Holding onto your folder blades when grinding?

Brian Avila

Brian Avila

Joined
Jan 2, 2011
Messages
1,286
I was wondering what you guys use to hold onto your folder blades when grinding?

I tried some vise grips but that messed up my finish and created some problems, which made me trash a blade.
 
I know some makers use a jig that's essentially a "handle" with adjustable pivot/stop pins. For example, an aluminum bar with some slots so screws or pivot pins could slide around in that you would bolt your folder blade onto. Some people also only grind fully hard (which works better for smaller blades, like slipjoints).
 
I've tried a couple different ways, including screwing it to a piece of flat stock for a handle, or just pinning it to the handle itself.
 
Normally I just use the handle unless i use a dedicated blade grinding jig. Some makers cut 2 blades out of the same stock, back to back, and don't separate them untill at a later stage. That way one blade will serve as a handle for the other.

Brian
 
the bar with the pivot pin plus an anti-rotating pin is a neat idea, but adding a leather pad to vise-grips is a widespread method for handling that small suckers ;)
 
Ah ha! something I can answer!!! I made a little holder out of a bit of spare scrap aluminium. I modelled out where I wanted the pivot to be relative to the tip, tapped two holes for 10-32 screws that just fit through 3/16th pivot holes, or through 7/32 holes with a bit of shimming. Two more 1/8th holes for a removeable 3/4" length of pin to support the tip.

The first time I used this, the blade wasn't too deep. On the one pictured I had to bond a 1/4" thick bit of Micarta on to the leading edge of the base to give enough clearance for the blade spine.

The aluminium is a great heat sink for the first side, you don't have to dunk the blade at all, but the second side requires dunking every few passes, ideally in a shallow pan that does not wet the whole thing...not all my screws are stainless.

This was in fully treated RWL34. I ground a 45degree lead in just holding the blades by hand, but in retrospect I would like to make another jig for that to get the edge thickness more precisely defined.


Bevel grinding using a pretty simple angle control jig.


Twin screws control angle and you can really micro adjust, but I found out the hard way that the best course was to set an angle and leave it alone, not to keep adjusting as final shape is approached.


Marker pen really helped show where the belt was hitting




and after getting down to 400 grit, the jig made a handy holder for "sanding" with EDM stones to pick up any deep scratches.


Back on the cork belts out to 800 grit gave a pretty good machine finish
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...and this is what I used to grind the radius on the tang. Very simple.

Checking the "jig" for grinding the radius with a dummy blade.
[URL=http://s289.photobucket.com/user/gps_deseng/media/Knives/Folders/IMG_0181.jpg.html]


This system does limit the type of grind one can do, but with care even someone as out of practice and dexterously challenged as I can make a half decent job on their bevels and plunge.

:) Chris
 
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Good photos - I use a similar idea, but I found it easier to work keeping the jig level for a wider sliding surface, and tilt the platen a tad. Gives same result, just easier for me to do.

I LIKE your idea for putting radius on tang.

Ken H>
 
What grinder do you use for the tilting platen?

The radius grinding works by pivoting upon the clamped end, finger pressure on the free, left hand, end. That way the tang can be brought to the moving belt with some control. After worrying about it a lot before I started, it turned out to work really easily and well. Felt a bit stupid for worrying! Just wish the micron belts worked better on the platen.
 
C_Claycomb how did you determine how you wanted the tip to set etc? How does the location of the tip determine how the grind turns out?
 
Brian,

The jig was originally set up for grinding a replacement blade for my Rapid Response Folder, which had a very different blade shape.


I assumed that the pin position that I had for that shape would not work for what I wanted this time, so I spent some time modelling up the fixture in CAD, traced out the profile of the blanks and put those into CAD as well, just to play around with angles and pin and pivot positions.



In the end, I reckoned that the position of the tip support pin didn't have a whole lot of impact. I could move it around a lot and the main difference was where the primary bevel met the spine. Large movements produced relatively small changes. Moving the pin up or nearer the pivot made the grind break onto the spine nearer the pivot. Obviously, moving the tip around changed the angle of the plunge, so there was actually a limited range of angles that the blade could be at where the plunge ran right and the grind behaved. If I had the jig to make again, I might have tweaked it a bit more for this specific blade, but I found that what I had looked about as good to me as any of the alternatives I tried.

If you want, I can get some screen shots of how it changes with tip position? You might be able to figure all this out without CAD. In this case, the change from full thickness to primary bevel is always equidistant from the edge, that was just automatic from following the same edge thickness at the same angle. That is also the limitation of using this jig, you can't twist the blade and change the look of the grind by changing its steepness from plunge to tip.

ATB

Chris
 
I like to clamp my blades (kant twist clamp - nice for less scratches) to a metal backing and just remove metal... after that I like to hold the blade in my hands for cleanup, I like balance holding a folder blade on each end has that way. Lately I have been using my work rest for the hogging part. I hand lap to remove light scratches later.
 
The grinder I use is what I call a KMG clone - I looked at photos and built grinder from those. Take a look at the thread below, 3rd photo down and you'll see the single 1/2" bolt holding the platen. This allows Platen to pivot to desired angle. The first platen I built I put bolt holes in 90 and 45º angles. Found it didn't need the extra bolts - just move platen to desired angle, tighten single 1/2" bolt and it doesn't move.

http://www.bladeforums.com/forums/showthread.php/1234634-New-Grinder-for-me

Ken H>
 
This is the jig I use grinding freehand. Simple piece of stainless with screws sized to my pivot. Only thing I do differently than the picture now is using 2 brass washers to sandwich the blade to make sure I don't mar the finish.

 
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