hook design theory discussion

[wsbpress]

I'm interested in discussing what makes the dimensions of a single hook good. I have a homework assignment for which I will be creating a few lockpicks and these will most likely be produced in our shop on a wire-EDM machine. I have already modelled the Falle deep curve, graduated curve, and progressive curve picks but I am looking to design something different, but not radically different. I am interested in designing a few picks for specific common keyways. Common in my region are Schlage C, Weiser, Best, and Kwiket to name a few.

The best way I can put it is that I am trying to create a set of guidelines to assist in designing an effective hook for a given keyway.

ie.
-hook must fit in keyway (obvious)
-hook must be able to lift farthest pin to the highest position without touching the second-farthest pin
-(possibly something like) the height of the hook should equal <some keyway dimension>
-and so on

This might seem obvious but I have a few questions like "What is the best arc to use when designing a deep-curve hook and why?" "Where is the best location for the fulcrum of a deep curve hook?"

Of course I am thinking this over myself but I thought that I'd tap into the fine brains of other LP101ers.

-wsbpress

[digital_blue]

Well, for the Weiser and Kwikset you could get by with a pick something about the size of a broom handle.

Seriously though, there are several factors that will effect which hook is "the right hook" for a given lock.

- Obviously, the keyway. Size as well as warding
- The pin configuration. High/Low cuts will often require a deeper, sharper hook to lift a low cut that is behind a high cut.
- The technique of the user.
- The skill of the user.

As you can see, only one of the above is consistant for a particular model of lock. You can anticipate the keyway, but not any of the other factors. So it would be difficult to design "the perfect hook" for a particular model of lock. The truth is, though you will come to rely most commonly on just a couple, there is a big benefit in having a variety of hooks to go to.

Hope this helps some.

db

[wsbpress]

- The pin configuration. High/Low cuts will often require a deeper, sharper hook to lift a low cut that is behind a high cut.

The kind of thing that I trying to come up with would be how deep and how sharp. And also if you had a sharp, deep hook that was effective at lifting a low cut behind a high cut ( a pro ), what are the cons to that hook (if any), and can the design be modified to remedy those cons. At what point is a hook too sharp and too deep? Why aren't there hooks with an inside right angle instead of an arc. Like:

Code: Select all

____| vs _____/


I know this stuff isn't rocket science and maybe I am trying to quantify something that doesn't need to be quantified. I mean its only a curved piece of metal. But I just like to try to come up with new and hopefully better methods and tools, and determining and identifying qualities and parameters is part of that process for me.

[Gordon Airporte]

The first thing I'd do is make a scale drawing in CAD or a vector graphics program of a cut-away side view of the keyway, showing the pin spacing, where the ledges are and maybe a line showing the highest the pins will set. Then you just start drawing and tweaking curves as you lay them over the drawing. You might want to take in to account any space that would be taken up by a standard tension tool. Or you might use a less restrictive type of wrench.
Personally, I'm enamored with the Falle #2 deep curve. It's supplanted my short hook.

[helix]

If you were to take into account:

*The maximum room between the bottom of the keyway and the pins.
*The maximum room between the bottom of the keyway and the top of it.
*The distance from the front pin to the back pin.

Use these measurements as length, height and width as a 'blank' pick.

Take the middle of the blank area, and mark a maximum thickness/height
that you want the curve to be (2mm?) from the bottom.

On the top TWO ends of the blank, mark your curves maximum thickness
(2mm?) from the top.

THIS IS NOT A PROPER MATHS FORMULA, IT IS DODGY AT BEST.
IT WILL GET YOU PRETTY CLOSE, BUT.

Line up something round on the THREE marks you have and trace around it.
For a proper arc, you will need to use two differently sized round templates.
The bigger of the two, should be twice the 'minimum curve thickness' bigger than the smaller.
(In this case, the curve is 2mm, the bigger template should be 4mm bigger in diameter.)

Just a bit of a brain storm for you, nothing scientifically worked out.
Maybe ask d0ded0 for a proper formula, I think he is a mathematician.

[digital_blue]

The kind of thing that I trying to come up with would be how deep and how sharp. And also if you had a sharp, deep hook that was effective at lifting a low cut behind a high cut ( a pro ), what are the cons to that hook (if any), and can the design be modified to remedy those cons. At what point is a hook too sharp and too deep? Why aren't there hooks with an inside right angle instead of an arc. Like:

Code: Select all

____| vs _____/


I know this stuff isn't rocket science and maybe I am trying to quantify something that doesn't need to be quantified. I mean its only a curved piece of metal. But I just like to try to come up with new and hopefully better methods and tools, and determining and identifying qualities and parameters is part of that process for me.

Well, consider this. The "perfect hook" for a lock that is pinned 78526 would be a hook that could adequately make up the difference between a 2 cut and a 6 cut, because that is the greatest variation within this lock. So you could go to the trouble of mapping out the lock complete with it's pin spacing and depths in an accurate model, then figure out just precisely what the appropriate arc would be to meet the need. You may come up with something that could be called the perfect hook for that lock. But consider now that we changed last pin to a 7. All of a sudden the dynamics change and our perfect arc no longer is.

Of course, real world examples show that the hook need not be the perfect dimensions, but merely close enough to get the job done.

Think of a range of picks along the lines of a range of golf clubs. You've got a club that is appropriate for a shot, say, from 75 to 95 yards. Then you've got a club that is good from 90 to 110 yards, etc. (I'm sure a golfer could be more specific, but you get the idea). If you were standing on the fairway 87 yards from the hole you wouldn't go looking for your 87 yard club, nor would you, back at your workbench, look to invent a club for that job. But rather you would ensure that you have a range of tools that covers the spectrum.

Perhaps this would be the kind of approach to take.

Just my thoughts, fwiw.

db

[Keyring]

Why aren't there hooks with an inside right angle instead of an arc. Like:

Code: Select all

____| vs _____/
 

I don't think anyone answered this one yet. There would be a real danger of getting the right angled pick end trapped behind a pin under some circumstances. The slope assists gentle removal, because pulling the pick results in downward force on the pick and upward force on the pin.

[Chrispy]

you would ensure that you have a range of tools that covers the spectrum.

Perhaps this would be the kind of approach to take.

That is the answer to this thread ladies and gentlemen.

[wtf|pickproof?]

Don't forget to mention: If the height of the hook is too big you won't be able do work around warding in tight keyways.

[wsbpress]

Thnx all for the input.

DB- I agree with your golf analogy. Maybe what I'd like to do now is try come up with a "sand wedge" that can be used when a lock is keyed xxx09 (probably a MACS violation). But I also would think that if a certain hook can accurately manipulate the 5th pin without affecting the 4th pin in this situtation then the hook would also be effective for the back pins of the 78526 pinning.

Gordon- I like your idea of making the CAD cutaway, I may give it a try.

I was not originally suggesting to create a hook for a specifically keyed keyway, just the keyway's dimensions. For example, I really like to use a specific deep curve hook in the Weiser keyway. What I would like to do is identify why that particular hook works well for me in that keyway. Then take those parameters and try to make a deep curve hook that is very comfortable for me in the American Padlock keyway, whose 6-pin keyway is shorter from front to back than the Weiser's 5-pin.

I'm really just thinking out loud and I appreciate the input that has been given.

[vector40]

I agree that a hook that could effectively pick the maximum difference in pin height in a given lock (you could restrict for MACS or not) would be ideal, and making it shorter just to make it easier to maneuver would probably almost never be worthwhile.

Obviously, that does mean you need a variety of hooks for different types of locks and keyways and whatever else.

Come to think of it, maybe that's what Falle did.

[raimundo]

hooks are used for lifting pins without the coded information present on a key. keys fit the warding, picks only get by by being thinner. The reason that a hook has a curve where a key would have a 45 degree angle is so that the hook is less likely to become jammed behind some ward and pin combination. Hooks can be made with 45 degree angles and will work well and not get jammed if they are sanded and rounded on the edges where the planes meet at 90degrees. I believe that the hook can use a much smaller radius from shaft to pick tip, such as could be cut by a round needle file. also, the hook can be of a greater angle, such as 65 degrees, so that most of the pick tip is in the channel cut through the wards for the pin. Once again, the key is to sand off all those square edges. I have been experimenting with hooks that have a round tip almost as wide as the pin, but taper a bit to the pick shaft so that the end of the pick is slightly fatter than the part that has the angle. I do not recommend a ball tip, as this will give undercuts that may be susceptible to getting caught, but a taper to the angle. Remember the designs of commercial picks take into consideration that the user may be a beginner or a person with a heavy hand. so they use a larger radius at the angle to make it less likely to get the pick tip jammed, and they make the shafts more thick than is really necessary.

[digital_blue]

Come to think of it, maybe that's what Falle did.

Bingo.

My golf analagy was intended to head wsbpress down precisely that road. The Falle-Safe set is created from this very idea of "a hook for any occation", and I think it is exactly where this excercise is eventually headed.


db

[wsbpress]

I don't want anyone to think that I am discounting the effectiveness of the Falle-Safe hook set. I am a huge fan. I don't have the originals yet but recently I made a the #2 end of a deep curve from a feeler guage and it is now my first-choice pick. I will sooner or later get an authentic set for myself even if I already have a complete set of copies just because they are what they are. I also agree that one should have a variety of tools to choose from when confronting a lock. I usually end up with four or five different hooks (and maybe a snake or a diamond) on the floor when I am trying to pop a stubborn lock.

I just wanted to clear that up in case I miscommunicated my opinions and intentions. With that out of the way I would like to explain that I believe that there may be a hook or set of hooks, not yet in existence, that will complement an already satisfactory hook collection. We may not need this hook or these hooks, but I appreciate innovation, whether it comes from myself or others. I think I may actually enjoy the process as much as the finished product.

Raimundo I like your idea of tapering the hook near the bend. It seems that the amount of metal actually touching the bottom of the pin would affect the surface pressure on the hook and I would imagine that this changes the feedback response. I suppose that the style of the picker would play a large role in determining the size of the tip that is most effective for that person. One could create an assortment of hooks with the same angles and heights but with varying tip sizes. Of course the smaller the tip the more succeptible it becomes to wear and deformation. I've noticed my LAB set does this to some degree (varies, not deforms). Of course the LAB picks also vary the type of tip too (rounded, notched, etc). My personal preference is just rounded.

[Gordon Airporte]

I recently made a very long hook (almost 1/4" high from the bottom of the tang - not convenient in many keyways) based on a Majestic template, and I found that I needed to dish out the tip to get a good feel with it. I think it's because of the tightness of the curve and the length; a round tip just slides all over the place. You get full, laser focus control over any pin without disturbing the others, but it's still kind of awkward and I haven't found (or pinned) a lock that really needs it.