One of the distinctive features of the regular type underreamer,
which makes it the favorite with many operators, is the exclusive body
design. The lower end of the body projects far enough below the cutters
to act as a guide to keep the Underreamer directly in the center of the
hole, so that an equal amount is cut from each arc of the circle, making a
perfectly straight hole and a perfect shoulder on which to set the pipe.
Off set or key-seated holes, especially difficult to overcome when
alternating strata of hard and soft formations are being underreamed, are
practically unknown to the RAMPP Underreamer. The pipe always follows. |
The cutters are so
designed that the full force of the Underreaming blow is taken on the
broad cutting surface, rather than on a thin sharp section, as is the case
with many other Underreamers. This permits long uniform wear and prevents
tight holes. The main bearing surface is the entire broad back of the
cutter. Additional bearing surface at the end of the cutter is provided
where it fits into the shoulder, which is machined into the solid body of
the Underreamer. These bearing surfaces distribute the force of the blow
over an exceedingly large surface, giving stability, firmness, and
built-in power, which enable the RAMPP Underreamer to successfully
underream the hardest formations. |
 
Cross section view, RAMPP Underreamer.
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MANY SUPERIOR FEATURES
- Tool Joint, may
be turned to any special size consistent with size tool.
- Substitute
forged from high grade special steel.
- Spring.
Controls position of cutters. Made of special spring steel.
- Body, forged
from a solid billet, heat-treated to relieve forging strains,
Brinell tested.
- Spring Rod.
Spring Rod manufactured from selected steel.
- Trips, engage
the projection on spring rod and hold the cutters in position while
the underreamer is being lowered through the casing. After cutters
come into position for Underreaming, trips are idle until tool is
again set.
- Cross Bar, a
simple connection between the cutters and spring rod by which the
cutters are moved to position for entering the hole.
- Bearing Surfaces
for Cutter, the entire broad back and end of the cutter
- Cutters, made of
solid block of high grade alloy steel, hard face.
- Guide, keeping
the tool in the center of the hole so that an equal amount is cut
from each arc of the circle.
- Perfect
Shoulder, due to the guide feature that permits the cutters to take
an equal amount from all sides of the hole.
- Setting Ring.
- Setting Hooks -
(Set 2).
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