I recently purchased "The Miho Company" coil tester. It was made in Cincinnati,OH. It operates from a 6 volt battery for power and measures amps. I think that it also tests spark plugs. I have never seen a tester like this before and would like to know more about it before I try it out. There was a KW coil in the tester dated 1960. Does anybody have information about this tester? Thanks
A picture would help.
I apologize for not responding sooner.
The photo is to large for the mtfca website upload size.
please contact me firstname.lastname@example.org and I will email you the photos.
Paul try this site:
It'll get you going.
hope this works-Paul
Your tester appears to be a typical tester that is often referred to as a "buzz box". The 6V battery connections are applied across the top side and bottom connections of the coil while the bottom side (spark) connection is connected to the small wire spark gap that is formed by the 2 small wires pointed toward each other above the spark plug connection trays. The ammeter is inserted in series with the battery connections to thus read the primary DC current when the switch is on and the power is applied. It is then that the spark should appear across the spark gap. If you place a spark plug across the 2 "V" shaped tray connectors the spark plug gap will be much less than the spark gap located just above the spark plug so the spark will then appear at the spark plug assuming it is not cracked or the internal connections broken. This type of tester will tell you if the windings are OK but not much else since to set up a coil properly you need to observe the space/time relationship of the spark as the coil is fed an AC signal that is synchronized with the rotation of a spark gap wheel. As a spark plug tester it really doesn't test that device very well either since the plugs big job is to provide a suitable gap when under high pressure of compression and it is a rare plug that will ever fail this easy sparking test since there is no pressure surrounding the gap. The other small device with a single contact on one side and a double contact on the other is a light bulb tester. You hold the single contact bulbs against the single bottom connection to the left side and the side of the bulb against the 2 side contacts. If the bulb has 2 bottom connections then you hold the bulb such that both bottom connections connect to the double contact pair on the right side of that "socket". The ON OFF switch is likey in series with the DC supply to the whole tester. I don't know the point to point wiring and it is possible that the switch only controls power to the coil tester portion and not the light bulb testing portion but those are just the small details. These testers are pretty common and they all work about the same. The spark gap should NOT be wider than 1/4" or you could in fact harm some T coils with this tester since applying power to a coil to cause it to buzz and not having a 1/4" or less gap can result in the coil sparking internally which causes it to lay down a carbon trail inside the coil which makes it misfire easily under normal conditions. Have fun with it all and as a piece of antiquity from the T era - it is a fun item. As a means to set up a coil with precision - not so hot.
I have copied more information from an email Jay sent me about the tester-Also, I would like to thank you for your help in learning more about the history of this tool-thanks Paul
Brent Mize, "The Coil Doctor, responded: "These were offered by several
companies during the T era. They are not extremely accurate since there is
no way to see the occurrence of double sparks. The spark plug gives one
the allusion that the coil is firing properly when in fact it may be firing
sporadically or not at all when the spark is called for by the timer. These
are neat collectibles, but really not an accurate tool for adjusting coils.
But, Im a little fussy about coils.??"
Doing a little research on my own, I found an announcement in February 1922
that the Miho Company was founded at 13 East Third Street in Cincinnati for
the purpose of manufacturing battery station equipment.
Jay G. Klehfoth
CEO, Model T Ford Club of America
Editor of The Vintage Ford
PO Box 126
Centerville, IN 47330-0126
After talking with Jay Klehfoth, I have decided to donate the tester to the museum. Thanks for all of your help-Paul