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This is going to sound like a stupid question..............but I have to ask it!


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I'm making a leather workers round knife for my pickiest customer. (me)  That long bevel is taking so much time to sand that I'm honestly wondering if there is a proper alternative to accomplish the same thing.  All my fingertips and both thumbs are completely numb right now and I'm not even completely through the 120 grit yet.  The 2x72 grinder left some "microscopic dips" that are killing me trying to sand out.  I used a 220 grit belt hoping to alleviate some of the grit marks, but I'm even having trouble getting those out with 120 grit water paper.  This blade has given me a whole lot more respect for those of you who specialize in Chef's Knives.  :o  To put my complaint in context, I've just finished a four hour hand sanding session and have had to toss in the hat for the day.  I honestly see a good two hours ahead of me tomorrow before I can confidently go on to the next grit.  Is there an alternative way to get this sanding done or am I just bitching too much and should shut up and "Pay my Dues"?  :D

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I hope you're using a hard backer that let's you keep your hands in a comfortable position.  Doesn't sound like you are though ;).  I do most of my sanding with a piece of 3/4" x 5/16" flat bar.  it keeps a small enough surface area on the workpiece to allow me to use some significant downpressure to get the paper to cut properly.  Also, make sure you're using your paper like a consumable.  It's easy to want to make each piece last as long as you can, but the only thing you end up making last longer is the hand sanding session!

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Actually, Alex, I'm attaching my paper to a granite plate and using my fingers to press down on the blade.  I can't hold it any other way.  I don't want to clamp this one in my vise and free hand it.

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Make a magnetic handle, or hot glue a handle to the blade.  Something to give you a better gripping surface.  Or I suppose you could use magnets (or glue) hold the piece and a block to sand with.

 

I feel your pain.  I've been draw filing a couple of daggers and my left index finger ended up pasted against my palm today.

 

Geoff

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8 hours ago, Chris Christenberry said:

 I'm attaching my paper to a granite plate and using my fingers to press down on the blade.

That was going to be my other suggestion, lol.  I like Geoff's method.  Never would have thought of that myself.

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I used a magnetic jig to grind the long bevel on the blade.   Since I  have vowed I'll never make another one of these round knifes (what a hassle it's been) I might consider taking the jig apart and clamping the magnetic portion that's holding the blade in my vise.  Thanks for setting the gears in my mind turning.

 

But addressing my original question..............I guess there's no magic wand or special trick that's going to keep me from hand sanding bevels, right?  My mind keeps going to that Damascus maker in Ukraine who has an automated blade sander.  Shurap, I believe his name is.  If I'm ever going to make a "go" of this knife making, I guess I'm destined to have to "pay my dues", huh!!!!! :rolleyes:

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12 hours ago, Chris Christenberry said:

Alex, I'm attaching my paper to a granite plate and using my fingers to press down on the blade.

This is probably  why your fingers aren't able to tolerate it for long.  

I'd figure out a way to clamp the blade to a board (using the tang perhaps?) and use a sanding stick.  My main one is a piece of micarta (it might be G10) about  1/4" x 1" x 11" with the ends rounded to fit in my palms for comfort.  This allows me to grab the stick with both hands (like handlebars on a bike) and use the palms of the hand to apply pressure, not just the thumbs.

1 hour ago, Chris Christenberry said:

But addressing my original question..............I guess there's no magic wand or special trick that's going to keep me from hand sanding bevels, right?

If you have a disc sander with a platen, you could set the angle of the platen, then hold the round knife on the platen at the center point of the arc, rotatingthe blade on the  platen around this point with the just the bevel contacting the disc?

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Do you mean something like this, Billy0?  :D  It's fun being on a forum with so many other inventive minds.  Kind of like being a member of a "think tank". :)

 

DSC_8649.jpg

DSC_8650.jpg

 

Since I have sworn never to make another of these blades.................I'm thinking I'll take the swiveling part of this fixture off it's pivot post and clamp it in a vise so I can use the magnets to hold this blade firmly and hand sand with a hard backer just like I do my regular blades.  By the way, this fixture produced too many divots that have been real buggers to hand sand out.  Not sure why though.  I figured this jig would eliminate the possibility of that problem coming up.  Handy little jig, though.  There was no way I was going to be able to put a 2" long curved taper on a .040" thick blade by hand.  :blink:

 

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That's a nifty little jig, though.

 

I am remembering watching a video of Sheffield grinders making palette knives and spatulas.  They use big stone wheels, and literally sit on those thin blades (well, on a board atop the blades) while pulling them over the stone.  I'm thinking a disk grinder set up with the disk horizontal would lend itself to this approach.  Not the sitting on it part, but the being able to use a lot of pressure by pressing down on the jig part.  Or maybe one of those flat stone Tormek plane iron wet grinders?  Those aren't cheap, but based on your past woodworking you may have one of those already...

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Posted (edited)

Nope, Tormek was never in my banking account's range.  Besides, I never put blades to a wheel...........even hand plane blades.  I've talked several of my wood carving students out of wasting their money on them.  We sharpen by hand only.

 

I pulled the pivoting part of the jig off the support portion and put it in a vise.  Using a hard backer behind my paper I've been able to 99% finish the 120 grit step.  This blade has been hardened to 62 RC, so it's not yielding very quickly.

Edited by Chris Christenberry
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I'm delighted to hear that. B) About hand sharpening for hand tools, that is, not how long it's taking to flatten the head knife. 

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Please, please, please, if anyone on this forum ever hears me even HINT I'm thinking about making another one of these, just shoot me, would you? :D  This has been a most unpleasant journey.  My little wife says she can't believe I've the patience to put in the hours of tedious hand sanding it takes to do this.  (that's funny because I can't believe it either!!!!!)  :wacko:  I plan on starting the 220 grit tomorrow.  From here on in, as everyone who's ever gone through this process knows, it goes quicker and quicker with each new grit.  I plan on taking this all the way to a 25 micron paper...........mirror finished.  (like I used to do with my hand plane blades)

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I feel the pain! I've hand sanded many hard chef knives. 

 

On your next one(if there ever is), try grinding the blade to #220 on the 2x72. Then switch to trizac or equivalent up to #320. Try using a large sharpie on your blade between grits. It'll help to spot deeper scratches. 

 

With that trick, you should be able to start hand sanding to at least #220 or even #330 instead of #120. The 120 grit wet/dry paper doesn't cut much at takes forever to hand sand. 

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Or, if you're going to stick with the granite plate, start with a coarser grit. Go to Home Depot and get some of the purple 3M paper in 80 and 120.

 

I know this sounds backward, but you and go from 80 to 120 petty quick with some serious stock removal. Then on to your fine grits.

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4 hours ago, Chris Christenberry said:

Do you mean something like this, Billy0?

Something, like that would probably work but I wasn't thinking jig.

 

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another thought is the hot glue method where you tape the back of the knife and tape your board then hot glue the knife to it for stability (saves clamping) 

I would also have started with stones rather than paper as the stones are a bit more agressive grit for grit. I belt grind post HT at 120 ceramic then go to 220 (trizact) then start with 240grit stones before going to 220grit paper then 350 and 600. Reduces the hand sanding time by signifecent ammounts.

I made a hand sanding block to take the stress off my fingers and with this one my palms can take a lot of the load. Since making it I have fixed a thin stainless plate on the base  which has increased the ability to butt into the plungeIMG_20210225_165216.jpg

 

IMG_20210225_165225.jpg

Edited by Garry Keown
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1 hour ago, Garry Keown said:

I made a hand sanding block...

That looks a bit more comfortable than mine, Garry.

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I recently made a small Ulu type knife to use as a leatherworking head knife. It was tricky to sand so I did this.

Uses for small pieces of micarta - Fit and Finish - Bladesmith's Forum Board (bladesmithsforum.com)

 

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16 hours ago, Chris Christenberry said:

This blade has been hardened to 62 RC, so it's not yielding very quickly.

I have found that there is an enormous (very scientific and quantifiable term) difference in how long it takes to sand something that is up around C62 as opposed around 58-59.  You can feel the difference in how the paper bites into the steel.  On more than one occasion I've started hand sanding and upon feeling how little bite the paper was getting, I threw the piece back in the oven a tempered a few degrees hotter.

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1 hour ago, Brian Dougherty said:

C62 as opposed around 58-59.  You can feel the difference in how the paper bites into the steel. 

Sadly, it also makes a significant difference on edge performance. My 63+HRC 26c3 chefs hold an edge for a loooong time with some light stropping from time to time. Of course, edge stability has to be taken into account. Not every steel will benefit to be tempered this hard. 

 

In other words, with the right steel,

you cry once when hand sanding and then grin every time you use the blade :lol:

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1 hour ago, Brian Dougherty said:

how long it takes to sand something that is up around C62 as opposed around 58-59.  You can feel the difference in how the paper bites into the steel.

 

24 minutes ago, Joël Mercier said:

you cry once when hand sanding and then grin every time you use the blade :lol:

 

This is why I love my disc sander.

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I have to admit I have a love/hate relationship with my disc sander.  I can't seem to find the happy mid-point of "paper sticks well to disc" and "paper stuck so tight to disc I can't get it off".    So I've most often a tiny area that pulls free and that makes it almost impossible to grind perfectly flat items like a knife blade that don't get hit by that loose "flap".  At this stage in my knife making journey, I prefer my 2x72..................though I need to install a glass platen so I can let the belt run on the platen and not have that minuscule gap.  I think that's why I have a couple of divots in this blade that are resisting my hand sanding.

 

Enough talk.  Headed to the shop to continue the destruction of my poor old hands..................though it is a bit easier with the blade stationary as was suggested.

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I know a lot of people hate it, but I've found that 3M feathering adhesive, if properly applied, is the best thing for disc sanders.  It's that "proper" bit that a lot of people seem to have trouble with.  Done right, it sticks hard, peels off easily, and a single application lasts for at least ten-fifteen changes of paper, even spaced out over a couple of months.  When it stops sticking well, wipe it off with a little lacquer thinner and re-apply.

 

 

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Thanks for that.  Maybe that's been my problem, Alan.  I've always just relied on the adhesive applied to the back of the paper at the factory.  Was always hesitant to use additional adhesive for fear it would stick FAR too well.

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1 hour ago, Chris Christenberry said:

I think that's why I have a couple of divots in this blade that are resisting my hand sanding.

On my part, when I get those is because I don't sit the blade parallel to the platen. Another trick to help with this is to not start your grind at the same place everytime. 

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