Scalloped Spine old name Multiple "Interior Swedges"

John Cahoon

John Cahoon

JWC Custom Knives
Knifemaker / Craftsman / Service Provider
Joined
Apr 13, 2017
Messages
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Hello, first, thank you all for the superb teaching and sharing. I've learned a ton. This is my first original post so if any protocols are breached let me know. I searched this and similar terms but did not find anything relevant.

I have a stock removal blade in .2" thick 5160 with a continuous shallow arc along the spine from the thumb stop/ramp to the tip (about 7" from thumb stop to tip). I'm thinking of grinding a series of 3 or 4 short "interior or inside swedges" along the spine (correct my wordage please), instead of 1 long one. They could be rounded onto the flats. Decorative filework is also probable.

These would arc smoothly in and out when looking down on the spine, progressively more acute until the final swedge at the tip is close to sharpenable. I would start on an 80 grit belt lightly, then 150 and 220 before hand sanding the finish. Has anyone done this? What's a good way to keep the ends even where the swedge widens out before the next one starts? Any strength or other issues? Any tips or tricks to get it right the first time? Lastly, did you or others like how it looks?

Thanks a lot
John
 
Can you post some sketches to give us a better idea of what you are trying to describe?
 
Doesn't sound all that attractive from the description .... and not simple.

File work on a spine that tapers is really nice when done properly. It should get smaller as the blade gets thinner. Marking it off with a fine tip Sharpie makes this pretty simple. A simple rope pattern is good.

I do a file work pattern that is something on the idea of your initial question. It is alternating scallops ( left-right-left) that overlap by half the length. They can also be directly across from each other, but the placement has to be very exact or it will look off.
The beginning scallops are about 1/2" long. They reduce as they go down the tapered blade until they are barely 1/16" when the filework ends about 1" from the tip. Even on a blade with almost no taper, they give the visual effect of a distal taper.
 
I4marc, I just need to join the 21 century, open a paypal acct and i'll post a sketch/photo. Stacy, scalloped is very descriptive of what I was trying to say. I was thinking of longer (1" or so) scallops directly across from one another, then a final full swedge near the tip. Your description gave me the idea to start each scallop in the middle, grinding forward and back towards the ends, then finishing with a file so they are dead even. Does that sound like it would work?

Thanks a lot for the replies.
 
Yes, that will work. For finish sanding, you can use various sizes of dowels and sandpaper.

Depending on your equipment, a lot can be done with various size contact wheels and Cratex burrs on a flex shaft or Dremel.

The scallop from 6", 4", 3", 2", 1", 3/4" and 1/2" contact wheels on the grinder will make a nice progression. VS is almost a necessity.
I use Cratex in 1" , 3/4", 1/2", and 1/4".
 
So here are the results. I first used a wood dummy to design and practice on. This is .20" x 2" 5160 steel with about 5.5" from tip to thumb rest, 9.5" OAL. The 3 scallops start 1/4" ahead of the thumb rest, progressively shorter 1 1/4, 1 , 3/4, then a swedge to the tip. I started in the middle of each scallop and gently grind forward and back to the terminus on a dullish 150 grit belt.

The key was not only to maintain the desired scallop angle (about 45 d), but also to track the angle of the upswept spine if you see what I mean by rotating the spine around the platen edge with the belt hanging over. On a pretty straight spine that wouldn't be necessary I guess. In the end I finished up with needle files, many times 1 stroke at a time, then check results. About 1/8" doweled sandpaper as Master Apelt suggested worked well to 400 grit where they are now.

One has additional file work between the scallops and I'm planning on leaving the other one as is. Any thoughts or preferences there? On a future blade I may get the nerve to add subtle vertical curves (sways?) down from the spine and then add these lateral scallops, but that might be too garish?

The photos aren't the best in the early morning partly cloudy skies but these ones show the best of many tries.

Edited to delete old photos, I ran out of allowable space on BF
 
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You did a good job. A bit more practice will help you with keeping things even. But good job
 
It looks good to me. I am sure if you are starting off this good then you will be a pro in no time.
 
From the side they don't look like much but from the top they're pretty. I had no idea that's what you meant, nice job!
 
I like it.
Constructive critisism: have an other look at the curve from where the indexfinger goes towards the edge.
Personaly I'd have that curve with a smaller radius. And maybe round the steel a bit there so when the indexfinger bumbs in to that steel it is round.
(and don't forget to drill holes before HT)
 
JT I see what you mean, I could have stopped sooner and finished to the ends with files for crisper end points.

Lapedog, thanks for your kind words, it means a ton.

Milkbaby, yes a 30 degree angle would have cut deeper into the flats and be more noticeable from the sides, great point. I'm not in a hurry so I still might modify a little with files.

Hengelo_77. Is this what you mean? These inside curves drive me nuts getting perfectly smooth, but I do round everywhere a hand might touch steel. I will drill for pins and epoxy pinholes prior to HT and hollow out the tang a little. What is the opinion on lanyards on knives of this general size?
View attachment 798596
 
Looking good, and I agree a little more rounding where you marked red will likely make them a bit more comfortable to hold and use. Anyway, you did a good job and they look great. I'd drill some lighting holes in the tang as well if your not going to taper them, it will help the blade to feel alive in your hand.
 
thanks very much everyone, very helpful and I will use the comments to forge ahead. :>)
 
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