Moving plunge lines back

R

rideslow

Joined
Sep 10, 2014
Messages
12
Hello, newbie here. I'm getting pretty fair at flat grinding simple knives freehand. I'm trying to learn to move my plunge line back after it's already established. The issue I have is undercut. When I'm using a 60 grit belt and bump the plunge back, as the belt is on the bevel, it's deeper than the ricasso. Instead of cutting the plunge back, the edge of the belt is undercutting the the ricasso.
Should I be lifting the bevel off the belt and grinding straight in to establish the new position for my desired plunge?
Currently I'm leaving the bevel on the belt and bumping toward the plunge, however this method is producing the undercut.
Thank you for any suggestions you may have.
 
Always grind straight on the face of the belt, not on the edge of the belt.

Hoss
 
You should use flexible belts or break the edge of your belt. Also overhang the belt and radius you platen edges. The alternative is a waterfall platen. Some also use Trizact gather belts due to the the profile and height of the grit to finish the plunges.
 
So, I am going to preface this by saying that I am by no means the best off the grinder (though I am getting better.) So I adjust my plunge lines a bit differently, but it ensures an even plunge.

I set my plunge with a file guide and a chainsaw file (usually 3/16 inch) after setting the initial bevel (breaking the edge to .030 of a scribed center line). Them I finish the bevel. After that I spray glue 180-220 grit paper to a granite surface plate with a 3/16" radius on the edge. Clamp the blade into a carbide file guide and run the bevel flat against the sandpaper to even out and adjust the plunge line. I move up grit usually to 400 grit to ensure no deep scratches at the plunge to contend with later. Been doing it like this for years and have had great success.

Edit to add, Nick Wheeler has a video on this on youtube.
 
I fine tune my plunge lines with a 180 grit felt backed belt, normally what Hoss said is true you don’t necessarily want to use the edge of the belt but with higher grits and flexible belts you can get the belt to curve around the edge of your platen which lets you grind in the motion you are trying to do. I’ve found the felt backed belts that Deerfos makes works best for this for me, I can get really nice plunges and correct if my initial plunges at the 50-60 grit level were off.
 
navman said:
So, I am going to preface this by saying that I am by no means the best off the grinder (though I am getting better.) So I adjust my plunge lines a bit differently, but it ensures an even plunge.

I set my plunge with a file guide and a chainsaw file (usually 3/16 inch) after setting the initial bevel (breaking the edge to .030 of a scribed center line). Them I finish the bevel. After that I spray glue 180-220 grit paper to a granite surface plate with a 3/16" radius on the edge. Clamp the blade into a carbide file guide and run the bevel flat against the sandpaper to even out and adjust the plunge line. I move up grit usually to 400 grit to ensure no deep scratches at the plunge to contend with later. Been doing it like this for years and have had great success.

Edit to add, Nick Wheeler has a video on this on youtube.
Click to expand...
I've seen a video of him talking about it, but I'm not sure I saw him actually doing it, but that definitely seemed interesting.
That's all PRE-heat treating though right?
I've been doing alot lately everything the Hard way... :/
 
Joshua Fisher said:
I fine tune my plunge lines with a 180 grit felt backed belt, normally what Hoss said is true you don’t necessarily want to use the edge of the belt but with higher grits and flexible belts you can get the belt to curve around the edge of your platen which lets you grind in the motion you are trying to do. I’ve found the felt backed belts that Deerfos makes works best for this for me, I can get really nice plunges and correct if my initial plunges at the 50-60 grit level were off.
Click to expand...
I profile by rolling the belt edge off the platen.
I have no real need for small diameter rollers with that trick.

are you getting the bevels by eye, or with a bevel/file clamp?
 
Crag the Brewer said:
I profile by rolling the belt edge off the platen.
I have no real need for small diameter rollers with that trick.

are you getting the bevels by eye, or with a bevel/file clamp?
Click to expand...
By hand and eye, jigs and clamps are great to learn but they are slow. Here’s a blade I just finished, I always start my bevels forward of where I want the plunge to be by 1/16-1/8” then move them back with the felt backed belts, you can see this example is really close but slight different side to side which could be from the rough sharpening to set the edge but I can get my plunges reasonably even and where I want in the time it would take to setup a file guide and if you aren’t careful you can undercut your plunge with a file guide.image.jpg
 
Joshua Fisher said:
I fine tune my plunge lines with a 180 grit felt backed belt, normally what Hoss said is true you don’t necessarily want to use the edge of the belt but with higher grits and flexible belts you can get the belt to curve around the edge of your platen which lets you grind in the motion you are trying to do. I’ve found the felt backed belts that Deerfos makes works best for this for me, I can get really nice plunges and correct if my initial plunges at the 50-60 grit level were off.
Click to expand...
Who sells the felt back belts?

Hoss
 
I use the edge of my belt all the time for this kind of thing, and I think 60 grit is too high. 180-220 for me, and lower speed. I'll start just shy of where I want the plunge to end and nibble off the corner of the plunge and work down from there. Lighting is super important
9y6Q7pl.jpg
 
Joshua Fisher said:
Pops knife supply has them under their economy 2x72 belts labeled as Deer SA they have quickly become my favorite finishing belts they have 180 up to 2000 in that line of belts.
Click to expand...
My next order will include these belts, I'll look elsewhere too....just to be safe.
;)
 
Thank you all! I will try with the flexible belts , overhang , and slow down my speed for starters.
 
Lorien said:
I use the edge of my belt all the time for this kind of thing, and I think 60 grit is too high. 180-220 for me, and lower speed. I'll start just shy of where I want the plunge to end and nibble off the corner of the plunge and work down from there. Lighting is super important
9y6Q7pl.jpg
Click to expand...
Good looking fuller too :)
 
You must log in or register to reply here.
Back
Top