Differences

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--- techtalk:ref:tools109 [2018/11/02 16:41]
hippysmack [Calipers]
+++ techtalk:ref:tools109 [2019/05/28 15:41]
hippysmack [Telescoping Bore Gauge (snap gauge)]
@@ Line 20: / Line 20: @@
 |{{techtalk:ref:tools:reading_verniers.jpg?direct&300|}}|{{techtalk:ref:tools:reading_verniers_2.jpg?direct&300|}}|
 |  10.770" reading on a vernier caliper  |  4.915" reading on a vernier caliper  |
+===== Telescoping Bore Gauge (snap gauge) =====
+For measuring internal diameters / round holes (cylinders, bushings or other), snap gauges are used in the bore I.D. \\
+The top end of the tool tightens the bottom arms in whatever length they are at the time. \\
+Typical use is to loosen the shaft nut on top, close the arms, tighten the nut, insert the tool in the bore and loosen the nut. \\
+Each arm snaps toward opposing sides in the bore (hence the slang 'snap gauge'). \\
+The arms are rounded on the ends and they will self center in the bore. \\
+  * The measurement is found by forward and backward movement in the bore with the gauge loose and with a slight drag.
+  * When you feel you are at the correct distance, (pulling straight in the bore with a slight drag on the tool), tighten the nut to keep that arm length.
+  * Before removing the tool from the bore, continue the movements to make sure you still have the same drag as you did before tightening the tool. \\ Then remove the gauge tool from the bore.
+  * Next, use a caliper to measure the length of the gauge arms to find the internal diameter reading. \\
+  * Take several measurements instead of just one and at different points around the bore to check for equal roundness.
+It takes practice and patience to get used to using this tool. \\
+One measurement is usually not enough to say that you have a good reading from it. \\
+Lots of factors are involved in getting the correct measurement with it also.
+  * Snap gauges are notorious for closing in (slightly) when the nut is tightened. This will give you a bad reading. \\ You should feel a slight drag in the bore with the arms loose and the same when tightened. \\ Continue with the forward and back motion until you feel like the tool is perpendicular to the bore (with a slight drag). \\ Then tighten the nut and double check that you still have drag on the tool BEFORE removing it from the bore.
+  * It's also easy to turn the tool sideways (even slightly) and feel drag. \\ Then while double checking the distance when tightened, you get even more drag. \\ Since a sideways measurement is longer than a straight thru measurement, this will give you a bad reading.
+  * Evo cylinders will naturally not be perfectly (a few thousandths variance in circumference). \\ To measure cylinder bore, the heads have to be off which releases the torque on the cylinder and distorts the bore.
+|{{:techtalk:ref:tools:measuring_cylinder_1_by_horseman1.jpg?direct&300|}}|{{:techtalk:ref:tools:measuring_cylinder_2_by_horseman1.jpg?direct&300|}}|
+|  Telescoping bore gauge and caliper for measuring cylinder I/D. ((photos by Horseman1 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1943121&page=7))  ||
+|{{:techtalk:ref:tools:measuring_cam_bushings_1_by_aussiegazza.jpg?direct&300|}}|{{:techtalk:ref:tools:measuring_cam_bushings_2_by_aussiegazza.jpg?direct&300|}}|{{:techtalk:ref:tools:measuring_cam_bushings_3_by_aussiegazza.jpg?direct&300|}}|
+|  Telescoping bore gauge and caliper for measuring cam bushinhgs. ((photos by AussieGazza of the XLFORUM http://xlforum.net/forums/showthread.php?t=692835&page=5))  |||
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