Switch anti-rotation washer?

[claycookiemonster]

Many of my recently delivered switches included a washer which has a small extension "key" to engage with the groove in the threads of the switch. The opposite side of this washer has another extension which must be intended to be held by the instrument panel?

Question: how did you create the small slot/groove/hole in the instrument panel to receive the extension on the washer?

 

[Mark Curley]

I drilled a small hole (1/16 I blelieve) in the appropriate location.

 

[Roadjunkie1]

Switch hole slot...

Many of my recently delivered switches included a washer which has a small extension "key" to engage with the groove in the threads of the switch. The opposite side of this washer has another extension which must be intended to be held by the instrument panel?

Question: how did you create the small slot/groove/hole in the instrument panel to receive the extension on the washer?

I used my tiny file set. The flat one makes the slot just the right size.... The square one was a little too big.....

 

[krwalsh]

Waterjet

Question: how did you create the small slot/groove/hole in the instrument panel to receive the extension on the washer?

I just added that little notch to the waterjet file for my instrument panel.

It took a LOT of planning to get all of the details like that in there, but it came out great.

 

[TShort]

I have 8 evenly spaced switches along the bottom of my panel.

I cut a strip of thin aluminum sheet and drilled the same switch hole pattern in the sheet, then drilled holes in the sheet to match up with the key on the washer. Inserted that between the switches and the panel.

I did the above because my panel was all painted and lettered, and that way if I screwed something up it was on a throwaway piece rather than the finished panel.

 

[PaulvS]

I made the indents for the key washers with a drill bit that was the same width as the lug on the washer, 3mm. I also filed down the lugs so the hole in the panel did not need to be as deep and risk drilling right through.
The attached pics show the shallow divots on the back of the panel and a key washer with its lug that has been filed to match the divot.

 

[wirejock]

Keyway washer

Another option
Cut a strip of .025 or .032. Whichever the thickness of the key. Drill the switch holes and keyway washer holes in it. Slap that behind the panel.
Install the switches. The key will lock into the strip and as long as there are two switches in the strip, it can't rotate.

 

[Scott Hersha]

I made a jig that fit into the hole made for the switch and it had an additional small #43 hole adjacent to the large switch hole. Mark a line with your T-square splitting the switch hole in the middle, insert the jig, and drill the #43 hole for the key washer. You can drill a whole row of key holes in a few minutes.





I don’t have a picture of the jig, but it’s a very simple tool.

 

[Ralph Ketter]

Question: how did you create the small slot/groove/hole in the instrument panel to receive the extension on the washer?

If you can find the appropriate data sheet for your switch it will show the dimensions. For example here is a data sheet for
Carling F-series Switches. Is shows the antirotation hole is .125" diameter with the center located 0.376" from the center of the 1/2" mounting hole.

I usually make a CAD drawing and print it on paper. I then use some spray adhesive to temporally apply it where needed. Then I center punch and drill through the paper. Acetone will remove the paper and adhesive.

I also have just put the anti-rotation washer on the switch with the tab up, inserted the switch backwards into the panel and rotated it to cause a small arc where the tab should be. You can use some masking tape on the panel to avoid scratching it. I then drill the appropriate size hole at the correct location on the arc. My panel gets covered with engraved labels hiding any marks.

 

[WenEng]

Add a backing strip to switch holes

Used scrap 063 to make a 1 inch wide strip that mimicks the switch mounting holes spaced on 1 inch centers. Under the mounting holes, I drilled .109 holes to catch the anti rotation lockwasher tab and therefore keep the switches straight up and down. You have the lockwasher on the switches, push the switches through the bar, then through the panel openings. The anti rotation lock washer tab engages the small holes from behind and as you tighten up the switch, it all just pulls together and all switches are held with one bar. I can make a smaller one for some of the upper left switches on the panel, as well.

 

[jliltd]

The small holes are the way to go if using the washer. Been well described above. Go find the data sheet for your specific switch (Mouser, digikey etc..). The data sheet will have the dimensions of the panel cut outs. I like the ideas submitted about using a locking strip with the holes on the forward side of the panel for a clean look.

As an alternative, you can get a panel laser cut or water jetted with little locking nibs left in place. Then you don't use the washer because the little nib will fit directly into the switch barrel's groove. Switches have the grooves on bottom and circuit breakers have the grooves on top. Here is an example. I have had this done with laser cutting and once the slag is cleaned up along the edges the results are excellent.

 

[Steve]

I was told this tip after the fact:
For that professional look, drill the tab hole on the back side of the panel just halfway through.