I am assembling a new (vintage) speedometer cable. I have a SW chain with links and I'm just about ready to grease the links and pull it through the housing. I have an expansion end piece connected to the one end and am ready to pull it through, but how do you determine the final length of links. I have mostly links that are 1 3/8 inches long and a few 1 1/8 inches long. I assume these are used to adjust the final length. If it is too long, it will put pressure on the Swivel joint and the Speedometer head. If it is too short, it will disengage. Any pointers on how to make that final adjustment in length?
As few links as possible. Too many and they bind up.
Lay the cable housing out straight. The lower Sliding Bar Clutch (the big one) goes at the ferrule with the flats as you have it and the Upper Clutch (the small one) goes where the ferrule is round. It attaches to the swivel and speedometer as you have it laid out.
Lay the chain next to the cable housing and add links to the Sliding Bar Clutch (extended) until the chain would be out the other end of the cable housing just enough to attach the smaller Upper Clutch to the chain.
You may have to mix different links to achieve the right length. The extra length sticking out the end will need to be less than the length of the Sliding Bar Clutch which takes up the slack when mounted.
When you pull the greased chain through the cable from the end ferrule with the flats on it, there should be just enough chain sticking out the end where the ferrule attaches to the speedometer head that you can attach the smaller Upper Clutch to the chain.
Grease the chain up good with front wheel bearing grease before you pull it in the clean cable housing. Leave a string in the cable housing as you finish cleaning it so you can pull the chain in.
Attach the Upper Clutch and pull it back into the ferrule and it seats. Then, push the sliding bar back into the end ferrule with the flats until it seats.
To mount the cable, jack the front wheel up that has the road gear on it. Attach the cable ferrule with the flats and Sliding Bar Clutch to the swivel. While jacked up, spin the wheel forward and let the swivel turn the cable links as they would while driving. This "lays" the links in the cable housing in the direction they will run while driving.
Do not attach the upper ferrule to the speedometer head until you have "laid" the links. Then attach the Upper Ferrule to the speedometer head.
Spin the wheel forward while still on the jack and confirm the speedometer reads a forward speed. If there is no binding and the speedometer reads a forward speed, you are good to go.
If you don't "lay" the links, they may be "pushing" each other rather than "pulling" each other and you will break a link.
Let us know how you come out. Your speedometer is very nice.
Russ Furstnow has a very good book he has written on the speedometers available from the vendors.
Ken in Texas
Thanks so very much for the guidance. Russ did the restore on my 160 head and as you can see, it is a beauty. I hated to call Russ again with another stupid question. I was looking tonight and I can't find Russ's book anywhere. I'll keep checking the vendors tomorrow. I've borrowed a digital copy of Russ's book but the installing of a speedometer is not covered well. The history and detail about different speedometers is incredible.
I'm writing this whole process down and putting it on our club website. Would you be okay if I use your instructions in my posting and give you credit? I'll send you a copy before I post it.
There are two different lengths of links, so you can get a pretty accurate adjustment that way. In addition, you want to keep as much of the sliding bar clutch slid in as possible after assembly. I've seen them twist if left out too far.
Russ helped me with a Model 100 setup for a '14 that continues to work beautifully. Do not hesitate to contact him.
Let us know how it works out. The Stewart speedometers are part of the Model T experience.
Ken in Texas
These are photos of the SW head I have after Russ Furstnow restored it. As you can see, it is a beautiful job. Thanks everyone for the help.
This is my cable with the lower clutch fully extended and the upper clutch with just enough chain link exposed to attach the clutch. I think this is correct for the cable. If this isn't what the adjustment should be, let me know.
Looks perfect. You need to drag the chain links through a pile of grease. Be sure there is grease on the end fittings too.
That is fine for now, but you need to seat that clutch end in the housing, and worry about the drive end! As Royce says, get as much light chassis lube in that housing as you can while assembling it. You should post another photo of the drive end when you have finished. I have Stewart speedometers in all three of my T's, and they all have chains and work well.
My wheels are off and getting ready to be re-spoked so it will be awhile before I have the road gear on. I greased the links and pulled it back in the housing. Rotates freely which is a bit of a surprise as I was expecting more drag. Connected the swivel joint and it also turns freely and turns the entire chain as it should. I noticed that when I reverse the direction I'm turning the swivel joint, it takes several rotations before the head end of the chain begins to turn. I am guessing that that is because the links twist at each link until they tighten up enough to rotate the entire chain. If I can get something that has big enough chuck, I'll hook the head on the top end of the cable and see if the speedometer works. Thanks to all of you that chipped in to help. Doug D.