Pivot Pin Question

Burchtree

Burchtree

KnifeMaker & Moderator
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Anyone use these types of pivots?

For installing, do I press fit one end to the back piece and slice off the remaining excess when it is all put together? If not, what is the process for this type of pivot?

Thanks --

pic stolen from knifekits -- :o :D

drspb4.jpg
 
michael, I let them go through both liners, grind off flush with out side liners, counter sink the bolsters to accept the screw heads so when you screw the blosters down tight it keeps everything nice and in place. when you grind down the pivot pin for length, be sure and make them the same length as the blade,washers and liner thickness added all together. I'll be watching this thread, I'd like to know if this is how others do it too.

Bill
 
Things can vary a bit...but I measure blade thickness plus two washers plus two liners and subtract a few thous..then grind or file to length. You must be a bit shy of overall length so that it pulls up tight or just short of tight so that it pivots freely. Things can vary a bit depending on scales. Normlly the screws have to be shortened also. I really like the pins with one integral shoulder. I then file a small flat on one side of cylinder wall, pein one liner next to the pivot hole so that the pivot doesn't pivot and put altogether. Questions??
 
Bill - -- that's what I thought I'd do. How are the actions on your folders working for you with that method? Are they smooth, or do they seem like they should be tighter?

If need be, I guess i could do a little countersink (this will be a straight frame-lock) and since it is a button-head screw it would pull the handles a little tighter if needed (or is that what you just said Bill?)
 
I make and use the same type of pivot for my folders. I use a mic to measure the thickness of my liners, washers and blade as a unit. I then put the pivot in a holder and using my surface grinder, grind the pivot to .0005 over my needed length. I then assemble the whole knife and check for blade play and freedom of movement. If things are loose I remove the bolster, scale and pivot screw on one side of the knife and run it across a piece of 400 grit to shorten the pivot just a bit. Reassemble and test as before. Continue until it meets your standards. This method works if you hide the pivot under the bolsters. If you use an exposed pivot this method will not work.
 
Michael, I do like Arthur does, leave the pin a tad long and then fit and test until it works the way you want it to. You can make them real smooth or a bit stiff depending on amount of pin removed, be very careful. I drilled and reamed a hole the exact same size at the pivot pin in a piece of plain 1/8" steel, I just slide the pin in take a measurement with my calipers and grind off square with the steel laying against the grinding disc, just push the pin in to remove excess, again be very careful and take measurements frequently, it grinds off really quick. then I finish up by hand sanding using a piece of glass to sand across. Good luck

Bill
 
Thanks again fellows -- one more question -- are you press-fitting this pivot or should this one just be reamed with the same size?
 
Mike, I'm in the process of making my first two framelocks. I have three reamers in and around 0.188. After testing on a piece of scrap ti, I had a nice press fit on the first pivot pin. I measured the second pivot pin and it appeared to be the same. 0.1882. When I reamed the second handle, the pin can be pushed out with firm finger pressure. I will have to do something to correct this. My message is, these things are very precise, so beware that when it comes to press fit, in so small a size, it reguires more control over fittings than some of us have. If I had a mill, if I had a lathe, if I had better mics, and so on, and so on. I don't have any of these, perhaps I should if I desire to make folders.
 
Hi Mike, I don't press fit my pins, I just ream, blade liners and bolsters to 1/8'', I then counter sink my bolsters for the screw head. I use .125 pins in my folders unless I make a big one then I use 3/16''.
I use this type pivot but I also use the integral type from pop's.
Hope this helps.
Don Hanson
 
Michael, I've been using the pivot pins from Halpern that Peter Atwood uses (he uses 3/16" now, but I watched his video and bought some 7/32" because that's what he did), that are press fit on one side and slip fit on the blade and the front scale. You grind off the excess and shape it how you like. I am *this close* to making a working folder, but I like that style of pivot a lot. I tried a balisong with the type of pivot you showed and it seemed overly complicated to me... I'm sure you'll make it work no matter what you use. Can't wait to see pics! I keep trying to cut corners ("GEe, I know these should be clamped together for this operation, but screw it, I'll drill and ream them separately...") and screwing myself on each folder project, so I know the next one will be THE one. Either that or you'll see a bunch of reamers, hardware, tappers, drills and titanium up for sale! ;)
 
Hello peoples!
Same pivot I use
I made a jig/holder so I can turn the pivot in my lathe.
I use a black sharpee to color it, then scribe the length with my calipers, need to come up with a better method for this proceedure, and cut near the line and clean up the face, take it off and measure. Usually only takes a time or two to get it the proper length. Them small Harbor Freight lathes are handy critters, I think everyone should have one!
 
I use the straight pivots as shown. I get them from Halpern titanium, and they never vary in size. I use 1/8 and 3/16 for the pivot, and 1/8 for dowel pins to hold everything in line.

I grind my pivots the length of the blade, two liners,and two washers plus .002" If I find that's a little too long at final assembly I grind or sand off a little.

Like Bill Buxton says. That way the bolsters squeeze everything together. Sometimes I counterbore the bolsters for the pivot screw head and leave them showing. Other times I hide the pivot under the bolster. Either way, the bolsters squeeze evrything together.

I use a standard size reamer for a tight slip fit in the liners.

Good subject, guys. :D
 
Thanks again -- the pivot is drilled and reamed. Now, all I gotta wait until tomorrow for a 3/16 reamer to come in from MSC to start on the stop pin.

This folder ain't going to be pretty, but it'll be going in my pocket anyway. :D
 
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