Diehead & Chaser Seminar

How To Grind Circular Chasers

Circular chasers must be sharpened by a single grinding operation with the chaser and its holding block mounted in a grinding fixture adapter. By grinding the face of the chaser in the fixture the three angles B, C, and D are ground simultaneously.

RSVP Tooling, Inc. - Circular Chaser Thread Rolling System - Diehead & Chaser Seminar - How To Grind Circular Chasers Image

Taper Thread Chasers

Regrinding and setting taper thread chasers and blocks for dieheads varies only in respect of the fixture base setting which controls the face angle.

Whereas the standard setting of 6 degrees produces a face angle of 1 degree 30 minutes on chaser, the base setting for taper thread chasers must be found by experiment.

These particular chasers when ground and set will have no face angle, but will be square with the base of the chaser block.

To achieve this, alter base setting from 6 degrees to 5 degrees. Grind two chasers to normal 22 degrees hook angle. Stand these on a flat surface and bring the two ground face angles in contact with each other. These two faces should touch from top to bottom in their length.


When correct base reading has thus been obtained, the chasers and blocks will then be ground and set in the normal manner, except that it is necessary to lower the bracket carrying micrometer A to the same level as micrometer AA. This will enable micrometer A to contact the chaser face at the depth of the thread plus 0.010”.

Finally, we find it advisable to grind the chasers to a slightly higher micrometer reading than normal.

Where hook angles other than 22 degrees are required, the base readings, as shown above would vary and have to be found by experiment

RSVP Tooling Link Icon Additional Seminar Information

1. Seminar Outline
2. RSVP Tooling, Inc. - Information Sheet
3. Diehead Maintenance Check List
4. RSVP DR Diehead Parts List
5. Using The Micrometer Setting Gauge
6. How To Grind Circular Chasers
7. Setting Chaser Ahead For Grinding
8. Setting The Grinding Fixture
9. Grinding The Chaser

10. Useful Hints On Chaser Care & Threading
11. Problem Solving
12. Guide To Checking Block Wear
13. Micrometer Barrel Certification
14. Suggested Grinds - 4 Per set Straight
15. Suggested Grinds - 5 Per set Straight
16. Suggested Grinds - Taper
17. Chart For Micrometer "AA" Readings

RSVP Tooling PDF Icon

Download this page as a PDF
Download this seminar as a PDF
Download the RSVP Tooling Catalog as a PDF

Follow RSVP Tooling on: