mechanical tach drive

It often happens that someone finds an old IHC mechanical drive tach and wants to install it on an engine without a tach drive dist.
I was looking thru Dakota Digital's new offerings, I saw they came out with a universal electronic pick-up to mechanical drive. You drill your bellhousing and add a common mag pick-up to read the ring gear, and their box will output to a cable drive like the tach uses. You can hide the drive down on the frame and run the cable in the normal way. Model ECD 100.
It has been very common for years to go the other way, cable drive on the engine to signal generator for an electronic tach, but this is the 1st I've seen go the other way. Only one (big) drawback, price is $300.

I like that drive conversion from Dakota digital. Does it require 12 volts?
I have built mechanical tach drives. A modern e-tachometer is so much better than the old m- tachometers.
There is very few good and practical reasons to do much of the stuff I do, really. I wanted a mechanical tachometer just for the charm of the bouncing needle. I would like to make a mechanical drive for a tachometer for the Old IHC motors.
Something in a cam drive off the front of the motor is what I am thinking. For me it is just time and the satisfaction of doing something out of the ordinary.
I have a design in mind for a mechanical tachometer drive to fit my Ruston Hornsby Diesel engine. The tachometer I bought in a garage sale is a reverse rotation, 0-500 rpm Stewart Warner with a 5 inch face. Do I need this tachometer? Absolutely not for any practical reason. For me it is all about the challenge that goes with making it work.
Our R120 with the 6.9 Diesel had my mechanical drive design. Our Cummins 4bta has a mechanical tachometer drive of my design. Pictures are posted on this forum along with YouTube links.
Sadly, the old Stewart Warner cable drive stuff is nearly impossible to find used. The new parts are expensive for SW or SS white components. A person is looking at about $300-$500 for the bits and pieces.
I still have a box of this old stuff, but, probably not the right pieces to complete a system.
I bought a zero to four thousand rpm electric tachometer for my 24 valve Cummins engine that will ultimately power a crewcab "R" 4X4.
So, I'm off to the garage for some more R and R after a short ride on my motorcycle.

Just amazing! Thanks, CB!

My Marmon came with cable drive speedo and tach in 1992, likely one of the last big trucks to do so. Most had gone over to electronic by the early 80's.
At about 1,000,000 miles the mechanical had about had it. I decided rather than paying big bucks to have the mechanical repaired, I would install an electronic. doing so made it easy when I also installed 2 spd rears, as the electronic already had the ratio correction for them built into it.
If I ever decide that the Marmon has pulled its last load, I might spring to have the original Speedo with MARMON stenciled on the face, re built. It matches the mechanical tach, which for whatever reason is still going fine. Then I would need this drive to run it, as I gave away my speedo drive gears.
My guess is the tach drive turns slower with less variation. 4 stroke tachs mostly turn at 1/2 crankshaft speed. Which for a 3406B is between means the cable is turning between 800 to 900 rpm for most of the time vs. 1100 and up for the speedo. (N-A std is 1000 rpm@60 MPH for speedo's)

I like that drive conversion from Dakota digital. Does it require 12 volts?
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IIRC the spec is 7-18 volts, meaning it is doubtful it would function on a 6 volt system well.

I had my electronic Speedo apart on my '83 Cabover and the motor to drive the odometer was labeled "6 volt ac". It must use a VFD to drive it based on the speed sensor input.

I have tach drive dist for both my K's and gave away another (missing the drive gear) with the 282 I gave to Dean.
It would be hard to find a E-tach that looked "period correct" for the K's. I bet someone could convert a mechanical to electronic, just keeping the old face and needle, but not sure it could be done for less money than the "box" in question.

Great Find!, now I can use that tach that has been sitting in my KB-6 for the last 33 years.