SM5 SWITCH PANEL ISSUE

[Steve Bryant]

Hi all. As expressed in my update of my van build, I am trying to assemble the SM5 switch that came with the car when I bought it. I originally thought that all the right bits were in the tin it came in but on assembling the switch I am wondering if the ammeter it came with is not the correct one for this particular switch. If I know what the two posts of the ammeter are supposed to  look like I can modify them and make the necessary parts to allow the ammeter to be fitted correctly to the switch.
Have a look at the pics and let me know what your thoughts are regarding this situation.

Thanks Steve.
   
   
   
   
   
   

[bob46320]

my 1932 RN had a Type BN very similar but different
   

[Howard Wright]

Hi Steve

Bob beat me to it.

The BN has female contacts not male ones. The contacts have small insulating rings over them. One is shown removed in this pic.

Might be difficult modify you existing meter?

Cheers

Howard


  IMG_0844.jpeg (Size: 116.49 KB / Downloads: 372)

[Steve Bryant]

Thanks guys. Now that I know what things are supposed to look like, you have given me the information I need to modify what I have to work.
Great stuff.
Stephen

---

One more question please. What is the length of the threaded posts from the insulator to the top on of the post of your ammeter?
Thanks,
Stephen

[Howard Wright]

Hi Steve

3/8”

Cheers

Howard

[Steve Bryant]

Thanks to Howard's  photos and information I have modified the posts of my ammeters terminals to allow it to be attached to the body with 5BA screws  that go down the centres of the wire terminal posts:

  Modified Ammeter.jpg (Size: 128.4 KB / Downloads: 198)

One thing I need to tell members to be aware of and check especially if you have had a short  with your ammeter develop at some time is the following:

When working with my gauge I noticed that the mechanism was slightly loose and not tight to the body and could be moved about a bit. I checked for contact of each post to the body with a voltmeter and discovered that it was shorting to the body as a closed circuit instead of being open. This would go away if I moved the post in relation to the body. Both posts have  to be insulated from the body. I intend to secure the mechanism in a position were it does not make contact with a suitable fixative.

Cheers,
Stephen

[Howard Wright]

Nice work Steve, I wondered if there was room to modify the posts. Good info on the likely shorting of the posts to body.

Cheers

Howard

[Steve Bryant]

Thank you Howard. There was evidence on the Bakelite body around where the posts contact the body of having been really hot at some time showing minor blistering and discoloration. So I think the original ammeter may have shorted out at sometime. I had to play some games with the body to allow the ammeter to sit at the right height. Here's hoping things all work properly when the time comes. One more thing done on the "to do" list for the van's build.

Stephen

[Dave Mann]

I suspect your SM5 is a later version which has lost it's cover         

[Steve Bryant]

Hi Dave thanks for your pics,
It's hard to say what year or model my switch came from as it came with the car when I bought it - actual source unknown. It was in pieces in a tin so I just put it aside to try and sort it all out later......40 years later !
Stephen