Folder makers? Final Fitting of Pivot...

[Hankins]

Final Fitting of Pivot...
Goal is to make a butter smooth Professional custom

Constructing some Bali's but the same is true for regular folders that use a Pivot with a screw. They are sandwich style.
Need to adjust the length of the Pivot barrel and get it flat.
Using Alpha Knife supply press fit pivots thru the handle liner.
Plan is to use the same sized steel as the blade for a Lapping thickness guide.
Press the pivot thru the handle liner. put two washers on then stick it thru the Lapping guide steel to get the proper height.

My question is: Do I make it a snug fit and adjust the tension with the screw (6-64 thread) and just use LocTite?
or
Try to get tension by hand lapping the blade thickness?
Have a surface grinder so that is not and issue.
Really could use some expert advice at this point:thumbup:

 

[Ed Caffrey]

I use bushings in all of my folders (either bronze or 416), carefully making the thickness of the bushing approx. .0005 to .001 thicker than the blade, then I "clamp" the pivot screw down tight. This forces the blade to rotate on the OD of the bushing, which produces less wear over a longer time. I also think that in order to achieve a "buttery smooth" action, a maker must consider the type of washer material used, and their thickness. (I personally use bronze washers in .010 thickness, and gently "lap" the washer faces)

Ultimately, getting a super smooth action on a folder also requires that every part be "dead on" as far as thickness, straightness, and finishes are concerned.

Concerned pivots, I use barrel pivots, that are ground to a length equal to the width of that liners with the back spacer installed. I used pressed in pivots for a while and found that I had a much more difficult time getting them right, simply because there are so many minor things that can go wrong....and it can be very frustrating and time consuming finding and fixing all those minor things.

 

[Hankins]

Thanks Ed!
I am using Bronze bushings as well as Bronze washers, mine are .013 thick.
You are right getting everything at a true 90 is key especially with longer blades.
So to "Clarify" the liners for the handles will rest on the top of the bushing, using the Pivot barrel as the tightening spot?

Then after having gently lapped the washer faces and bringing the blade to its final finish. The Bushings should be just a "Hair" above the washer on ea side to allow smooth opening... Correct?

 

[balibalistic]

Robert, that is correct! only on bali's you will want the bushing atleast .002 thicker then the blade. i find .003 even better. these knives have alot more rotation then a standard folding knife. and we want NO pinch what so ever. i suggest you use back spacers that are atleast .040" thicker then your blade and use .020" thick washers. this will give you enough room to make bushings up to .003 oversized and still prevent your blade from ever hitting insides of handles.

i'm working on a knife right now with .200" blade and .230" spacers with .015" washers and i'm having a hard time getting things right. the spine is at full thickness so theres very little room and tolorances need to be right on. save yourself the frustration and go with thicker back spacers

 

[Fellhoelter]

If you do go with bushings, I preferred the method of bushing being a bit longer than the stack of blade/washers.
The washer hole is a little larger than the diameter of the bush.
It makes assembly/disassembly for fitting the lock, etc easier.
Stack everything up, slide it in, and everything stays together until you get it to the pivot hole and get your pivot in.

 

[Hankins]

Great advice! Took a few pics today of a Jig that hopefully will work to get the Bushings to size and keep everything squared-up.
Bushings are press fit in place, then a washer added. Surface grind both flat and Repeat. Re-Lap the washers for clearance.

Of course I have no 1/4" ID washers on hand that are worth using.
Took the pic using an oversized washer what was on the bench for illustration purposes.

Hope this is what you guys mean...

 

[Hankins]

"Yea Baby" Thats what I'm talking about :thumbup:
Now if I can only repeat it.... Will know soon!
Yep it worked. Second blade not as perfectly parallel first shot but was easily corrected.

 

[Hankins]

We are getting there slow but sure!
Got her smooth as butter, perfectly centered blade, no side play and thin washers as well...
Need to get a finish put on but it's getting close.