Hand sanding a hollow grind

[Hengelo_77]

I'm practising hollow grinding and I actualy like it. (11,5"wheel, 25% speed)
I also like hand sanded blades, so I'll be needing a sanding block in the same diameter as my wheel is.
What do you guys use for hand sanding a hollow ground blade?
Can you show me a pic of your sanding block/stick?
Any othe general tips?


I did these on a 80 grit belt followed by a 120 grit belt:

 

[Daniel Carraher]

I have a radiused sanding block but I use diemakers stones way more than the radiused block

 

[Joshua Fisher]

I'm practising hollow grinding and I actualy like it. (11,5"wheel, 25% speed)
I also like hand sanded blades, so I'll be needing a sanding block in the same diameter as my wheel is.
What do you guys use for hand sanding a hollow ground blade?
Can you show me a pic of your sanding block/stick?
Any othe general tips?


I did these on a 80 grit belt followed by a 120 grit belt:

I use EDM stones to hand sand my hollow grinds when I make knives from W2 and need to bring out the hamon, I dunk them in water and they slowly form to match the hollow or you can shape them to match the hollow. Other than that you could take some thick micarta and cut and grind the radius to match. You would probably want to keep the sanding stick/block relatively narrow so you can effectively wrap paper around it, think of it like a sanding tooth brush.

 

[eric brinkerhoff]

In my opinion hollow grinds look better with the vertical pattern left by the belt. It brings out the hollowness of the grind , especially when you turn the blade around in the light!

 

[Joshua Fisher]

In my opinion hollow grinds look better with the vertical pattern left by the belt. It brings out the hollowness of the grind , especially when you turn the blade around in the light!

I agree but there are times that you would want the grind lines running length wise, especially if making a knife with a hamon, San mai, Damascus those patterns can look better hand sanded and some look good with a belt finish it just depends on how busy the pattern is, with Damascus I think it looks good but hamons I think they need to be hand sanded lengthwise.

 

[AVigil]

I use a piece of aluminum or micarta and trace the radius from the wheel onto it allowing for some rubber or leather glued on top.

On folders I like hand sanded blade, on fixed blade a belt finish

 

[Signalprick]

Kyle Daly (khdaly knives) makes radius sanding blocks to your specs on his 3D printer. He calls them a Sanding Buddy and they are absolutely awesome. I also go 2" down from whatever size wheel I'm using. For instance when I do a hollow grind on my 12" wheel I use a 10" radius block to sand and then sneak up on my grind lines. This keeps your lines looking crisp and not washed out.

 

[eric brinkerhoff]

If your contact will is not serrated you can put a fine grit belt on that and move the knife back and forth across it bringing the knife to the tool rather than bringing the tool to the knife.

 

[fitzo]

I use Norton AO shop roll abrasives and wet-or-dry strips I cut and a plain old pink rubber eraser as my sanding block for the hollows. Just the right width, and always the right arc, so to speak.

 

[Lorien]

I've watched this a few times

 

[Hengelo_77]

Thnx for the vid, Lorien, a very good one
(I'll check out his other vids later, they look good)

 

[Hengelo_77]

I definitely need to work on the plunge line but this one is about the hollow grind. And for a first one I'm pretty happy with it.
I'll have it HT-ed, put a simple handle on it and use it in the kitchen to see how I like it.

This is what I did this afternoon.
All tips/comments welcome

 

[FredyCro]

I will follow this thread further. I did 2 hunters with nice hollows but then f*d the plunges so had to regrind to ffg.

Now I put the hollow on the KITH knife and on another nakiri I am working on. Couldn't get a nice machine finish on whole blade so had to hand sand. I can get a decent 400g finish on the hollow but my lines are not fully crisp (serrated wheel might be part of this problem...). Pics of my attempts, critic, advice welcome.

After widening the hollow and trying to finish the flats with a surface condition belt I had to hand sand. Hand sanding washed the crisp lines away. I hand sanded with a hard wood block with a 1" smaller radius. I will do a micarta block next.

Went up to 400g and then hand sanded. Again lost the crisp lines but finish is uniform after hand sanding.

 

[AVigil]

If you want nice plunges, grind ahead of where you want the plunge until almost finished.

Then switch to a J-flex belt, in the grit of your choice, and then form the plunge by backing up into it. So do not "plunge" at all, it is more like backing up your car.

The J flex will form a nice raidus and using a file guide makes them even.

 

[john april]

i found that if my half moon sanding block is the same size as my contact wheel, i cannot do alternate 45 degree angles. if my blocks radius is too small, there is hardly any contact area. i do my first grit lengthwise to the blade to get rid of the machine scratches running across the bevels from the belt. it seems to be the most efficient way. then on the second grit i go to alternating 45 degree angles to be absolutely sure i got rid of the previous scratches. i like a hard block so i do not run over the centerline of a double edge grind, or the bevel to a flat above a single grind. you can feel when your block is running on the edge of a grind. for my 4 inch wheel i use a 3.5" radius block, for the 10 inch wheel i use a 9 inch radius block. i use micarta, or sections of pvc pipe.

27A802EA-7892-40AC-8E90-D838605C7961 by john april, on Flickr

 

[Natlek]

I definitely need to work on the plunge line but this one is about the hollow grind. And for a first one I'm pretty happy with it.
I'll have it HT-ed, put a simple handle on it and use it in the kitchen to see how I like it.

This is what I did this afternoon.
All tips/comments welcome

OK , my 2 cents about this ............
Some year ago I get from USA / my friend brought them/ ceramic belts 2x42 , Fandelli or Fendeli brand or something like that .20 pieces are 40 grit and 20 are 100 grit.I used all 40 grit belts and they work just fine .Not like Klingspor but good enough .BUT I never try 100 grit .A few months ago I convert my 1 x 42 grinder to direct drive so now I have only about 21-23 m/s belt speed .I had to make one kitchen knife and I didn't have any good 2 x 42 and 40 grit belts ......I remembered I had 20 belts in 100 grit ............Surprise ......they work perfectly good on that speed. Steel was 1.2519 , 1.5mm thick and 64Hrc. They do not generate too much temperature , cooled in water after two to three passes . Now about finish..........comparing 100 grit on mine steel to what I see in this picture ....A45 -320 grit whatever that mean ... finish was much better , much better so I recommend you try it at a higher speed.
About plunge .........don t start removing steel from exactly where you want to be plunge , leave about 2-3 mm. Finish them when you are almost done with grinding bevels.When you do that , if you work on right side .........MOVE belt about 2 mm out of wheel on same side ......And I must say this to .IF there is place where grinding jig shine ............... making symmetrical plunge is so easy with jig .
I have no advice about hand sanding hollow .All I do is little sanding with small piece of scotch brite on my right thumb and that make difference ............

 

[Hengelo_77]

Thnx for all the replies guys. I'll look in to those J-fles belts.

I can see why sometimes you want a hollow ground machine finish, but I just can't help myself, I like hand sanding and a hand finished blade.
I made pics of the sanding "blocks" I ended up using.
First cheap chinese stones, then a push stick to sand spine to edge and two pieces of sole leather.

This one is ready to send out for HT, 3" blade with the bevel at 1000 grit and the rest at 2500.
Niolox+ steel and I may end up using that block of Macassar ebony as a handle.