Index pins in the spine??

L6steel

L6steel

Joined
Sep 23, 1999
Messages
5,855
Yuck, sounds horrible don't it!!!:barf: :barf:

Well not when you're talking about the spine/spacer of a folder. :D
I was thinking about adding a couple 3/32" stainless index pins thru the liners and spacer on my big liner lock to add some strength. I just don't think two 2-56 screws are stout enough for a big hard use folder like this.
Anyone ever done this or know of another maker that does it?
Does it make sense or should I just add a couple more screws or even bump em up to 4-40 maybe?
Thanks up front guys!!!
 
Michael, I use 1/16" pins to keep the back bar solid. 2-56 screws are plenty strong for user folders but the pins just make me feel better.
 
Mike,
I use 1x72 screws and no pins. A 1x72 screw is .074 and a 2x56 is .088 (best I remember), so why would a .062 pin help?
With a good fitting pivot bolt and backstop pin, and 2 or 3 screws what can move?
So much to learn about these folders ;) :)
 
If I use the back bar as a blade stop I always put two 1/16" pins along with the screws. As Kit said with a good stop pin they arent needed. My pins are worn out drill bits. There are plenty of them laying around my shop.
 
Kit, I'm not using stop pins anymore. I'm making the spacer work like the back spring on a slip joint. It's the spacer and the blade stop. It's 440c and I heat treat it just like the blade.
Hmmm, maybe I'm just being paranoid.
I have been known to lean that way a time or two. :D
 
Mike,
Yea, I know. Remember the bolsters with the gazillion screws in it? :)
I have did a lot of folders like you are talking about, so I know what you mean. Try putting one screw thru the end of the backspacer (where the backstop pin would normally be) and 2 or 3 toward the back end.
I had to do the Crosslocks that way since the backstop pin couldn't go thru both sides (blade comes out each side).
 
I use 2 1/16 hardned dowel pins when putting together my knives. It helps keep everything aligned espically when drilling holes in the liners for scales and bolster screws. I think my knives have a more solid feel with them in. They are espically necessary when building autos.
 
Mike,
We could tell you a dozen ways you could possibly make your folders stronger but only you will know when you reach the point of diminishing return.
 
Originally posted by Kit Carson
Mike,
I use 1x72 screws and no pins. A 1x72 screw is .074 and a 2x56 is .088 (best I remember), so why would a .062 pin help?
With a good fitting pivot bolt and backstop pin, and 2 or 3 screws what can move?
So much to learn about these folders ;) :)
(best I remember),
Click to expand...

I can't remember so I looked :) considering wire size and cut..
a little less than that figuring the bottom of the pitch
and toped with a stress factor of the v shape
( thread grove .0670 opox)

TAP****TAP DRILL**Decimal*Drill Size***Theo. % of Thread
2-56******51*********.0670**************82

but in turn you have a clamping factor too to keep things put.
the little boogers do well..but as kit says more screws the better.
I use pins sometimes,, other than the pivot and back stop.
not really needed all the time but I have the holes there anyway in the way I
make mine, they are alignment pins also on the tooling jig I made.:D :)
 
If the back spacer is being used for a blade stop, at least two dowels are necessary to keep the spacer from moving when the blade hits it.

Screws won't keep anything in location. Only dowels (and screws).:)
 
Originally posted by Don Robinson
If the back spacer is being used for a blade stop, at least two dowels are necessary to keep the spacer from moving when the blade hits it.

Screws won't keep anything in location. Only dowels (and screws).:)
Click to expand...
sorry but
82 deg counter sunk holes with matching screws, will align and hold:)
 
And in this corner at 98.6 pounds we have..........
Looks like I asked a good question, lol!
I trust Kit's opinion and methods 1000%!
I just wish I could learn to trust my own work, ugh!
Reason I was considering using index pins is because these little 2-56 screws can be sheared off easily. I know there's a big difference between when they're holding a folder together and when they're stuck in thru one piece of steel lined up with a sharp blade that's made to cleave them but that image stays in mind and I would hate for someone to be using one of my folders, especially in an emergency situation and have one of the screws shear and the knife come apart.
I guess this is one of those better safe than sorry situations.
Is it better to go ahead and take the time to put in the two pins and have the peace of mind or just leave things as is.
I agree with Bruce, the pins would need to be hardened steel to be effective.
Looks like some testing is due.
I'm going to put one of my folders together in the semi finished stage and beat the bazookies out it and see if I can shear the screws or not. I'll post results and pix when available.
Thanks for the input and puttin up with me guys!!!
I love all you bastids and wouldn't know what to do without you!!!!!!!!
 
And now for another kick at the can --on one of my first folders I tried the screws only approach but after a bunch of "flick of the wrist " openings I found the liner lock bottoming out on the far side. It was difficult to get the liner screws out ,and on inspection I found that the threads on one side of the screws had been hammered almost flat,allowing the spine/stop to shift back slightly.I think that the knife would have been unusable long before any catastrophic failure. Now I use a piece of 1/16" spring wire in a reamed hole close to the blade contact point and have had no problems.You can pick up spring wire in a variety of sizes at most machine tool shops. Stay sharp,Don
 
The dowels don't need to be hardened. Driving a close fitting hardened dowel thru a thin hardened piece like a back spacer might break the spacer. Something's gotta give. :rolleyes:

It's better to use a small slip fit pin of stainless or brass, or better yet, a roll pin for that.

Roll pins compress as they are driven in,giving a tight fit, but not straining the material too much. :cool:
 
Originally posted by Don Robinson
The dowels don't need to be hardened. Driving a close fitting hardened dowel thru a thin hardened piece like a back spacer might break the spacer. Something's gotta give. :rolleyes:

It's better to use a small slip fit pin of stainless or brass, or better yet, a roll pin for that.

Roll pins compress as they are driven in,giving a tight fit, but not straining the material too much. :cool:
Click to expand...

***also known as spilt pins

If you use hardened dowel pins and ream size for size it will be
a press fit and will work find too, if it moves it wears.

an over press fit, yes you could have problems with thin metal,
depending on the press size.
I use the hardened pins for obvious reasons, less wear and one less problem. just my opinion
 
Well folks, I finally did the testing.
I had the post in my mind from the git go. I couldn't wait to get the testing over with and get in here and post,
KIT CARSON 1 PARANOID BASTIDS ZIP :D

But I can't post that.

The test I did was to strike a 2 by 4 with an unsharpened blade in one of my big folders. It had three 2-56 screws holding it together with a heat treated 440c spacer/blade stop. It only took 7 strikes to shear all three screws off clean. I was floored!
On the seventh strike the spacer came completely out the back of the knife and into my hand.
I know I used more force than anyone would be putting on a folder during normal use, hopefully, but that's where the parameters of testing should go. I'm just glad I predrilled the index pin holes in the spacer before heat treat so I can now put the folder together with confidence it will stand up to use and abuse.
Now my only problem is how am I going to get those stinkin sheared off screws out of the liners?

Here's a pic of the knife after testing.

foldertest.jpg


Maybe this is a sign that spacers/blade stops aren't a good idea after all. Maybe on big folders we should stick with stop pins which are in effect an index pin.
This sure is making me do some thinking about it!
 
Don't know how I missed this.

I've only done a couple folders with the solid spine/stop. On the last one I put a 3/32" hardened pin through it and into a blind hole in both slabs (framelock) and then a 2-56 screw through one scale and the spacer and then threaded into the opposite scale. Made it pretty solid with a minimal amount of fasteners.
 
What did I tell you? At least 2 dowels or roll pins are necessary to prevent shifting. :rolleyes:

I'm glad you did that test that way, Michael. It certainly shows that Murphy's Law always applies, doesn't it?
:eek:
 
Michael, If the liners are titanium just throw them in the etchant for a few hours.--also works on broken taps (0-80 takes 95 min. 2-56 takes 127 min, average!!!) Don
 
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