Pee Wee Coil Clips

[aa5wg]

Hi to all:
I just read in an old 73 magazine article about the link antenna coupler.  The author made reference to "Pee Wee" coil clips for making tap connections on the tank coil.  Has anyone seen these coil clips and is there a source for them?  I don't like the alligator stile clip because is offers minimum contact with the coil.  I need a spring loaded type of coil clip that wraps around the body of the tank wire or tubing.
73,
Chuck  

[W7TFO]

Well, the 'Pee-Wee' IS an alligator clip:

http://parts.digikey.com/1/parts/389264-clip-pee-wee-steel-5a-bu-45.html

They were very popular for that purpose.

73DG

[W2PFY]

Wow, I never heard of clips called PEE WEE??

This is the only Pee Wee that I know.

[kb3ouk]

i never considered those alligator clips, what i call an alligator clip are these, like what are used on the end of a set of clip leads.



i have a few smaller ones too that are very hard to get open, unless you use a pair of needlenosed pliers.

[aa5wg]

I remember seeing a picture of a spring loaded coil clip that actually wrapped around the wire or tubing of the coil.  Does anyone know of these?
Chuck

[Jim, W5JO]

Pee wee clips are totally different from the pictures here.  They were small clips that had a screw to tighten it against the winding of a close spaced coil.  Millen, I believe, made them.

[kb3ouk]

the only thing i can think of that would be like that is a fahnestock clip, but they're a type of early connector.

[aa5wg]

I Googled Millen coil clips but came up zip.  Anyone else have a source or picture of these coils.
Thanks guys.
Chuck

[KC2ZFA]

here are some knock-offs:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220734809467&ssPageName=STRK:MEWAX:IT

[Jim, W5JO]

To me, when you say Pee Wee Clip, this is what I think of.

[k4kyv]

I think that is what he is talking about.  I ran across a source for them a couple of months ago when I was looking for the kind that used to be made by EF Johnson for clipping onto edge-wound coils. Didn't make note, since that wasn't the kind of coil clip I was looking for.  Do a Google search for "coil clip".

I had a few of those in my junk box.  They worked FB OM for the air wound coil stock I use in my BC1-T that replaces the original crappy grid coil wound on bakelite. With the new coil, I get 30% more grid drive for the same driver plate current.

[aa5wg]

The two sizes of copper tubing coil I am using are 1/8 inch (.125) and 1/4 inch (.250) outer diameter.  The clips in the photos are to small.  I have some of them.  Dose anyone remember those spring loaded dual "S" shaped type of clips that wrapped around the conductor?  Or, are there any other suggestions for a high quality coil clip for the sizes I need?
Thank you.
Chuck

[Jim, W5JO]

A friend of mine built and sold bug catcher mobile antennas and he used small alligator clips.  He would use a small file to remove the teeth then needle nose pliers to form the flat surface so that it made maximum contact with the coil surface.

If you are building a high power tuner, you need as much surface contact as possible to carry the current.  To improve efficiency you really should wrap the wire around the turn of the coil then solder.

[KM1H]

Those are B&W clips. 3942 for up to #12, 3943 for up to #8 and 3944 for edgewound.

I believe it was B&W who developed the airwound inductors in the mid 30's.

Carl

[Todd, KA1KAQ]

There's another type that are a small, flat, criss-cross arrangement. Along the lines of an alligator clip but without teeth and no spring or pivot - much simpler. I have some on an old 1930s balanced feed tuner with a plug-in coil at top and the clips attached to wires. Just clip them onto the coil then adjust the air variables.

They sound like what you might be describing, Chuck. My laptop with the camera software is in the shop or I'd snap a couple shots. These things are very small and simple, but adjust to a larger diameter when you squeeze them open.

[k4kyv]

Those are B&W clips. 3942 for up to #12, 3943 for up to #8 and 3944 for edgewound.

I believe it was B&W who developed the airwound inductors in the mid 30's.

Looks like this is all they have now.

Just like our dwindling bio-diversity, as time goes on, the variety of available manufactured products to select from, for about any purpose, is steadily decreasing. 

[aa5wg]

Everyone thank you for all your help.  However, none of these coil clips are what I saw.  The B&W coil clips now available are to small.  Todd if you have time could you take a snap shot of the coil you mentioned. 
Thank you.
Chuck

[kg8lb]

In the old days the hams would have made their own. Pretty simple part to form.

[KM1H]

Seems like B$W creatively extended the 3942 to #10. I used to sell a package of 25 for $10.50....looks to be simple enough for a small garage shop to come up with a product.

Carl

[aa5wg]

What would be the steps in tooling to make a quality coil tap for 1/8, 1/4 or 3/8 tubing?
Chuck

[Todd, KA1KAQ]

Using thin aluminum strips, it should be easy enough to bend them to suit, Chuck. You could even use something like a finish nail of similar diameter as a form.

The ones I have are flat and just pinch the coil. The tuner doesn't look like it was designed for huge power, though. It will probably be a few days, but I'll see if I can get a couple pics with a cellphone and post them. The other pc with the camera software won't be ready for another week or so.

[k4kyv]

Using thin aluminum strips, it should be easy enough to bend them to suit, Chuck. You could even use something like a finish nail of similar diameter as a form.

You would need something like phosphor bronze or a springy stiff alloy of copper. Aluminium is notoriously non-springy and subject to fatigue; I have heard it said that even in solid form, the metal still retains some characteristics of the molten state and tends to gradually flow away from pressure points.  That is why the stuff is such a disaster when used for internal house wiring; the metal flows away from clamped connectors, eventually resulting loose connections that form arcs and cause fires... also the reason why power line noise from "hot clamps" has become such a common nuisance, now that the electric power industry has turned away from copper power line conductors in order to "save money".

E F Johnson once made the familiar clips that slide onto edgewound coil stock. Using some sheet copper I had on hand that happened to be about the same thickness as what they used to make those commercial clips, I homebrewed a few exact copies of the EFJ clips about 30 years ago and they are still in use.  They work fine, even though the pure copper was never quite as springy as the nickel-plated alloy that EFJ used. Clips for round wire coil stock should be easy to make if one could find some sheet metal stock of the same alloy as used to commercially manufacture the clips. The nickel plating retards corrosion, but pure copper probably makes just as good electrical contact, particularly if lacquer or other substance is sprayed over the permanent connections to keep oxygen away once the spot is located on the coils for the taps.

Unfortunately, I no longer have any of that copper stock to make more clips.

[kg8lb]

 Todd, You are very close to any easy home brew clip. Copper or brass stock would work FB and a nice finishing touch with electroless nickel plate (easily done at home with any one of many kits)The closer you place the clamp screw to the tapped coil, the more secure the connection. Yes, you could use spring bronze but not really a must have as copper is readily work hardened as is brass.

[KM1H]

Hmmm, finally a use for those damn SB-220 shorting bars that I always remove and toss in a box.

[k4kyv]

Yes, you could use spring bronze but not really a must have as copper is readily work hardened as is brass.

Would you have any specific recommendation for "work-hardening" a piece of copper strip, while preserving its shape and leaving its surface smoothness intact? By definition, "work hardening" involves deforming the metal, something like banging the piece with a hammer until it is slightly flattened, or hammering a straight piece to form a bend. Stretching a piece of soft-drawn copper wire is another example that comes to mind and I have actually done that, but it would be very difficult to stretch a short piece of 1/2" copper strip. You want the part of the clip that contacts the wire or flat ribbon on the coil to be as smooth and flat as possible to assure maximum surface contact.

I have observed that heating a piece of copper until it is red-hot, and then letting it cool back to ambient temperature, leaves it very soft and pliable. Bending the softened and cooled piece a time or two immediately re-stiffens it, but I am not sure how the end result compares to its original state. I have never noticed any hardening effect from simply bending a piece of cold copper. If anything, it would seem to soften it, and bending more than just a few times would result in metal fatigue and it would break.

I am not sure what metal the commercially manufactured clips like the EF Johnson ones are made of, brass, bronze or copper, since I have never had enough lying around that I would be willing to damage one by filing, bending or cutting on it to test its characteristics.