Tention wrenches - which dimension is the most important?

[LeeNo]

In deciding which tention wrench to use for a given lock, which property is considered paramount?

Depth, width or height?

Let me explain what I am talking about as I don't know the proper terms (assuming their are lingo terms for what I am talking about).

The "depth" is what I am calling how far into the keyway the tension wrench extends.

The "width" is what I am calling how fat the wrench is. Obviously a wrench with too much width won't even fit in the keyway.

The "height" is what I am calling how much vertical space within the keyway the wrench occupies.

So, which of these measurements is the most important?

Also, I have watched many lockpick vids on YouTube and am not sure I understand how the tension wrench should be used.

Should it be used like a key (twisting/torque)? If so, this means that a wrench with a width smaller than the keyway would be creating an angular pressure point on both high on the key ward opposite of the direction of tension and low on the key ward on the direction of tension.

Or should it be used on an arc perpendicular to the keyway (frontal pressure)? If so, no angular pressure points would exist and a direct pressure point would be created that is evenly distributed within the keyway on the side being tensioned.

[MacGyver101]

In deciding which tention wrench to use for a given lock, which property is considered paramount?

The thickness ('width') of the tension wrench is the most important dimension (in my own experience, anyhow).

When setting security pins, in particular, you need to be able to both apply tension and release tension in a controlled manner -- and a properly-fitting tension wrench is essential to this. If the wrench is too thin (relative to the width of the keyway) it becomes more difficult to reduce your tension and allow for a slight "backwards" rotation of the cylinder. With a wrench that is too thick, you're much more limited in how you can insert it. (And I'll leave the obvious joke hanging for someone else to swing at...)

Should [a tension wrench] be used like a key (twisting/torque)?

Yes. It's a poorly-named tool: "torque wrench" would probably be much more descriptive.

[LeeNo]

If the wrench is too thin (relative to the width of the keyway) it becomes more difficult to reduce your tension and allow for a slight "backwards" rotation of the cylinder.

Does this mean, then, that your tension wrench should be as wide as possible while still allowing for a minimally frictive insertion?

With a wrench that is too thick, you're much more limited in how you can insert it. (And I'll leave the obvious joke hanging for someone else to swing at...)

D'OH!

Should [a tension wrench] be used like a key (twisting/torque)?

Yes. It's a poorly-named tool: "torque wrench" would probably be much more descriptive.

Thanks much! I was worried about a too-thin tension wrench damaging locks when the torque in the wrench was transferred to the opposite keyward. It aslo seemed to me that slippage could occur if the wrench were too thin, deep or short.

[MacGyver101]

Does this mean, then, that your tension wrench should be as wide as possible while still allowing for a minimally frictive insertion?

Ideally, yes. (Again, this is in my experience, anyhow.) In practice, you'll find that you can't practically carry enough wrenches to precisely fit every keyway you'll encounter; I have a few that vary in thickness and give me some options to work with.

I was worried about a too-thin tension wrench damaging locks when the torque in the wrench was transferred to the opposite keyward.

You'll find that you require very, very little pressure on the tension wrench: you're only having to apply enough force to overcome the spring pressure on the pins. (And the pins are being driven by very, very tiny springs.)

[Gordon Airporte]

If the wrench is too thin (relative to the width of the keyway) it becomes more difficult to reduce your tension and allow for a slight "backwards" rotation of the cylinder.

Does this mean, then, that your tension wrench should be as wide as possible while still allowing for a minimally frictive insertion?

Yep. You seem like a guy who owns dial calipers so I'll give you the dimensions of a wrench that I find quite versatile.
.118" x .031" x around 3/4" on one end, and on the other end, for the top of the keyway .115" x .031" x .177"
The trick is finding the ~.03" thick wiper insert. Try to leave the edges square when you file so it catches the keyway better.

That's just one wrench, but another really important 'dimension' is the number of different wrenches you have. They're free, and easy to make, so make a bunch and experiment. Eventually you'll settle on a few that you like best.

[LeeNo]

Does this mean, then, that your tension wrench should be as wide as possible while still allowing for a minimally frictive insertion?

Ideally, yes. (Again, this is in my experience, anyhow.) In practice, you'll find that you can't practically carry enough wrenches to precisely fit every keyway you'll encounter; I have a few that vary in thickness and give me some options to work with.

I was worried about a too-thin tension wrench damaging locks when the torque in the wrench was transferred to the opposite keyward.

You'll find that you require very, very little pressure on the tension wrench: you're only having to apply enough force to overcome the spring pressure on the pins. (And the pins are being driven by very, very tiny springs.)

Thank you so much MacGyver101! I know my questions sound very obvious, but I am trying to understand the forces at play here first.

The point about only needing to overcome the pressure of the springs now seems obvious because they are the only force at play (ignoring the friction between the housing and cylinder itself), but I wasn't thinking that way - now I am. And it makes sense.

Thanks again!

[LeeNo]

You seem like a guy who owns dial calipers

LOL!

Actually, I don't

But I used to be an aircraft electrician (and I stayed at a Holiday Inn Express last night....) and find I work better when I understand the actors in play.

[josh0094]

harbor frieght tools is awsome! look it up!

[MacGyver101]

harbor frieght tools is awsome! look it up!

Um... okay. I'm sure they are.

[josh0094]

there the home depot version of the doller tree

[mitch.capper]

Also one tension wrench isnt going to satisfy all your needs, different keyways and different tension options. You will find some locks you have to pick from the top and will need a shallow wrench. Really its best to try and figure out what locks you would like to be attempting, and custom a wrench to each rather one to all.

[criminalhate]

harbor frieght tools is awsome! look it up!

I'm pretty sure he was mentioning it because they sell cheap($9.99 us) digital calipers that work ok for most of what we do (I own a pair).

[rakemaster]

Dial (or digital) calipers have gotten so cheap that there's really
no excuse for someone interested in locks not owning one.

I prefer the dial kind myself, no batteries to worry about.