What ? Another plunge question?

Mark Barone

Well-Known Member
Here’s my ghetto plunge system. I really need a guide. My file guide is too big to modify my jig so I thought I could just clamp a piece of steel in front of the blade and at a choil line. So the question . I know I hang the belt a tad over the platen. Is the goal to just ride the edge of the belt on the edge of the guide or the goal for the belt to roll up onto the guides edge. Also look at the clamp, you can see how horrible I was using the clamp as a
plunge guide. So basically tying to mimic free hand using a file guide.. But with a jig
Instead 53CFF437-CD56-488D-BC7F-798A9E84D683.jpeg
 
Last edited:
Here’s my ghetto plunge system. I really need a guide. My file guide is too big to modify my jig so I thought I could just clamp a piece of steel in front of the blade and at a choil line. So the question . I know I hang the belt a tad over the platen. Is the goal to just ride the edge of the belt on the edge of the guide or the goal for the belt to roll up onto the guides edge. Also look at the clamp, you can see how horrible I was using the clamp as a
plunge guide. So basically tying to mimic free hand using a file guide.. But with a jig
Instead View attachment 71360
i don't have any answers but I do have a question: why are you wearing golf pants?
 
I think you're putting the cart before the horse so to speak. Although it MIGHT seem logical to use plunge cuts/lines as a starting point....just the opposite usually works far better. Much depends on how good you personally are with your grinder, but I not only do it, but also teach students to START a very shallow cut, significantly forward or where you wish the plunges to end up. Then through the grinding process, both rough and finish grinding, step the plunges back a bit with each grit. I usually get them to their final location after heat treat, and when I'm at 220 grit...then just touch/clean them up with 400 and 600 before hand finishing.

This is just a guess on my part, but HOW you grind also have a big impact on how well the plunges come out....what I mean...and this is how I teach it. When starting your grinding pass, start by contacting the middle of the blade to the belt. No/minimal pressure, then gently go back to the plunge area, then apply pressure, and make your grinding pass. The repeat, repeat, repeat, until you're where you want to be. The most common thing I see when teaching grinding, is that most do not understand that unless your arms/hands are LOCKED into your body, it's just not gona work. There is not a human on the planet who has the strength/ability to hold a knife blank without "bouncing around"....without the arms/hands locked into the body for support.

Of course, those who use a work rest/jig combination likely don't have that issue, but then those who do are usually locked into a single blade profile.

Personally, if I were going to use, or make a recommendation to use a jig during grinding, it would be to first, leave the plunge forward of where you want it, and finish it during final grinding. AND....if a jig is used..... use a carbide file guide during finish grinding and have it aligned where you want your plunges.
 
I think you're putting the cart before the horse so to speak. Although it MIGHT seem logical to use plunge cuts/lines as a starting point....just the opposite usually works far better. Much depends on how good you personally are with your grinder, but I not only do it, but also teach students to START a very shallow cut, significantly forward or where you wish the plunges to end up. Then through the grinding process, both rough and finish grinding, step the plunges back a bit with each grit. I usually get them to their final location after heat treat, and when I'm at 220 grit...then just touch/clean them up with 400 and 600 before hand finishing.

This is just a guess on my part, but HOW you grind also have a big impact on how well the plunges come out....what I mean...and this is how I teach it. When starting your grinding pass, start by contacting the middle of the blade to the belt. No/minimal pressure, then gently go back to the plunge area, then apply pressure, and make your grinding pass. The repeat, repeat, repeat, until you're where you want to be. The most common thing I see when teaching grinding, is that most do not understand that unless your arms/hands are LOCKED into your body, it's just not gona work. There is not a human on the planet who has the strength/ability to hold a knife blank without "bouncing around"....without the arms/hands locked into the body for support.

Of course, those who use a work rest/jig combination likely don't have that issue, but then those who do are usually locked into a single blade profile.

Personally, if I were going to use, or make a recommendation to use a jig during grinding, it would be to first, leave the plunge forward of where you want it, and finish it during final grinding. AND....if a jig is used..... use a carbide file guide during finish grinding and have it aligned where you want your plunges.


Yes I was thinking about your method and still,want to incorporate it. I just have this pattern of not being able to stop myself from plunging it back to far or clipping the ricasso. So I will start forward and move it back to the “guide” and I know that guide might only last one time. I want to get the creative man jig and use the carbide guide with it. It’s just a little pricey for me right now.
 
However you end up accomplishing it, please re-read Ed's post. A HUGE takeaway is walking your temporary plunge back with each grit and only reach the final destination at your finer grits. Aside from getting even plunges, one of the biggest hurdles to knifemaking is conquering those scratches INSIDE the plunge. The best way to get rid of 60 or 120 grit scratches is to not have any to begin with. Effectively, you cut all new plunges right at the end. Even a 400 grit belt will have no problem doing that if you're only removing .020 of material.
 
I bought a couple of the Norton U396 x16 belts and yes, they clean things up nice, when my knife comes out of the clamps in the morning I’ll post a pic of the finish they gave me
 
Back
Top