Got a neat old Aircraft Tachometer ( curved glass woo hoo ),,The sweep is right to left,,,now is this an internal thing ? like hooked to a tach drive distributor will it work or is car and airplane different direction rotation ( figuring it is but just wanna make sure ) Now if I have to change the direction,,is there an adapter to do this?? I know there are reductions and right angle adapters ok heres pictures any idea what the adjustment thing is for ?? never seen one on a Tach also the spline on teh inside says CAT 5878,,is that the cable I need to drive it ?
mechanical tach? Spin the thing on the back counterclockwise (if you are looking at the back) and see if the needle moves the opposite way
I have seen these and taken various units apart to figure out what to do. it kinda depends on who actually made the tach. some will not move the pointer if rotated in opposite direction... you can easily test this with a drillmotor and then reverse the rotation of the drill... most have a one direction flyweight or magnet that spins only one direction.... the "drag" is what makes the little needle move. some are made to rotate reverse by way of a planetary gear... so if you can remove the planetary gear and make the magney rotate "normal" then you can get it to work.
Little Wing, Many of the replica Cobras use the original style counter clockwise (CC) speedo. They have a reversing adapter that fits behind the speedo, you could possibly use one of those to faciltate using the CC Tach. Just a thought. Johnnie.
Little Wing , I think it would just be one of those thing I would put into my car just to screw with people ! I would use it if you have a way to hook it up ! RetroJim
the direction of the SWING NEEDLE is kinda secondary. the underlying issue is which direction does the IN PUT SHAFT have to rotate in order for the tack to show MOTION....?? hook up a drill motor to it and see....
get the right tach, and you can change the direction of rotation of the cable, by moving the drive from one side to the other
Almost all tach drives can be reversed. Most speedometer shops can handle it if you don't want to do it.
Posted some pix ,,,to move it does have to rotate the other way,,so gonna start the search for the stuff to do it
Suspect that is not an Aircraft Tach. The Aircraft Tach's that I have had and seen didn't go over 3500 RPM. Most likely used for a commercial or industrial application. But if it works, use it.
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