PINS,PLEASE TELL ME ABOUT PINS!

#1
Hi Guys,
It is the blade pivot pins I am mainly concerned with.
Sure! I know they come in brass and SS but do pivot pins have a consistent diameter or does this vary according to the physical size of the knife.?
I am grateful for what ever you can tell me about this subject,

Grahame
 
#2
Hi Grahame

I’m not really sure what you are asking here? Pins are usually same diameter all along, pivots generally have a barrel that a folder pivots on and then usually larger diameter ends often screws that tighten against scales and hold everything together. You can get different sized pins, barrels and screw heads so many combinations are available. Larger folders generally have larger pivot diameters but I am not sure there is a real rule for this.
 
#3
hi Ian ,
Thanks for your reply

Given that I intend making and repairing traditional folders I guess I am trying to minimize the stock diameters I need to have at hand.

From what I see small knife - small pins and same for a large knife - large pins .

Do knives generally use the same stock diameters available as, say on a K &S brass selection.

Or are knifemakers like firearms makers who place the own special spec (thread) sizes. Do Knife manufacturers keep to standard pin stock sizes. ?

Thanks again

Grahame
 
#4
Hi Grahame

Well I was waiting to see if anyone else responded as I'm sure there are others with more experience on this subject than I but here goes.

Yes small knife smaller pins and the opposite. For scales there can be pins that look larger than the actual hole through the tang if Corby's are used.

For folders I don't think there is a actual standard but if you had some 1/8, 3/16 and 1/4 (maybe 3/8 also) the you would cover most bases. But then you have pivot length and thread size. 2-56UNC in a 3/16 pivot is what I would think of as a common combination but at the end of the day I think you are going to need to look for correct pivot hardware after you have the knife you want to repair. Trying to forecast what you are going to need is going to be fraught with danger.

If you end up wanting to buy a couple of small parts from USA knifemaker and get a shock at postage cost I'd probably put a small order in as well and share some of the postage pain to Australia. No pressure - just a thought. USA knifemaker is where I have sourced my pivot parts in the past.

Ian
 

EdCaffreyMS

Forum Owner - Moderator
#5
Likely the biggest thing that most don't understand when it comes to folders of any sort, is the need for PRECISION size of pins/parts. The reason that most folding knife parts cost what they do, is because you are paying for the precision. For example, the K & S materials you mentioned are based on NOMINAL size....meaning that they are usually +/-.005 of the size they are listed. That doesn't sound like much, but with folders, we deal with such tight tolerances, it means the difference between a part working, and not.

When it comes to purchasing pin stock for folders, keep looking until you find ones listed a "precision", then check with the seller that whatever you are considering purchasing is indeed precision...... in other words, if you purchase 1/8" pin stock for folders..... it must consistently be .125"..... NO VARIANCE...... otherwise you'll drive yourself nuts, trying to figure out why the pin won't work as it should. ;)

Something to think about, that may be helpful...... when we build or work on straight knives, we generally can get away with thinking and working within fractions of an inch. When it comes to building or working on folders, you have to train yourself to think and work in fractions of a thousandth. Some will find that silly.....until they actually start building or working on folders....then it becomes obvious.
 
#6
Thank you Ed and Ian both, for your replies.
Ian, its good to know there are more than two Aussies other than myself, interested in pocket knife repair.

I will send you a PM. My interest is primarily in Traditional knives.

Ed,
Your practical knowledge regarding how precise these pivot pins need to be is just pure gold to me. I felt there was something more to fitting pins but was unsure of what it was. You have splashed your ink of knowledge on my blotting paper of ignorance.

I have read a great a great deal in the specialist books written about pocket knife repair and have yet to find information about the precision required. I had some K&S pin stock in 1/16th and 1/8th and measured them with my metric vernier after checking it against a standard block.
Knife Dogs was one of three forums I have joined and your knowledge of the pin precision is the only I have found.


The 1/16th 3 pieces came in at 1.58mm (against the package info nominated 1.57mm) and 1/8th bang on at 3.18mm which if my maths is right, makes it one half of a thou. 0.0005"? oversize. I realise there may be variance between the K & S packs. I shall take your advice and seek precision pins.
I see new factory sharpened drills in my near future. I can sharpen my own but realize they won't be accurate enough for this work.

That, in turn, opens a can of worms in having drills that drill spot on diameters or are the holes reamed?

If that's the case where does one buy the reamers?I have never seen any advertised that are so small?

Thanks to the both of you for the effort taken in replying to my questions.

Grahame Collins
 
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BossDog

KnifeDogs.com & USAknifemaker.com Owner
#7
Only a few styles of knives use solid pins as pivots. Most folders use a machined pivot.
For knives that use pins, the majority in the US will use a 3/32” or 1/8”, some might use a 3/16”, but not many.
For knives that use machined pivot, the majority are 3/16” or 1/8”.

Knives made in metric countries use metric stock and diameters rarely align with the typical US stock.
 
#8
Thank you for the reply Boss Dog,
Now knowing that the pivot pins I will see in repairing a folder will be precision machined I would now surmise there needs to be a procedure.
Can you elaborate further on "solid' pins.are they just plain precision solid stock and cut to length and fitted as against a piece of "solid" stock that is dimensioned by turning in the lathe?

Knowing that a nominal size drill will likely drill slightly oversize, I understand that I should need to know the know the specific hole diameter in the blade, liner and bolster in advance before any pivot pins are turned up. Now that I know precision pin fits are required, how do I measure the drilled blade hole and bolster hole diameters? Do you blokes make go/no-go gauges for that?

Am I on the right track here? I seek to establish an order of procedure to avoid major mistakes in the repair sequence. I course I realise I will make mistakes but by enquiring into established procedures, I do hope to minimise any errors I might make..

I have a lathe and necessary collets to hold small brass so I envisage being able to buy oversize pin stock and turn it to the required diameter.
The procedures are was different from fixed blade knives. The addition of the pivoting blade changes the whole perspective.

Do those of you that fix folding knives in any numbers open up hole sizes in blades and bolsters to accept a larger pin for the convenience of pin standardisation and holding less pin stock? No, I would not do it to a rare folder but for the run of the mill knife that is going to be a user again, is this an acceptable way to go?


Thank you, everybody,

Grahame
 
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#9
Hi Grahame

You will want to drill undersize then ream to size rather than drill to size - it will be the only way to get a truely round hole and accurate fit to your precision pin/pivot.
 
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