Hey, red.green... H-4 mag coil

Bob

Well-known Member
A while back we participated in discussion about H-4 coils and the core that passes through them.

I wrote "It's made of laminated steel plates riveted together and ground to a round shape."

"If you get rough with it trying to press it out of the old coil, you will deform the riveted together laminated pieces and render the core useless. You do NOT want to know how I know this!"

You chimed in and wrote "H4 coil core is not laminated."

Well, last night I found the core that I had messed up a few years ago, saved in a box of H-4 mags, parts and pieces. Here's it is... still say it's NOT laminated? (I squashed it a little more in the vice to make the laminations more evident.)



<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/IH/H4a_zps24e5cb12.jpg">

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/IH/H4b_zps909aaeae.jpg">

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/IH/H4d_zpsa8cada17.jpg">

After it's been squashed, the rivets are sure evident!

I can't say ALL of the H-4 coil cores were made like this, but is seems reasonable to guess that they were.
Previous thread
 
I’ve taken a lot of them apart and never ran across one, but I suppose anything is possible. Since the screw threads into the end if the laminations I would expect it not hold well, just like driving a nail in the edge of plywood. Maybe it was a flaw that was recognized early on; even the F4’s have a solid bar. I honestly just don’t know…
 
I have never seen a laminated core in a H4 but I will have to admit I never cut one apart. They look pretty solid to me.
 
I have a junked H4 out at the farm and I will see what is in that one. A hack saw will tell the story.
 
That's interesting -- the two I have had apart and changed the coils in have had solid cores. The book tells you to not deface the ends in any way so as to get as tight a fit as possible in the core for maximum magnetic transfer. I would think it would be more difficult to keep a laminated core aligned and flat on the ends.
 
Started thinking about this after talking to my neighbor, maybe the laminated core came in replacement coils at some point. What kind of covering is on the coil, is it cloth wrapped or plastic coated? It’s just a guess, as I stated earlier over the last ten years or so I have had numerous H4’s apart and don’t recall seeing laminated cores.


In another conversation some time back someone asked about steel vs. aluminum SAE flanges on the H4’s. I never saw any rhyme or reason for those parts either. I haven’t notices it to be based on serial numbers, year of production or the like. I always assumed that maybe it had to do with the war and the availability of materials. Maybe this is the same reasoning, I just don’t know…
 
Old coil was fish-paper/tar covered... that's why I got rough with it... the core was stuck in the coil.
 
these coil cores are all laminate, i rebuild these mags. all the time for people , have also destroyed some of those core pins getting them out , any way i thought i could make some after i ran out of original ones so i did out of solid rod , put one in a new coil installed in a freshly rebuilt mag. put on test stand spark started out ok but weak (in my thoughts) but after 5 min. of running it lost all spark , played with it for a good while would get weak spark but nothing id sell to the public , took coil out installed a laminate pin and fixed it right up spark would knock you down to your knees ,i have researched this matter alot so as to understand why a solid pin dont work, havent found a good answer yet but it dont, maybe my exsperiments will save someone els alot of time
 
i forgot to add some of these pins are hard to tell there laminate , but they are , F-4 mag. uses the same coil and pin as H-4 mag
 
(quoted from post at 20:49:19 06/14/13)took coil out installed a laminate pin and fixed it right up spark would knock you down to your knees ,i have researched this matter alot so as to understand why a solid pin dont work, havent found a good answer yet
When the points open and the field around the coil collapses, it causes a current flow within the core (just like it does in the output wire). Laminating the core isolates each layer from the next, preventing the induced current. This is the same reason the armatures of starters and generators are laminated.
 

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