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Crimpers for automotive

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nctnico:

--- Quote from: tooki on March 14, 2024, 08:04:23 am ---
--- Quote from: nctnico on March 08, 2024, 07:27:59 pm ---So no, I'm not mixing anything up. Just take a ratcheting crimper and notice how the amount of travel of the jaws is reduced for each 'click' the jaws close further but the travel distance for the handle stays more or less constant. There is also a typical difference between the cheap Chinese crimpers and the professional ones. The professional ones typically have a much more sturdy construction (more steel plates in parallel or thick solid steel) compared to the cheap crimpers.

--- End quote ---
You’re still confounding things.

Yes, nearly all ratcheting crimp tools use more complex mechanisms to give a large mechanical advantage. But a crimp tool with complex mechanisms for large mechanical advantage can be made without a ratchet. There are crimp tools like that.

--- End quote ---
I just wanted to simplify things. I know non-ratcheting crimp tools with progressively increasing force on the dies exist but I didn't want to add another facet to an already complicated topic. Add too many details at once and people get lost.

Berni:
Yeah the point is not the racheting, more that the racheting ones tend to all have a mechanism inside that increases the mechanical advantage towards the end of travel to really squeeze that crimp down hard. Giving a better crimp and requiring less strain from the user.

The actual ratcheting part just removes the users hand feeling from the equation, making sure you put enough ooomph into it before it lets you complete it. Not really a problem if you know what you are doing and know to squeeze the living shit out of a regular non ratcheting tool when doing the thicker gauge wires. But a lot of the non ratcheting tools also don't have the special mechanism to increase mechanical advantage at the end, so for those you have to know to know to squeeze really really hard (and your hands might not appreciate it if you need to do 100 crimps).

As for wires sliding out of a crimp made with a racthering crimper. Usually it means you selected the wrong die size for the crimp pin, or used the wrong wire size for the pin. This is why (if possible) i tend to pull test a new unfamiliar combination of die+pin+wire to destruction first, then do the actual crimp.

shabaz:
Agree with the comments from everyone above.
A while back I tried a Molex ratchet versus a generic ratchet tool. The Molex tool cost five times as much, but both appeared to produce strong crimps. The pull test amusingly showed a fivefold difference however.

Overly built down to a cost or bad ratchet tools, or ones with no indication of what crimp or wire size to use, and ratchet tools that might be used for different crimps they were not intended for, could be problematic. (Of course, the 'ratchet' is just a description and doesn't mean there are no other ways to achieve the force, e.g. 2-foot long crimpers, or hydraulic versions). 

A good brand name is one way to attempt to reduce the chances of buying a bad tool, but there might be cost-effective gems out there (especially for general prototyping use where you just want an electrical connection that won't be subjected to environmental conditions). Reviews/advice can help narrow down the choice, too, but a pull test will provide decent peace of mind.

Siwastaja:

--- Quote from: nctnico on March 14, 2024, 10:44:33 am ---I didn't want to add another facet to an already complicated topic. Add too many details at once and people get lost.

--- End quote ---

The best way to make people confused and cause unnecessary hassle is to call X Y because there is an assumed correlation between X and Y, which you think is the case, but leave the fact you made such statistical assumption completely undisclosed, and simply instead call X Y.

The best way to avoid confusion is to keep clear, concise, and truthful, and use correct terminology. This way, leaving out details does not hurt, because one can always look for more detailed information, as the fundamentals are correct.

We have seen similar problems when people come up with made-up rules of thumbs in component specifications they think are true, but are not: for example, saying that increasing voltage rating of an MLCC cap increases usable capacitance under a fixed DC bias, while in reality this correlation is very weak, and better correlation would be had to (nominal capacitance / package size) i.e. volumetric energy density, than voltage rating. Even better is to keep short and truthful, and just say: look at the actual datasheet. This can't go wrong, and having "what if there is no data?" as the next step in discussion has the benefit that everyone will then know, from the context, that we are just speculating; better than going straight into speculation without saying so.

shabaz:

I don't think it's as much of a problem here as you say. For what it's worth, to me, the comments so far were all clear. There's no trouble at all if someone asks for deeper advice or clarification, because others may be better at explaining particular detail (I for sure would not be able to explain the subtleties about change in force as the crimper is pushed further in, but I can certainly comment on the practical result from pull tests, and about any specific tools I have used that might be useful for the OP to rule in or rule out).

Most people in life are happy to clarify (if they can) when asked for advice. I think it's a normal life-lesson that you might not get a complete picture from just one paragraph or two. To work around that, sometimes I will seek the opinions of several people and then factor that into my decision. Regardless, it's still possible to end up with an unsuitable product/wrong capacitance/bad bargain.

You can try to change people to make them answer in correct terminology, might be an uphill struggle, or you can choose to accept that honest advice might have some qualification that's missing.

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