Hand rubbing questions

[REK Knives]

Hey guys! I've read some stuff from several people on hand rubbing and crisp lines, but I'm wondering if you guys have any tips for Sabre grinds and especially when it gets to plunges to make them look clean all the way to the end with no fish hooks?

Nick wheeler among others had excellent info on hand sanding hollow grinds, wonder if it carries over?

Also, do you clamp the blade and work it or hold the blade and fix the sandpaper?

 

[jdm61]

I have seen it done had have done it both ways, but with a blade that has not been handled, I clamp the blade in a Moran vice. On only clams the paper and move the blade if I am trying to remove a ding fro a finished knife. The way I avoid fishhooks is to finish on grit higher than what I want and then go back with fresh paper one grit courser and make one straight pull, using a fresh part of the paper for each stoke. What I do is cut up sheets into 2 or so inches wide strips and wrap them around a 3M hard rubber sanding block. I learned that trick from Dr. Jim Lucie at Batson's hammer-in around 2007.

 

[Park Swan]

The way I avoid fishhooks is to finish on grit higher than what I want and then go back with fresh paper one grit courser and make one straight pull, using a fresh part of the paper for each stoke.

This is brilliant, thanks for sharing.

 

[Bob Ohlemann]

I made blocks that match the radius of finish grind on each of my wheel sizes. The blocks are made of oak and faced with hard rubber. They are not the size of the wheel itself but, radiused to the Gator belt over the wheel. For flats, I actually use a machinist parallel with the ends taped up into handles. I have one with hard rubber on it and one without. My usual hand finish is to go to 800 grit with the blade clamped. I will do the long pulls as mentioned previously with each grit as I move up. When I'm finished at 800, I place a fresh piece of grey Scotch-Brite on the edge of the bench and pull the blade across it several times in long straight pulls.

Bob

 

[NickWheeler]

If you go to Lowe's or Home Depot... go into the plumbing section. They sell a bulk, brick red gasket material. It's pretty soft, I'd say about 35-40 durometer.

Cut and glue a strip of that to your sanding stick.

It will easily conform to a convex geometry.

The method of holding the blade and fixing the sanding block is popular with some... I've tried it, and think it's a PITA and really hard to see what you're doing. But what works for each individual is always different.

 

[REK Knives]

I have seen it done had have done it both ways, but with a blade that has not been handled, I clamp the blade in a Moran vice. On only clams the paper and move the blade if I am trying to remove a ding fro a finished knife. The way I avoid fishhooks is to finish on grit higher than what I want and then go back with fresh paper one grit courser and make one straight pull, using a fresh part of the paper for each stoke. What I do is cut up sheets into 2 or so inches wide strips and wrap them around a 3M hard rubber sanding block. I learned that trick from Dr. Jim Lucie at Batson's hammer-in around 2007.

Good info, thanks! Is this the 3m hard rubber block you are referring to or something different?

I made blocks that match the radius of finish grind on each of my wheel sizes. The blocks are made of oak and faced with hard rubber. They are not the size of the wheel itself but, radiused to the Gator belt over the wheel. For flats, I actually use a machinist parallel with the ends taped up into handles. I have one with hard rubber on it and one without. My usual hand finish is to go to 800 grit with the blade clamped. I will do the long pulls as mentioned previously with each grit as I move up. When I'm finished at 800, I place a fresh piece of grey Scotch-Brite on the edge of the bench and pull the blade across it several times in long straight pulls.

Bob

Thanks Bob. A question if you don't mind! Which hard rubber do you use to face your machinist parallels?

If you go to Lowe's or Home Depot... go into the plumbing section. They sell a bulk, brick red gasket material. It's pretty soft, I'd say about 35-40 durometer.

Cut and glue a strip of that to your sanding stick.

It will easily conform to a convex geometry.

The method of holding the blade and fixing the sanding block is popular with some... I've tried it, and think it's a PITA and really hard to see what you're doing. But what works for each individual is always different.

Hey Nick, glad you chimed in

Yeah I have found that there are all sorts of ways to accomplish the same things, I just have to figure out what works for me. But all of these ideas ^ are great!

I saw where you posted before on a thread about hollow grinding where you use this red gasket material ONLY on the finishing passes, do you still recommend this? And do you recommend the same for a flat/sabre ground knife? I'm wanting to avoid any convexing if possible...

 

[Bob Ohlemann]

It is 70a duro 3/32" that I ordered from McMaster-Carr

Bob

 

[NickWheeler]

Hmm, I guess that's a terminology mix-up... I always had the understanding a saber grind was a short height flat grind that was convexed at the edge.

If you're wanting to avoid convexity, I wouldn't recommend the red gasket material at all, LOL.

I actually don't think I've posted too much about finishing hollow grinds on here... I have done them for many years. But 95% of my work is a full height flat grind that's feathered down to an edge with subtle, convex geometry. And that's what I have posted most about.

I never use anything but steel until the end.

My go to sanding stick for final pulls has 90 durometer urethane glued to it. It's barely got ANY give, so it won't wash anything out, but helps give the nicest finish. IMHO.

 

[Matt Rochester]

I talked to Ralph Smith once and he does his hollows by clamping the contact wheel still and pulling the knife across it. Then roll the wheel and belt a little and continue. I have tried it and it's a little tricky but does work.

 

[Del Raso Knives]

I've also employed both sanding methods and prefer fixing the blade. Something you my want to try to avoid fish hooks is to angle the blade tip down 10 to 15 degrees from horizontal. With the tip angling down you are essentially falling downhill as you sand, making it much harder to pause and interrupt your finish. Everyone I have shared this tip with has remarked on how much their finish has improved. It may help you too.

 

[REK Knives]

Hmm, I guess that's a terminology mix-up... I always had the understanding a saber grind was a short height flat grind that was convexed at the edge.

If you're wanting to avoid convexity, I wouldn't recommend the red gasket material at all, LOL.

I actually don't think I've posted too much about finishing hollow grinds on here... I have done them for many years. But 95% of my work is a full height flat grind that's feathered down to an edge with subtle, convex geometry. And that's what I have posted most about.

I never use anything but steel until the end.

My go to sanding stick for final pulls has 90 durometer urethane glued to it. It's barely got ANY give, so it won't wash anything out, but helps give the nicest finish. IMHO.

Ok I was referring to this post =) Yeah by saber I just meant a mid height flat grind, roughly. Great tip on the 90 duro, I will have to order some!

I've also employed both sanding methods and prefer fixing the blade. Something you my want to try to avoid fish hooks is to angle the blade tip down 10 to 15 degrees from horizontal. With the tip angling down you are essentially falling downhill as you sand, making it much harder to pause and interrupt your finish. Everyone I have shared this tip with has remarked on how much their finish has improved. It may help you too.

That's a great tip! Thanks man.

_______________

Any tips on working the plunge to ensure the previous grits are erased and everything still look crisp? I guess it would depend on which method you used, clamping the blade or the paper...

 

[jdm61]

What Dr. Lucie told me about the rubber block is that you can bang it right up against the plunge cut with no worry about scratching anything even if the paper tears. Had enough to be stiff but not that hard. It may not be ideal for the heavier grits compared to a hard block, but on the fine grits, it works like a charm.