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Re-fitting stripped plastic knobs

danalog
By danalog
in Hobby Electronics
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I am in the process of restoring a 60s Magnavox radio, on which the two plastic knobs on the clock dial have become detached. 

One of the shafts these screw onto is threaded. For fixing this one, I was thinking of filling the knob with a bit of epoxy and sticking it onto the shaft so that, as it dries, it molds to fit the screw threads. 

For the other, it is not threaded - looks like the shaft had a part that broke off inside the knob. For this one, I am not quite as sure what to do because the metal shaft it needs to attach back to is completely smooth. I could rub the metal down with sandpaper to rough the surface and then use the same epoxy strategy, I suppose?

These knobs do not simply flip a little electronic switch, they turn springloaded mechanical parts that require a considerable amount of force to move. 

 

Advice would be appreciated! 

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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Do you have any photos to aid your description? Also are you trying to restore in a way where the part(s) are still removable as originally designed or are you okay with a more "brute force" solution?

Dreaming of the day when my brain cell doesn't betray me.

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33 minutes ago, CasualExtremist said:

Do you have any photos to aid your description? Also are you trying to restore in a way where the part(s) are still removable as originally designed or are you okay with a more "brute force" solution?

They don't need to be removable, the knobs should be quite firmly secured. 

image.thumb.png.c1bb6aaaabd15d452883d3a525a1d11f.png

There are the described left and right shafts. 

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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If the diameter is right there are off the shelf knobs that squeeze a "fork" as you tighten from the end, might work...

 

image.thumb.jpeg.f73ef5d312b8b8c931f8c2ee5716fac6.jpeg

 

image.thumb.jpeg.7d8c17d30ee7e651058164156f5dee46.jpeg

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some form of universal glue (as long as the glue says it bonds to metal and the type of plastic you're dealing with, it should be good) will probably have enough strength to operate a knob as long as you make sure the metal is properly clean and just a but scuffed up. you want to sand the shaft length-wise so the score marks go along the length, not around, so they can provide additional friction.

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If the goal is to preserve the original knobs:

It would take a decent amount of precision, but my first thought is to drill a 1/16th inch hole in the shafts that also goes through the body of the knobs and then put a roll pin through that drilled hole. You might still add epoxy for added strength/rigidity, but that roll pin should help distribute the load into the aged plastic. (Do you have photo of the original knob?)

image.thumb.png.cc6f11a76c86b7432781f738a84ea376.png

Dreaming of the day when my brain cell doesn't betray me.

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