sharpening plane blades

Sharpening 101 *LINK*

Eric Hedberg

>Go to one of the must have shop books. There answer you will find. Eric

(Andy Rae's book on Choosing and Using Hand Tools is a good quick reference too)


The Complete Guide to Sharpening

Re: sharpening plane blades (Long)

James Watriss

>You're right. You'll need to do some grinding.

If it's way out of square, you may want to try blackening it with a marker and scribing a line so you can see what's square as a general guide. If it's just a little bit off, you should be able to get away with freehanding it.

The first step is to joint back the edge to get it square. This means to grind with the blade at 90 degrees, right into the wheel. I know, I know... at first this baffled me, too, and went against everything I thought I knew about sharpening. You want me to do WHAT?!?!? But trust me. Taking the edge off will reduce the possibility of blowing the temper. This is because the blade doesn't thin down as much, and won't heat up as fast. But don't joint it back too far, because you're going to have to grind a bevel on it next, and the less you joint the blade, the less bevel grinding you'll have to do. You don't have to take off the entire bevel... just enough to get the blade square.

Dress the wheel first... it's a lot easier to make a straight edge with a straight wheel.

Joint the blade with a combination or engineer's square handy, and check the blade for square as you grind. If it's not square, keep trying. Take your time, grind very slowly, only a little at a time, and get it as precise as you can.

If you have access to a variable or slow speed grinder, use one of those. The slower the wheel is spinning, the less likely you are to burn the blade. Use very little pressure. A grinder can take off a lot in a hurry.

Once the blade is completely square, adjust the tool rest to the desired angle for grinding, and grind your new bevel. Make slow, easy passes, very lightly, and hold your blade with your fingers as close to the edge of the blade as possible. You'll feel when the blade starts to heat up this way. When it does, stop grinding, and let it cool down. If it's too hot for your fingers, then it's too hot, and you need to let it rest a minute or three. Grind the bevel in this manner until you've eliminiated as much of hte jointed edge as possible without actually touching the edge. If you grind too far, you'll make a wavy edge, and it won't sharpen properly.

Bring a radio down for this part. It's boring. It can take forever. If the edge of the blade starts to turn brown or blue, you've burned off the temper, and those brown or blue spots have a nasty habit of growing very very quickly. And then you need to joint the blade back again to get rid of the blue spot if that happens. So take your time.

Like anything else, it's a balancing act. You want to grind the bevel as close as you can to the edge, because whatever you don't take off at the grinder, you'll have to hone off on the stone, and that can be a VERY tedious process. At the same time, you don't want to screw up the nice, straight, square edge you just made, either. And the closer you get to the edge, the more frustrating it is, because you have to actually slow down as you get closer to where you want to be.

I can't tell you where to stop exactly. Look for light reflected off of the edge of the blade. It's basic physics... light will only reflect off of a part that's flat enough to do so. If there's still a jointed edge, it will reflect light. There should be a thin hair of jointed edge left when you leave the grinder, but not too much. In any event, if the balde was out of square, but you jointed it square, the jointed edge should be thicker on one side. Don't take it to the stone until the jointed part is an even thickness all the way across the edge.

How far to grind is a hard thing to teach in this medium, and it's partly dependent on your skill with the grinder. It may actually be easier and more time-efficient in some cases to hone more material off. If you're a novice, with a fixed, 3200RPM bench grinder... it may be easier to spend more time honing on the stone than grinding on the wheel the first time, to keep from burning the blade. On the other hand, everyone has to learn some time, to maybe it's better to push and find your limits. It's part of the tuition you pay at the school of hard knocks, and sometimes you just have to grind it again. Just remember, if hte blade does turn blue, it's not a crisis, it's not a failure, it's not a catastrophic F!ck-up. It's just a blade, and it's all part of the process of learning a skill. Learning to properly profile edges is a valuable skill in woodworking, and hollow grinding an edge tool is, too. Hollow ground blades will help you hone freehand.

The smaller or thinner a piece of metal is, at any particular point, the faster it will heat up to the point where you'll draw off the temper. Thin blades, thin edges, sharp corners especially... When you get close to having an edge again, go very very slowly. The thinner the edge gets, the faster it will heat up.

So just because the blade looks close to being done, that doesn't mean you're almost there. The cooling off sessions will need to be longer, because you want to let that blade cool way down. As it gets thinner, you have to be more careful. If you have some chisels or other plane blades that need to be ground, now is the time, because one can cool down while the next one is being ground.

That's why I said bring a radio, or something else to do. From time to time, you're going to get fed up, and you need to get used to listening to that little voice that warns you to back off, so the process won't drive you insane. The more you have to joint back the blade, the greater the amount of metal you'll have to take off, and then it'll take you a REALLY long time. I learned that the hard way on a 3/8" chisel when I was first learning, 2 years ago. It took me 8 hours to grind one stupid chisel. Man, I was mad. But I learned real quick to listen to that stupid little voice.

Re: sharpening plane blades

Matt

>Thanks much for the info. This is quite helpful. I'll give it a try. Matt

Re: sharpening plane blades *LINK*

Peter Michaux

>I spent a long time worrying about this about a month or two ago. Not necessarily all practical info but maybe something worthwhile.


http://members.shaw.ca/petermichaux/workshop/BevelDownSharpening.html

Another option

Adam Cherubini

>Matt,

Maybe if the blade isn't too far out of whack, or when you want to change a bevel angle, you can use the blue or purple Norzon (is it Aluminum -Zirconia-ium? something like that) belt sander belts on a piece of glass. These belts cut very aggressively and last a long time. You can easily shape a bevel using one or the like.

Otherwise, I think the trick to grinding is using an insanely light touch. If you push hard, you can only hold that iron there for 2 seconds before it burns. But with a light touch, you should be able to grind for 20 minutes without the thing getting warm.

I use a really loose 6" craftsman grinder that my Dad bought 30 years ago. I'm using the wheels that originally came with it. Yeah its junk, but a light touch works.

But try that Norzon stuff.

Adam

water cooling question

Clay C in Miami

>Hi, I've walked that multi-hour chisel grind road too ... while humming 'True Love Travels On A Gravel Road'

But, you made one comment I want to ask about - "If it's too hot for your fingers, then it's too hot, and you need to let it rest a minute or three."

Is resting for a time necessary, or is a dunk OK? That is, does it harm anything to dip a warm-ing edge (but one whose color has not yet changed, even to straw) into water to cool it down, rather than sitting around waiting for it to cool in air?

And, now that I think of it, would iced water work better? It'd draw heat off faster, which may or may not be a good thing. It'd also start the edge back at the grinder about 50 degrees cooler than would shop-temperature water (say at 40 degrees, v. 90 degrees summer-Miami-shop-temp). There's also a perverse part of me that likes the idea of putting ice cubes into the foul and noisome soup that the grinder's dip bucket usually holds ...

Inquiring minds ...

Clay

YES

Jim Reed @Tallahassee

>By all means use water and ice if necessary. After a while the water warms up (physics in action). I hate to be a spoil sport, but if you have to spend a few hours, you are doing something wrong. I can bevel and sharpen 60-80 blades in under an hour. Taking one 220 blade to square is less than a minute.

Nice link and Question,

Gerry Doll

>Peter,

How did you arrive at the .003" standard for sole flatnesss? I've been messing and rehabbing planes for about a year now and have never been able to find a definitive answer to this question.

Thanks,

Gerry

contrary view

Warren in PA

>I can't recall seeing a plane iron so crooked that it couldn't be used, albeit at a slight angle. I would spend a little more time on your coarse stone every time you sharpen and straighten it out gradually. The curvature of the edge is important; perpendicularity to the sides of the iron is not.

Many years ago someone told me about grinding a crooked edge at 90 degrees. I thought it was absurd then and I still do. After you grind the end square you have a narrow bevel to work off of and still a lot of work to do.

contrary view

Warren in PA

>I can't recall seeing a plane iron so crooked that it couldn't be used, albeit at a slight angle. I would spend a little more time on your coarse stone every time you sharpen and straighten it out gradually. The curvature of the edge is important; perpendicularity to the sides of the iron is not.

Many years ago someone told me about grinding a crooked edge at 90 degrees. I thought it was absurd then and I still do. After you grind the end square you have a narrow bevel to work off of and still a lot of work to do.

Re: sharpening plane blades (Long)

Todd O. Cronkhite Maine Native in FL. Exile :~(

>It took me 8 hours to grind one stupid chisel. Man, I was mad. But I learned real quick to listen to that stupid little voice.

Matt,

Along that same vein as James said above, I'll tell you what I did when I first started. I had a modern White&Red handled Buck Bros. I believe. 1/2" wide 6 inches long. Edge looked like rip saw. I ground the entire bevel off on my high speed 'lectrik grinder, than tried to grind a bew bevel. I burnt the edge many times because I was trying to grinf right down to the finished edge, so I'd grind off the blue, grind a bevel again, burn it again. grind it off, burn it again...................... By the time I finished that chisel was only 3 inches long! I finally figured out that I could grind all the way down to the feather edge, but only close to it. Than it's off to the stones.

I now do my grinding on a handcranker with a very coarse stone. It grinds quickly and more importantly COOLER I tried the white stone on my high speed grinder and didn't care for that either. If you're gonna go with a HS grinder get the coarsest stone you can find for it as it grinds cooler and quicker than the white high $$$ ones do.

When having to square up a chewed up edge I "paint" the back of it with a black magic marker than use a mini machinest square to scribe a line thru the ink. I grind to that line than flip it over grind the bevel, than go to the stones. Takes just a few minutes.

Best advice I can give you is to get your mitts on some new cheapies to practice on before moving on to Vintage Steel. As James said I was some kinda' mad with myself over that chisel, and I too spend several hours wasting it away, but I got a good education from it and I much rather of gotten it on that chisel than say a vintage Witherby. I still have that chisel just to serve as a reminder.

One more important think that James didn't mentiopn is that in order to get a edge as sharp as it can be you MUST FLATTEN THE BACK FIRST. Thius can be time consuming but it worth the effort by at least 1000%

Just practice and you'll have it down pat in no time. It sure is gratifing to be able to take a misused tool and give it a new life in a short time. Good luck and enjoy the process.

Todd O.

Oops! Self Edit

Todd O. Cronkhite Maine Native in FL. Exile :~(

>I finally figured out that I could grind all the way down to the feather edge, but only close to it.

What I meant to say was:

I finally figured out that I COULDN'T grind all the way down to the feather edge, but only close to it

Also, by far the best book on sharpening is "The Complete Guide To Sharpening" by Leonard Lee. Worth every cent of the purchase price and than some.

Todd O.

Re: YES

Clay C in Miami

>"I hate to be a spoil sport, but if you have to spend a few hours, you are doing something wrong."

Yeah - I did actually figure that out! I was just empathizing with the prior post (although mine wasn't 8 hours) - it was my first effort, and I learned about squareness, and burning, and bevel angles, all while making every error possible (and maybe even a new one or two!)

I can do 'em a lot more quickly now, but I too prefer the hand-crank wheel. It's almost impossible to burn steel with it, and it has the additional advantage of putting a pretty short-radius hollow grind on the bevels.

But, I wanna try precise microbevels (which I've done freehand till now) and back bevels (which I've never done, and am leery about) so I'm awaiting (and not any too patiently, either) my LV MkII honing guide - anybody else gotten theirs yet (or know if they've even shipped)? The LV site doesn't seem to remember that I have ever ordered from them - order status/history comes up blank.

Clay

And also

Jim Reed @ Tallahassee

>I like your idea of practicing with scraps first. It's easy to get lost in the heat of the battle and grind the little soul to a nubbin, but prior practice and training is GOOD. Also, get a diamond dressing stone and some good wheels. I use the grey wheels for raw steel and good Norton type stones for heat treated steel. Dress the wheel often and it runs cooler.

Re: And also

Todd O. Cronkhite Maine Native in FL. Exile :~(

>Good point Jim,

I have a star wheel dresser that I use. got it at a flea market for $1. the guy didn't even know what it was! I use it every so often, probably every 5th chisel. I intially bought it so that I could get flea market find wheels back into true roundness. Sure makes a big difference. I really never need to use it to "unclog" my coarse wheel, just to true it up from time to time.

Todd O.