Grinding clip bevels, radius(horizontal) platen

JG Custom Metal Works

JG Custom Metal Works

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Nov 27, 2013
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I need to grind the bevels on a clip(sharpened, not false edge) point Bowie that I’m making, and am wondering how to go about it. My first thought was to just use the edge of my flat platen that has a piece of leather glued to the front. Then I started thinking about making a radius to glue onto the front of one of my extra flat platens. When I say “radius platen” I’m talking about a radius going horizontal, from left to right. Not a vertical radius, like the ones Nathan Carothers sells, that goes from top to bottom.

Have any of you guys made a platen like this before? If so, do you have any advice? I’m trying to figure out how I’m going to grind it evenly round. I’m also trying to figure out how much of a radius I’ll need. I’m also trying to do this with using as little math/trig/geometry as possible. Math has always been my worst subject. With these types of radius platens, are you able to use any regular belt, or do they work better with j-flex belts? How about the tension settings on the belt? Does it work better a little loose?

I’ve researched a good amount on how to do this and from what I’ve found, the best way to go about it would be to have a flip to horizontal 2x72 and use a contact wheel with a diameter that matches the concave of your clip. Then have either a tool rest, that can be tilted to the desired angle. Unfortunately this isn’t an option for me at the moment. I DO have a DD tool rest that tilts, but it doesn’t match up to my larger contact wheels and I can’t flip my grinder horizontal. Although I am batting around the idea of trying to rig up some way to do it vertically.

This is kind of what I’m talking about:


Lastly, what angle do you guys grind your clips at? I was planning on going with 20-25 degrees per side, bit I’m not 100% sure yet. IIRC that’s what a lot of guys are using for theirs. Also, do you just grind to zero and the strop the burr off? Kind of like a obtuse scandi? Or do you grind a secondary bevel on the edge?

Any help would be greatly appreciated. This is the knife. The main bevel is uneven, but not done grinding yet as it will be a full flat grind. I’m going to grind the clip soon and then go back to grinding the main bevel so I can make them intersect at the tip. BTW:

DlHY7Eo.jpg


79gcIrr.jpg
 
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ron_m80 said:
Post HT?
Click to expand...

Yes, I’ve already heat treated the knife. That really doesn’t have much to do with my questions though. I’m trying to figure out the physics of grinding the clip, more than when to grind the clip. Thanks though.

I forgot to mention, the knife is .200” thick.
 
I would grind the clip at around 30-35 degrees.

I would mark my edge on the swege and grind it like you would any bevel.

Just follow the edge on the flat platen but do not use the entire platen, use the sides so work inside the radius.

This is a perfect case for a bubble jig.
 
i scribe a centerline on the spine and set my dd work rest between 50 - 70 degrees. i do the clip first before the bevels, so the blade will stay flat on the work rest and give a consistent angle on each side.
 
I freehand mine and don't really do a set degree lol. But I can see the advantage to doing it with a jig before the main grind for sure
 
I don’t like the bubble jig. Had one and sold it. I like to watch the blade as it’s contacting the platen. I found whenever I used it, I’d catch myself looking over to see if I was level or not. I’d just as soon use a angle iron jig/fixture and set the angle with my platen. Which is what I might end up doing.
 
Don't forget hand work guys.
Many times I first mark the bottom edge of where the false edge will end up with a fine tip marker on both sides of the blade so they match.
I will do the majority of the stock removal on the grinder staying back from where I want to end up.
Stick the knife in a sturdy knife vise and finish the false edge by draw filing with a good file.
Finish the shaping with EDM stones.
Slower = better. Better = faster.
 
Karl B. Andersen said:
Don't forget hand work guys.
Many times I first mark the bottom edge of where the false edge will end up with a fine tip marker on both sides of the blade so they match.
I will do the majority of the stock removal on the grinder staying back from where I want to end up.
Stick the knife in a sturdy knife vise and finish the false edge by draw filing with a good file.
Finish the shaping with EDM stones.
Slower = better. Better = faster.
Click to expand...

I second that. I do the rough grinding of my clips freehand on the beltgrinder and then I clean everything up with files. I don't like using jigs, there is nothing wrong with them if they work for you, I just personally don't like them.
The best tip I can give for these kind of things is to initially remove not as much material on the grinder and do more work with files and then slowly start getting your clip grinds closer to where you want them to end up on the grinder when you are more comfortable to work those rather narrow bevels after you've done it a couple of times.
The most important thing is scribing a good centerline to work towards...then you can move towards that line on the grinder with a very steep angle and then work the grind lines down the blade and back with files when you are not that comfortable yet doing it on the grinder.
This is a big bowie blade I am currently working on where I ground most of the clip on the grinder, but established a nice curving line with files...because I feel I have more control that way:

9X6Cxo.jpg


Edit: also when using files you have way more control over where your clip grind terminates on the spine because obviously you are not removing as much material as quickly.
 
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A good thing about doing the swedge first is it is set in stone and dead symetric
JG Custom Metal Works said:
I don’t like the bubble jig. Had one and sold it. I like to watch the blade as it’s contacting the platen. I found whenever I used it, I’d catch myself looking over to see if I was level or not. I’d just as soon use a angle iron jig/fixture and set the angle with my platen. Which is what I might end up doing.
Click to expand...

If you still had the BJ you would put it directly under the swedge so you would look at the grind and bubble at the same time.

If you are wary about free hand grinding the swedge then definitely use an angle iron jig for the swedge. I use one on swedges often and just tilt the platen to the desired angle. It makes the swedge easy peasy and quick work
 
The MAIN problem that I’m looking to address with this thread is grinding the curved section of this knife(which happens to be the clip). Grinding a straight section of a blade is easy. Swedges are easy for me to grind, as long as they aren’t curved(concave). Same goes for knives with substantial recurves. So that’s what I’m trying to get advice on.

Thanks for all the help everyone.
 
JG Custom Metal Works said:
The MAIN problem that I’m looking to address with this thread is grinding the curved section of this knife(which happens to be the clip). Grinding a straight section of a blade is easy. Swedges are easy for me to grind, as long as they aren’t curved(concave). Same goes for knives with substantial recurves. So that’s what I’m trying to get advice on.

Thanks for all the help everyone.
Click to expand...
The earlier question I had, was for me. I don't know if I do clip points the "right" way.

I have used a HSS parting tool as a scraper, which removes good quantities of metal but makes ugly cuts (post HT o-1, 1095, and the like). I have found an "MT2 dead center" has the right taper on it for me, for sanding a nice even flat into a curved clip point.
 
Just taking an opportunity to share. (definitely not showing off... everyone can see the rough handling and poor finish)

Ground off bulk with the grinder, worked the rest by hand as I described above. Clip is offset because the tip is near full width, and won't be ground down until after I send it out for HT.clip.jpg
 
JG Custom Metal Works JG Custom Metal Works , regarding the curved platen idea, I recently saw a video by "Dos Gatos Forge" where he does exactly that. Looks like a nice way to grind in a curved clip and I may have to try it sometime.

I personally also do it the way Karl describes. I hog off the main bulk grinding vertically on a wheel and then clean up with files and finish refining with stones.

Here is the video I'm talking about:


~~~~~~~~~~~~~~~~

Karl B. Andersen Karl B. Andersen - I remember seeing your "Alaskan" Bowie WIP a number of years ago and also remember seeing that you marked in (with a sharpie) the curve for your clip and then proceeded to file it. May I ask how you mark(ed) the curve for the clip so it's symmetrical on both sides? I've tried using a paper template with the clip area cut out so I could lay it on the blade and scribe along the cutout area, but that gave me its own problems and I ended up just having to eyeball it as best as I could, which causes more back and forth than I'd like to do. Thanks



~Paul
My Youtube Channel
... (It's been a few years since my last upload)
 
JG Custom Metal Works said:
This is what I’ll probably do. I have a flat steel platen that I glued a piece of leather to. Do you think it would be better to use that, or the plain steel platen.
Click to expand...

I would overhang my belt 1/8" on the platen and use it to sculpt the swedge, then move to a steel bar with sand paper for and sanding.
 
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