does a fixed blade NEED pins?

D

drano

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Jul 17, 2005
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if i epoxy handles onto a full tang fixed blade, do i really need pins?

this hypothetical knife is a small skinner with a blade of 2.75" or so and wouldnt be put into any "hard" work.
 
On a full tang knife, pins will give extra hold for the scales but on a small knife like that, it should be fine without pins IMHO. Just make sure the tang is extra clean from oils and stuff. You should rough up the scales and I'd even drill partial holes on the insides. I'd also use slow setting JB weld.
 
Most epoxies I'm familiar with really don't bond that well to metal (even those that list metals on what they stick to). And very few I've tried have much strenght against lateral forces. I wouldn't trust the handle slabs to stay on any full tang knife with just epoxy.
 
I have a couple of knives that I used either epoxy or JB weld on, they have not failed yet but I do not use them that often either .
When I do use them I always have in the back of my mind that Iwish they had pins as well :D

Also , IMO pins can add pizazz to an otherwise same ol-same ol handle.(think mosaics).
 
I have a Randall model 14 and a model 15. Both have the full finger grip micarta handle epoxied on without pins. Randall Made Knives has been doing it like that for years. Neither of mine has come loose yet, and they both have been used alot. I'm not sure if they partially or fully drill their tangs or not. Anyone know?
 
Short answer - YES you need some sort of pin!

Longer answer - Epoxy is made to be an adhesive,not a structural component. Epoxy columns connecting the sides through holes in the tang are good,but they do not replace structural components like pins,rivets,and bolts. Most epoxy jobs fail because all the epoxy is squeezed out by over-clamping the scales during glue-up. There should be a thin layer of epoxy between the scale and the tang. No epoxy=no strength.Some makers put thin washers on the pins to raise the scales a few thousandths of an inch to allow for an even epoxy layer.Dying the epoxy to match the wood makes this layer nearly invisible.Some dye it to a contrasting color and leave it a little thicker.
Another method is to relieve the center of the scales about .050 to allow for a good layer of epoxy in the middle. This makes the edges a flush meet to the tang.The flush area only needs to be about 1/8" wide,inlet the rest.No need to make the relieved area nice and smooth,either.The rougher surface provides a better grip on the epoxy.
Stacy
 
I often will use a single mosaic pin and then do hidden pins. Drill multiple holes in the tang, then drill about 1/2 way into the handle scales on each side. Cut the pin short, and you can then glue with pins without seeing them and those hidden pins will help in the same way for lateral forces. You can do this and I think its nearly as strong as a full pin, since you would still need to basically shear those pins before the handle would come off.
 
One more option on the hidden pin design is to drill holes for pins, say for 1/4" pins, and thread the holes. Then you simply thread a standard 1/4-20 bolt in and cut or grind the ends off. The threads give a lot of surface for the epoxy to bite and being threaded directly into the tang they will not move all over the place.
Matt
 
From my short knife making experience, my awnser is yes you need some sort of pins, either hidden or otherwise. I made a small skinner, with walnut scales inlayed with corian, I epoxied the scales on with no pins, within about a week the scales were falling off. so my awnser is yes I would pin it in some way
 
Drano,

I just shipped one of the only full tang sporting knife I build. I built and sold the first one of the same design 26 years ago and have not heard a word of problems on any of them I've built since. The key is to do ALL OF THE ABOVE ADVISE for hidden pinning. Relieve the scale centers, pin through with 4x20 or 6x20 headless screws, rough all surfaces and I go as far as to reverse bevel the holes in the scales bigger to form epoxy heads for the screws. Make sure the steel is clean and rough. The rougher the better. I grind or drill channels all the way through in the tang to make sure the epoxy has something to grip to besides steel. Also these guys are telling you right…the epoxy WILL release from the steel if you give it half a chance, so don’t.

I would add…spine flex is the enemy of epoxy. Harden the tang and use the thickest steel you can stand. I’ve built some saw blade kitchen knives over the years that are pretty thin and only had one problem, but if it’s a knife I’m going to depend on…don’t take any chances.

Hope this helps. Keep pushing the technology.

chiger
 
Also, look up the glue wars thread.

One of the main conclusions there was that the single most important factor in glue strength was proper surface prep done just before gluing. Sandblasting worked best in their tests. Those of us without a blaster will just have to rely on rough sandpaper, but doing it just before glue-up is critical.
 
If the knife ever gets dropped (ARRRGH!), you'll be glad it's pinned.
 
"if i epoxy handles onto a full tang fixed blade, do i really need pins?"

Yes!

Hidden pins work.

You should also experiment with making patterned pin arrays. You don't have to stick to boring looking 2 or 3 pin handles. Try things like having two groups of pins, one set of three or four at each end. You can vary the sizes. The possibilities are many.
 
If you absolutley want to go without pins you can use fiberglass resin, it holds to bare metal extremely well but i would still recommend you at least use hidden pins. If you do go with just resin sand the metal surface with 80 grit sand paper and wash with some windex or ammonia based cleaner. I glued some walnut scales onto my throwing knife 3 years ago and it withstood the abuse.
 
I also would have to say yes. If it's a hard use knife, as soon as you would have any type of shock to the blade such as chopping, batoning or lateral force those scales will pop off.
Scott
 
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