Smiths chronometric odometer reset

[Sparky]

I'm in the process of rebuilding my Smiths chronometric speedometer.  The trip odometer never worked and in fact, there wasn't a reset knob or even a hole in the case where one could go. Now that I've opened it up, I see that the internal speedometer body has the provision for a reset shaft (the version that comes out the side of the case rather than out the back), but of course there's no reset shaft present.  I've repaired the trip odometer itself, and now I am fabricating a new reset shaft.  My question is (and I know that this is a long shot), does anyone have a good photo of the reset shaft, gear, and especially the top of the shaft that apparently has some kind of disk or retainer that engages the lever that retracts the shaft during normal riding?  A picture is worth a thousand words, so here is a picture of what I have, and hopefully someone can show me what the original shaft looks like so I can make a reasonable facsimile.

[wilko]

I'll have a look in my spares today and send some pics.

[wilko]

here.

[Sparky]

Wilko-

Thanks so much!  That really helps. 

From your photo, it looks like the diameter of the reset shaft on the left between the gear and the little cone shaped cap is smaller than the diameter of the other "knob end" to the right, which on mine is a tad under 1/8".  Is that true, or is it just the way it looks in the picture?  Also, would you be able to measure the distance from the top of the gear to the bottom of the "cap".  I suspect that is a fairly strategic distance in order for the reset to engage and disengage properly.

[wilko]

Surely you're not attempting to make such a thing? What do you need? I can't even remember if this is a side mounted one or from underneath?

[RichardL]

Hi Sparky,

Mine is a rear reset, but you might get something out of the photos. In my case, also, the shaft was broken. In the first photo in the second post with photos you can see the star wheel on the broken shaft. When pulled out, this star engages with the star on the tripometer wheels. In another picture (or two) you can see the awl I used to replace the broken shaft. The original star is swadged to the awl. I used the drive gear from a slot car as the reset knob. A little funky, I know, but still working well.


www.a7a10.net/forum/index.php/topic,680.0.html

[Sparky]

Surely you're not attempting to make such a thing? What do you need? I can't even remember if this is a side mounted one or from underneath?

After searching unsuccessfully for a replacement, I decided to try to make one myself.  The shaft is a piece of stainless 1/8? rod from the hardware store, and the gear was modified from one I found on e:bay that is made for an R/C helicopter.  I purchased the knob from a chap in England, and all that remains is to make the small cap on the end of the shaft.

The one you have is the side mounted style like mine.  I added comments to your photo to show you what measurements I need.  If you can tell me the distance between the gear and the cap at the end of the shaft, and the diameter of that section of the shaft, it will help me avoid what will otherwise be trial and error in getting it to work properly.


Manosound:  Nice work on your speedo!  I also wondered about lubricants.  Since it looks like you did the rebuild in 2008, apparently the Marvel oil has stood the test of time.  Once I finish the odometer reset shaft, I will be launching into the speedometer clockwork itself.  Unfortunately, the center of the three gears which I think is a phenolic or fiber material is quite worn.  Perhaps I will have some luck finding something I can use in the R/C hobby market.