Smooth opening folders !!!

[Diggerdog]

I've been building lock back folders and trying to find the best way for smooth opening and closing of the blade. Mostly I've tried using a 1/8" pivot pin with using no washers and using washers. Without washers the blade will open and close smoothly however the pivot pin has to be a bit loose and so there is a slight amount of blade play. The nylotron washers I have are approx. 16 thousands each so to use them I have to mill out that amount of space from each liner. I get no blade play but the blade is stiff to open and close. Would using a larger pivot pin make a difference. Is there some other way to mount the blade so that it will open or close more freely. Any help would be most appreciated. Thanks. Dave

 

[Stacy E. Apelt - Bladesmith]

Don't mill out all the washer thickness or your blade will be rubbing on the liner.You still have to set the pivot tension exactly right to get that smooth blade "walk and talk" action.

 

[Don Hanson III]

On my slip joints I use two .005 bronze washers and surface grind the blade .010 thinner than the back spring. No milling nesesary and smooth with no blade play but everything must be very flat and all holes must be 90 deg.s. I also use a 3/32'' pivot pin on slips. For liner locks I use an 1/8'' pivot for smaller folders and a 3/16'' for larger folders, .010 washers and grind my blade .020 thinner than the back spacer, again most important is "everything flat and all holes 90 deg.s" This is a good rule for all folders including lock backs and the thickness of blade plus washers must be exactly the same as lock bar, back spring or back spacer for a smoth folder. The last lock back I built was a small one, I used .005 washers and a 3/32'' pivot pin, it worked very good. Hope this helps.

 

[Diggerdog]

Thanks guys. Sunfishman, I have been grinding the lockbar a couple thousands thinner than the blade and the backspacer just to eliminate friction there and then milling out about .010 on each liner to accomodate a .016 washer. My holes are drilled at 90 degrees but I think I definately need a surface grinder, especially to work with 0 degree clearances. Thanks for the advice. I'll start a new thread to see what opinion is out there for the Harbor Freight surface grinder. Cheers guys.

 

[Darrel Ralph]

Phospourous Bronze works fantastic!

Knifekits.com has them in a bunch of sizes.

 

[B . Buxton]

You've gotten info from two of the best folder makers around and I forsure am not even close to being any kind of an authority. But my folders are baby butt smooth and I do everything without a mill or a surface grinder, I'd love to have both but its not in my near future. I made little things that help me get pretty precise measurements. just an example, I use a piece of 1/4" x 1 1/2" stock with a hole drilled and reamed the exact size of my pivot and stop pins, this way I can using a worn 280 belt at low speed on my grinder place the bar stock against the belt and then gently press the pin through the stock into the platen take it slow and check often and I can get my pins within .002, anyway thats what my caliper and micrometer says. And I drill all my holes using a bench top drill press from home depot, I just took a great deal of time to make sure my table was set at true 90 degrees.
Those precise machines would be nice to have, but don't think it can't be done without them, it might take longer and more head scratching, but you can make a pretty nice folder without them.

Have fun,

Bill