Drill bit screw tip
View Patent ↗A drill bit comprises a shank having a longitudinal axis. A cutting head is formed at one end of the shank. A removable and replaceable pilot tip such as a screw tip or pilot point is formed on the cutting head. The pilot tip is designed for controlled failure. A tool is also provided for removing the broken tip. A kit comprising a dill bit adapted to receive a removable tip, a removable tip for attachment to the cutting head, and/or a removal tool for removing a broken tip from the drill bit. A method for removing a tip from a drill bit and replacing it with another tip is also provided.
1. A drill bit comprising:
a shaft;
a cutting head formed on the shaft;
a removable tip having a stem and a leading end, said stem threadably engaged with a threaded bore formed in the cutting head, said removable tip having a controlled break point between the stem and the leading end where the tip will break if a force above a predetermined force is applied to the tip wherein the cutting head has a cutting edge and said controlled break point is arranged from a point substantially flush with the cutting edge toward the shaft, the controlled break point comprising a narrow web that includes a flat face arranged such that a cavity is created between the flat face and the threaded bore that is dimensioned to receive a tool, said cavity being covered by said tip.
2. The drill bit of claim 1 wherein the tip has a cutting member for engaging a workpiece.
3. The drill bit of claim 1 wherein the tip has threads for engaging the cutting head, said controlled break point being located between the cutting member and the threads.
4. The drill bit of claim 2 wherein the cutting member is a screw.
5. The drill bit of claim 2 wherein the cutting member is a lead point.
6. The drill bit of claim 1 wherein the controlled break point is approximately flush with an exterior surface of the cutting head.
7. The drill bit of claim 1 wherein the bit is a spade bit.
8. The drill bit of claim 1 wherein the bit is a fluted bit.
9. The drill bit of claim 1 wherein the bit is an auger.
10. A kit comprising:
a drill bit having a cutting head formed with a threaded bore adapted to receive a removable tip;
a removable tip having a stem and a leading end, said stem threadably engaged with said threaded bore, said removable tip having a controlled break point between the stem and the leading end where the tip will break if a force above a predetermined force is applied to the tip wherein the cutting head has a cutting edge and said controlled break point is arranged from a point substantially flush with the cutting edge toward the shaft, the controlled break point comprising a narrow web that includes a flat face arranged such that a cavity is created between the flat face and the threaded bore that is dimensioned to receive a tool, said cavity being covered by said tip and a removal tool dimensioned to fit into said cavity for removing a broken stem from the threaded bore.
11. The kit of claim 10 further comprising: a plurality of removable tips for engaging said cutting head.
12. The kit of claim 11 wherein the tool includes a pair of fixed jaws, said fixed jaws dimensioned to engage said flat face and a second flat face formed on the removable tip.
13. A method for removing a tip from a drill bit comprising:
providing a cutting head having a bore on the drill bit;
providing a removable tip having a stem extending into said bore;
providing a controlled break point on the tip, said controlled break point comprising a narrow web that includes a flat face;
defining a cavity arranged between the flat face and the threaded bore that is dimensioned to receive a tool;
inserting a tool into said cavity to remove the tip from the cutting head; and
inserting another tip into the cutting head.