I bought a fully serrated #45S Big Chief with a broken backspring, just to see if I could repair it, and besides, I own a #45EO I can use as reference. Reading the patent on my #45EO, it seems the Big Chief is assembled quite simply and with minimal parts (blade, frame, backspring, pin). Four parts, vs. roughly a dozen or so for a standard traditional slipjoint (four bolsters, two liners, two handle slabs, three or more pins, blade, maybe a spacer, and backspring) Thus, I chose a Big Chief as my "first" for knife repair.
The patent shows the backspring slides in through the second slot, located at the butt end of the the knife. But, I'm not sure how exactly it would go in with a blade installed By design, it has no rocker pin, and the soft aluminum frame and the pin for the blade are all that really hold the knife together.
https://pdfpiw.uspto.gov/.piw?PageNum=0 ... %3D2728139
Is this a simple job I can do with a Stiddy (in addition to a drill press, center punch, and standard peening tools), or am I out of my mind? And does anyone have a Big Chief backspring or a complete knife I can use for parts? And if I learn this right, can the same method be used on Barlows?
Repairing a Big Chief
Re: Repairing a Big Chief
Having not taken one apart, I'm wondering, if that spring is under compression (traditionals are)? In compressing a traditional spring...you have access to the spring, for using some "vise-type" tool. Looking at the diagram, I'm wondering how you would compress the spring...it appears that the handle would block traditional methods of spring compression? Hopefully, it's not under compression...which would make it even easier to put together. I'm interested in what those, that are smarter than I, have to say. I'm guessing that finding the replacement spring will be the hard part; however, I shouldn't underestimate the AAPK community. Take pictures, when you do it! If you can place and peen pins...and have some means of compressing the springs...traditional knives shouldnt be any harder; although, having the equipment to cut and finish handle materials comes in to play.
Heretical Refurb / Mods of cheap old folders, since late 2018
Re: Repairing a Big Chief
I put one back together after repairing it a few months ago. It is a very simple, quite ingenious design. The tab on the butt end of the spring (32 in figure 4 of your diagram) locks in through a slot on the back of the knife ( 22 in figure 4 ) and then you compress the spring from inside the knife ( I used a small scrap of micarta the same thickness as the width of the blade well in my vise) the tab at the front end at the front (30 in figure 4) comes out in the front slot as the spring compresses. Slide the blade in place, insert and peen the pin and you're done. For the pin I used a steel nail that fortunately was the correct size to better match the aluminum. You will need a complete spring for this knife. I got my knife as a parts knife from a seller of Queen parts and there are a lot of leftover parts out there. Let me know if you want some pics of my knife or need any more help.
"Better to do something imperfectly, than to do nothing flawlessly." ~ Robert H. Schuller
Herb
Herb
Re: Repairing a Big Chief
That was my hallucination...that if it was under compression, some type of insert, to fit in the well, would be required.herbva wrote: ↑Thu Oct 29, 2020 2:06 pm I put one back together after repairing it a few months ago. It is a very simple, quite ingenious design. The tab on the butt end of the spring (32 in figure 4 of your diagram) locks in through a slot on the back of the knife ( 22 in figure 4 ) and then you compress the spring from inside the knife ( I used a small scrap of micarta the same thickness as the width of the blade well in my vise) the tab at the front end at the front (30 in figure 4) comes out in the front slot as the spring compresses. Slide the blade in place, insert and peen the pin and you're done. For the pin I used a steel nail that fortunately was the correct size to better match the aluminum. You will need a complete spring for this knife. I got my knife as a parts knife from a seller of Queen parts and there are a lot of leftover parts out there. Let me know if you want some pics of my knife or need any more help.
Heretical Refurb / Mods of cheap old folders, since late 2018
Re: Repairing a Big Chief
You are too hard on yourself Doc! This is the first knife I remember working on that didn't have a rocker pin, or even a butt pin for that matter. Those "tabs" at each end of the spring do all the work and the front pivot pin holds the spring under compression and holds everything together. As I said, quite ingenious. I think there may be other folding knives with somewhat similar arrangements involving a "concealed" spring.Doc B wrote: ↑Thu Oct 29, 2020 2:20 pmThat was my hallucination...that if it was under compression, some type of insert, to fit in the well, would be required.herbva wrote: ↑Thu Oct 29, 2020 2:06 pm I put one back together after repairing it a few months ago. It is a very simple, quite ingenious design. The tab on the butt end of the spring (32 in figure 4 of your diagram) locks in through a slot on the back of the knife ( 22 in figure 4 ) and then you compress the spring from inside the knife ( I used a small scrap of micarta the same thickness as the width of the blade well in my vise) the tab at the front end at the front (30 in figure 4) comes out in the front slot as the spring compresses. Slide the blade in place, insert and peen the pin and you're done. For the pin I used a steel nail that fortunately was the correct size to better match the aluminum. You will need a complete spring for this knife. I got my knife as a parts knife from a seller of Queen parts and there are a lot of leftover parts out there. Let me know if you want some pics of my knife or need any more help.
"Better to do something imperfectly, than to do nothing flawlessly." ~ Robert H. Schuller
Herb
Herb