I'm too sleepy to do any math so I'll just say this:
No, that last crimp doesn't look too good and, personally, I wouldn't use it.
Did you get any MagnaLugs for #4? If so wait until they come and try one of them. The material is a good deal thicker, including the barrel, and they may fit your dies better.

 

I still can't figure out why my calculations don't work. However, I do like the empirical approach - let's measure some crimped connectors and see if we can determine the cross-sectional area each has. Then maybe we can figure out what size the die should be.

I can mill smaller die to fit a little larger terminal. So, if the 16mm die is too small for #4 I could mill them - if only I knew what size they should be. (And, I assume we have to squeeze things smaller and expect them to rebound a bit. Right?)

Tom - I missed your post. I got MagnaLugs for the wire sizes I need, and new wire to match, so my hope is that it'll all work. But, the stuff won't be in until next week, so I'm calculating and stewing until then.

 

Yeah, I saw that you'd ordered them.
It occurred to me that I can mic some of my magnalugs for you if you'd like. Maybe it will give you an idea of how close they will be. Off hand I can't remember if I have and 2/0, but definitely #4, #2, 1/0 and probably some others.

 

If you would measure them I'd appreciate it. The wall thickness of the barrel would be the major question, but the lug thickness would be interesting as well. Thanks in advance.

 

I don't have as many cable sizes as I thought. I guess I need to order some more. Anyway, this is what I have:
#4 x 5/16" stud PN 6404E -- barrel OD: 0.396 -- barrel ID: 0.264 -- tab thickness: 0.094
#1-2 x 3/8" stud PN 6401F -- barrel OD: 0.546 -- barrel ID: 0.371 -- tab thickness: 0.158
1/0 x 3/8" stud PN 6410F -- barrel OD: 0.631 -- barrel ID: 0.445 -- tab thickness: 0.178
That's measured with calipers and not a micrometer so the barrel ID and tab thickness might be slightly off.

Oddly, as you can see, for #1 and #2 cable they have only the one lug barrel size.

 

Tom, thanks a bunch! I have those #4's coming in, so can think about what die to use.

And, thinking of what die to use, wow - this gets deeeeeep. Some random thoughts that y'all may be able to correct if need be:

• Wire diameter:the AWG diameter is for the cross-sectional area of the COPPER, not including the air. So it is difficult, if not impossible, to accurately measure stranded wire to determine its gauge, and the more finely stranded it is the less accurate the measurement.
• Area inside lug: Lugs start out round, which has the maximum area of any shape. But, they are deformed into a roughly hexagonal shape by the die, which has less area. And, they are probably compressed such that they have even less area. All of this is supposed to displace the air and compress the copper of the wire and terminal into one solid mass.
• Thin-walled terminal: If the terminal is made of thin and/or soft copper it will have a tendency to bulge outward between the die, and that material will then get caught by the die and flattened into ears. This would be especially true if the wire wasn't large enough to support the terminal. But, perhaps the multi-crimp approach helps with this as the ears would get compressed back in when the terminal is turned in the die.

Lots to learn!

 

Oh, boy... here we go again....

I've been real busy and haven't been reading much of this site the past several days... but I got a PM today alluding to another 8-page microanalysis in the making.... yep, and here's where we begin methinks...

 

Do you read lips?

 

It's already WELL past eight pages at the default 15 posts per page!

Unbelievable that the U.S. can't get with the program the whole rest of the planet uses.

 

As in AWG vs mm2? It would be nice. This feels like placing a metric bolt in an SAE nut. Not sure if you can even buy metric wire and terminals here, or at least within reason.

 

5/16-18 & 8 x 1.25 are *really* close.
you can usually get a turn or two...

Yes, I'll be that metric wonk, and not ashamed one bit.

It would be nice if you can figure out why your lugs are too big.

 

That's the plan, Stan.

 

Wow, bottom of page 2, we're slacking here.

I tried finding specs on crimps and it seems the only one is the pull test.



For making new dies, I figured I'd just take the smallest dies and machine them close to what I think would work, test, and machine more if necessary. Don't really need the smaller ones as I have a good ratcheting crimper for those already.

 

Yeah, I can't find any specs anywhere on the finished crimp size. Nor do I have any crimped cables to measure. Have considered stopping by NAPA and see if they would let me measure their die.

I don't have the MagnaLugs in yet, but did get the other lugs in that I ordered as well as the 2/0 and #4 wire. Plus I got the battery isolator/relay and one of the two new battery hold-downs. Perhaps by the end of the week I'll have all of the parts so I can get started on the boat - and crimping the cables.

 

Damn, that looks familiar, I don't even want to say how many of those I performed at NNS.