. Railway mechanical engineer . Bicknell-Thomas Thread Lead Indicator ing the lead on both the screw and inside the tapped use, the tool is held in one hand, preferably the left, andthe screw is pressed against the two points which are spaced54 in-, y2 in. or 1 in. apart, as desired. If the lead of the. Testing an Internal Thread for Lead thread is normal the indicator needle will register at zero;if the lead is short the needle will show on the minus side;if long, on the plus side. Each line of the graduation repre-sents .001 in. The little table on which the screw rests in testing is
. Railway mechanical engineer . Bicknell-Thomas Thread Lead Indicator ing the lead on both the screw and inside the tapped use, the tool is held in one hand, preferably the left, andthe screw is pressed against the two points which are spaced54 in-, y2 in. or 1 in. apart, as desired. If the lead of the. Testing an Internal Thread for Lead thread is normal the indicator needle will register at zero;if the lead is short the needle will show on the minus side;if long, on the plus side. Each line of the graduation repre-sents .001 in. The little table on which the screw rests in testing is easilyadjusted to any height to accommodate screws of any dia- meter. For internal measuring the table is removed merelyby loosening the thumb .screw and drawing it off. The endof the instrument containing the point is small enough sothat tapped holes, as small as ■-< in. in diameter, can be testedand of course from that up to any size. This is a featurewhich is of the utmost importance in making sure that the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
