Why pins?

R

rupsty

Joined
Mar 14, 2013
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Hi - forgive my ignorance on this. I'm guessing pins are for strength and stability but wouldn't today's modern epoxies be able to hold the scales on pretty well? Could you make a kitchen knife or other solid type knife with no pins?

Thanks
Rusty
 
You could make knives without pins... many do. They provide a mechanical bond that guards against sheer. When epoxy lets go, it lets GO.
 
In a word, no. You could use hidden pins, but the pins are there to give shear strength, so they must of ample length to do so. If you were to drill a series of holes in your tang, they would allow the epoxy to form bridges from one slab to the other. That gives great strength to slabs that will allow a good bond. Oily type woods will not. BUT, you still need pins hidden or otherwise for insurance. I once had to remove horn slabs from a knife I made using pins and many hole bridges. I was able to punch the pins out with not too much trouble, but after beating those slabs with a 4 pound hammer, and no success, I had to burn them off. Even so, I would still recommend at least hidden pins. The epoxy was the much maligned Devcon 2 Two Ton.
 
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LRB said:
In a word, no. You could use hidden pins, but the pins are there to give shear strength, so they must of ample length to do so. If you were to drill a series of holes in your tang, they would allow the epoxy to form bridges from one slab to the other. That gives great strength to slabs that will allow a good bond. Oily type woods will not. BUT, you still need pins hidden or otherwise for insurance. I once had to remove horn slabs from a knife I made using pins and many hole bridges. I was able to punch the pins out with not too much trouble, but after beating those slabs with a 4 pound hammer, and no success, I had to burn them off. Even so, I would still recommend at least hidden pins. The epoxy was the much maligned Devcon 2 Two Ton.
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Post does not compute. You say you need pins and then demonstrate that you don't.

Without a doubt you can make a good kitchen knife handle without pins, and even if the bond failed failed a kitchen knife handle separation is not catastrophic, i.e. you don't need to buy the insurance of pins. You can choose to, but you do not need to. You choose to use pins, I choose not to.

OTOH for several other types of knife that the extra insurance is wise, on knives that see hard use far from home.
 
Cutting a turnip (rutabaga) or a pumpkin or other hard vegetable that you have to really bear down on and having the handle slip would be pretty catastrophic. Honestly except for chopping trees I probably never put as much force on any knife as I do when trying to cut up a big ass turnip.
 
I made a hidden tang kitchen knife wit no pin. It holds up fine.
I did make the tang jagged and rough to give the epoxy something to hold on to
 
You don't necessarily need the extra "insurance" for something like a kitchen knife, because you're not really going to be in a life or death situation...

BUT You do want it because you are trying to make a knife that is the best you can possibly make. When a customer uses your knife, you want them to know that they bought a handmade custom knife, and the person who made it made it to the best of their abilities.

How disappointed would they be if 2 years after buying this nice custom knife, their kid drops it on the ground, it hits on the handle, the sheer force against it pops one of the scales right off? Even if you offer a warranty, if I were in their shoes, I would be rather unhappy.



It's not because we necessarily "need" to make a knife the best we can, but because we want to make it all we can.



That's how I look at it at least.
 
ernestrome said:
Post does not compute. You say you need pins and then demonstrate that you don't.

Without a doubt you can make a good kitchen knife handle without pins, and even if the bond failed failed a kitchen knife handle separation is not catastrophic, i.e. you don't need to buy the insurance of pins. You can choose to, but you do not need to. You choose to use pins, I choose not to.

OTOH for several other types of knife that the extra insurance is wise, on knives that see hard use far from home.
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I don't think you read my post fully. I did not advocate using epoxy only, and I would not. I am only saying that with epoxy bridges there can be great strength, if the material used takes a good bond. I would pin regardless. You are free to do as you please, but I would never buy a knife with grips held only with expoxy. Hengelo, hidden tangs are a different matter than slabs. Even cutlers rezin will hold well on a hidden tang.
 
Personally, I would avoid full tang, scale handled knives without pins... but not necessarily from having experienced any that have failed... it is purely speculative.

I don't see a big problem with hidden/stick tangs that are epoxied only... if they are done properly. 90% of adhesive success is in the surface prep.... and 74% of all internet percentages are made up on the spot, 83% of the time.:thumbup:
 
I personally like pins myself - at least visually. I had been trying to figure out how to get the pins done properly. I had already drilled the holes in the steel prior to gluing but I couldn't figure out how to drill the holes in the scales and have them marry up properly with the holes in the steel. So I glue them on with no holes. I figured I would try and drill the holes in the scales while they're glued to the knife. Is this acceptable?

Also while I'm on the topic, I want my pins to be 1/4" diameter. The next size up in drill bit (I forget the size) makes the hole slightly too big and leaves space around the pin so it flops around in the hole. How do I drill a hole just ever so slightly bigger than 1/4"? I know this is childsplay for many of you but this is my first knife. I expect to make many mistakes so I'm not worried about messing up. I have six knives in progress at the moment but this particular knife would be considered my first.

Thanks so much for the help guys. This forum teaches me so much.
 
I typically use super glue to temporarily affix the scales to the tang in order to drill them.

I use a .252" reamer to ream the holes so the pins fit tightly enough to minimize slop, but not so tight that they give me fits installing them.
 
rupsty said:
I personally like pins myself - at least visually. I had been trying to figure out how to get the pins done properly. I had already drilled the holes in the steel prior to gluing but I couldn't figure out how to drill the holes in the scales and have them marry up properly with the holes in the steel. So I glue them on with no holes. I figured I would try and drill the holes in the scales while they're glued to the knife. Is this acceptable?

Also while I'm on the topic, I want my pins to be 1/4" diameter. The next size up in drill bit (I forget the size) makes the hole slightly too big and leaves space around the pin so it flops around in the hole. How do I drill a hole just ever so slightly bigger than 1/4"? I know this is childsplay for many of you but this is my first knife. I expect to make many mistakes so I'm not worried about messing up. I have six knives in progress at the moment but this particular knife would be considered my first.

Thanks so much for the help guys. This forum teaches me so much.
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Rusty, to align the holes drill your holes in the tang, then spot glue one scale. A clamp or two is also a good idea. Get your drill or go to your drillpress and drill right through the holes you put in the tang into the scale. You now have one scale with aligned pin holes. Noe, spot glue the other scale, use the clamps again if you need to, go back to yourdrillpress and now drill through the holes you just drilled into the scale. Your bit will pass through the scale, into the holes in the tang, and then into the second scale. You now have perfectly aligned holes in both tang and scales. Hope that helps a little.
 
LRB said:
I don't think you read my post fully. I did not advocate using epoxy only, and I would not. I am only saying that with epoxy bridges there can be great strength, if the material used takes a good bond. I would pin regardless. You are free to do as you please, but I would never buy a knife with grips held only with expoxy. Hengelo, hidden tangs are a different matter than slabs. Even cutlers rezin will hold well on a hidden tang.
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I assure you I did. I was just pointing out that you said you need pins and then detailed how you could not break epoxy only slabs off.
 
I still say a slab handled knife needs pins. For insurance if for no other reason, but again, you do what pleases you. Your customer is not going to complain to me if a slab comes off.
 
I've kinda been round the block with this. Carbon steel kitchen knives get a lot of abuse: moisture, oils, hard use, occasional trips through the dishwasher.
There are bonding issues with stainless/epoxy, according to the epoxy makers.
Windows through the tang <should> work well, but they don't always...the type of wood used in the scales has a lot to do with this- oily tropical hardwoods that hold up well with moisture have major problems sticking to epoxy. Sometimes the epoxy just shears at the window. That happens less or not at all with a fiber reinforced epoxy like PC7...if you can stand the fugly glue line.
What works for me (on carbon steel) is Ospho overnight, a light sanding, and Loctite epoxy...I bet Acraglas would beat it every time. I still put a pretty lil' peened brass rivet in just so I don't have to worry about it.
 
The real question is- "Why epoxy?"
Properly used mechanical fasteners make any glue unnecessary.
 
Bill DeShivs said:
The real question is- "Why epoxy?"
Properly used mechanical fasteners make any glue unnecessary.
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Helps in making a moisture seal, if nothing else. Glue is nothing new to making knives. Cutlers rezin probably goes back to the Cromagnons
 
Bill DeShivs said:
The real question is- "Why epoxy?"
Properly used mechanical fasteners make any glue unnecessary.
Click to expand...

On commercial kitchen cutlery, a stainless blade plus the use of Corby bolts or cutlers rivets and a well fitting set of scales would indeed make epoxy needless.....but for health reasons, sealing the scales to the tang permanently eliminates the possibility of bacterial colonies.

I do agree that hickory handles were riveted on carbon steel blades for hundreds of years, and many are still there.

Proper mechanical bonding is a must in any handle construction that will see hard use and lots of wet/dry cycles ( like washing). The epoxy is part of that process, but a strong mechanical bond is also required. I prefer Corby bolts for rock solid bonding, but any similar method is sufficient. Pins and "rivets" that have no mechanical bond like flared heads will eventually pull loose.
I like mosaic pins for their look, and they have their place, but they provide almost no holding strength beyond shear resistance. I like to use a three pins setup with two mechanical rivets and a mosaic in the center.
 
For all the negativity the cheaper epoxies get, I think much is unwarranted. I have 20 + year old joints with 5 min epoxy in musical instruments that have had exposure to heat and cold on the road, tension from strings, shock from drops and falling amplifiers etc. The strength of the glue joint comes from the quality of the prep, and using the right product for the job. Fit the pieces properly, ie. no gaps, rough the mating surfaces with the appropriate grit for the material, clean, clean, clean and make sure there is no oil or wax contamination, and mix the epoxy thoroughly. The only failures I have had are from either gluing in the cold, not mixing the epoxy long enough (most common mistake) or clamping too tight. When a joint breaks, it is the wood that breaks, not the epoxy joint.
 
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