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small cord pass through grommet for cast iron

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
I would like to run a small lampcord through the cast iron base of my mill to power a goldenrod type heater in winter to prevent condensation. I just want a small hole not a 1/2NPT size hole. All the grommets and strain reliefs I can find are designed for sheetmetal not 1/8" thick cast iron. I think I need a better search term.
I would prefer to do it right and not just use a short piece of rubber hose and some caulk. I have used spark plug silicone boots for similar.
Bill D
 
I would use one of these McMaster-Carr

If a plastic version of what I linked above is acceptable, I have 1/4"npt and 3/8"npt versions, send me an address and I will send you 1 of each.

The 3/8 version is long enough to go thru casting and use the plastic nut, the 1/4 version would probably require tapping the cast iron. The 3/8 version also accepts a larger cord, your cord size may be determining factor on which size you use.
 
If you are actually referring to the flat, two conductor 'lamp cord', I would think twice about using that anywhere other than inside the house, on the light next to your easy chair. A 3 conductor cord would be much safer and more durable...IMHO.

Stuart
 
If you are actually referring to the flat, two conductor 'lamp cord', I would think twice about using that anywhere other than inside the house, on the light next to your easy chair. A 3 conductor cord would be much safer and more durable...IMHO.

Oil resistance is likely necessary. Cable type SJEOW is traditional.

For a goldenrod heater, which range from 8 to 25 watts, 3-conductor 18 AWG suffices. 7082K21

McMaster-Carr
 
Thanks you Dalmatian girl. I received the cord pass thoroughs you mailed to me. They look exactly like what I was looking for. Smaller versions of the ones for romex cable. I think it is great how people here help each other ,even beyond online. Now I have to figure out if the threads are NPT or bolt since I have a feeling the casting is too thick to use the nut and just drill a clearance hole.
Bill D

PS: In the latest 101 Dalmatians movie Cruella drives a stock 1985 Panther De Vil.
 

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I like this one. The other two above it are Mickey Mouse.

I have used those aluminum squeeze-rubber-with-threads a few times and they do work. But they are made of very thin aluminum. Up on the ceiling or wall, absolutely. But not down by the floor.

They also make the same product out of zinc-plated steel: McMaster-Carr

Much stronger.

metalmagpie
 
Heyco makes them for up to 3/8" thick panels.

Heyco(R) Thick Panel Rubber Grommets

I suspect they sell them in large quantities only, but if you do a web search by P/N you may find vendors such as on ebay who repackage them into smaller quantities. Another trick is to take a couple of standard grommets and shave/sand the second flange off and glue one inside and one outside. The cord won't chafe.
 








 
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