Weston Ammeter threads

[DanM]

Does anyone know the specifics of the threads on the mounting studs of Weston Ammeters? They seem to be 38 or 40 tpi? The tips of mine have been buggered, and I'm trying to think of a way to restore them? And where are the nuts available?

Thanks! Dan

[exeric]

Dan, the Weston ammeter I have has 10-32 studs, which is a standard thread. Your's may be different. Do you have a thread guage ? When you find out for sure, (and if it is an odd-ball thread) you can go to MSC industrial supply and get a special thread die to chase the treads. You may also want to get a matching tap so you can run it through an appropriate size nut.

[DanM]

THX Eric. I did use a thread gage- the threads seem so fine, I was hoping it is -32, but will check again. I also considered opening up the gage and seeing how the stud is secured, and simply replacing it with a new piece-
THX

[Perry Ruiter]

Does anyone know the specifics of the threads on the mounting studs of Weston Ammeters? They seem to be 38 or 40 tpi? The tips of mine have been buggered, and I'm trying to think of a way to restore them? And where are the nuts available?

Thanks! Dan
The early Super X parts book lists the thread as 3/16-40. If anyone has a source for a tap and die in that size I'm interested. The closest I've been able to find is 10-40 ... Perry

[DanM]

I remeasured, and agree with Perry. OD of stud is right at .185 and the threads are -40. I found the tap and die at www.minicastings.com, $5.70 and $11.88 respectively.

[exeric]

That's a good price for a tap and die. You'll probably never use them again but if they save your guage, it's money well spent.

[DanM]

I have accumulated quite a few taps and dies with 1 use on them. I'm doing a JD, and the exhaust valve cover threads on the lifter block were damaged. I actually bought a crazy die on ebay and managed to rethread the 2 blocks!

[bobbyt]

I believe the nuts are 10 x 40

Bob Turek
$769

[Perry Ruiter]

I remeasured, and agree with Perry. OD of stud is right at .185 and the threads are -40. I found the tap and die at www.minicastings.com, $5.70 and $11.88 respectively.

Let us know how those work out. I had found some 3/16-40 ME taps/dies but passed as I was worried ME was some nutbar British thread, that, while close isn't quite close enough with the proper thread form ... Perry

[bselph]

Does anyone know the specifics of the threads on the mounting studs of Weston Ammeters? They seem to be 38 or 40 tpi? The tips of mine have been buggered, and I'm trying to think of a way to restore them? And where are the nuts available?

Thanks! Dan

Check with Kevin at Indian Guage Co.
http://indiangauge.com/INDIAN%20WEBSITE%20COVER%20PAGE%202.html

[DanM]

Well, you are right. The supplier said "ME Model Engineering (British Straight Thread"

I ordered anyhow. Will report back.

[DanM]

I received the tap and die. I rethreaded brass nuts with the tap. I ran ther die carefully over the old stud, about 1/3 -1/2 way down. The nuts run down fine with decent engagement.

Only the very tip of the stud that was most stripped doesn't really hold the nut because so much metal was gone from the original stripping.

So, I'd say mission accomplished!

www.minicastings.com

[awander]

M.E. Thread is a 55 degree thread-similar to the Whitworth, and British Standard threads. For a low-stress application like an ammeter, I would think you could mix'-n'match 60-degree and 55-degree threads and never know the difference.