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Forum topic by Bryan posted 10-11-2011 10:49 PM 3079 views 3 times favorited 18 replies Add to Favorites Watch
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Bryan

50 posts in 1582 days


10-11-2011 10:49 PM

I just won a set of marples chisles made in england they are still in the package. I want to flatten the backs using the scary sharp system here are my questions. If you do not use scary sharp or dont like it please dont reply.

What grit do I start with?
Should it be wet/dry sandpaper?
Where should I by this paper?
Does it need to be adhesive backed or will 3mm spray glue work?
Will scary sharp polish the backs of the chisels?
What grit do I end with?


18 replies so far

View crank49's profile

crank49

3481 posts in 1696 days


#1 posted 10-12-2011 12:39 AM

I have used this method for fifty years. Only heard it called “Scary Sharp” for the last few, but even my dad, who, if he were still alive would be 102, used sand paper to sharpen his tools. Anybody who hates dull tools and wants the quickest way to get them sharp will eventually use this.

A huge mistake some people make is to start with too fine a grit.
Another mistake often made is to be anal about perfection. Do you want to sharpen tools all day, or get-r-done and get back to work?
Having said that, you do need to get it right the first time, then it is easy to keep things sharp with an occasional touch-up.

I use wet/dry silicon carbide paper. Never saw it with sticky back, I use 3m spray.
I bought a couple of 12” square granite floor tiles from Home Depot for $4.99 each and stick my paper to those.

The first step with new chisels is wipe them down with some lacquer thinner to get the anti rust coating off. That coating is like a clear lacquer they coat tools with and it will quickly gum up your paper.

If I am re-grinding a damaged tool, like one where I hit a nail or dropped on the concrete floor, I start with 80 or 100 grit on the belt or disk sander to shape the edge. Carefull not to over heat. Keep a glass of water handy and dunk often.

Then for regular sharpening, clamp the blade, plane iron or chisel, in a jig that holds the angle consistent.

Starting grit for me is usually 150 grit.
Flaten the back first.
Then flip and grind the bevel.
Next I like to go to 200, then 400, then 800 and 1000.
I like to finish with 1200 then lap on a hard felt wheel and Zam compound.

About half way through this process I increase the angle in the holder by just a fraction of a degree.
That way I’m only honing the front 1/4 of the bevel. Speeds things up considerably.

After all this you got a scary sharp edge.

If each step takes longer than 5 minutes you are using too fine of grit.
After the initial sharpening, as described above, I only start at 400 grit, about 2 minute each grit, to replenish the edge.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View chrisstef's profile

chrisstef

11350 posts in 1731 days


#2 posted 10-12-2011 01:45 AM

Crank nailed it. You can go to the local automotive store for the wet/dry sand paper. Personally i go up to 2000 grit. Probabley ovekill but thats what i do.

-- "there aren’t many hand tools as awe-inspiring as the #8 jointer. I mean, it just reeks of cast iron heft and hubris" - Smitty

View Craig's profile

Craig

23 posts in 1308 days


#3 posted 10-15-2011 03:48 AM

I don’t keep the coarser grits glued down, since I go through them fairly quickly and only use for lapping and reforming an edge. I keep the higher grits glued to a piece of granite to hone chisels and plane irons. Other than that, Crank is spot on.

The grits I don’t glue down, I just wet and they stick to the granite pretty well. The marples I lapped took a bit of work, but as Crank mentioned, I started too fine of a grit and ended up working backwards to a coarser grit. Now I just hone and use the finest grit (2000) to remove the wire edge.

To get an idea of how much lapping you need to do, take a couple of swipes and look at the scratch pattern to see how much flattening you have to do. From there, you can judge what grit to start with. Mine had an inconsistent hollow.

I like scary sharp, but haven’t tried any other method yet. I am taking the advice to get comfortable with this method first before I move on to others. I’m much less experienced than the wealth of knowlege on this site, but went through this recently so wanted to share my experience.

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startingfromscratch

66 posts in 1917 days


#4 posted 12-07-2011 04:26 AM

So, how does this work in practice…I’m trying to get a set up for this in my shop and am wondering what most people do.

I’m leaning toward using 12×12 granite but I can’t figure out a good way to have this ready to go in the shop. Do folks just have a stack of sandpaper in all the grits and put down what they need and then peal it off and put down the next kind (i’m thinking they must because if not, with six grits and probably 2 grits per 12×12, you would have to have three tiles all ready to go). I gotta believe, though, that pulling up sandpaper once glued down damages it…so having to swap it off before the finer grits are ready to trash must be a waste, no?

Or, should I have three tiles (they are cheap) and just keep one with 80 and 120 on it, another with 200 and 400 and other with 800 and 1000?

I saw one example that had two tiles, one with two coarse grits that looked like 4×8 strips and another with 4 squares of finer grits that looked like 4×4 squares…that might work.

Any thoughts?

View crank49's profile

crank49

3481 posts in 1696 days


#5 posted 12-07-2011 04:54 AM

I use 1/3 of a sheet wide strips and 3 strips per tile.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View startingfromscratch's profile

startingfromscratch

66 posts in 1917 days


#6 posted 12-07-2011 03:14 PM

Very helpful, thanks!

Yeah, I think my confusion is because I have a ton of lapping to do (because I’ve amassed about a dozen old chisels and have two #4s, two #5s, a 60 and 1/2 low angle, and a 220 hand planes), so I’ve been trying to figure how to have the sandpaper on the edge so I can get the use of the whole strip to flatten the backs, while wanting to use six or so different grits.

I think my solution will be (for this first run) three tiles, two 1/3 sheet grits per tile. Then, once the lapping is done and I’m just in maintenance, I can go to three 1/3 strips per tile and have two I can reach for to tune up my edges (sounds like if I’m getting this right, you mostly only need the finer grits anyway for regular maintenance sharpening).

Couple follow ups? Do you use babyoil as a lube? I’ve see others say they don’t use anything and brush or blow the sandpaper clean to make it last longer. Also, is this your same set up for plane blades as well as chisels?

Thanks!

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crank49

3481 posts in 1696 days


#7 posted 12-08-2011 12:14 PM

I use no lube.
Be careful to avoid getting residue from one grit onto another grit.
Clean the blade and the paper often.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Gene Howe's profile

Gene Howe

5939 posts in 2153 days


#8 posted 12-08-2011 01:03 PM

Water to hold the paper to the tile, (in my case, glass) water for lube, if you feel it’s necessary. I don’t.
Plus, see Crank49. Keep it clean.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View startingfromscratch's profile

startingfromscratch

66 posts in 1917 days


#9 posted 12-09-2011 12:09 AM

Thanks a ton! I’m gonna launch into this this weekend. I’ll report back. :)

View azwoodsmith's profile

azwoodsmith

3 posts in 2511 days


#10 posted 12-09-2011 01:22 AM

I use the method but I use a few peices of 3/8” glass epoxied to a MDF base. You might get a peice of glass free from a glass store that is throwing it away. Get, buy a peice that will cover the sandpaper you buy. I have one peice that is 3/8” x 3” x 8” where I buy from Supergrit.com.

-- God created the wood for us to have fun with. Are you having fun yet?

View HorizontalMike's profile

HorizontalMike

6960 posts in 1639 days


#11 posted 12-09-2011 05:30 AM

A Home Depot 12×12in granite flooring tile works real well and cost me just $3.49 +tax

-- HorizontalMike -- "Woodpeckers understand..."

View helluvawreck's profile

helluvawreck

15983 posts in 1591 days


#12 posted 12-09-2011 02:00 PM

Will good quality plate glass work or does it need to be granite?

helluvawreck
http://woodworkingexpo.wordpress.com

-- If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. Henry David Thoreau

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azwoodsmith

3 posts in 2511 days


#13 posted 12-09-2011 02:41 PM

The plate glass has worked for me for the last 7 years. I just wet with water and place on the glass. I go to 1000 grit sandpaper then use a peice of dry grocery bag. Someone said that is is like 1500 grit and cheaper.

Sharp enough to shave is good I need.

-- God created the wood for us to have fun with. Are you having fun yet?

View shopdog's profile

shopdog

564 posts in 2210 days


#14 posted 12-09-2011 02:54 PM

I also use plate glass…1/4”
I either buy PSA backed paper, or use 3M spray glue.

One thing that I do, before I start to sharpen is take a sharpie, and color the bevel black.
Then I set up the jig, and take a light stroke on a fine grit. If I set the blade correctly…all of the black ink would be gone. If it isn’t, I re-ink the bevel, adjust the blade, and test again.

-- Steve-- http://www.urbanexteriors.biz

View ChuckM's profile

ChuckM

505 posts in 2391 days


#15 posted 12-12-2011 02:54 AM

Brent Beach’s article in Fine Woodworking (May/June 2006) recommends these for honing:

15 micron, 5 micron and 0.3 micron sandpapers used with mineral oil.

His website -http://www3.telus.net/BrentBeach/Sharpen/index.html

I found the sandpapers at LV: http://www.leevalley.com/en/wood/page.aspx?p=33004&cat=1,43072

If you prefer the Woodsmith’s approach, watch this video: http://www.woodsmith.com/magazine/extras/165/sandpaper-sharpening/

You’ll need 80, 180, 320, 800, 1500 & 2000 sandpapers.

I’ve used the sandpaper approach but am using waterstones now (1000/4000/8000) because I also use them to sharpen card scrapers and scraper blades. I still use sandpapers to flatten the stones though.

-- The time I enjoy wasting is not time wasted

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