Help ID this screw. What size spanner nut socket? Radio/speaker ??. 1970 DVC

[chrisntam]

I have several questions for the experts.  I'm (re)installing the factory radio in my '70 Deville convertible.  Right now, the factory radio is in beautiful South Carolina getting new life breathed into it.  It's a non stereo am/fm signal seeker.  Right now, the car has an old aftermarket radio in it and I think the prior installer butchered the dash to get it to fit.      I do have an extra dash bezel I think I'll be using when the original goes back in.

In an effort to be all ready for the install, I pulled the dash pad last weekend and the original speaker was missing as was the speaker harness.      I think the front (one in the center only) speaker receptacle takes a 4 x 10 speaker.   What do you think? 

The speaker fasteners are missing as well.  How hard would it have been for whoever removed the speaker to put the fasteners back?  Is the screw pictured the right type for those 4 holes??  That one pictured holds the dash pad to the dash bezel.  What is that screw called?

What size spanner nut socket do I need?  Where does one go to purchase said socket?  I suppose I could make one, but I'd rather buy one.

The speaker pictured is a 6 x 9 taken from the center of the back seat, I assume the front replacement speaker will have the same speaker connection, colored wire to the spade lug, the other (black) wire to ground?

Here are the pics, what say you?  Thanks in advance!  It appears everybody's cars are all fixed, been kinda slow around here lately!

The last pic is the underside of my top, do other's under tops look like that?

[Scot Minesinger]

Chris,

Front center speaker is a 4 x 10, I bought mine from Electro Tech in MN - perfect fit.

Not sure what those types of screws are called, but likely you can get them used from Cadillac King, Cadillacs Only in CA, Willington CAD and many others for reasonable cost if they are not available from Fastenal.  Go on line with Fastenal and see if you can find what you are looking for.  I got the rear speaker fasteners on my 1970 SDV from Fastenal, which were 3/16 carriage bolts.

Spanner nuts - standard SAE sizes will work on your original 1970 Cadillac radio (may be using your deep 1/2" drive set), but it is a standard size.  You may need a metric to remove the radio presently installed.  An adjustable wrench carefully used to not scratch wood may work too.

BTW that top does look original

Enjoy your Cadillac!

[fishnjim]

With the integral washer they are called SEMS fasteners.   The one you show is a double lead thread.   Those are used in non-nutted and soft, non-metal applications.   You can probably use just standard hardware store flanged hex head sheet metal screws to install a speaker into sheet metal, if you're not OEM particular or doesn't show.   If it's in particle board or plastic, then use the double thread.   They come without the washer in hex head screws also.
The spanner nut is a standard part and they're around but the one you show look like a full size one.  They come in full and half widths.  Uses a spanner wrench.