Swedges

[KnifeHead]

I posted this over in the Traditional forum and thought it is also appropriate here, especially for new knifemakers like myself.

Someone asked a while back, "What is a swedge and what are they used for?"
My mentor Tony Bose sat me down with this stockman to explain what is going on there with the swedges and they have 4 basic purposes:

1. They improve the eye appeal of a blade.

2. They make the blade thinner at the spine and therefore improve it's ability to cut.

Specific to slip joint folding knives they:
3. Make room for the blades to pass each other when opening and closing.

4. Provide access to nail pulls

This 3 blade premium stockman has some good examples of swedge work. From the top you can see that there isn't a lot of extra room for blades. The swedges on each blade play a part in making this knife work well. Imagine what this knife would look like without swedges. Eye appeal is definitely at work here in the lines on these blades.

There wasn't much worry about blades rubbing on the old knives because they were USED! In today's collector market, blade rubs are a no-no so care is taken to make sure there is plenty of room for the blades to pass. But, you don't want a knife that is too wide so swedges will enable the maker to keep the knife as narrow as possible.

Now take a look at the position of the blades in the image below.

The master clip blade has symmetrical cut swedges. It has it's own spring and therefore it's own pocket to house in, but still the sheep's foot blade is very close. The drawn swedge of the sheep's foot and the cut swedge of the clip blade allow plenty of clearance.

The spey and sheep's foot blades share a spring. Special attention has to be paid to make these two blades play nicely together. A cut center liner(not a full profile liner) is used and the sheep's foot blade is crinked(bent) toward the center. You can see in the image above that the tip of the sheep's foot blade is about centered over the center liner. Crinking one blade doesn't provide enough clearance between blades so cut swedges are employed between the spey and sheep's foot blade.

There are 2 types of swedges: cut swedge and drawn swedge

The cut swedge plunges in where it begins on the spine and tapers out towards the tip. A correct swedge will end before it gets to the tip of the blade. Otherwise, blade sharpening over time could potentially involve the swedge resulting in an ugly blade.

The drawn swedge tapers gradually from where it begins on the spine and tapers out again toward the tip.

You can see more images of this knife here http://www.bladeforums.com/forums/showthread.php?t=468281&page=42
(post #824)

 

[Barkes Knife Shop]

Great Job Kerry: I like it. A+--------:thumbup:

 

[Chuck Gedraitis Knives]

I would like to think that the swedge, or false edge also adds geometry to a blade. Basically your stacking triangles on top of each other.

 

[TekSec]

I love the look that a swedge adds. The problem I usually have is getting them symmetrical. I've improved over time, but does anyone (Kerry ) have any suggestion on keeping the symmetry between the sides?

 

[the possum]

Thanks for posting that, Kerry. I never knew the terminology difference for cut swedges vs. drawn. In addition to your list, I have found they can really help piercing ability of the tip.

I might slightly disagree that they should "end" before the point, but still think they should not be wider than the edge bevel. I have plenty of blades sharpened enough to where the tip has been shortened into the swedge, and as long as the edge is kept reground for thin enough cutting geometry, aesthetic balance is maintained.

I might also add that at least on fixed blades, they can also help with some other things. They can be used to improve or fine tune the balance, and aid in removal of the blade if it's chopped deeply into a binding target. If taken thin enough to where they could be sharpened, they are also useful for scraping, aid in piercing/thrusting ability, and of course, improve looks.

 

[KnifeHead]

I love the look that a swedge adds. The problem I usually have is getting them symmetrical. I've improved over time, but does anyone (Kerry ) have any suggestion on keeping the symmetry between the sides?

That's a whole different topic. Putting the swedges on is my last greatest opportunity to screw up a blade after all the other work is done.

I think it takes a lot of practice to get good at it but the mechanics of the operation is important too. I use a 10" wheel, slow belt speed, and nothing greater than a worn 220 grit belt. I also clamp a grinding guide at the point where you start the swedge midway on the blade...starting there and grinding toward the tip just like you were grinding the main bevel.

One of the problems I have had in the past is what my pal Tony calls "chasing the swedge". That's where you do one side, then go to the other side and grind to even it up and go too far, then back to the other side and repeat. I think my errors have been due to taking off too much material too quickly. Slowing down the wheel and keeping the grits lower seems to help me.

The other thing that seems to help me is just stepping up to the dang wheel and grinding. It is cliché but seems to make a difference; If you are hesitant or afraid you're going to screw it up then you probably will.

 

[langchop]

That's a whole different topic. Putting the swedges on is my last greatest opportunity to screw up a blade after all the other work is done.

I must confess to being very surprised by this. I would think that for your regular/career/ proffessional knifemakers who grind primary bevels freehand on a belt ( which I wouldnt even attempt at this stage!), that swedges would be a piece of cake?

I think the swedges add a lot of character to a knife in addition to the practical reasons

 

[KnifeHead]

I must confess to being very surprised by this. I would think that for your regular/career/ proffessional knifemakers who grind primary bevels freehand on a belt ( which I wouldnt even attempt at this stage!), that swedges would be a piece of cake?

I think the swedges add a lot of character to a knife in addition to the practical reasons

I agree about the character that is added by a dang fine swedge.

I bet guys that have made hundreds of knives don't have problems with swedges so this next part doesn't apply to them. Putting on swedges IS a piece of cake. Putting on good swedges that are symmetrical and have the same angle (or even ONE angle ) are NOT a piece of cake. This is why some knifemakers either don't put on swedges or find some way to jig the process. Think about a blade that is finished in every way except for that final touch of the swedge and then screwing that up. All that work goes in the mistake box. I've had a few....too many. I think this is why I have grown to appreciate a really good swedge when I see it.