Much improved drill bit design is possible with a mud pump.
The reason we have to leave
the middle of our "drill bit" open when we are
washing/drilling a well with two hoses is that at the end of
the drilling process we need to be able to slip a wellscreen
down through the pipe and "bit" and then pull the drillpipe
up and out of the ground. Otherwise the sand at the
bottom of the hole will quickly collapse when we pull the
drillpipe out and we won't be able to get a well screen back
down to the bottom of the hole.
We could achieve much
more effective drilling if we could use a point or some
other shape in the middle of the bit. Basically with
teeth cut in the end of a pipe, we are grinding away at the
circumference of the hole and just using the general
associated loosening to evacuate the center of the
hole. This is obviously not the most efficient way to
do this.
With a mud pump and a re-circulating
drilling fluid system, everything changes. It gets
much easier. Drilling is more efficient.
We can add bentonite to the drilling fluid and solidify the
sandy walls of the hole so they won't collapse when we
remove the drill bit.
Using this techique permits us to drill the hole with a more
efficient drillbit that will mechanically eat away the
entrie area of the hole, not just the edges. After we
drill the hole, the bentonite will hold the hole open so we
can remove our drilling pipe and replace it with out well
screen pipe. Here are some photographs of the drill
bit I use. It was fabricated by a local welding shop
for $55.00.
MUD PUMP DRILL BIT -
NOTE THE SET SCREW
MUD PUMP DRILL BIT
DESIGNED FOR MINIMAL FRICTION WHEN REMOVING FROM HOLE
MUD PUMP DRILL BIT
DRILLS A HOLE SLIGHTLY LARGER THAN THE 2.0 INCH PVC
DRILLPIPE
Jonathan in Cantonment, Florida was kind
enough to send photographs of the drill bit he fabricated
for use with a mud pump. Check it out!
John, in Brandon, Mississippi sent this picture of a drill bit
that he fabricated. It has square pieces of carbide on the
outside and he welded a piece across the middle and ran quarter
inch bolts through it. This looks like a great bit for mud
pump drilling!
JOHN's DRILL BIT
EDSON FROM BRAZIL SUBMITTED THIS DRILL BIT. (crafty no welding
design!)