A Massachusetts drill press operator strangled after his shirtsleeve was caught and tightened by rotating drill bit.

Traditionally, three CT markers are attached to a surgical guide of dental implant surgery to correlate the implant positions in CT images and the drill positions of a drill press. To allow the drill press to know the positions of the CT markers, users need to use the press to probe the positions of them manually. This process is inaccurate and time-consuming. The objective of this research was to develop a new process to eliminate the traditional probing process. This new process uses two identical pairs of locating pins both in the plaster mold cavity and on the fixture of a CNC drill press, respectively. Since the position of the drill bit relative to the locating pins and the positions of the locating pins relative to the CT markers are designed by us, the drill press knows the positions of the CT markers without probing them. According to the preliminary evaluation results, the mean errors of the location and angle of the drilled holes were 0.696 mm and 1.23°, which indicate that this innovative idea presented in this paper is feasible and promising.

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Preparation of cross-sectional samples for near-surface TEM studies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012669x ◽

1987 ◽

Vol 45 ◽

pp. 380-381

Author(s):

R.C. Dickenson ◽

K.R. Lawless

Keyword(s):

Standard Sample ◽

Surface Region ◽

Specimen Preparation ◽

Thick Sheet ◽

Drill Bit ◽

Sample Holder ◽

Metal Interface ◽

Cross Sectional ◽

Near Surface ◽

Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

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