Quick tang lenght question

[Hengelo_77]

Is a 3" hidden tang long enough for a 3,5" blade with a 5,5" handle made out of a single piece of zebrano?

 

[Fish30114]

More experienced folks may chime in, but I would have no issue with those dimensions. In fact, I recently bought a Mora blade that had similar dimensions--the tang was actually a bit shorter than that and it had a 3.5" blade. I don't know what Zebrano is, but if it's a normal handle material I think you would be fine.

 

[DEllis]

Unless you plan on serious prying with it(not likely with a 3.5" blade), you should be fine.
I prefer thru tang construction with a nut placing the handle material under compression, but it's not needed for smaller blades.
Darcy

 

[RX-79G]

I don't see a problem as long as you are filling the handle with a quality, slow cure epoxy.

Over the long term, I think a tang properly bonded into a blind hole is more stable than a compression fitting.

 

[bodog]

Is a 3" hidden tang long enough for a 3,5" blade with a 5,5" handle made out of a single piece of zebrano?

I just found this out myself. I'd say no. I had some knives with similar dimensions break with really light use. Unless you're sure the wood can handle unsupported perpendicular forces I'd advise against it. I just basically wasted a couple of weeks worth of part time work (not to mention the money for the wood and other supplies like new belts) doing what you're talking about. Talk about freaking pissed off.

If you're going to do a partial hidden tang then don't leave more than maybe half an inch of wood past the end of the tang unless you're dealing with some strong wood cut the right way.

It is super hard to find information about this specific issue. Hell, it's hard enough to find a specific name for partial hidden tangs. Stub tangs? Partial tangs? Partial rat tail tangs? Hidden tangs? Half tangs? Scandinavian tangs? Should the tang be mortised? Should the block be cut into three pieces to cover the tang? Should a rod be welded or brazed to the tang to create a through/ rat tail tang?

Is cross grain in reference to glued joints on furniture? Is cross grain saying that you're looking at long pieces of end grain wood? Is cross grain referring to the face of quarter sawn pieces?

These are all things I've seen conflicting with each other while searching for the exact answers you're looking for.

Basically it came down to what I mentioned earlier to be safe. Don't let the wood end more than maybe one inch past the end of the tang, but half an inch would be better.

 

[RX-79G]

I just found this out myself. I'd say no. I had some knives with similar dimensions break with really light use. Unless you're sure the wood can handle unsupported perpendicular forces I'd advise against it. I just basically wasted a couple of weeks worth of part time work (not to mention the money for the wood and other supplies like new belts) doing what you're talking about. Talk about freaking pissed off.

If you're going to do a partial hidden tang then don't leave more than maybe half an inch of wood past the end of the tang unless you're dealing with some strong wood cut the right way.

It is super hard to find information about this specific issue. Hell, it's hard enough to find a specific name for partial hidden tangs. Stub tangs? Partial tangs? Partial rat tail tangs? Hidden tangs? Half tangs? Scandinavian tangs? Should the tang be mortised? Should the block be cut into three pieces to cover the tang? Should a rod be welded or brazed to the tang to create a through/ rat tail tang?

Is cross grain in reference to glued joints on furniture? Is cross grain saying that you're looking at long pieces of end grain wood? Is cross grain referring to the face of quarter sawn pieces?

These are all things I've seen conflicting with each other while searching for the exact answers you're looking for.

Pics?

Basically it came down to what I mentioned earlier to be safe. Don't let the wood end more than maybe one inch past the end of the tang, but half an inch would be better.

What was holding your knife together?

Was the grain of the wood oriented in the same direction as the tang, or something else? "Cross grain" would indicate that the end grain of the wood was facing the side of the knife. Is that what your knife used?

BTW, your knife is probably repairable by drilling the breaking and epoxying in a pin reinforcement where the tang isn't.

 

[bodog]

What was holding your knife together?

Epoxy

Was the grain of the wood oriented in the same direction as the tang, or something else?

Grain ran the length of the knife. Unstabilized blackwood, stabilized maple burl, and stabilized oak. The oak was not cut for a hidden partial tang so that was my fault.


BTW, your knife is probably repairable by drilling the breaking and epoxying in a pin reinforcement where the tang isn't.

I was thinking the same thing. Gonna go talk to someone much, much more experienced than me tomorrow and see what he says about it.

 

[RX-79G]

I just found your thread:
http://www.bladeforums.com/forums/showthread.php/1372378-Partial-hidden-tang-knife-handles-breaking

For wood to be strong, it needs continuous grain oriented perpendicular to the bending forces - like the way branches grow. Burl is just fractured wood with resin in between the fractures. You wouldn't glue two pieces of wood end to end and expect to be able to bend them.


Consider the wood handle of a hammer or hatchet. There is no metal running through them at all, and they don't break.

Even a pine handle with a stub tang would hold up fine, if the grain is going the right way.

 

[RX-79G]

What was holding your knife together?

Epoxy

Was the grain of the wood oriented in the same direction as the tang, or something else?

Grain ran the length of the knife. Unstabilized blackwood, stabilized maple burl, and stabilized oak. The oak was not cut for a hidden partial tang so that was my fault.


BTW, your knife is probably repairable by drilling the breaking and epoxying in a pin reinforcement where the tang isn't.

I was thinking the same thing. Gonna go talk to someone much, much more experienced than me tomorrow and see what he says about it.

That is not grain oriented the length of the knife. The grain is oriented in your pictures 90° to the tang. You can see that in the fractures.

 

[bodog]

The blackwood was cut like this. I do not honestly know what I'm missing here.

If you can show me a proper cut of wood for partial hidden tang knives that is different than above I'd freaking love to see it. When I look up hammers and axes and hatchets all the wood grain looks exactly like that. I feel totally stupid here because I see no difference.

And I'm willing to say that I have no freaking idea about this that's why I'm asking. When I received the wood it looked exactly like the two pieces above, just darker obviously.

How is it possible to have the wood cross grained when the grain runs the length of the blade? I know this is probably super simple to a lot of you guys but I'm not seeing it. Please bear with me.

If the blocks in the photos are cross grained, how do you tell? I thought it was as simple as looking at which way the grain runs. If it's not that easy, please enlighten me.

 

[Darrin Sanders]

The general rule of thumb is that that tang should be 4/5 of the length of the handle. So a 5" handle should have a 4" tang.

 

[RX-79G]

I think you're being confused because your confusing "grain" with the lines in the wood. The "grain" is a matrix of cellulose fibers that all run in the same direction, like a ponytail of hair. Those fibers are arranged in layers from the growth rings of the tree, but those rings can be viewed in a way that makes it look like they are the grain, but they aren't.

If it isn't clear what the grain orientation is, try to find the end grain. This is the side of the wood that looks most like little dots rather than stripes, and you can often see the curve of the tree's rings. The end grain should be on the pommel and guard ends of the handle:

I am certain you have end grain on two sides of your handles, instead of the ends.

 

[RX-79G]

Bodog, here's pic from your other thread:

Looking at this picture, it is very obvious to most people that the grain is oriented parallel to the plane of the knife, but perpendicular to the tang. In other words, the grain is running from the lower right to the upper right of the picture, and the knife is oriented from the lower left to the upper right.

You can not only see the lines of grain in the fracture, you can see the same LR to UR grain on the polished sides of the handle. I'm sure you can see that, too. The "end grain" is running along the extended line of the bladed edge and spine. Those grains should have been pointed at the tip. IF that had broken, it would have come out looking like this:

So is the problem that you can't tell on the block of wood where the grain is, or is it still not clear looking at that picture what the orientation problem is? I'm struggling to understand where you difficulty lies.


As far as stabilized burl goes, I think it is fair to say you can never use that unsupported by a tang or something else. It is no stronger than a block of brittle resin.

 

[bodog]

Thanks for the info, maybe I was just careless with the other pieces.

I thought, and I guess I was wrong, that it was cut like this with the grain running the length of the handle.

 

[bodog]

Bodog, here's pic from your other thread:

Looking at this picture, it is very obvious to most people that the grain is oriented parallel to the plane of the knife, but perpendicular to the tang. In other words, the grain is running from the lower right to the upper right of the picture, and the knife is oriented from the lower left to the upper right.

You can not only see the lines of grain in the fracture, you can see the same LR to UR grain on the polished sides of the handle. I'm sure you can see that, too. The "end grain" is running along the extended line of the bladed edge and spine. Those grains should have been pointed at the tip. IF that had broken, it would have come out looking like this:

So is the problem that you can't tell on the block of wood where the grain is, or is it still not clear looking at that picture what the orientation problem is? I'm struggling to understand where you difficulty lies.


As far as stabilized burl goes, I think it is fair to say you can never use that unsupported by a tang or something else. It is no stronger than a block of brittle resin.

That's the picture of the oak crotch which I took a gamble on knowing it was cross grained. I guess stabilizing the wood doesn't add significant strength.

The blackwood block is the one that I thought was not cross grained. It looked just like the kingwood I just posted and what you described, the end grain at the front and back of the piece rather than the sides. After it broke you can see the flecks of wood breaking off side to side rather than lengthwise so I get what you're saying, but when it was a block it looked different. It looked like the end grain was at the front and back.

Thanks for the pictures, by the way. And for letting me know that the grain doesn't necessarily correspond with the lines. I didn't know that and is probably the reason I was having a hard time figuring out what went wrong.

 

[rustyrazor]

I agree... stabilizing doesn't add significant strength to a handle. i got some amazing end grain stabilized spalted blocks and i broke one in half just trying to tap it off with a rubber mallet when fitting it. then i tried testing them against parallel grain and (not surprisingly) the end grain cuts broke soooooo much easier every time. beautiful but no way they are going on a knife i make without engineering some sort of support