I purchased an AC Speedometer a while back that was nos. It was complete except it was missing the fiber wheel that connected to the sprocket attached to the wheel. I have since obtained that wheel. My problem is that the speedometer is made of pot metal which has expanded and it is therefore frozen . Is there any one who can make it operational?
Great find, a pity it's a pot metal speedo.. Unfortunately there are usually few options to make it operable - they are usually junk if they're stuck.
An accessory collector would likely still give a fair price for your complete package to use it as a display.
Making a new housing out of aluminum would be a interesting winter project!!
The largest danger with that AC is the upper bearing support for the MPH wheel is very VERY thin and if it's looked at cross eyed it will break.
I bought what was advertised as a complete, working, AC speedo on ebay.
Upon receipt the MPH wheel would never zero......stopped where it wanted to stop.
I had no choice but to open it up and found the fella the seller had bought it from had attempted gluing some of the pot metal parts back together.......unsuccessfully......
I wish you luck but if I was a betting man (I'm not) I wouldn't hold my breath.
There is a working AC in my '27 Tudor and I'm scared to death to even remove it.
Anybody do 3 D printing (additive manufacturing) that could take on the pot metal carrier project? If the piece were standard for speedometers, find a good one and scan it for the machine. How about it Russ----ideas on restoration?
Most 3D printers work in plastic (at least the ones for the hobbiest market)
In the non hobby world they have gone past plastic and are doing stuff with carbon fiber and a few other thing.
The main frame seems to hold up ok, it's the part that holds the spring and speed dial as stated.
Unfortunately, your AC speedometer is a "shelf item". I have gone through nearly 50 AC heads and have found only two good ones. As has already been discussed, the pot metal frame that holds the speed drum swells and cracks, and it is such a delicate piece, it cannot be successfully repaired. I think the coolest part of your find is the original box!!!
If you can find an AC head where the speed drum is free and returns to zero, you might have a restorable head. Also, check to see if the pot metal threads that attach the ferrule nut to the head are swollen and cracked. If there is any sign of swelling on the input shaft threads, the speedometer head is no good.
I hope this helps,
As you are probably aware, ALL speedometers had pot metal components up through the late 1960's. "White metal" (aka: pot metal) is extremely easy to form and is cheap to produce. By the mid 1920's, only AC, Waltham, NorthEast, and Stewart Warner were in the speedometer business in the U.S., and they all made their speedometers with pot metal internal parts.
Also, no one figured these speedometers would be around 100 years later, so they weren't produced with the highest quality components. The one speedometer manufacturer that used only brass and steel in its speedometer internals was the "Jones Speedometer Co.", and this company sold out to the Johns-Manville Co. in 1913. J-M stopped producing the Jones Speedometer in January 1916....it was just too costly to produce. Johns-Manville continued to produce speedometers until the early '20's when Stewart Warner acquired the company, and the J-M speedometer used only pot metal internal components in their speedometers!!
I hope this helps,
I've thought about reproducing some of these obscure internal components in order to repair speedometers. Unfortunately, the cost is very high and the demand is very low. You know where this is going...I just try to find operational units that can be restored at a reasonable price. I know that many Model T owners feel that the cost of a restored original speedometer is too high already, so making these parts probably won't happen any time soon. The good part is that you don't need a speedometer to have a GREAT time in your Model T!!!
Sure, Ross, maybe I should have written: "Pity it's a speedo made out of low quality pot metal that rarely survives until present days" since there are speedos from other makers that seems to last a little better and be repairable at a higher rate, even if they also are made from pot metal (and I suppose the mix of metals in what was called "pot metal" varied between makers)
You are correct in that some pot metal speedometers are MUCH better than others. The best is Stewart, then Johns-Manville, then Sears-Cross. The worst are Standard and AC.
I hope this helps.
I know there are commercial 3D printing shops that will "one off" for a price in various mediums. Might check into some of them to see what the price would be to reproduce the part.
Like you said however, one does not need a speedometer to have a GREAT time in a T. (And if you have a cell phone and the right app, you have a speedometer), Regards, Tim
It looks like I only need one part to make it work; however that part has to be positioned exactly. It what holds the wheel with the mph numbers. Mine is broken in one place. I thought of trying to epoxy it back together but it looks like the whole part has expanded which is what caused it to break in the first place.
Russ, My 1925 Gray (not Dort) which is now in restoration, uses this AC speedometer. I've got about three acquired over the years. One seems to be free. Any suggestions as to a suitable replacement? Thanks.
Marty, A Stewart Model 131/160 is about the only thing that comes close. A later AC Series C or D would also work, and these units do not have the fragile pot metal frame. The later AC Series C and D unit uses a different cable though. I hope this helps,
Russ, thanks. It does help and thanks!
Good to know Russ.......is the drive ratio compatible with the earlier AC?
And it so which cable?
The ratio is the same, and the cable is just a Series C/D cable. The ferrule that attaches to the transmission/wheel gear may have to be adapted to the specific application.