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drilling out ring terminals

Stockmanreef

Well Known Member
Is it OK to enlarge the holes in ring terminals? The cable supplied with the kit for the alternator is not the correct size ring terminal. The internal hole had to be enlarged to 1/4" from 7/32" (I think). The ring terminal is 15/32 wide, so the ring portion is still thick. I do see exposed Copper now that it the hole has been enlarged.

This is the second terminal I had to replace or drill. I wonder why Van's even bothers putting the terminals on in the first place.

Thanks
 
A drawback of ?kits?.

Drilling out a connector is really only applicable to the big battery connectors that come undersized - for just this reason. The difference is they have plenty of meat left over after being drilled out. A standard connector will, in most cases become mechanically fragile. This is a special concern for the high fatigue problems with alternator connectors.

Get a nice plastic parts box from Harbor Freight and buy an assortment of quality ring and Faston connectors - everything you will need for your plane and perhaps some to have when another builder runs short. You will find that box will become one of your valued possessions for maintenance and the inevitable panel changes.

Carl
 
So the ring terminal after drilling is 7/32" and before, I think that it was 1/8". Is taking that little amount out that big of a deal?

My concern is that my crimp on such a large wire (not sure the size), would not be as good as the original. So I would likely have it fall off rather than break from fatigue. But of course I am just guessing. I have not crimped a wire that large. Not even sure I have the correct tool to crimp it.

I also need to determine the gauge of the wire before I get anything. I will probably get from Stein Air or Van's if/when I change it out.

Rocketman--are the connectors from that place aviation quality?
 
The large diameter wire needs a special crimper to make good connections. I bought a 10 ton hydraulic crimper on Amazon for under $40 and it worked great. There were several places I needed it during the build either to change connectors or shorten wires and re crimp terminals on them.
 
question

"...are the connectors from that place aviation quality?..."

I am not sure what you are asking. They are comparable to the AMP connectors that I have used...I have been happy with them and they do have nylon insulation...

For the larger cables, I used AMP lugs and a hydraulic crimper...
 
The main power terminal on a lot of alternators is metric. That may be why you are having to work the terminal. Enlarging the hole is not advised however.
 
OK--so I pulled the wire off completely. The end I had on the shunt will fit on the alternator, but the other end will not fit on the shunt. So the small end is still too small for the shunt even though I drilled it out.

The shunt is 1/4"
the alternator is 6 mm.

Now I am completely confused about drilling and not drilling. Both ring terminals are exactly the same size (8) except for the hole in the middle. I am confused as to why I can't drill out the smaller hole to the correct size, if the hole I drill out is still smaller then then ring connector on the other end. Does drilling somehow compromise the terminal?

The one I drilled will just fit over the 6mm post, but not the 1/4" one.
 
Digikey has every ring terminal you could want, in every wire size too. They will ship for First Class Mail making it cheap to get just a couple things. I went through this when I did my firewall forward adding in the shunt and fuse along with a backup alternator; but it was worth it to have the right sizes.

I also have a local hardware store with most sizes of things, but the quality of the parts was far inferior to what I got at Digikey.
 
Now I am completely confused about drilling and not drilling. Both ring terminals are exactly the same size (8) except for the hole in the middle. I am confused as to why I can't drill out the smaller hole to the correct size, if the hole I drill out is still smaller then then ring connector on the other end. Does drilling somehow compromise the terminal?

Nope, I would have no problem doing this. Obviously if you drill a ring out too much you would compromise it mechanically. What you propose sounds fine to me.
 
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