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The Folding Knife (& Switchblade) Forum The materials, techniques and the designing of folding knives. |
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#1
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Help slip joint!
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#2
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Those are some nice friction folders.
I would take a look at this tutorial by Chris Crawford. This should be plenty of info to get you started. http://www.knifenetwork.com/workshop...crawford.shtml |
#3
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Those are some nice looking knives, Mariano. Post any slipjoint questions to this forum and I'll be glad to help you however I can. -chris
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#4
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Beautiful work, Mariano.
The tutorial by Chris is a good one. Chris and I will help you with anything. Thanks for the offer, Chris. |
#5
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Thanks everybody!
Chris and Don! thanks and I take the offer! is and honor for me "talk" whit you. Saludos Mariano |
#6
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I've read the tutorial by Chris and found it helpful. But he just uses a pattern rather than "getting into all that" about getting the geometry right. I haven't found any way other than fussin' and foolin' to get the relationships between the placement of the blade pivot hole, length and height of tang, placement of spring pivot hole. I've read everything, I think. The "How to Make a Folding Knife" is all about lockbacks. I got Shadley's chapter on multiblades but he, too, skips over this all-important part of getting these relationships right. Are there any reliable rules of thumb or do you just have to mess around until you get it right?
Rebecca |
#7
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Hi, Rebecca.
If you're talking about slipjoints I made myself a little fixture with a dial indicator on it to get the rise and fall to match in all 3 directions before heat treat, then it's simply a matter of cleaning the surfaces up after heat treat. I can get the backspring to close within .002" open, half stop, and closed. The fixture has a slide with a 3/32 pin and a 3/32 pin right in front of the indicator. You get the blade to backspring aspect by putting the back spring pivot on the pin in the adjustable slide and the blade on the other pin. Now as far as the geometry, as you know, i use CAD to design the mechanism details. When I get thru with the design, I know absolutely that the folder will be correct in all positions before ever cutting metal. Maybe I can post pictures of the rise and fall setting fixture in use the next time I make a slipjoint, which will be after Chrstmas. |
#8
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Happy Thanksgiving! I'm eager to see this jig - it sounds very clever and helpful. And yes, I'm talking slipjoints.
I know you use CAD, Don - isn't that cheating?! Seriously, though, is there really no rule of thumb for, example, how far back should the pivot hole be from the end of the spring ramp? I know that pivot hole to top and bottom of tang should be equal, and the distance from pivot to end of tang should be longer than these distances. And then, how to get an appropriate amount of preload on the spring? It's all pretty much guess work to me.... Rebecca |
#9
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[QUOTE=Don Robinson]Hi, Rebecca.
Now as far as the geometry, as you know, i use CAD to design the mechanism details. When I get thru with the design, I know absolutely that the folder will be correct in all positions before ever cutting metal. OK, now I'm looking at CAD programs! What do you do your drawings in? Can you do them in the CAD program or do you import them to CAD from Illustrator, or something else? Or scan them in from a hand drawing? What is the learning curve like? Rebecca |
#10
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Now you're talking, Reb.
Google DeltaCad. It probably has a trial download. It only costs about $50.00 if you buy it. Start with the pivot, draw a circle around it the width of your blade, and then draw the blade. Now you can rotate the blade around the pivot to whatever position you want closed. When you have the blade open and closed, just draw the handle around it to whatever shape you want. If you've never seen one of my designs, I have a single blade slipjoint design I made for the Knet class. Let me know and I'll sell you a copy for a few dollars. With that and the DeltaCad software you will be designing your own knives that operate properly. Better yet, take my slipjoint class next time it repeats. I always start from scratch on a new design, just as I described. The learning curve should be several hours to get started since I happen to know you're a smart person. Having an existing design made with the same software to refer to should lessen the learning time. And,,,, I'm always around to help. I've been using CAD since the very first generation. I'm a mfg. engineer. Last edited by Don Robinson; 11-23-2006 at 11:22 AM. |
#11
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Quote:
Depending on the type of steel the back spring is made of, the rise should be about .030 to .060". For an ATS34 spring, .030" rise is enough. You can change the strength of the spring by removing metal on the underside ahead of the pivot. |
#12
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[QUOTE=Don Robinson]Now you're talking, Reb.
Google DeltaCad. It probably has a trial download. It only costs about $50.00 if you buy it. If you've never seen one of my designs, I have a single blade slipjoint design I made for the Knet class. Let me know and I'll sell you a copy for a few dollars. With that and the DeltaCad software you will be designing your own knives that operate properly. Better yet, take my slipjoint class next time it repeats. I always start from scratch on a new design, just as I described. I absolutely will take the slipjoint class. The only reason I haven't taken it yet is that I thought you just started with the CAD design and didn't do any teaching/learning about the design process itself. Please send me a copy of the slipjoint design - let me know how much $ to send. I don't recall seeing a slipjoint design on your website.... There is no DeltaCad client for Mac - I don't have one of those jazzy new Macs that run Windows natively, worse luck. There are several options - TurboCad, for example. Do you know if that's any good? Reb I imagine Turbocad will do the job, and maybe has some features that DC lacks. DC is the easiest to learn in my opinion. Email me your address. I don't teach design, though that gets my brain thinking about it. The students receive a copy of the design for the knife as part of the cost of tuition. Last edited by Don Robinson; 11-23-2006 at 09:19 PM. |
#13
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Quote:
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#14
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There may be rules of thumb for this, but I don't know them. Depends on the blade width and length. I see references on the internet where people take apart a knife and copy it. Most knifemakers don't use CAD, but it's like second nature for me to use it. I've been using it in one version or another since it was invented. I don't want to use hard patterns and I don't like to make scrap. I also like to make one of a kind knives. When you get the design, make copies, cut out the blade and other parts and play with the paper patterns. That'll be the same as taking a knife apart to see how it's made. |
#15
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[QUOTE=rebglass]
Quote:
126 Eagle Ridge Yellville, AR 72687 I'll go to your website and see if I can use PayPal. Yes, I thought that the students just got a copy of the design and went from there. I would be very interested if there were a course on how to do the design itself. Would it be possible/interesting to do a course on how to actually develop a design for the various kinds of folders? Maybe simple slipjoint, multiblades, liner lock, automatic? Maybe with CAD and then/alternatively, "by hand?" Reb |
Tags |
blade, folding knife, forge, knife, knives, switchblade |
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