Tap and a method of tapping

• US 7,575,520 B2
• Filed: 08/02/2004
• Issued: 08/18/2009
• Est. Priority Date: 08/04/2003
• Status: Expired due to Fees

• Current Assignee: Adcock Technology Limited
• Original Assignee: Adcock Technology Limited
• Inventors: Adcock, Neil Walter Lindh
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US10/566,918
• Publication Number:
  US 20060199654A1
• Time in Patent Office: 1,842 Days
• Field of Search: 72/88, 724/69, 470/18, 470/96, 470/105, 470/198, 470/204, 470/8, 470/9, 470/10, 470/199, 408/226, 408/227, 408/228, 408/222
• US Class Current: 470/204
• CPC Class Codes: B23G 2200/26 Coatings of tools
• CPC Class Codes: B23G 2210/16 Multiple start threads
• CPC Class Codes: B23G 2225/60 Titanium nitride
• CPC Class Codes: B23G 2240/12 Means for cooling or lubrication
• CPC Class Codes: B23G 2240/36 Methods of threading not otherwise provided for
• CPC Class Codes: B23G 7/02 Tools for this purpose
• CPC Class Codes: B60N 2/067 by linear actuators, e.g. linear screw mechanisms

Abstract

The present invention provides a tap (10) adapted for formation of female screw-threads in a plurality of metal parts. Each female screw-thread is capable of imparting translational motion to a threaded second member engaged therewith, the threaded second member having a matching male screw-thread and the translational motion occurring on relative rotation between the first metal part and the threaded second member. The tap (10) is fluteless and comprises a threaded portion (23) with a triangular form thread (11) with an angle of thread (gamma) in the range 29°-40° and radiussed crests (16). The present invention also relates to a method of using such a tap.

Claims

1. A tap adapted for formation of female screw-threads in a plurality of metal parts, each female screw-thread being capable of imparting translational motion to a threaded second member engaged therewith, the threaded second member having a matching male screw-thread and the translational motion occurring on relative rotation between the first metal part and the threaded second member, the tap being fluteless and comprising a threaded portion with a symmetrical triangular form thread, wherein the symmetrical triangular form thread has an angle of thread (α

) in the range 29°

-40° and

radiussed crests with a radius of curvature in the range of 0.165 to 0.175 mm.

2. A tap as claimed in claim 1 wherein the angle of thread (α

) is 29°

to 31°

.

3. A tap as claimed in claim 2 wherein the angle of thread (α

) is 30°

.

4. A tap as claimed in claim 1 wherein the tap has a chamfered front end.

5. A tap as claimed in claim 4 wherein the chamfered front end extends over at least four turns of the thread.

6. A tap as claimed in claim 4 wherein the chamfered front end has a chamfer angle (β

) in the range 5.5°

to 6.5°

.

7. A tap as claimed in claim 1 which has at least two starts.

8. A tap as claimed in claim 1 wherein the roots of the threaded portion of the tap are radiussed.

9. A tap as claimed in claim 8 when the radiussed roots have a radius of curvature in the range 0.178 mm to 0.188 mm.

10. A tap as claimed in claim 1 wherein the thread has a pitch of 0.995 mm to 1.005 mm.

11. A tap as claimed in claim 1 comprising additionally lubrication grooves.

12. A tap as claimed in claim 1 comprising a shank portion extending rearwardly from the threaded portion and a rearmost portion with a plurality of flat surfaces to enable engagement of the tap by a chuck.

13. A tap as claimed in claim 12 in which at least one of the flat surfaces is precision machined in order to precisely set a distance between the front of the tap and at least one end of the flat surface.

14. A tap adapted for formation of female screw-threads in a plurality of metal parts, each female screw-thread being capable of imparting translational motion to a threaded second member engaged therewith, the threaded second member having a matching male screw-thread and the translational motion occurring on relative rotation between the first metal part and the threaded second member, the tap being fluteless and comprising a threaded portion with a symmetrical triangular form thread, wherein the symmetrical triangular form thread has an angle of thread in the range 29°

-40° and

radiussed crests, and the roots of the threaded portion of the tap are radiussed with a radius of curvature in the range of 0.178 mm to 0.188 mm.

15. A tap as claimed in claim 14 wherein the angle of thread is 29°

to 31°

.

16. A tap as claimed in claim 15 wherein the angle of thread is 30°

.

17. A tap as claimed in claim 14 wherein the tap has a chamfered front end.

18. A tap as claimed in claim 17 wherein the chamfered front end extends over at least four turns of the thread.

19. A tap as claimed in claim 17 wherein the chamfered front end has a chamfer angle in the range 5.5°

to 6.5°

.

20. A tap as claimed in claim 14 which has at least two starts.

21. A tap as claimed in claim 14 wherein the radiussed crests have a radius of curvature in the range of 0.165 to 0.175 mm.

22. A tap as claimed in claim 14 wherein the thread has a pitch of 0.995 mm to 1.005 mm.

23. A tap as claimed in claim 14 comprising additionally lubrication grooves.

24. A tap as claimed in claim 14 comprising a shank portion extending rearwardly from the threaded portion and a rearmost portion with a plurality of flat surfaces to enable engagement of the tap by a chuck.

25. A tap as claimed in claim 24 in which at least one of the flat surfaces is precision machined in order to precisely set a distance between the front of the tap and at least one end of the flat surface.