Film-Tech Forum ARCHIVE: Help with Drive-in Speaker Problem

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Posted by Peter Berrett (Member # 672) on 06-29-2006, 07:36 AM:

Hi all

Here's my project - can you help?

I am in the process of outfitting an old drive-in speaker with an FM radio (Think about it - you can take it to a drive-in that doesn't use speakers any longer and enjoy the drive-in the old fashioned way, also no danger of ripping the window out).

Anyway my problem is this. I want to open up the speaker but it is outfitted with screws with circular heads as pictured.

As you can see the screw heads are virtually round but they have a serated edge like a cog. The difficulty is that some of the screws are sunken in holes making it difficult to undo unless you have the correct tool.
How can I get the screws out? I do not have any tools for screws this shape.

Regards Peter

Posted by Paul Trimboli (Member # 1509) on 06-29-2006, 08:45 AM:

Hi Peter

Now I don't have any experience with drive-in speakers, but if that is actually a screw I would use a slot cutting file and file a slot in the head of each screw and then just use a normal flat head screwdriver to undo it. I would let some CRC soak on them before I tried to undo them as it looks a bit rusty.

Posted by Phil Hill (Member # 371) on 06-29-2006, 04:16 PM:

You might try gripping it with a screw-thread hand tap holder or perhaps a Jacob's chuck for a twist drill.

A pair of pliers may even work since it looks like you have side access to the screw heads.

Good luck... [thumbsup]

Posted by Monte L Fullmer (Member # 2797) on 06-30-2006, 02:23 AM:

..and a large set of Vise-Grip pliers might help twist those serratated edged screws off..

but, prior before the twist, soak those screws with stuff like WD-40 to soak into the threads since the casting is aluminum and the screws of steel - which the two metals really don't like each other...

Posted by Phil Blake (Member # 2012) on 06-30-2006, 02:54 AM:

Hi Peter, I would just drill the screws out and retap new threads, that was the ultimate solution when I was repairing drive in speakers in the past.

Posted by Peter Berrett (Member # 672) on 06-30-2006, 03:53 AM:

Thanks

Success!

I have managed to get all the screws out using pliers, WD-40 and by banging on the heads of the screws with a hammer (old trick).

Regards Peter

ps You might be curious to know what FM radio I am going to use. I have decided to use an FM radio salvaged out of a $A20 cushion radio. It has push button volume and tuning which is ideal for this type of installation.

[ 06-30-2006, 04:56 AM: Message edited by: Peter Berrett ]

Posted by Tim Reed (Member # 137) on 06-30-2006, 08:46 AM:

FWIW, I think those are the infamous Gulmite screws...

Posted by Bruce McGee (Member # 131) on 06-30-2006, 12:55 PM:

I used to have a little security screwdriver for those screws... its long gone... I have 5 old D-I speakers. 2 of them are used as rear surrounds in my home theatre system. They work fine.

Posted by Phil Hill (Member # 371) on 06-30-2006, 07:39 PM:

Thanks Tim. That's the name I was trying to think off...

I think the "official" Gulmite screw-head tool is available from Jensen and others. But VERY overpriced.

Posted by Peter Berrett (Member # 672) on 07-03-2006, 11:32 PM:

Hi all again

Here is my finished Drive-in Speaker Radio

There is a red light to show when the radio is on and six buttons - On, Off, Vol+, Vol-, Channel Up, Reset.

It sounds quite good. The radio was salvaged from a $20 radio cushion which was ideal for this project.

No chance of driving away from the drive-in only to hear one's side window smashing into a thousand pieces!

Regards Peter

Posted by Tim Reed (Member # 137) on 07-05-2006, 01:36 AM:

Very good, Peter! Nice work. If anyone was going to do this, it certainly was you. [Smile]

Posted by Barry Floyd (Member # 385) on 07-05-2006, 05:07 PM:

Peter, that looks great. I did something similar a few years ago with 2 sets of old "Projected Sound" drive-in speakers.

Two of them I gutted and installed a 120 volt candelabra lamp base and a 4 watt nite lite bulb. I replaced the volume knob with a rotary on-off switch, and made two night lites for my boys bedrooms. They hang the "Speaker-Lights" over the edge of their headboards.. and they make a decent "reading light" too.

I took a rotary wire cup-brush in my cordless drill and polished the 40 years worth of crud off the cases. They shine like chrome now.

Posted by John Wilson (Member # 269) on 07-05-2006, 05:56 PM:

Picture please, Barry.

quote: Tim Reed
Very good, Peter! Nice work. If anyone was going to do this, it certainly was you.

Agreed. Peter's holding the torch here...that's for sure.