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The Folding Knife (& Switchblade) Forum The materials, techniques and the designing of folding knives. |
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#16
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Of course it can Good point there, i would forgot to mention that
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#17
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Where is a good place to purchase the springs?
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#18
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I got mine from www.knifekits.com
the smallest and weekest one they carry is strong enough even for a big folder |
#19
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Papi, I have both right and left hand wound tortion springs on hand.
Which will you use? |
#20
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Automatic knife-second part
I didn't get much done today, had some catching up with friends to do, and got to the shop at around 6PM.
But, i did manage to take a photo of my springs for you to figure out if they are left or right wound(i couldn't figure it out myself ) And i managed to draw my patterns onto the 1mm thick titanium, and the steel: on the pattern, you see the three holes placement that i described in the first part. liners cut out and one of them profiled(no need to profile them both yet) I also drilled all the holes with the smallest drill i'm using- 1/16" diam. , for M2 screws. You should do that with a drill you use for tapping your screws. That's it for today, i promise i'll get more done tomorrow, hope i'll have working mechanism by tomorrow evening. Take care, Ondrej PS: i decided to use that nice piece of zebrawood on the last photo for my scales, got it today from a friend. |
#21
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Looks good to me so far but I'm going to wait to cut out parts untill I see a little more and gain a better understanding. With my luck I'd cut parts today that wouldn't work and I'd have to recut them anyway...
Don |
#22
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Automatic knife-third part
So, picking up where i left it yesterday, i got quite a lot done, before i had to leave the shop because of heat. I hope i'll do a little more work in the evening.
Here are all parts cut-blade, liners and bolsters. i'm using temporal backspacer made of G10, as the final backbar will be made out of wood, and i don't want to mess it up. the liners are clamped together and match drilled (these clamps are $15 each, but are worth at least 100 ) the front liner is then clearance drilled and countersunk, and the other is tapped a real shop helper the bolsters drilled and countersunk for screws, and the liners are tapped. As you can see, i drilled one more hole in the back liner, to hold the bolster with the screw from underside-THIS IS VERY IMPORTANT! you need to have two screws in the back bolster, not including the pivot (you'll see later why) the blade and front liner are drilled to fit your pivot, you can use any diameter and screw you want, as long as it's not bigger diam. than 5mm. The back liner is drilled to 12.5mm-half an inch. Now you see why you need an extra screw. this fixture is used to make a channel around the pivot to accomodate the spring. You can do it in the lathe like me, or on the mill using rotary table. the channel should have same outer diameter as your spring, and inner diam. as your pivot. If you have no way to do it like this, just use an endmill to bore a pocket, and drill your bolster to fit your pivot, and use the pivot with the larger end(hope i made it quite clear) now you just screw the bolster onto the liner, and the pivot onto the bolster, and it should look like this. my 12.5mm drill was a little out of center, so my hole in the liner is off center, but it's no big deal, it will still work...(actually, the angle of the photo suggests it's way off, but actually the offset is about 0.25mm, it's just a badly taken picture) This is what i got so far, more to come in the evening Take care, Ondrej |
#23
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Papi
First off , thanks for doing tis. I have wanted to make an auto for a long time. A couple of questions. 1. the screw in the very front of the bolster, is the blster tapped, if so how does that look on the outside of the bolster, your screw goes partway into the hole that you made for the spring, is this necessary? 2. Is the island that the pivot is standing on required or can that sinple be flat? Thanks Steve __________________ Stephen Vanderkolff Please come on over and check out my website. http://www.vanderkolffknives.com/ Thanks |
#24
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Thank you, Papi.
I'm watching with great interest. I'll wait until I see a little more before starting my knife. I want to see how you handle the button mechanism. I'll probably use some different methods to obtain the same results. The mechanism will match yours, though. I'm here to build one of yours. So far I haven't even been able to imagine how I want the blade and handle to look. Big, mean, small, pretty......??? Or otherwise. I've made several of my autos, but they don't use a torsion spring. |
#25
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Man, you got a big old ugly workbench there, my friend.
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#26
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Hi guys, thanks for the feedback
Steve, the front screw goes from inside into the blind tapped hole, and is absolutely necessary, you simply must have the bolster fixed to the liner with one or more screws. But, you can(instead of using blind hole) do it normally from the outside, but you'll have the screw visible. that is just a thing of a design. As for the pivot placement, like i said, you can just make the pocket with flat bottom, and put the pivot in there from the outside, like this(imagine the mechanism cut in half on the picture) You can also mill a pocket from the outside of the bolster and make the head of the pivot flush with the surface of the bolster |
#27
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How thick are your bolsters?
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#28
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0.1 " , and 0.040 liners. the channel in bolsters is about 1/16" deep
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#29
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Automatic knife-fourth part
Today's progress:
i milled a small channel in the bolster to anchor the spring-had to cut the leg of the spring shorter, to fit. milled a pocket in the blade to accomodate the spring-there was not enough space for the spring in the bolster pocket-it's more than 1/8" high. i also drilled a small hole to anchor the other end of the spring-to do this, you mark the spot with the blade about half an inch more open than it will be when finished-to ensure the spring will have a little tension even when the blade is fully opened i also profiled the other liner, both bolsters and blade, here are the parts i put the knife together and mark the placement of the stop pin, then drill thru now close the knife, but close it more than it will be closing when finished, the tip of the blade should be about 1/8" further in the handle about like this and mark the hole for the button |
#30
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Automatic knife-fourth part
now enlarge the hole to have a loose fit onto the shaft of your button(0.01" in my case)
and drill/mill the pocket from the under side of the blade-same diameter as the pocket in your bolster and liner now mark the parts of the blade that has to come off and work your way thru them until you can open and close the blade with the button in place should look like this: now you can fix the front bolster to the liner(using pivot pin), and drill thru it, to fit your button-drill the liner with a bigger drill, to allow the button to travel up and down like this i did a little chamfer around the hole, so that i can make the button shorter-it's safer now i need to make a washer. i'm using 0.2mm teflon on the other side, so my washer needs to be thickness of a liner+0.2mm. you do your own math for your liners and washers anyway, the diameter of the washer should fit into the hole in the liner, and the hole in it should be big enough for the spring to go cleanly thru i used bronze for my washer, and made a little notch on one side, so that the button can fit into it's pocket. Last edited by papi; 06-10-2009 at 01:45 PM. |
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auto, bee, blade, coil spring, hunting, knife, knives, making, switchblade |
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