Carbide bolster
View Patent ↗A degradation assembly has a carbide bolster brazed within a hole formed in a surface. The bolster has a substantially straight cylindrical portion mostly disposed below the surface and a top end and a bottom end. The top end narrows from the cylindrical portion with a substantially annular concave curve to a planar interface adapted for bonding to a carbide substrate and the bottom end narrows from the cylindrical portion to a stem which bottoms out on a geometry of the hole.
1. A degradation assembly, comprising:
a carbide bolster brazed within a hole formed in a surface;
the bolster comprises a substantially straight cylindrical portion at least mostly disposed below the surface and a top end and a bottom end;
the top end narrowing from the cylindrical portion with a substantially annular concave curve to a planar interface is bonded to a carbide substrate;
the carbide substrate is also bonded to diamond on an end opposite the planar interface,
the diamond comprising a conical geometry;
the cylindrical portion being longer than the annular concave curve; and
the bottom end narrowing from the cylindrical portion to a stem.
2. The assembly of claim 1 , wherein the stem comprises a cylindrical side wall.
3. The assembly of claim 1 , wherein the stem comprises a taper less than 5 degrees.
4. The assembly of claim 1 , wherein the hole encompasses the entire diameter of the cylindrical portion.
5. The assembly of claim 1 , wherein the surface is incorporated into a working surface of a fixed cutter drill bit.
6. The assembly of claim 5 , wherein the surface is on a blade formed in the working surface.
7. The assembly of claim 5 , wherein the bolster is positioned at a positive rake on the working surface.
8. The assembly of claim 7 , wherein the cylindrical portion is at least 150 percent as long as the stem.
9. The assembly of claim 1 , wherein the surface is incorporated on a cone of a roller cone bit.
10. The assembly of claim 1 , wherein the cylindrical portion is longer than the stem.
11. The assembly of claim 1 , wherein the bottom end narrows from the cylindrical portion via a 40 to 60 degree angle.
12. The assembly of claim 1 , wherein the annular concave curve is a radius.
13. The assembly of claim 1 , wherein the annular concave curve is a parabolic, an elliptical or a hyperbolic curve.
14. The assembly of claim 1 , wherein the substrate is less than 10 mm thick.
15. The assembly of claim 1 , wherein the diamond comprises a greater volume than the carbide substrate.
16. The assembly of claim 1 , wherein the bottom end comprises a flat that bottoms out on a geometry of the hole.
17. The assembly of claim 1 , wherein the planar interface comprises a diameter greater than the stem.