experimental tension wrench.

[Squirrel_Cop]

Hey everyone,

I'm not 100% sure that this hasn't been done before, but Ive never seen it.

I wanted to share an experimental tension tool design that I am playing with.
In a sentence, its "An adjustable, flexible tension wrench which allows for maximum access to the keyway." It shares the principal function of the Falle style tension tools, however, it is smaller, and allows for a flexability, as found in a standard, twisted tension tool.

Materials needed:
-1 piece of brass tubing. 1/8" .032" thickness. +/- $2.00 at hobby shops.
-2 pieces (4.5" and 6.5")of windshield wiper blade insert (or similar material) .0275 thickness / .0975 width

tools needed:
-vise
-files (or dremel)
-hacksaw (or dremel)
-heating torch
-pliars

1. prepare the tube by cutting it to length (aprox 3.75-4") filing and sanding the cut.
2, CAREFULLY crush the tub in your vice to an oval shape. place the tube in the vice horizontally, with the entire piece within the vice. crush a little and check, crush a little and check. The end result will be a tube which allows both arms (wiper blades) to be inserted, but causes friction so that they are tight.
3. remove the two arms and set the tube aside.
4. file the tips of the arms to a very narrow, tapering tip. The long arm should be slightly narrower than the short arm. The long arm will be entering the top of the keyway.
5. bend the arms as noted in the illustration. heat the tips and make as SHARP of a 90* bend as possible. (this is important) then, at the base of this turn make the second bend. the idea of the bends is to have the tool exit the keyway, and move out of the way of the picking space in as small a distance as possible.
6. insert the small arm into the tube.
7. insert the long arm, and stop just before it exits the tube.
8. bend the small arm's tail so that it wraps around the tube and locks it in place. The long arm should be tight, but able to slide up and down in the tube.

finished!



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The tool is compact and sturdy. The two arms, when closed, support each other to protect against damage.

The long tail allows the tool to be flexible, like a regular twisted tension tool.

You can make index marks on the tail that correspond with different brand keyways. (kwikset, schlage etc.)

Use requires a thumb to be placed on the top of the tool, to prevent it from being accidentally forced out of the keyway when raking. The nose picker finger can apply pressure to the long tail to apply the tension.

Enjoy!

[Schuyler]

Brilliant! These exist in the wild, but this is a really lovely version. Never seen anything quite like it. Falle has some adjustables and I know the guys behind DIYTDS provided info on keyway-spanning-spanners but really, this is quite the tool you've come up with.

Independent discovery sometimes creates the more attractive solution

[Raymond]

This an excellent idea. I am going to try and make one.

Suggestion: how would it work using square tubing that was an exact fit for the two flat pieces of steel? A small screw could freeze the two probes and make the whole tool less likely to wobble or shift.

Why did you taper the points? Off the cuff I would think a nice thin but square, sharp edge would hold better.

What other variations did you try and reject, and why?

BRAVO!

[Squirrel_Cop]

Thank you Schuyler!

Raymond, Thank you for your compliment! I was working the idea around in my head for awhile, mostly how to join the two arms. I considered wire wrap, heat shrink, and shim stock. I tried longer tapering arms, thinking that ti would allow for use in different size keyways. but it was too long and thin and, as you can guess, was striking the first pin in the stack and not offering enough material to bite and stay put. I cut the tips down, so they may be all but straight, small squares by the end.

I think the square tube would work, and be a nice, clean look. A set screw would be nice. I went with round because I could adjust the spacing by collapsing it. The whole thing is slightly more than 1/8" in diameter. If Im reading you right, Im not sure if you could find a set screw that wouldn't break away, and threading a tiny hole would suck. Way beyond my garage workshop capabilities.

[dallalama]

the best ideas are generally the simplest,and when you see it ,You think why did i not think of that,well done.This will look good in that awesome pick case you have

[femurat]

I like your idea very much! Your wrench seems simple and effective, well done

Cheers

[shadow11612]

Suggestion: how would it work using square tubing that was an exact fit for the two flat pieces of steel? A small screw could freeze the two probes and make the whole tool less likely to wobble or shift.

To freeze the two flats against the side of the tube, could a small third piece of spring steel be inserted at the bottom to wedge them against the sides and lock them in place?

[SAM PICK]

Love the idea. Ray's square tube adds lots of strength.

You could even take up slop between the square tube if you can't find an exact fit. Then take it up a notch and solder a pair of opposing triggers (Like a "Grabber" or hypodermic syringe)to the back end of the tube and a 90 degree bend to the back of the movable second "arm". This may allow quicker adjustment.

Other rambled ideas...

add a way to lock the two arms under tension. Maybe a third piece with an arc bend so it acts as a spring to push the two arms together inside the tube and create friction that could hold the adjustment. (That might need tempered)
or...
Introduce a coil spring that would push the two arms apart that can be collapsed momentarily while the other end is inserted into the key-way.
or...
Low tech on the last idea use a rubber band instead of a spring.
or...
If you like the set screw idea, you could find a brass nut and solder it to the tube over a hole and use a thumb screw just go easy on the tension.

Guess I gotta make one and experiment too.

[raimundo]

You could use a longer tensor blade for the bottom tension to better stabilize it from being dragged out of the keyway if that becomes a problem.
you could add a coil spring forcing the to to spred and this spring could be applied at the far end of the handle.

before you decide on the length of the lever/handle, do these experiments,

take and ordinary tensor and grip the tensor blade between thumb and forefinger, then press on the the far end of the lever with a feather or the edge of a piece of paper, you will be able to turn the tensor supriseing hard with this leverage.

take your tensor and put it in a lock plug that you hold between thumb and forefinger, this plug will give much advantage when compared to the first experiment just as the handle of a screwdriver is so much better than the shaft of one without the handle. However you still have a huge leverage.
press on the long handle at the far end, then a places in the middle which will decrease leverage, you can use these experiments to adjust the length of the handle.

also if you are just including the lengh of handle for its springiness, remember that you can fold this back and get the springiness without the length.

shorter tensor handles give better tensor feedback as well as less overbinding force.


Very good design. Kudos. and thanks.

[Legion303]

This looks like a good workable design. I've tried making the "dualies" from wiper blade inserts before and never quite got it right, but I might give your design a shot now.

-steve

[yono]

thanks Squirrel_cop, this is very good. i will apply this to my next project. based on your design with a little modification on mine. "the two combined adjustable tension wrench that will be fastened by a screws" for stable positioning. regards

[pin_pusher]

great picture, and great design. i'll have to make a swing at it myself, the directions seem easy enough to follow. very inventive, we'll see who changes up the design in the future as well. keep it up.

[pjzstones]

this design could also be made into a more stable interchangeable core removal type tool. for some key ways, ic core removal tools just won't stay. seems that this would keep it in place much better. i'm going to have to give it a try. very nice idea.

[zeepia]

Searching at the depth of old topics and found this very nice tension tool. And of course had to do my own...

Went to that aluminium profile shop which I use normally, they have a great recycling container. All kinds of different aluminium profiles in short pieces and I get these for free for my prototype constructions

This time they had this profile, don´t know where it is used...



I then machined it and here is the result. The width of the groove is 3,2mm and a perfect fit for my bristles.



You must always keep your eyes open, you never know what lies in front of you!

Thanks for the great idea, have had some locks where this kind of tension is much better than normal TW.

[Emrys]

I have often considered the idea of a "universal tension wrench" to eliminate all of the wrenches I carry in my case. This idea seems right along the same lines as designs I have recently had in mind. My biggest shortcomings with adjustable tension wrenches in the past is the flex between the two prongs & the lack of feedback.

I think the first and most important milestone in getting a universal tension wrench to work is eliminating any flex. It has to be constructed as solid as possible.

Zeepia, how has your tension wrench worked for you so far? Can you go into a little more detail about how you made it?