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Scratch Direction ?

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Dwane Oliver
Posts: 40
Member
Topic starter
 

Today I spent WAY too much time hand sanding the first forged knife I have made.

Karl Andersen said in one of his videos " a good hand sanding job is not the product of alot of hand sanding , a good hand sanding job is the product of good grinding " I totally understand that now , thanks Karl.

Anyway

I was so proud of all of the work I had done today, so I brought it in the house. I handed it to my best critic ( my wife )and said " check out the finish on this blade "

She says " wow , it looks great, but the scratches are going long ways instead of up and down "

I say " yea , thats what I did for 2 hours today , sanded it by hand "

She says " Why "

I say " ...... I dont know, thats the way all the pro's do it "

She says " Why "

I said " thats a good question honey , I want to know too"

So my question is , Why do we hand sand the blades lengthways instead of up and down ?

Sorry for my ignorance on this subject.

Dwane Oliver

9-11-01 , We Will Never Forget.

Work smarter NOT harder

 
Posted : 26/02/2012 11:56 pm
BrionTomberlin
Posts: 1675
Member
 

Good question Dwane. Personally, it looks better and adds to the flow of the knife. The finish is going in the same direction as the blade if you get my meaning. Say you have a nice swoopy southwestern bowie and the you have the hand sanding marks going from spine to edge instead of along the blade, it would draw your eye to those marks because they are standing out as not in the flow of the knife. Also that is the way I learned and I think it looks best. I do have belt finishes on some knives, but they are working knives, not higher end ones.

I hope this helps.

Brion

Brion Tomberlin

Anvil Top Custom Knives

ABS Mastersmith

 
Posted : 27/02/2012 12:05 am
Posts: 149
Member
 

I had wondered the same thing. And now I know. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />

Cheyenne Walker

Apprentice Smith

 
Posted : 27/02/2012 2:49 pm
Lin Rhea
Posts: 1563
Member
 

The scratches running longitudinal will also help the blade's ability to withstand distal flexing. That is my primary reason for choosing this direction of finish.

Lin Rhea, ABS Mastersmith

[email="[email protected]"]Email me[/email]

www.rheaknives.com

 
Posted : 27/02/2012 3:29 pm
Posts: 123
Member
 

Hey Dwane,

I have some theories on why we do it longitudinally:

1) It allows you to cover 100% of the surface area per stroke, making it more efficient

2) Similarly, blending several smaller stroke areas can be VERY tricky

3) It's a longer stroke, which is easier to control/maintain/direct

4) Depending on your abrasive media, sanding perpendicular to the spine and edge could tend to roll those lines, which are better left good and crisp.

And I agree with the aesthetic and structural benefit as well.

Zack

Zack Jonas

Journeyman Smith

 
Posted : 27/02/2012 6:32 pm
Posts: 59
Trusted Member Apprentice Bladesmith
 

Good info! Do u guys put yr knife in some kinda jig for the sanding?

Michael Arguello

Apprentice Smith

 
Posted : 02/03/2012 12:57 pm
Admin_DJC305
Posts: 1999
Member
 

Michael:

I place the knife on a jig that I made from a piece of angle iron that has a flat metal surface with leather on the bottom and clamp the tang down tight with no flex in the blade. The jig is set in a bench vise and I use leather wedges under the blade to keep the blade surface flat with no flex.

Dan Cassidy
Journeyman Smith
Send an email to Dan

 
Posted : 02/03/2012 2:30 pm
Posts: 123
Member
 

My setup is pretty simple.

I use two C-clamps (one large, one small), a 1" square piece of gasket rubber, a 24" length of 1x2 lumber, and some duct tape. Here's how it all goes together:

First, take your 1x2 and grind or cut one end down to a broad spear-point shape.

Next, using a c-clamp, fix one end of the 1x2 (which I call my "sanding board") to your workbench--leave enough overhang to accommodate the full length of your blade.

Next, cover the sanding board with a few layers of duct tape.

Next, lay your blade down on the duct tape, with the curve of your point overhanging the tip of the sanding board (see why you put a point on it now?)

Clamp the blade down to the sanding board with the second c-clamp, placing the small piece of gasket rubber (which you can get at any hardware store) between the clamp and the knife.

Sand away.

Tip: When you've finished one side at one grit (say, 220), remove the blade and pull off the top layer of duct tape--replace it with a fresh one. The duct tape is there for cushion and convenience--it is soft enough that it won't scratch the blade, and it will keep it from moving around too much, but it will also accept and hold grit from your sanding. So each time I've finished a round of abrasive, I swap out the tape.

I like this configuration because it is very flexible. You can get right up close to the knife on either side, it's very easy to reposition, etc. It is secure, simple, cheap, and in my experience very effective.

Zack

Zack Jonas

Journeyman Smith

 
Posted : 02/03/2012 4:09 pm
Posts: 0
New Member Guest
 

Dwane, I would just like to say wether you ment it or not, that's funny. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' /> I am not remotely as educated in the way of blades as allot of you gentlemen, but I always thought you hand sand the ones that are special. You know the ones for an old friend, a relative, or somebody special to you. Perhaps even just because the blade itself stands out as something different or special as that it deserves more attention; or ofcourse the ones that might break the average wallet. That last part is a pun. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' /> As for sanding direction I have never thought about direction as it comes to the aesthetics of a blade. Interresting.

 
Posted : 02/03/2012 9:52 pm
BrionTomberlin
Posts: 1675
Member
 

My set up is pretty standard. A flat piece of 1" X 2" paudauk 24" long that I clamp to the bench top. I use leather spacers also to make sure the blade does not bend. One thing to make real sure of is that your point does not stick out past the end of your set up. Bad things can happen when it does. My next project is to make a larger one for larger blades.

Brion

Brion Tomberlin

Anvil Top Custom Knives

ABS Mastersmith

 
Posted : 02/03/2012 11:14 pm
Posts: 0
New Member Guest
 

Just a quick story to stress the importance of having NO part of the blade hanging off your table...

I was inexperienced and dumb(not too long ago) and would clamp the tang to the bench and leave the rest hanging off. I thought I had safety covered because it was off the edge of my island bench in the back corner, away from foot traffic. One day, my 4 year old came ripping into the shop.(something they KNOW not to do but he was running away from his older sister for fear of death.) Before I could catch his attention he sprints around the back of the bench and gets completely clothslined by my BLADE. To make it worse, it was SHARP! My heart just about stopped beating with the thought of what I was about deal with. It has a happy ending, though. Luck was on our side. He had ran into the spine. I had thrown a rag over it which cussioned the blow. He walked a way with only a 1" long bruise across his forehead. Honestly, I cried that night and just about gave up knifemaking. I still get a lump in my throat discussing it.... but I tell as many makers as I can, when the subject pops up.

Now, I use a 2x4 clamped in a swivel vice so I can get whatever angle I need. I shim with leather and use masking tape instead of duct tape.(cuz it's cheaper)

I run my lines lengthwise for the same aesthetic and structural benefits. Karl is spot on about good grinding making for easy handsanding.

 
Posted : 11/03/2012 12:53 pm
Admin_DJC305
Posts: 1999
Member
 

Thanks Rich! After that chilling story I think that everyone will properly secure and tape their blades during hand sanding operations.

Dan Cassidy
Journeyman Smith
Send an email to Dan

 
Posted : 11/03/2012 1:35 pm
Posts: 0
New Member Guest
 

Great question for sure.. never actually thought of WHY we do it.. LOL clean grinding is the key.. progressive grit refinement.. Sometimes I get into hand sanding and find that I get a couple stubbron scratches that dont seem to want to come out.. In the early days I would hand sand and hand sand until I got it out.. I've learned that it's best to just go back to the grinder and grind out those last few scratches.. then back to hand sanding.. Saves a ton of time/work. I, like others, chuck up a stiff board in the vice and clamp my blade to it. I use small pieces of leather under tip of the blade to support it.. I've learned the hard way that it is good to have your board at least as long as your blade..

Walked past a blade chucked up for hand sanding... yep, the sharpened clip opened my arm right up just above my elbow.. Had a nice evening in the emergency room and went home with some stitches 🙂

Cheers,

Jerid

 
Posted : 29/03/2012 5:22 pm
Posts: 7
Active Member Journeyman Bladesmith (5yr)
 

At what belt grit is it time to start hand sanding? Also do you need to start with the same grit? I like the hand finish but have also gotten the question "why are the scratches running the wrong way?" Maybe I am not going fine enough with my hand finishing or people are just familiar with the machined finish on production knives. Thanks,

Russell

 
Posted : 23/04/2012 11:49 pm
BrionTomberlin
Posts: 1675
Member
 

Russell I usually go to a 400 grit finish, actually an A45 trizact belt. The equivalent of 400 grit. Then I go back to 220 grit for hand sanding. Then progress up from 220 to 320, then 400, then 600. This is for a basic hand rubbed finish. For knives with hamon I go higher, usually up to 1200 grit. Funny I have never had that question on hand finishes.

Good luck

Brion

Brion Tomberlin

Anvil Top Custom Knives

ABS Mastersmith

 
Posted : 24/04/2012 10:09 pm
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