Crimpers for automotive

[mendip_discovery]

For those that like the reassuringly expensive tools I think the 3M TR-490 might fit the bill for automotive use.

My shed just has a set of cheap red/blue/yellow, a un-insulated set and recently I bought a cheap hydraulic set for battery terminals. I do have it on my list to buy a set for doing old british bullet and modern Japanese bullet connectors.

[Siwastaja]

A pull test will confirm the huge difference between a non-ratchet crimp result, and one done with a ratcheting crimper.
...
For automotive, I'd be really unhappy to know if the engineer used a non-ratchet crimper.

So hydraulic crimper is not OK? Pretty interesting viewpoint, given these non-ratcheting tools are how pretty much all mission critical large crimps are being made.

Can you explain how the crimp knows if the mechanism had a ratchet or not, given that the crimping pressure and die shape are exactly the same, and pressure is applied in monotonically increasing curve? This is what hydraulic crimpers, lacking your beloved ratchet, do, and what we also emulate when we use hand tools without ratchets, which obviously are larger and need more care to use correctly. So can you explain where exactly does the difference come from?

[shabaz]

If you have tools capable of interfacing with a hydraulic system and designed to crimp with the required pressure, I don't see anyone suggesting you shouldn't use it?

My comment was in response to the person who suggested the PAD tool (which is not a hydraulic tool).

Not sure where you're going with "beloved ratchet". Can you keep the question technical without emotion, and I'll do my best (if I can) to answer it politely?

[shabaz]

For what it's worth, I can't completely recommend Knipex MultiCrimp but it's not bad.

The crimping dies are automatically attached/removed by pushing the crimper into the holder.
The tool has worked reliably, I have no complaint there, and it's comfortable to use, but a disadvantage is that there are only about half a dozen different crimping die choices.

The second photo shows how the hot-swapping works. The jaws are held aligned using a flip-out lever, and then the jaws are docked into the holder and a round metal button on the holder is pushed back to release the dies from the holder.

[nctnico]

A pull test will confirm the huge difference between a non-ratchet crimp result, and one done with a ratcheting crimper.
...
For automotive, I'd be really unhappy to know if the engineer used a non-ratchet crimper.

So hydraulic crimper is not OK? Pretty interesting viewpoint, given these non-ratcheting tools are how pretty much all mission critical large crimps are being made.

Can you explain how the crimp knows if the mechanism had a ratchet or not, given that the crimping pressure and die shape are exactly the same, and pressure is applied in monotonically increasing curve? This is what hydraulic crimpers, lacking your beloved ratchet, do, and what we also emulate when we use hand tools without ratchets, which obviously are larger and need more care to use correctly. So can you explain where exactly does the difference come from?

You missed the point where ratched crimpers have eccentric pivot mechanisms so you can build up the required pressure manually without needing a pump action tool (like a hydraulic crimper) to amplify the force from you hands. Just take a good look at a professional ratched crimper and you'll see that for each 'click' the jaws close less while the (angular) movement of the handles for each 'click' stays the same.

If you picture an eccentric (for example a piston + rod on the crankshaft in an engine) and rotate it starting from 90 degrees towards 0 (top dead center), you'll see that the amount of movement per degrees of rotation decreases when approacing 0 degrees. If you apply a constant torque + speed = constant power to the excenter, the closer you get to 0 degrees, the more force you can excert. This is because power = force * travelled distance. As the power (which can not be lost) is constant, the travelled distance becomes less the so the amount of force must go up. Tools like the engineer pliers don't have this feature and thus can't produce enough force on the crimp to create a cold weld.

[Siwastaja]

You missed the point where ratched crimpers have eccentric pivot mechanisms so you can build up the required pressure manually without needing a pump action tool (like a hydraulic crimper) to amplify the force from you hands. Just take a good look at a professional ratched crimper and you'll see that for each 'click' the jaws close less while the (angular) movement of the handles for each 'click' stays the same.

What makes you think I missed this? This is exactly why I mentioned that non-ratchet tools are significantly larger and more inconvenient to carry around and use: the handle length has to be dimensioned for the peak pressure, and then the total movement range must be larger because unlike the ratcheting version you described, die movement is linear to handle movement, so for anything larger you need two hands. But inconvenience and not working at all are two separate things.

From photos alone, I can't say if Engineer tools are good or not. But they are primarily for very small crimps so I have no reason to doubt their usefulness. We already saw that your calculation of 100kg of force was off by a factor of approximately ten. Sure, even with 10kg they are not convenient, but this amount of force is not impossible to produce, and if you mostly use them for smaller connectors than what you used for this calculation, I don't see a problem.

[Berni]

Non ratcheting crimpers are fine on some kinds of connectors.

IWISS brand tools from AliExpress are a very good deal for what you get for the price:
https://www.aliexpress.com/item/1005002766345160.html

The ratio between the crimp tool and handle is large enough to produce plenty of force to properly crimp the smaller wire gauge crimp pins. These simpler tools are cheap and since you crimp wire and insulation separately they are very flexible in what they can crimp. So 2 different sizes of these will crimp just about anything, from tiny 1mm JST to big automotive connectors. For the larger gauge wires >1mm2 the force requires starts getting pretty high so for those you really want to squeeze down as hard as you can both hands to make sure it is a good crimp. You can pick up 2 crimpers for 50 bucks easy and you are set. Only get fancier ones if you do a lot of crimping.

And yes i do pull test the connectors by grabbing it with pliers and pulling hard (before even crimping insulation), it takes an unreasonable amount of force to separate them, at what point the wire itself breaks or the connector pin rips apart. For large gauge wires, i don't have enough physical strength to reach the failure point by just pulling it with my arms.

So my advice is <1mm2, use regular pliers like crimpers. For wires <8mm2 you want to use racheting crimpers to avoid having to whale on the handle like a gorilla. For things bigger than 8mm2 use hydraulic crimpers. The big long handle mechanical crimpers for large gauge wires are crap (they don't make good crimps and it is a workout using them with how much force is needed)

If you need hydraulic crimpers for some big wires the chinese can get you one for like 100 bucks, i have a set and it handles 75mm2 wire just fine.

[tooki]

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.

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.

Ratcheting does one thing, and one thing alone: it ensures you don’t release before a full cycle has been completed. No more. No less.

If, as is the case in many cheap Chinese crimpers, a full cycle doesn’t produce the right force or the correct dimensions, the crimp will still fail.

[tooki]

A pull test will confirm the huge difference between a non-ratchet crimp result, and one done with a ratcheting crimper.
You can do that test using a tool that looks like a luggage weighing hanging device, but one that stores the value. After seeing the difference, you won't ever want to go back to non-ratchet (apart from non-critical use like prototypes for lab use).
For automotive, I'd be really unhappy to know if the engineer used a non-ratchet crimper.

While nearly all good crimp tools have a ratchet, so do many cheap ones whose crimps fail. The ratchet only ensures a full cycle has been completed. The rest of the tool design is what actually determines the quality of the crimp. (If you were to take a good tool and remove the ratchet, it would continue to make good crimps, as long as the user always squeezes all the way.)

[tooki]

As for whether a crimp creates a cold weld, or is simply gastight: I think it depends on the type of crimp.

Indent crimping (as used in military and aviation/aerospace connectors, among other things) are definitely supposed to produce a cold weld.

On the other hand, insulated terminal crimps (the ones where you crimp the plastic collar), I don’t think those ever produce a cold weld. Gastight if you’re lucky. (Actually luck has nothing to do with it: like all crimps, success hinges on using the correct match of terminal, wire, and tool.)

[nctnico]

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.

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.

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]

I didn't want to add another facet to an already complicated topic. Add too many details at once and people get lost.

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.

[tooki]

Writing for the target audience is a good thing, but it’s important to not oversimplify. A lot of people think that simplifying to the point of being wrong is okay, but it’s really not, and it’s really not necessary!! Skillful wording lets you formulate a statement that is both easy to understand and correct.

[shabaz]

That makes sense to me, and, as you point out, there's also a lot to be said for wanting to simplify to a level suitable for the target audience without deliberately introducing errors.

Unfortunately in practice, at one extreme, some people might struggle to put together a single sentence, and it might still be full of errors (such as mhz instead of MHz). I don't think anyone minds correcting things, it's no trouble for people (themselves or others) to hit the reply button and correct wrong assumptions or to add more details in areas they think they can assist in. That's how lots of information is discovered; people might not realize they are working on an assumption, and it takes others to point it out, and readers benefit from the discussion.

I should add, what's wrong is to deliberately reprimand or ridicule people for an honestly held opinion. In any case, Siwastaja didn't eat his own dogfood by keeping things concise. Instead, he resorted to untechnical, emotional terms like "beloved ratchet". On the other hand, maybe English isn't his first language, and he didn't realize how typical native English readers can interpret that. It cannot be expected for people to be language/grammar experts before they contribute to a forum conversation; people get things wrong.

Perhaps a slightly more ideal response to the OP would have been that the PAD tools are unlikely to be suitable for automotive use, and that attention should be directed to tools that can apply sufficient force, and they are typically likely to be (but not exclusively) ratchet-based tools, and [optional] here's the reason why....<xyz>". The xyz has been brought out in the longer discussion, by those who were able to better describe it.