Reading all this, I can't help wondering if some people are thinking of a different type of ratchet tool altogether. Most are talking about the basic crimping tool for small insulated crimps - as it wold be correct to say that the force required would be almost identical were the ratchet mechanism removed, it's only there to stop you releasing on a partly made joint.
I've admitted that my OP might not have been totally clear, but I did mention 'budget' tools (per the portrait repeatedly posted by BAS) in the first sentence, and that vis what the remainder of my post also referred to. I also think (but cannot be certain) that everyone else who has contributed has probably been talking about the same things. As you say, the ratchet does not affect the relationship between the force applied by the operator and the force exterted on the crimp Ithe 'mechanical advantage', MA). In fact,
no simple ratchet can do that.
But I think there are tools (for bigger crimps) where the ratchet action actually closes the jaws in steps. There's a lot more mechanical advantage - but you can't close the jaws with one movement of the handles. So you squeeze-release-squeeze-release-... each time closing the jaws a bit more and then backing out the handles to get another bite on the ratchet.
Indeed, and I've refered to those more serious bits of kit. As you say, the point is that the greater mechanical advantage (well, it's what we used to call 'velocity ratio', the reciprocal of MA, that really matters here) is such that the jaws do not close completely with one complete squeeze - so one
has to have more than one squeeze, which means one ideally has to have a ratchet (to avoid release of pressure between squeezes. The amount of effort required to use these is less, due to the MA resulting from length of handles and pivot arrangement - the presence of a ratchet is a
consequence of, not a cause of, that high MA.
The budget ratchet crimps are a cross between the two - the jaws
can be closed completely just with one squeeze, so they don't 'need' a ratchet for the same reason as the high-MA/VR tools - but they do have one.
The feature everyone is going on about is the 'release latch', which operates when the amount of force reaches a pre-set level, which obviously makes for consisitent crimping. Such a mechanism does not actually require a ratchet (could just be done with a pressure operated 'clutch' or cam, as in a torque screwdriver), but having a release mechanism on a ratchet is one way of doing it. As I've said, the problem is that this feature does not work on mine (or other similar ones I've used) - which is why I didn't think it was meant to happen with these cheapo ones!
Also, the difference between the cheap flat pliers and the 'proper' tools isn't just the width of the jaws, nor the mechanical advantage. The cheap pliers don't actually make the crimp properly as they have no side support. When making the proper crimp, the crimp is supported on it's sides so that as you crimp, it can't just flatten. The cheap tool just flattens the crimp and you get minimal contact pressure as the wire spreads sideways as well.
I thinnk that you must be looking at something slightly different. With the TLC-like ones, the only difference really is the width of the die - although 5-10 times 'wider' than the flat pliers type), the die is flat across its width (i.e. the gap between die faces is the same all the way across). It obvioulsy 'affects' a greter length of the crimp, but it does not 'support' some bits of it and 'crimp' other bits - it crimps equally across its whole width.
Kind Regards, John
Even if I squeeze very 'gradually', it clicks over the teeth of the ratchet as I go, but never releases (no matter how hard I eventually squeeze), even if I adjust it to it's most feeble setting - I have to release the latch by taking a tool to the manual release lever (between the handles).
