tension tips

[raimundo]

Most of you are probably using commercial tensors. these are usually made from sheet metal that has been cut to ribbons in a 'slitter' which will leave very sharp edges on the blades. these blades in the bottom of the keyway come in contact with the immobile wall of the cylinder, and the sharp edge can cut into the brass. On locks that have been used a lot by beginers I have seen groves eroded into the cylinder wall from this, Such grooves would be a good security feature against picking. The tensor should try to rotate the plug, but it can get in a position to bind the plug against opposite cylinder wall when the edge of the tensor cuts into the cylinder. If you tensor is stuck, and not completely freely moving, at least some of your tension is going into binding the plug. several things are possible, stroke a file along the sharp edge of the tensor, then sand it smooth, making it harder to dig into the brass. Some people use tensors that have slight bends in them that make them press on opposite walls of the keyway in the plug, these tensors are meant to bind in the keyway somewhat. and usually do not dig into the cylinder wall, but there is no guarantee that they won't. another method is to produce a bend accross the width of the tensor, by gripping the edges in the grooves of two baby vise grips, with about a quarter to half inch between the pliers, and making a slight bend on the tensor. This produces a tensor that contacts the cylinder wall at only a small point rather than along the full length, and if that contact point is well sanded, it will not cut into the brass wall. This also gives the tensor the ablility to ajust the width of its footprint in the plug according to how deeply you insert it. Its usually best to insert such a tensor as far as it will go, then draw it back a bit to prevent binding. A wide blade tensor that has been filed to a taper also will resist binding if well sanded. Tensors made of sweeper bristle do not need to be sanded on the edge, because they are not made of sheetmetal cut on a slitter, they are made of round wire flattened in rollers and always have rounded edges. the rollers are set differently and the bristle comes in variations of width and thickness. it is well tempered and usually won't break, but some of it does have a brittle quality which is probably something in the alloy, melted shredded car cubes contain aluminum (burns off,becomes air pollution) zinc, magnesium(burns up) copper, lead, etc. so the alloy for this wire is not really well controlled although lighter metals can be skimmed off the top, or drained at their melting temperature as the car-cubes are heated. rubber, plastic, glass, etc also mostly burn off or become slag floatling on top of the brew.
Split tensors leave more room for the pick to move up and down, some of them are spred by springing and can still cause minor binding if the wall of the cylinder is already rough. others, like the falle type, have no spring in them, and work quite well on some locks that are difficult to open with the straight blade tensor. A non ajustable non spring tensor is easily made from brickstrap or similiar flat steel that can be bent (not hard tempered.) could even be made from .020 -.030 feeler gauge stock, just cut a groove into the strap with a chain saw sharpening file,then cut the outer areas down with a flat file til they are the width of a key blank for that lock, then use the flat file to widen the inner part of the groove, and bend the tips down, make sure that the one that goes into the top of the keyway does not reach the first pin, but make it as long as possible just short of this, the bottom one should be longer. When picking, if you encounter difficulty, change tensors by size or by type, and a lock that is very resistant with one type of tensor may become easy when using a different type. A very important part of the "feel" is the feedback from the tensor.

[Chucklz]

Raimundo, thanks for another wonderful post. Its good to have you back writing Romstar length posts. All of the windshield wiper inserts I have have rounded edges, I assume that these are also made from flattened wire. I have found that sanding the front of your tensor really keeps you from scratching up plugs, and lock faces if you ever slip. It also keeps you from giving yourself a nasty cut.

[kendale]

Whats with the rounded edges, peterson tools make tension wrenches with teeth cut into the wrench so it bites into the keyway, if you are inserting the wrench into the top of the keyway they dont come out when picking.

[Romstar]

Whats with the rounded edges, peterson tools make tension wrenches with teeth cut into the wrench so it bites into the keyway, if you are inserting the wrench into the top of the keyway they dont come out when picking.

Peterson is trying to make a unique tool that is a sort of cross between the regular North American style wrench, and the tighter fitting European style wrench, without it being all that tight.

The serrations in the Peterson wrenches acomplish this, but in some case have binding problems as described by Raimundo.

Romstar

[raimundo]

Yesterday I made a tensor differently from any described in the original post, i gripped the metal in two pliers toward the end of the piece, and with the pliers about 3/4" apart, and gave it a 90 degree twist. This twist is longer than the typical twist you see on tensors, then I cut the part that the plier held at the tip off, and bent the tensor blade-handle bend at the other end of this twist. This gives a tensor blade that is twisted, and is another variant of the tensors that have bends to make them either widen footprint or tighten against the keyway wall. Of course all the heavy pressure pickers already have such tensors, and there are those tensors that have the twist on the blade rather than on the handle end, People with these tensors are probably already familiar with the jamming of their twist into the keyway opening. All of this needs to be done with care that it dosent jam on the cylinder wall at the bottom of the keyway. A TENSOR FOR ABUS DISCUS IN SHROUDED HASPS. A tensor can be made for this type of installation where the keyway is pins down, and the shroud restricts the play of usual tensor. make a bend that is both the 90 degree transition from the blade to the handle and the twist to 90 degree handle in one simple bend. Place the tensor stock blade in a vise, then grip the handle end, about 3/4 inch from the vise jaw, bend it in a roll over that spirals a quarter turn. Such bends come in right and left handed. You should probably make both on either end. This produces a tensor that can be placed in the bottom of the keyway and which will turn down and out of the way, the same tensor in other applications can be used from above the keyway, and once again it will come out of the keyway and roll out of the way of the pick. The bend should be heated and squenched, this can be done with a bic lighter in about 30 seconds, just wait for the metal to get a blue patina and put it in a little water quickly while its still hot. In the case of a shrouded discus lock, this type of tensor will be able to swing the 90 degree turn that is enough to open the discus, without being obstructed by the shroud over the staple.

[raimundo]

replacement windshield wiper blade cartridges include the stainless steel wiper stiffeners that are either one wide piece or two thinner pieces depending on the wiper blade, and they also include some rocking fork mountings, look at those mountings closely, they can be modifed with little filing into a nonspring split tensioner, made from the two fingers that hold the wiper, and also can be used in making special tensioners for special uses like Bi Lock keyways, although the Bi lock tensioner can also be made from pieces of umbrella strut, ( find broken umbrellas the day after a rainstorm with very strong winds, they will be up against fences and in blind corners where the wind deposits the harvest.) The fork mountings could probably be used to make a type of snapper pick by mounting a blade on an axle between the forks and tensioning it with rubber bands or clothespin springs.

[raimundo]

there is a school of heavy tension as if the step, at the shear line can be made more secure if the brass is pressed on the brass harder, I don't really believe this, if a pin is caught between the plug and the cylinder, it can be bound very hard by heavy tension, but how does binding help? there is light tension that allows some feedback from the shearline and there is heavy tension that prevents this, and any more than heavy tension will bend the tensor, Some people say it will actually bend the pins but I don't believe that, If the plug and cylinder were made of steel, it could shear them, but brass is not hard enough to cut brass, it just deforms, mashing it. Heavy tension should only go so far, and any more is very counterproductive. probably with the tolerance between the plug and cylinder and the tolerance of the pins in their channels, some heavy tension is valid, making all the pin channel tight instead of having just one of them blocking the light tension, that is, it may remove all the extra leeway that is possible to be left in the lock, but after a certain point, tension is just a manifestation of the desparate desire of the lockpicker to make these insensible bits of metal do his will.