To sand or not to sand

daizee

daizee

Knifemaker / Craftsman / Service Provider
Joined
Dec 30, 2009
Messages
11,071
It's all in the wrists... (ow, ow, ow).

I've seen many variations of blade finish work in these fora, and would like to know how various makers decide how to finish their blades. Many seem to leave the vertical grinding marks on the primary bevel and that can look pretty good, especially on a modern style knife.

To date I've been flat-sanding my bevels (discovering how un-flat they often are!), but invariably there are nearly impossible to remove marks at the plunge. I'd like to take my finishes to the next level, but patience, time, and technique aren't all up to snuff...

How do you decide which finish to use? If you leave a ground surface, do you step up grip on your belts? Do you use same grinder/belt dimensions? How high do you go? How do you protect the final finish, or do you leave the ground surface only on stainless blades? (is that a reason to move to stainless? :-) )

If you hand-sand, what's the grit minimum you're happy with? Any techniques you're willing to share?

Thanks for your input,

-Daizee
 
A brief response, answers in red:

daizee said:
How do you decide which finish to use? It often depends on customer preference. It also depends on the projected price range of a knife. I feel in general that sanded is nicer than belt, and it takes a bit longer. Also, a vertical finish just looks good on some knives. If you leave a ground surface, do you step up grip on your belts? If I leave ground finish, I go through the gator belts, from A65 to A45, and finish at A30. (Roughly 600 grit.) They blend well and the A30 is a nice, fine scratch pattern. Scotchbrite belts can leave a nice finish too, I use it after 400 grit. Do you use same grinder/belt dimensions? Yep. How high do you go? How do you protect the final finish, or do you leave the ground surface only on stainless blades? On any knife, I warm the blade up and rub down with WD40 after sharpening, as the very last step before shipping. (is that a reason to move to stainless? :-) ) NO. But try it if you like...

If you hand-sand, what's the grit minimum you're happy with? 400 can look okay, to me 600 is minumum. For hamon, I prefer at least 1000. Any techniques you're willing to share? Do I! Check out my links below, hopefully there is material there that can help. A lot about grinding, plunges, sanding, J-flex and gator belts, etc.

Thanks for your input,

-Daizee
Click to expand...


http://www.prometheanknives.com/shop-techniques-3/grinding-tips

http://www.prometheanknives.com/shop-techniques-3/finishes-polishing-tips
 
For me, it depends primarily on what I want out of the knife (I'm not in this for the money, so I rarely have to think about what a customer wants or what it's going to cost. When I am selling a knife, I do whatever the customer wants.) I realize that this isn't much of an answer, but what it really comes down to is what finish you or the customer want on your knife. If you want a knife with a mirror finish, make a knife with a mirror finish. If you want a knife that's hand sanded to 100 grit, then do that. If you want to leave the grinder lines on there, then do that. To me, the finish of the knife is just a part of the composition, just as handle material and blade shape are.
For blades that are not left with a forged finish or etched heavily, the lowest grit I have used for the finish is 320 (it was stainless steel and made for use by a soldier, so a higher polish wasn't required for any reason.). The knife doesn't look unfinished or rough by any means. The 'shadow' by the edge is from the buffer when I put the final edge on.
306141_183430751726649_182236548512736_433067_5880830_n.jpg

For most other knives I make, 600 is standard. I hand sand all of my blades, which I think looks more finished than the same grit from a grinder.
262575_183431295059928_182236548512736_433068_5398069_n.jpg


- Chris
 
Salem, thanks for all the detailed information here and on your site.
It gives me a lot to think about. My pre-hand-sanding techniques have to improve so that it's not such an utter chore that I avoid it.

The WD40 thing makes sense. I've puzzled over that and tried a number of things. Recenly I got some Flitz Rifle & Gun wax and have started using it on everything, and like it a lot.

Hesparus, right now a mirror finish is pretty much unachievable for me whether I want it or not. I could get SOME parts that shiny, sure.... Getting them ALL there is the issue! I'd like to get to the point where the option is mine.

-Daizee
 
Using edm stones around the plunge area is way easier than using sandpaper for me. Actually when I hand sand I do a few minutes with the starting grit to see the biggest stratches that need to be removed and then switch to the same grit edm stone to remove them, then clean up with the sandpaper again.
 
Using a sanding paddle can speed up sanding tremendously.
BeltSandingBoardL656.jpg


This is just a board cut to length with the ends rounded over onto which I put a 2x42 belt. (Does that make it a belt grinder?!?!) I made one that fits a 2X72 belt also.

Some people use orbital sanders with a hard backing and switch to hand sanding for the last grit. This is something I want to try out as soon as I get around to modifying my orbital sander. The hard backing is needed to save your hard corners and lines.

I've usually gone to 600 grit but have started playing around with 1000 grit paper. I think I do a better job when I wear a magnifying visor and critically check it that way. I see the scratches and am not as tempted to stop sanding early.

- Paul Meske
 
lonepine said:
Using a sanding paddle can speed up sanding tremendously.
BeltSandingBoardL656.jpg


This is just a board cut to length with the ends rounded over onto which I put a 2x42 belt. (Does that make it a belt grinder?!?!) I made one that fits a 2X72 belt also.

Some people use orbital sanders with a hard backing and switch to hand sanding for the last grit. This is something I want to try out as soon as I get around to modifying my orbital sander. The hard backing is needed to save your hard corners and lines.

I've usually gone to 600 grit but have started playing around with 1000 grit paper. I think I do a better job when I wear a magnifying visor and critically check it that way. I see the scratches and am not as tempted to stop sanding early.

- Paul Meske
Click to expand...

You know I started doing this too and noticed a much better quality finish on my knives now!
 
I will hand sand anything...3V, M4, Elmax, even K390 or M390. The key for me is to make your surface very flat and true on the grinder, then whatever you have to sand will be much less than if there are some deep scratches. Don't start sanding until you have an almost perfect flat blade. On a user I think a good 400 finish is fine. 600 is of course better.

My routine is to grind up to 220 x weight, then x65 norax, sand tip to ricasso with 220. Grind conventionally with x45 Norax, then finish with 600 redline indasa paper.
 
blackcatt said:
Don't start sanding until you have an almost perfect flat blade.
Click to expand...

Well said. If you're coming off the grinder with a clean, consistent surface, all work after that will be much easier. If not, you're just standing on your own toe.

One problem with grinding, and especially "machine" finishes, is that nasty 50-grit marks can be hidden between much finer scratches. It only takes a couple minutes to go over your blade lengthwise with 400-grit paper after you think you have it pretty even at 80, 160, 220 or whatever belts you're using. Any deep rough marks will show up pretty quickly.
 
Wow, lots of good feedback.

Tonight was Knife Night over on the island with Mr. M hosting, and my main project for the evening was heat-treating an A2 knife I've been looking forward to.

While waiting for the knife to cook, I pulled out a piece of 1/16" 1095 that had a mini rigging knife pattern glued on it, which had been cluttering my bench for months. Time to get it out of the way, should be fast on the Bader. On a whim, clearly influenced by Salem and JohnnyMac's recent gallery posts, I sorta wharncliffed it for variety (not QUITE a straight edge) and then decided to give it a chisel grind and leave the 60grit finish on the bevel. I promptly hit it with WD40 when it came off the grinder and then polished the flats to 360 by hand with a block. If not for other stuff going on, this could have gone all the way through heat-treat in just a couple hours, which would have been neat. The idea was to just MAKE IT without fuss, and leave the fretting for the others with the fancier material and greater emotional investment.

-Daizee

IMG_20110924_012611-small.jpg
 
I like both of those profiles very much. They're both clean, graceful and balanced-looking, as any working tool should be :thumbup:

I forgot to answer the minimum-grit thing... regardless of aesthetic concerns, I feel strongly that anything below 400 is just begging for corrosion problems. It's surprising how any sort of coarse scratch can trap tiny bits of gunk or moisture and leave you with a pit or stain when you thought you had a clean blade the night before. The good part is, once you get good and smooth at 400 hand-sanded, each subsequent grit goes much more quickly. So it's really a matter of taste at that point.

I go at least to 600-grit for a hand-satin final finish. Meaning I actually go up to 800, then step back down and sand dry, lengthwise only with fresh 600 on each stroke. I prefer to go up to 1200 and step back down to 1000. But then it's really only a matter of minutes to continue all the way to 2000 and get what I call a "silk" finish... close enough to a mirror that a couple passes on a buffer would probably be all it takes, but it still looks hand-done. I've yet to try the even finer 3M polishing papers (they go up to 5000 or 6000 grit, something like that) but I definitely will in the future.

Anyway, the finer the finish the more it will show normal scratches from use, but the better it will resist corrosion.
 
Following advice here, and on Salem's site, I've ground two new blades. My bevels are flatter almost everywhere, especially the plunge, and I adjusted my sanding techniques according to my friend's advice. They sanded to 360 much more easily than my earlier blades, and I THINK the grinding lines are gone from the plunge. In any case, the bar is raised. Now the trick is to keep it there :-D
Thanks again for the tips!

-Daizee
 
Way to take some good info and run with it Daizee!! Glad to hear you're happy with the results.

Keep it up!:thumbup:
 
Good to hear you're stepping up your grinding/finishing game. I like hearing about positive results, especially if I contributed in any way.

Gonna post some pics soon?
 
You guys have been a great help.

Gonna post some pics soon?
Click to expand...

Heat-treating this weekend, hopefully, then a week's delay, then hopefully cleanup, polish, and finish.
They'll be up in the Maker's gallery when done, for sure (assuming success!).
That bundle of temporal qualifications is dictated by my work schedule...

Here's a teaser of the evolved-technique sanded pair in my nifty blade-carrying tupperware:

IMG_20111017_231433-small-rot.jpg
 
Looking nice! How did those other ones turn out? I also have been reading up on Salem's site. Very handy stuff! It's really incredible to me how much great information people are willing to share; I found an awesome sheath making tutorial today, and made up 3 leather sheaths that don't look half bad from it. Not pro, but not fugly either. The knife-making community is truly wonderful :)
 
Oh, those other ones turned out awesome. Not perfect, but awesome by my standards. :-)
Both are up in the Maker's Gallery area. The bigger one is called the 'Hiker', and the other doesn't have a name. I'll find 'em... one sec...

The experiment:
http://www.bladeforums.com/forums/s...in-amp-rough-finish-bevel-chisel-semi-wharnie

The Hiker that happened to be in that picture with the experiment (frickin' love this knife):
http://www.bladeforums.com/forums/showthread.php/888179-3.4-quot-A2-quot-Hiker-quot-in-G10


A couple summers ago (3 now?) I decided to learn to make leather holsters. It was a bit hard to get good info to begin, but as I learned I posted over on another forum. It turned out to be a wildly popular post because I showed my WIPs and progress. A whole bunch of other people started making their own and posting on the same thread and sharing their tips, techniques, and experiences as they progressed. One or two started selling. It really took on a life of its own and was very rewarding.

This IS a very lively and sharing community, I dig it.

-Daizee
 
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