Clip swedge geometry

I

Ian Fifelski

Joined
Oct 4, 2017
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528
I recently ground a few harpoon clips and it brought up some questions.

I have been grinding both vertically and horizontally (depending on the clip length) on my platen because they are straight clips. I have noticed that the angle of the clip needs to be different at the beginning than at the tip.

Is this correct? Because if I grind without accounting that fact, either the tip is ground to much and goes into the main bevel or the beginning of the clip at the spine gets too thin while the tip is thick.

Thinking it over, I realized that a distal taper would change this. Is a distal taper needed for the correct geometry with the clip grind totally flat? Might I not be grinding the tips thin enough?

Am I just over thinking this and I should just do whatever works to make it look right?
 
The clip should be set at the same angle on both sides. You can very how it tapers from back to front by monitoring the grind symmetry on both sides
 
I have just screwed up another harpoon clip. I wonder if anyone has tips for the problems I am facing?

I ran into the problem again that even though the clip at the spine is straight, the grind line is curved. Also, I am finding it again to be a bear to grind because the bevel angle is different from the tip of the clip to the beginning of it.
 
AVigil said:
The clip should be set at the same angle on both sides. You can very how it tapers from back to front by monitoring the grind symmetry on both sides
Click to expand...
I don't totally understand this. Because the width of the back of spine (clip edge) to the peak of the grind line of the clip is very different from the back to the tip, to get the width of the clip grind at the back, you need a smaller angle and at the tip you need a larger angle to make the zero edge.
 
Maybe try filing it by hand? It will take time, but it will be extremely controllable.
 
MBB said:
Maybe try filing it by hand? It will take time, but it will be extremely controllable.
Click to expand...
I have done that and it works. It just seems their should be something I am doing wrong that is making it such a hassle for me, because so many guys do them.
 
Maybe the geometry of my main bevel is off?

I guess what I am asking is should you be able to get an even, straight clip that has the same bevel angle the whole way? Or does it need to be curved and have different angles for it to work?
 
Mine are straight. The distal taper is needed to make it look right.

I’ll see if I have a couple blades at the right stage and get pics.
 
Willie71 said:
Mine are straight. The distal taper is needed to make it look right.

I’ll see if I have a couple blades at the right stage and get pics.
Click to expand...

This basically. The distal taper of your main grind influences the straightness of your clip grind a great deal.

If you are concerned that you are removing too much material at the tip, remember that you are grinding a bevel not into a flat piece of steel, but a piece of steel that already has a taper to it because of your main bevel. So you have to take more material away at the point where your clip starts initially. Go slow and rather use the edge of your platen to slowly carve away the steel. Try to go 2/3 on the grinder and finish up the rest by hand at first. If you have good files this won't take long and the risk of screwing up on the grinder is not as high. Clip grinds are small bevels and it is difficult to get them absolutely perfect on the grinder. I do them on most of my designs and still do the finishing touches with files because it gives me more control.
 
When I do a clip or false edge, I grind it before grinding the primary bevels, using a disk sander. For me this does two things:
1. Allows me to get a centered accurate clip, and
2. Helps keep the tip of my primary grind aligned properly.

This is just the way I do it, not necessarily the "Right" way.

glwfnIp.jpg
 
That was an old harpoon point one I finished when I was still using a 2x42 craftsman special, but I do the same process with the Pheer.
 
I grind the clip in first, pretty much the same width from start to finish. I then grind the bevel which of course, tapers out to the point. For the clip, just lay the thing on your platen lengthwise at the correct angle on each side and go at it. For curved clips, i use my Nate 72 inch platen for big knives and my 36 incher for small ones. Straight on to set the curve and then roll it over onto each side. No sweat.
 
The grind should be held at the same angle from plunge to tip. Any change in angle will be noticeable.
 
jdm61 said:
I grind the clip in first, pretty much the same width from start to finish. I then grind the bevel which of course, tapers out to the point. For the clip, just lay the thing on your platen lengthwise at the correct angle on each side and go at it. For curved clips, i use my Nate 72 inch platen for big knives and my 36 incher for small ones. Straight on to set the curve and then roll it over onto each side. No sweat.
Click to expand...
I must be grinding the main bevel incorrectly, and letting it get too thick nearer the tip.
Would this work similarly with a forged blade that has a forged in distal taper and clip?
 
my clips are the same angle from the starting point all the way to the tip. i do my clip before the bevels because the knife will lay flat on a work rest. scribe a center line on the edge where the clip will be, tilt my work rest between 50-75 degrees, and do my clip all the way up to 400 grit. then do the bevels.
 
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