Ratchet Crimpers

[JohnW2]

Having recently seen yet another posting of a picture of BAS's favourite TLC budget ratchet crimper (even though he could link to the wiki!), I'm moved to ask something I've been meaning to ask for ages ...

I guess I must be missing something, because I really can't understand what the ratchet action, per se, is meant to achieve - it provides no 'mechanical advantage' (i.e. the crimping is all down to human force) and I don't really see what it achieves that I could not equally achieve without the ratchet, particular with red and blue crimps.

I do agree that this sort of crimper is preferable to the 'cheap and nasty' ones (which are usually also pictured in the posts) - but because they have much wider crimping dies (usually about 10mm, as compared with just 1-2mm 'jaws'), not because of the ratchet.

What am I missing?

Kind Regards, John

 

[dhutch]

What am I missing?

It surely does act as an advantage? You can crimp it all the way down in one go, you have to release and reapply, thus have moved the handle further, more travel, same input force, greater output energy and hence force?

They also obviously then release when the join has been made to a certain size, rather than it being upto the user to gauge when its tight enough.

Daniel

 

[Chri5]

The ratchet is just that, it provides a constant similar force to all crimps. You can't under or over crimp, all you can do is have the same force applied each and every time.

Thus it is perfect for the job intended and offers a huge advantage over non ratchet crimps which depending on the user wrist strength will vary from person to person.

Sorry to say, but you are talking nonsense

 

[Johnmelad]

Sorry to say, but you are talking nonsense

He made a comparison and asked for views. Why do you think that you can reply that he is talking nonsense?

 

[JohnW2]

What am I missing?

It surely does act as an advantage? You can crimp it all the way down in one go, you have to release and reapply,

I presume you meant to write "You cannot crimp it all the way down in one go". If so, that's my very point - I can do that, certainly with red and blue ones, and usually also yellow, and I'm no strongman!

...thus have moved the handle further, more travel, same input force, greater output energy and hence force?

Even if one did do it in 'multiple goes', what you say would surely not be true, unless you know some different laws of physics from those I was brought up with. With a simple ratchet mechanism, the total amount of 'movement x resistance (of squashing crimp)', aka 'work' has got to be the same, whether one does it in one go or several?

Kind Regards, John

 

[Chri5]

Sorry to say, but you are talking nonsense

He made a comparison and asked for views. Why do you think that you can reply that he is talking nonsense?

Because he mentiuoned

I guess I must be missing something, because I really can't understand what the ratchet action, per se, is meant to achieve - it provides no 'mechanical advantage' (i.e. the crimping is all down to human force)

As you both know the crimps of the rachet type only unlock at a set point. When the rachet has provided a fixed compression on the crimp. It is a fixed mechanical action, it is not down to 'just' human force.

Yes a force is required, but it doesnt vary. All it means is that a big strong lad will find it easier to do than a 10 y.o. girl, but both have to apply the same force to work the rachet crimps.

Thus my Dear Watson, John has not thought his post through and as such is talking nonsense.

They are designed to apply the same force before allowing the crimps to open, that force does not vary depending on how will your biceps are developed

 

[JohnW2]

The ratchet is just that, it provides a constant similar force to all crimps. You can't under or over crimp, all you can do is have the same force applied each and every time.

You seem to not be talking about ratchet functionality, per se, but rather about force control/limitation (as in torque wrenches and torque screwdrivers etc.). Maybe all the ones I've encountered have been faulty, then - since they do not achieve what you describe.

Sorry to say, but you are talking nonsense

In terms of the ones I currently have, and others I've used in the past, it certainly is not nonsense - it's the truth. However, as above, maybe I've never used one which works as intended.

Kind Regards, John

 

[davelx]

Isn't the point of the ratchet to control the amount that the crimp is compressed? The ratchet ensures that the correct amount of compression is applied every time, since it doesn't allow you to compress too far and it doesn't release until you have compressed enough.

The force needed to achieve that compress may surely vary, for example, between crimping stranded or solid core cable.

 

[ericmark]

I have also a pair of crimp pliers looking like mole grips and the point is not the ratchet but the way that they can't be released until they have been forced fully home.

In all the jobs I have had only one GEC Large Steam Turbines had the crimp pliers regularly calibrated. And without being calibrated one can still end up with terminals being slack. There were four sizes Orange, Red, Blue, Yellow for 1mm, 1.5mm, 2.5mm and 4 - 6mm and I can't see how the same crimp pliers can crimp both 4 and 6mm with the same force. And only ever seen the 1mm version when working for GEC.

Some sort of torque setting would seem better then the over centre used at the moment but again I have used shrink types which you heat up after crimping not sure if they need same force.

So suppose we should always use same make of crimp and crimp pliers but can't see that happening. My 10mm - 120mm crimp pliers only have a screw to adjust so one just goes by feel anyway. There is a mark but crimping 120mm would never get it in one anyway.

 

[dhutch]

I presume you meant to write "You cannot crimp it all the way down in one go". If so, that's my very point - I can do that, certainly with red and blue ones, and usually also yellow, and I'm no strongman!

My apologies, cannot, indeed.

Ive always found the first squeeze brings the jaws down onto the crimp, second one squeezes it off, using the whole travel twice. Where as in a normal 'cheap set' you only use about half or 2/3 of the movement you can generate to do the whole job.

Daniel

 

[JohnW2]

Because he mentiuoned

I guess I must be missing something, because I really can't understand what the ratchet action, per se, is meant to achieve - it provides no 'mechanical advantage' (i.e. the crimping is all down to human force)

As you both know the crimps of the rachet type only unlock at a set point. When the rachet has provided a fixed compression on the crimp. It is a fixed mechanical action, it is not down to 'just' human force.

You appear not to understand what 'mechanical advantage' (MA) means. Although the 'lever' action will provide some fixed MA (as with any pivoted tool, like pliers, scissors or even cheapo crimpers etc.), there is no way that the rachet mechanism can (i.e. it cannot result in a certain amount of human force resulting in greater force being applied to the crimp than would be the case with the same tool without the ratchet). What you are describing is force limitation - something which, as I've said, mine (and others I've used) do not appear to provide.

Thus my Dear Watson, John has not thought his post through and as such is talking nonsense. They are designed to apply the same force before allowing the crimps to open, that force does not vary depending on how will your biceps are developed

Maybe they are designed to do that, but mine don't. It therefore seems to be the case that I've been misled by malfunctioning tools - in respect to which I'm certainly not talking nonsense. ... so maybe I've just been extremely unlucky with the specimens of tools that I've come across.

Kind Regards, John

 

[JohnW2]

OK. Judging by all your replies, it sounds as if, quite amazingly, I've only ever expertienced duff 'budget ratchet crimpers' - although I agree that very expensive (and certainly larger) ones do function as you're all describing. I should perhaps have been clearer in my comments and questions only related to the 'budget' ones (which are what is always being advocated here), not to 'serious' bits of kit.

I've ordered another pair of 'TLC's best', and will report back!

Kind Regards, John

 

[ericmark]

Mine have a plate which can be adjusted which is on a cam so everything is there to be calibrated. However although in GEC they were calibrated not a clue how it was done.

With my experience of getting a PAT tester calibrated only to find out 6 months down the line it was of an old design and could never have been set to the standards now required I regard sending items away for calibration as a complete waste of money.

I suppose we should ask to see a copy of the calibration certificate for the calibration equipment but where would it stop?

 

[JohnW2]

Mine have a plate which can be adjusted which is on a cam so everything is there to be calibrated.

Even the humble TLC ones have an adjustment facility, but I don't get the functionality which has been described here at either end of the range of adjustment, nor anywhere in between! It seems that they are probably just 'duff'!

Kind Regards, John.

 

[Click4]

Im surprised that nobody has mentioned that the way the jaws work on the ratchet crimpers means its possible to exert a higher force on the jaws when criming than a non ratchet crimper.

It pivots in 2 places.

if you want to undo a tight bolt, or nut.. you use a pry bar, to get a higher amount of leverage, for the same amount of force applied.

on ratchet crimpers, due to it pivoting in 2 places, it levers twice... so you get double the amount of force exerted for the same amount of force applied.

another example of how that works, is rope and pulleys, they wrap the rope around multiple pulleys so the amount of force required to pull on the rope is halved each time it loops around a pulley.

being careful not to crimp ones fingers lol... its possible to see this in action, by trying to hold the jaws open with 1 hand, and moving the handles together with the other hand... it takes far more effort to hold the jaws open than it does to pull the handle.