Put a slab handle on a full tnag knife?

Do you mean a slab handle on a stick tang or scales on a full tang? For Slabs I would say drill out the slab until you can fit the tang into it. Drill through both the slab and knife tang. Fill with epoxy and put in pins.
 
Well, it depends on if you're using something like corby rivets, or plain brass/nickel silver pins. The answer also depends if the blade has been heat treated or not, and whether the tang has been drilled already. Is this a knife blank you're putting a handle on?

If everything is right here, and you have a properly drilled tang... You drill the scale pin holes through the already-drilled tang holes. You put scale A under the tang on your drill press (or a flat surface w/ a hand drill) and have the handle scale flipped so that the side the bit pops out of (and sometimes causes to splinter/chip) is glued to the knife when you put it back right. Then repeat for scale B, same way, placing the pin material in the holes as you go to keep things straight and held right. After the scales are pinned on sans-epoxy, start shaping the scales. After the scales are shaped right, and just need polishing, I like to go ahead and epoxy the scales on with 2 ton epoxy. Clamp the scales on with only moderate pressure (too much squeezes out the epoxy). After you clean any excess epoxy up (Acetone), I start polishing the handles, with the blade taped up so as to not scratch it.
 
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I kinda do as above, but lock the oversized scale in place with 2, or 3 tiny drops of super glue. TINY drops. Then drill the pin holes. The scale will pop off by rapping it on a wood surface. Before permanently attaching, I drill numerous holes in the tang to lightenn it, but mostly to act as epoxy bridges connecting both scales. I Clamp as tight as is practical. The bridges lock it all together and there is no need to worry about squeezing all the epoxy out. In many cases one would not really have to pin such a grip, the bridges will hold, but the pins should be installed for looks, and reassurance.
 
Well, I drill mine through the tang holes and then start shaping the handle. Take it off and pin it together to shape the front. Put it all together at mostly final shape, glue it up and put the pins in. I use a ball peen hammer to swell the pins.

I do lighten some tangs with extra holes, but I don't subscribe to the epoxy pin ideology. There are two main reasons I don't buy into them:

1.) Epoxy strength does not follow a linear scale with thickness. What I mean is that a 1" thick seam of epoxy is not 64 times strong than a 1/64" thick seam. Furthermore - if you took a 1/8" 'pin' of epoxy and twisted it, I think you'd have a far easier time ripping it apart than you would with a metal pin (unless it was lead or something).

2.) My understanding of epoxy bonds is that they work better in uniform thickness. I've been told that you can place a strip of fiberglass cloth between two epoxied pieces and increase bond strength, not because the of the fiberglass, but because it help hold a uniform thickness throughout the bond. I believe that the lateral strength of the epoxy is compromised by epoxy rivets and in lightened tangs/scales I would be more apt to use a mechanical fastener.
 
Well that may be in your world of theory, but I have had to remove such a handle of buffalo horn, which isn't going to have the greatest bond strength to start with. After removing the pins, I could not even beat them off with a hammer. From any direction. I had to burn them off. But what do I know after 37 years of making knives?
 
Don't know what you do or don't, but your argument doesn't cover the points that I made and one sample does not make a valid set of data.

Show me 20 knives each way and give me some example of how much more force the lightened tangs needed over flat tangs. Show tang and scale preparation, how glue was mixed and applied, etc and then we can talk.

I intended no disrespect, I was simply stating my opinion and backing it up with what I know. The guy asked how to do it and I put my methods and why I feel the way I feel. Didn't mean to get anyone's panties in a bunch.

I don't know if 37 years of experience makes you good at anything if all you do is get upset when people voice a differing opinion. Kind of hard to learn if you don't listen once in a while.
 
You stated, that you think, you have been told, and you believe this, that, and the other. Show ME proof contrary to the strength of my method. I never stated not to use metal pins, only that it might be possible. I have knocked off scales by removing pins, and whacking them on their edge with a hammer, or slamming them on a bench top, but any that had an adequate amount of hole bridges do not remove that easily. Do as you please.
 
I stated (I assume you do understand what a statement is) "epoxy strength does not follow a linear scale". This I challenge you to refute. In all of your 37 years experience, you are ignoring this important detail of my post.

I also stated "My understanding of epoxy bonds is that they work better in uniform thickness". If your understanding of epoxy behavior is different, please enlighten us.

Does non-uniform epoxy work better somehow? Does epoxy follow a linear strength scale? Does a 4mm sheet of epoxy have four times more tensile strength than a 1mm sheet? Perhaps you can't give an example of how you know that your epoxy rivets add strength over a standard epoxy joint and that's why you refuse to back up your argument with facts.

Yes, I was told certain things and I accepted them as reasonable. I was told the fiberglass trick by Alan Folts (he's only been making knives for a pitiful 13 years) which was seconded by Tommy McNabb. Maybe you don't know Tommy, so maybe you don't know that he has all those decades of knifemaking experience, that he teaches classes on knifemaking and that he spent many years as the president of the North Carolina Custom Knifemaker's Guild. You don't expect their information to be good enough, yet somehow you expect folks to take your advice at face value.

You gave me an example of why your knife was great with the epoxy rivets. I'll give you a bit of an incredible story about epoxy. The front door of my garage/apartment was held on with Devcon for the four years I lived there. It was a little hard for me to believe it when Devcon did so poorly in the glue wars, after all, I'd seen it with my very own eyes - the stuff was awesome. But, my test was only one. Perhaps if I'd tested 20 doors I'd have found the flaw vs using mechanical fasteners.

I never accused you of saying "don't use mechanical fasteners", I never accused you of making knives "the wrong way". I only gave my view of how to accomplish the OP's goal. Free information exchange and all that, you know. Didn't know it'd start a moan-fest.

Don't we always say "more than one way to skin a cat"? I guess mine is the wrong way and yours is the only way.
 
When we braze metals the optimum gap is .003", both for capillary flow and strength. Is there an optimum gap for epoxy ?? Epoxy also depends on surface material and surface condition .
 
For what it's worth, I was just "told" by a tech at loc-tite that they recommend 3-5 thousandths thickness with a max of about 10 thou for most of their epoxy products (gap filling/glass bead etc not withstanding). Since I was only told this information, it's probably not true.

Here's a link to a datasheet I pulled from their website:
http://65.213.72.112/tds5/docs/3421-EN.pdf

Interesting that while they made both 1.2mm and 4mm thick samples, they only strength test on the 1.2mm one.

Here's a link to another that they do the same thing on - oh, they also mention a maximum gap of 3mm (just under 1/8" for anyone who doesn't want to do the math). Guess those maximums don't count with knives though.

http://65.213.72.112/tds5/docs/9489-EN.pdf

and another with 3mm max:

http://65.213.72.112/tds5/docs/9484-EN.pdf

one more:

http://65.213.72.112/tds5/docs/9484-EN.pdf

I don't know what I'm talking about though, I'm not old or experienced enough to do this kind of research.
 
If the grip on one of my higher end knives had a .003 gap, between it and the tang, it would not leave my shop. As I said, do as you please. I will do the same.
 
Guess that's why some makers use CA and poly glues. Something to be said for having a good looking knife with a good bond.
 
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Just a quick question... Do I need to drill the holes for the pins a tad bigger than the pin itself?

Not long ago I downloaded a set of videos from Twisted Nickel and the guy there said that he used 6,4mm drill bits for 1/4" pins (1/4" is like 6,35mm). He stated that that little gap was needed for the epoxy to fill in and help keeping the pins in place. When he put them in still needed to use a few taps from a hammer so it seemed tight. He also said that if you are using a 1/4" drill bit with 1/4" pins, chances are that if you are using wood or any other non-fibrous material for the handles (antler I guess) they could crack when the pins are hammered in.

Any clues?

Thanks,
Mikel
 
Using a bit the same size as your pin, the pin will not fit in without being forced a bit. So if nothing else, it's important to have the hole big enough that the pin will go in through the tang and scales without trouble when everything is covered in epoxy and sticking.
 
Blue_Dragon said:
Using a bit the same size as your pin, the pin will not fit in without being forced a bit. So if nothing else, it's important to have the hole big enough that the pin will go in through the tang and scales without trouble when everything is covered in epoxy and sticking.
Click to expand...

So you are telling me that for 6mm pins I need 6,1mm drill bits for example? I may have access to those drill bits here... mmm.
Thanks!
Mikel
 
The drill will usually provide enough clearance, but if you have trouble getting a pin through, you can just run the drill a couple more times through the hole in the tang. Handle materials give me much more trouble than the tang does, as they can compress a bit when drilled and the holes can end up tighter. A reamer can come in handy. Putting a slight taper on the end of your pins will also help get them in.
 
So you are telling me that for 6mm pins I need 6,1mm drill bits for example? I may have access to those drill bits here... mmm.
Thanks!
Mikel
Click to expand...

Well, usually I just use some scraps of sandpaper and make little sanding cylinders, and sand the inside of the holes(1/4" holes) a little. If it's 1/8" pins, I'll sand the pin down a tiny bit till it goes in smooth. (Can't roll the sandpaper that tiny)

So if you can't find the slightly-larger-than-your-hole bit for your size hole, my way is easy to get materials for. :thumbup:
 
what do i know.....but to me the more epoxy you have to an extent the better, for example, you dont just put one tiny drop on the handle, you have to go down the length of the tang....this in itself proves that the area covered to an extent does improve the bond......and think about this.....maybe the epoxy adheres better to the scale material than to steel?

if the epoxy adheres to the scale better than to steel than the whole "linear" theory goes out the window for this instance.

do you get what im saying?

say a 1/64 " stream was perfect amount and no thicker amount improved the bond to the steel, and acrids theory is right, still, if you have a enough contact between the two scales with epoxy thats a completely different bond.

acrid i think your missing the trees because of the forest...no offense, but i always take experience, and knowledge over peoples half understood theories.
 
To get this back on track -

Moose,
Take the scales (wood slabs) and make sure they are flat on the mating sides. Make sure the tang is flat,too. If the end of the scales will be exposed at the ricasso ( no guard or bolster) , tape the scales together ,shape, sand ,and polish the end. You will not be able to do it once the handle is mounted without scratching up the blade.
The holes in the tang should have been drilled prior to HT. They should be larger than the desired pin size. I usually make them about twice the pin size, so for 1/8 pins I would drill 1/4" holes. This allows a small (1/16") gap around the pin which will help with scale alignment and any fitting problems. If the holes all match up too exactly, sometimes you can only get one or two pins to go through. This is because the wood ( and the metal to a lesser degree) will change length due to heat and humidity. The epoxy will fill this small gap quite nicely. If you wish, drill extra holes in the tang to lighten the handle and provide the epoxy a path to adhere from wood to wood (epoxy rivets). These holes need to be at least twice the tang thickness in diameter to make the epoxy strength work. It is based on a ratio of length to width of the epoxy bond, and not just linear.A long as the epoxy rivet is wider by a factor of two than it is thick, it will have the full strength of the epoxy. Generally , make them 1/4 to 3/8".

About the epoxy -
Use a good grade ,slow cure epoxy. I find System three T-88 structural epoxy one of the best. 2 hour Devcon will work ,OK. Don't use 5 minute epoxy. Mix the epoxy well and measure the amounts as closely as possible, according to the directions.
The scales will be on for a lifetime, so use a good grade of slow cure epoxy. The slower, the stronger generally.Clamp with even and moderate pressure. If you clamp hard, you can squeeze out all the epoxy, and leave a glue starved joint.

Now, take ONE scale, and epoxy it to the tang, making sure of the position at the ricasso. BTW, I use the whole 6X2" scale, with the ends sanded and polished as noted above.

When the epoxy is fully dry and cured (wait 24 hours for best cure), you are ready to drill the holes. Place the scale on a backing block of wood, on the drill press ( to avoid splintering on drill through). Drill from the tang side, using the tang holes as placement guides. Drill a hole in the center of each tang hole (the ones that will get a pin,that is), using a drill bit slightly smaller than the pin size. ( After drilling the first set of holes, I often take the knife to the band saw and cut off the excess wood following the profile, but leaving about 1/8- to 1/4" around the tang.)
Epoxy on the second scale, making sure to align the front edges well. Drill the second scale ,using the first holes as a guide for the drill ( all this is much easier on a drill press.) Now that the scales have holes that goes all the way through, and are aligned, take a drill bit the size of the pin ,or a few thousandths larger, and re-drill the holes. Use the pin stock to check the fit. The pins should go through with just a slight bit of resistance ( finger pressure). They should not need to be driven in.
Put the pin stock in the drill, and at low speed hold a piece of 100 grit sandpaper to it, briefly. This will slightly score the sides with micro-rings to aid in the epoxy bond.Don't sand down the pins much, or they will become too small (It is OK that they will fit a little looser after the sanding).
Mix some epoxy and apply it to the pins and in the pin holes (a bamboo skewer helps a lot with this). Install the pins, rotating them as they go in, and let everything cure for a day. Clip or saw off the excess pin material, and cut off the excess wood on the second scale, then sand/grind the handle to rough shape. Always avoid getting the handle hot when using a belt sander. The pins will be ground down along with the wood. Brass and nickel will work down easier than stainless pins, so remember not to grind too fast or hard on stainless, or they will heat up and burn the wood around them. Shape and sand the handle to at least 400 grit ( 800-1000 is better). Buff and polish or apply finish as desired.

Some thoughts:
Grinding a slight relief (hollow ground) to the center of the tang will make sure there is a slight reservoir of epoxy that can't be squeezed out in the clamping. This allows a zero fit look to the edge,with a good epoxy bond inside.

Use the best epoxy you can get. It is senseless to save pennies here.$20 of T-88 will do hundreds of knives, so that works out to be about 10 cents a knife.

Epoxy is normally a surface bonding product, and excess thickness is not a plus. However, there has to be enough thickness for the epoxy to make the bond. This is not an issue in the film thickness and size of a knife tang. The techs are talking in different parameters than we deal with.
STRUCTURAL epoxies like T-88 and Accraglas are not the same as bonding epoxies (Devon, etc.) and are uniformly strong regardless of thickness
The bond of any resin needs to be wider than it is thick to assure proper strength. In a knife handle, the width and length of the bond is hundreds of times the thickness. As long as any epoxy rivets are at least twice as wide as they are long, they will be strong, too.

Tape the blade up to avoid getting epoxy or scratched on it. Use acetone to remove any cured epoxy from the blade when finishing the handle.

Hope this helps,
Stacy
 
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