To Peen Or Not To Peen, That's The Question.

T.Saslow

T.Saslow

Periodic Thinker
Joined
Jun 12, 2013
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This is a question I have been trying to figure out for a while and have gotten some varying opinions. Some people peen their pins, others don't. Then there are those who cheat and use corbys, loveless, or other forms of screwy hardware ;) I like to use straight up brass, SS, or nickel silver pins for simplicity sake, but I find myself second guessing my methods every time I do a glue up. I do not peen my pins or flare out my lanyard tubes and I use G-Flex epoxy under all my handles thanks to all of you who indirectly convinced me to get out of my hardware store adhesive isle and get some of the good stuff!

Keeping in mind that (from what I have heard) Pins are for shear force and the epoxy is for pulling the scales towards the tang, Is it necessary to peen the pins when using a good epoxy? One of the reasons I ask is that I have a bird and trout I want to put a piece of snakewood on and I know that snakewood is prone to cracking over time. I don't want to put it under any unnecessary stress.

Thanks for your thoughts!
Tanner S.
 
The first time you have a scale pop off you'll start peening your pins or switch to corby pins.
Some adhesives are better than others and you can improve adhesion a number of ways, but adhesives still fail. That's especially true in a field knife that will see a wide range of temps.

If the knife is for indoor use you'll be fine. If it's going to see a wide range of temps, like being carried outside on a freezing day then getting stored in a hot vehicle, then it's worth your time to peen.
 
Thanks, I will keep this in mind :)
Now, I have this customer blade I have been working on and he wants some Hawaiian mango on his handle with a 1/4" tube and two mosaic pins . Since you can't peen the mosaic pins (or at least I don't think you can?), how should I go about affixing the handle to this blade? Would I have to add additional pins to the handle to be peened over?
 
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With respect to the previous post , In my 25 years as a maker I have never had a scale "pop " off with glued in pins and my knives are used hard by professional guides in the hunt business , among others. I think you have answered your own question , especially with snake wood that will crack even with glued in pins . I don't think anyone would flare the pins in that situation. I use four small pins on my handles ,3/32 . This more evenly distributes the holding force around the handle and I believe the four small pins has more surface area for the glue to adhere to than two larger pins. Even with the 4 small pins I wouldn't have them so tight that you need to tap them in . Have the holes just slightly oversize so you can push them in just with your fingers and glue up with the West systems or even better the new Blade Bond epoxy . It holds better then the G flex and is more impervious to temperature fluctuations according to the manufactures and the few makers that have used it.
 
Well this adds a new piece to the puzzle. I guess it would be best to see what others have to say, but thank you both for your opinions.

In this particular case (the bird and trout) I am using one 1/4" tube at the rear end of the handle and one 1/8" pin towards the front. I generally drill the holes the same dia. as the pin itself so the pins are tough to push in like you said.
 
when I was at Carter Cutlery, I learned Murray peens all his pins, nickel silver.
I don't think Murray does anything he doesn't need to do or feels is unnecessary IMO
I just started peening my pins
 
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I do not peen my pins, but I am considering doing so.
For a 1/8" pin, I generally drill at 9/64" it doesn't give too much room for the gap to be visible, but it does provide enough for the joint to not be dry.
That being said, I have done my share with a 1/8" hole and pin and I have yet to see any failures.

I don't know if the additional gap I provide the pin is sufficient or just a mental thing, but it works for me. It is nominal (.016 gap surrounding) which still may not be enough, but I am still experimenting.
-----
What size bits and pin stock do others use?
 
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In snakewood, i would not peen. Some woods are very good about slight deformations, while others will crack in a heartbeat.

Woods I do peen on: Rosewoods "not including african blackwood" maple, walnut, most softer stabalized burl, bocote, bubinga, and ziricote

Woods I dont peen on: Ebony, ironwood, snakewood, African blackwood, anything endgrain, lignium, pink ivory or katalox
 
Ben, it seems that the higher hardness woods you prefer to not peen.
Does density have anything to do with this?
Does stabilization have any affect of your preference?
 
I haven't been doing this 25 years, but I have had a scale come loose. It didn't pop off, the rear 1/3 of the scale near the pommel came loose. Amazingly enough, the tang had been left with 60 grit scratches, and then degreased and blasted before using G Flex epoxy. Sometimes things just fail. I use Corby's now.
 
NJBillK said:
Ben, it seems that the higher hardness woods you prefer to not peen.
Does density have anything to do with this?
Does stabilization have any affect of your preference?
Click to expand...

Not exactly. While there is some correlation, a wood like kingwood, with a hardness rating of 3,340 foot pounds can be peened without too much trouble, where as technically softer woods like gaboon ebony "3,080 pounds" or desert ironwood "3,260" are more likely to crack.

It comes down to things like modulus of elasticity and rupture, but over all rosewoods are the kind of shining exception to the hardness rule. If you have done much work with ebony, im sure you know it cracks like all hell. Same with snakewood.

As for densities relation to all this, in wood density and hardness are over all pretty much a direct correlation. There are certainly some outliers with this, but its a general trend. Woods like Bocote are soft for their weight, where as woods like purple heart and black locust are very strong for their weight. When i am saying strength, im mostly measuring by janka ratings, which is a measure of a woods resistance to deformation. A very strong/ hard wood like ebony would not stand up to being whacked by a hammer as well as a tough wood like say, hickory. That is not to say ebony is a bad choice. It is a great choice for knives, but when you would be putting it under forces like those from peening, it would not be a great choice.

Most stabilized woods are are alright, as the woods you commonly stabilize "walnt, maple, redwood burl, koa" are relatively soft and forgiving on there own and the resins used are also slightly elastic.
 
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Greenberg Woods said:
In snakewood, i would not peen. Some woods are very good about slight deformations, while others will crack in a heartbeat.

Woods I do peen on: Rosewoods "not including african blackwood" maple, walnut, most softer stabalized burl, bocote, bubinga, and ziricote

Woods I dont peen on: Ebony, ironwood, snakewood, African blackwood, anything endgrain, lignium, pink ivory or katalox
Click to expand...

This helped a ton! Thanks!


Thanks for all the comments guys, It really helped me out :)
 
I don't peen pins unless doing a domed pin. Made well over 1000 knives with glued in pins and never a problem.
 
While adhesives MIGHT hold for a long time, mechanical fasteners WILL hold for a long time. If you use mechanical fasteners properly, there is no need for glues.
If you are cracking material (especially woods) when peening, you are doing it wrong. I routinely peen pins in mother of pearl without cracking it.
I can't understand why knifemakers refuse to learn to peen pins, and use the excuse that it's not necessary.
 
Personally, I prefer to peen pins just for an added safety factor. You don't know where the knife will end up, what kind of conditions it will see, how many times it will be dropped, left in a hot car, etc... that may contribute to the epoxy wearing out prematurely.

Now, obviously you can't peen mosaic pins, so there are a couple of ways to get around that. Some makers will shorten a same diameter corby to set about 1/8" below the surface of the handle or so, and then slice off a short length of mosaic pin to inlay over the now hidden corby.

You can also just rough up the outer walls of the mosaic to give something for the epoxy to grab, although I like the previous method better.

Lastly, you can add some additional peened pins or corbies to the handle and just use a mosaic in strategic locations, but this is more a matter of personally preference.

Of course, just drilling and gluing mosaics may be fine for the rest of the usable life of the knife, but I think a little insurance is nice. YMMV
 
BTW, this may go without saying, but when inlaying mosaic pins over a mechanical fastener, be mindful of heat when flushing up to the handle. Any excess heat will weaken the adhesive behind the inlay.
 
I use a lot of copper and aluminum pins, usually 1/8" and 3/16. Is there a general consensus on the best way to taper the holes? A deep narrow taper or a shorter steep taper? I epoxy my scales without the pins and then pein the pins in after with a bit of epoxy. It's hard to find information about peening as everyone prefers modern mechanical fasteners, but aren't peened pins really the original mechanical fastener?
 
Bill DeShivs said:
If you use mechanical fasteners properly, there is no need for glues.
Click to expand...

Maybe not from a keeping the scales attached to the knife standpoint, but as far as preventing liquids from getting under your scales and causing corrosion... yes, you NEED some sort of glue.
 
When using a mosaic pin, I will often notch the inside or the hole in the scales at the 12:00 position with a small round burr in my Dremel and cut a small notch in the pin at the corresponding position with a similar burr or tubular bit (cutting width ways).

This will allow the epoxy to bind to each piece and secure them against one another as opposed to just a cylindrical bite.
 
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