Does anyone know what the thread is on a small boyce motor meter? I have picked up a nice original dog bone cap and a nice aged meter to suit but the meter is missing the nut to hold it onto the cap. I tried to fit the nut from the new repo meter on my other car but it was a different thread??? Thanks in advance.
im not sure but i know that a place like fastenal could help you. Is it fine thread or coarse? if its coarse you can likely find a nut at lowes. Lowes has a very limited selection of fine thread nuts. But a good hardware store should have a thread gauge and should be able to help you out.
its aprett fine thread and i think the nut 9/16"
if you have a tap and die set, use the included thread gauge to determine the TPI (threads per inch)
I'm guessing it's not a standard thread. I just tried to measure my two and looks like 7/16-26 threads per inch. Might even be metric. I'm sure someone else on the forum will have a more informed answer or is better at counting threads than I, but that is my best guess.
i kinda doubt a period motometer would be metric... if it was a repop id agree. Also, just realized you are an aussie.. you likely dont have fastenals haha my mistake Fastenal is a store that has everything you would ever need to fasten one thing to another. Nails, screws, bolts, nuts, ect ect ect cheers and good luck. sorry i am of no further help
Did the same on an original nut, seemed to be 7/16-28 to me. Its a real thin brass nut, so the thread form isn't too important, unlike if you were to use a thick nut with lots of threads.
One source might be a lighting/household lamp supply store, they use lots of small brass thin nuts on wiring ferrules, perhaps a mate could be found there.
just found this on Fordbarn says original motometers have fine thread repros have course thread. Not much help but will keep looking.
OK bad link. Sorry
Maybe this one
7/16 28 sounds right. I would have to find my tap that I used to make nuts for mine. I do know the nuts sold by the suppliers are for the modern Boyce not the original.
I found my tap, it's 7/16 27 not 28. Took me a bit to find that tap but there are suppliers that have them.
$9.50 TAST-7/16-27 7/16-27 HSS Special Tap 7/16" 27
Thanks guys for the responses. Once again the forum comes up with the required help. Thanks for the tap size Mark. Very handy to know. On Dan's suggestion I will try my local lighting shop on Monday. I know they have lots of fine threaded brass nuts for fitting lights to ceiling fan motors and other types of lampholders. Should have remembered myself as I used to use them in my job as a sparky! Watch this space and hopefully I will have the new/old motormeter mounted up on Barnies(barn fresh) radiator.
IIRC, the thread on "fine threaded brass nuts for fitting lights to ceiling fan motors and other types of lampholders" is 1/8-27 NPS
If you don't find exactly the right nut, I'd get the tap mark listed and retap one that's close to the right size.
Hey warwick, if all else fails just give me a hollar with your complete address. I've got a spare original nut and I'll send it to you......free!
Well, I got lucky with Dans idea. A trip to the light shop with the motor meter and we tried nearly every brass nut in the shop spares jar and finally found one that fit! They gave it to me so that was a bonus. The motor meter is now in place and looking great ready for a Summer of Aussie touring. thanks again guys.
I was unable to find the right tap, so I found a metric that was very close - drilled & tapped some 5/16-18 brass nuts out so they had the right hex size, then I annealed the brass and force-fit them over a junk meter. Made a bunch while it was set-up. I'll try and remember to find the tap and let you know which it was.
Happy for you to find that nut!
Usually I add a thin neoprene o-ring to the base of the Motometer, between it and the cap, to seal around the upper hole. That base has a recess for such a thin fiber/washer or an o-ring.
Underneath, place a stainless steel washer, and at times another rubber gasket, under the washer, if the hole in the cap is wallowed out or oversize of the Motometer stem, followed by the nut.
And...nice to see that dogbone cap of yours, I have the same matching style with bevel radius around the cap.