Topic: 1967 Reproduction Antenna Modification

[Deuce]

From discussions and information in this forum, we know that the 65-68 reproduction antennas on the market are styled after the 65/66 design, where the screwed-on ball affixed to the top/third mast section remains extended about 1 1/4" above the second mast section when the antenna is fully retracted.

Designed differently on the factory-orginal 67/68 antenna, the ball atop the third section collapses all the way down to the second section when the antenna is fully retracted, hiding completely the third mast section.

Shown in the below pics is the result of a recent project on my 67 coupe; i.e., cutting down and re-threading the third mast section so the top ball bottoms out against the second section when fullly retracted.  Given the availability of original or NOS 67/68 antennas, this is as close to the original configuration it's going to get for this car.  Original AM radio reception is acceptable and there is No rattle.

Btw, still have the C7 antenna base, cable and fittings that came with the car when new.  The press-on mast is missing; therefore the reproduction antenna is installed. 

[RoyceP]

Big improvement.

[ruppstang]

Great idea. I like thinking like that, doing what it takes to make it correct. Seems to me it would be so simple for a manufacturer to do something like that. Their altitude most often is close is good enough.

[Bossbill]

I like it!

[67gtasanjose]

 
Nice work Robert.

[68Metuchen390GT]

Thanks

[67350#1242]

Are you saying that the ball on the repro antenna was threaded onto the mast?   I guess I assumed they were press fitted or glued.   Can you give more detail on how you went about the modification?
Thanks,  Kurt.

[Deuce]

Are you saying that the ball on the repro antenna was threaded onto the mast?   I guess I assumed they were press fitted or glued.   Can you give more detail on how you went about the modification?
Thanks,  Kurt.

Appreciate your comments!

Yes, the ball on the repro antenna is threaded on to the mast.

What follows below is correct for the repro Scott Drake antenna I ordered from NPD five years ago: https://www.npdlink.com/product/antenna-radio-round-base-repro-us-made/103158?backurl=search%2Fproducts%3Fsearch_terms%3Dantenna%26top_parent%3D200001%26year%3D1967&year=1967. (I don't know if there are other repro 65-68 antenna manufacturers).

- Mic'd the diameter of the third (smallest dia.) top mast section:  0.094"
- Researched the nearest thread spec for 0.094" diameter stainless steel rod: #3-56 UNF, or #3-48 UNC
- Selected two taps to determine which is correct thread size, by chasing the taps into the ball:
       -- 3-56 UNF tap threaded into the ball
       -- 3-48 UNC tap did not thread into ball
- Deduced the correct thread inside the ball is 3-56 UNF
- Cut length of third section rod down by about 1.25"
- Used 3-56 UNF die to rethread newly cut tip of top mast section
- Trimmed / adjusted the tip of the top mast section so the threaded-on ball would bottom out on the second section when mast is fully retracted
- Done!  Clean & Lubricate mast, turn radio on and drive.

The stainless steel rod is hard material.  Use a quality die (my #3-56 UNF die is fitted for 13/16" diestock handle), and liberal application of cutting oil.  Go slow.  My die cut the new threads nicely using plenty of cutting oil.

Happy to take any questions.
 

[67350#1242]

Thanks for your excellent how to proceed rundown.

[RoyceP]

What is the diameter of the ball on the Scott Drake reproduction antenna? I have OEM antennas on both of my cars. What I notice at car shows is that the reproduction antennas have smaller balls on the end, and that unlike the originals, the reproduction balls are stainless steel while the originals appear to be chrome plated.

[Hipo giddyup]

Can you explain what you used/how to hold the mast when removing and then when rethreading?

Thx

[Deuce]

What is the diameter of the ball on the Scott Drake reproduction antenna? I have OEM antennas on both of my cars. What I notice at car shows is that the reproduction antennas have smaller balls on the end, and that unlike the originals, the reproduction balls are stainless steel while the originals appear to be chrome plated.

The ball is mic'd at 0.309"

Non-magnetic, no corrosion, so assuming it's stainless steel material.  Could be brass I suppose, but internal threads don't have a yellow cast as brass would.

The diameter of the OEM antenna ball is ______ ?

[Deuce]

Can you explain what you used/how to hold the mast when removing and then when rethreading?

Thx

Thought about this and the various repair options (uninstall antenna, place in vice, etc.). Decided to do the work with antenna mounted on the car.  Covered the fender area around antenna base with blanket to protect the paint finish.

The stainless rod is hard material.  Ended up using vice grip pliers to hold the antenna rod stationary while using the die in the diestock handle.  Afterwards, there was not a mark or blemish in the rod from using the vice grip pliers - tough stuff!   (First tried using a cloth rag or rubber sheet to protect the rod material from the tightened plier jaws.  The rod would still spin with the pliers clamped very tight and the die in place, so this didn't get very far).

Another comment:  I used an industrial-strength bolt cutter designed to cut up to 6mm (~ 1/4") stock.  Sliced right through the rod. 

Finished job:

[RoyceP]

It measures .303".

The ball is mic'd at 0.309"

Non-magnetic, no corrosion, so assuming it's stainless steel material.  Could be brass I suppose, but internal threads don't have a yellow cast as brass would.

The diameter of the OEM antenna ball is ______ ?

[Deuce]

It measures .303".

Just a few thou (0.006") difference in diameter. 
Repro:  0.309"
OEM:    0.303"

The OEM ball might be a little bit shinier though, might have to polish mine.

Thanks,