set.

The square upset shoulder between the tine and the tenon, and the reduced shoulder between the tenon and the pin can be clearly seen.