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DrewDel
124
Jun 28, 2017
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I don't know why integral knives are inherently more expensive that the other option of having two separate sides. They are easier to manufacture, and easy to fit & finish. When the pivot hole is drilled then bored, it is always perfectly inline because it is bored before the slot for the blade is milled Also when creating a "two piece" knife, it needs to have the pivot hole, and the holes for the screws that hold the two sides together PERFECTLY aligned. This is difficult because the two sides are done separately. So even tenths of a thou (0.0001") of variation can cause alignment issues, and affect the smoothness of the knife. The integral design eliminates the need for screw holes you hold the two sides together; therefore eliminating these issues altogether. Integral manufacture has decreased operations, less fixturing, less issues when fitting the blade.
Spidey12341
220
Jun 28, 2017
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DrewDelWhen making a knife with two pieces for the handle i think its easier because its a linear cut and the machining is easier, and with the two pieces they only need to make one side then mirror it so a mistake would only come from the machine not from the program. Also when making an integral it needs to be a small drill head and can take many passes to mill out and might take longer, with higher end knives like this they want to make sure the milling is as near perfect as they can get and thats hard with small things.
enkidu
313
Jul 1, 2017
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DrewDel The pivot hole is not the problem, in fact, even with two sides to the handle the answer is trivial, align the two halves using rods and drill once. Or (more probably) have a jig which holds each handle in the same position and drill.
The problem making an integral handle is the slot and the lock. Machining the lock bar on a two piece handle is straight forward, all exterior cuts and mills, machine some slots into one scale, heat, and bend to desired tension. When the handle is an integral, you need to cut the big slot for the blade without going all the way through. A deep trench in Ti with a narrow long bit is tough (haha) because the length of the bit will give you a lot of flex and chatter.
Next, you can't just cut the separation slot for the lock-bar with your plasma/laser/waterjet, because you can't cut all the way through. You need to cut with a very small bit or thin bladed saw. Cutting Ti with any small bit is, uhm, difficult.
Next, you can't bend the lock bar without hitting the other side of your big slot. I have no idea how this is done or solved.
Dude, if it were easier, believe me, everyone would be doing integral handles. There's a reason there are only a handful of manufacturers who do true integral, reeves style locks; and for a loooong time there was only one (name the knife and maker for bonus points!). The reason is because making integral handle knives is really hard and really expensive.
DrewDel
124
Jul 13, 2017
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enkiduTo "align the two sides with rods" will require drilling holes in the two sides. (I assume you're suggesting using the standoff holes for alignment.) Using those two holes for alignment for drilling the pivot hole exaggerates misalignment.
The lock bar it's bent using rotary torsion rather than just "bending" it. You use a tool with a slit milled in it, and you twist it.
The separation of the lock bar from the body is done before the central channel for the blade is milled out. It is one of the first ops done.
The sides can be milled two different ways. The first easiest way is to mill one side, then use a fixture plate, with a negative of the first side that was milled, to hold the body while side two is milled. This is when the pivot hole is drilled; and possibly a lanyard hole.
The second way is to leave a rib of metal sticking out of the blade slot area while the sides are milled. That can then be clamped in a trunnion 5th axis for three+2 milling or 5-axis milling of the sides. Then the body can be held in the negative fixture, or held using the pivot hole and a clamp, or the pivot and lanyard hole; so the rib is milled away while continuing deeper for the blade slot.
Also, the 3/16" end mill is plenty rigid enough to mill the slot. The interior corners and bottom of the slot can then be cleaned up with a ball mill, or something like a 0.125" radiused end mill. A 1/16" stub length end mill, with only about 0.250" of stick-out is plenty rigid enough to mill the slot for the lock-bar. It would only be stuck out 4x the diameter. (4:1 stick-out to diameter ratio). Also once you get the recipe right, get your feeds and speeds dialed in, and have the CAD/CAM tuned, you can cut them very easily.
Using gauge pins, to align two halves/scales/sides of the frame, can be off by a couple tenths or a nanoradian/wavelength of light/arcfourth (1/3600th of an arcsecond) or whatever exponentially small unit subdivision you feel like using. LOL), and that can be detrimental to the smoothness of the pivot and blade centering. Over 2-4" of blade, by the time you get to the tip, that decision will really show. It is especially noticeable on a 3¾"+ long blade, and obviously compounds as it gets longer.
The lock bar it's bent using rotary torsion rather than just "bending" it. You use a tool with a slit milled in it, and you twist it.
The separation of the lock bar from the body is done before the central channel for the blade is milled out. It is one of the first ops done.
The sides can be milled two different ways. The first easiest way is to mill one side, then use a fixture plate, with a negative of the first side that was milled, to hold the body while side two is milled. This is when the pivot hole is drilled; and possibly a lanyard hole.
The second way is to leave a rib of metal sticking out of the blade slot area while the sides are milled. That can then be clamped in a trunnion 5th axis for three+2 milling or 5-axis milling of the sides. Then the body can be held in the negative fixture, or held using the pivot hole and a clamp, or the pivot and lanyard hole; so the rib is milled away while continuing deeper for the blade slot.
Also, the 3/16" end mill is plenty rigid enough to mill the slot. The interior corners and bottom of the slot can then be cleaned up with a ball mill, or something like a 0.125" radiused end mill. A 1/16" stub length end mill, with only about 0.250" of stick-out is plenty rigid enough to mill the slot for the lock-bar. It would only be stuck out 4x the diameter. (4:1 stick-out to diameter ratio). Also once you get the recipe right, get your feeds and speeds dialed in, and have the CAD/CAM tuned, you can cut them very easily.
Using gauge pins, to align two halves/scales/sides of the frame, can be off by a couple tenths or a nanoradian/wavelength of light/arcfourth (1/3600th of an arcsecond) or whatever exponentially small unit subdivision you feel like using. LOL), and that can be detrimental to the smoothness of the pivot and blade centering. Over 2-4" of blade, by the time you get to the tip, that decision will really show. It is especially noticeable on a 3¾"+ long blade, and obviously compounds as it gets longer.
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