Can't get sharpening angle right

[Tim Booher]

All, I'm struggling to learn to sharpen my chisels.

I purchased GREBSTK 4PCS Professional Wood Chisel Tool Sets Sturdy Chrome Vanadium Steel Chisel, 1/4 inch,1/2 inch,3/4 inch,1 inch which are supposed to have a Sharpening angle of 25 degrees.

I have tried everything from wet stones, to diamond plates and now trying the scary sharp float glass + sandpaper solution.

I have a sled that allows me to set the angle accurately. I set that to 25 degrees, but only the very back top the chisel blade is making contact.

https://www.dropbox.com/s/7mrfhpp939...21.00.jpg?dl=0

I increased the angle to 30 deg and that helped a bit, but I'm nervous to get off the factory spec.

How do I get the front of the blade to contact? I know I could keep sharpening for a _long_ time and the chisel would eventually sharpen at that angle.

Thanks for any help.

Tim

[Thomas McCurnin]

1. Put it on a wheel, like a Rikon, and grind it to the proper angle; or

2. Match the existing angle, whatever that is. Use an angle finder or one of those small brass circular notched angled finders to figure out the existing angle; or

3. If you are using scary sharp, try some 80g paper; or

4. Make a wood jig that looks like a a drawer handle to bridge a belt sander and rough sand the chisel to something equivalent to 25 degrees.

[Tim Booher]

so I could find the angle -- but it seems like I should just grind it to the right angle and work with that.

[Jim Koepke]

I increased the angle to 30 deg and that helped a bit, but I'm nervous to get off the factory spec.

so I could find the angle -- but it seems like I should just grind it to the right angle and work with that.

Tim, don't worry about the factory spec.

Don't worry about the "right angle."

There is no "correct angle."

It might help if you included your location in your profile. You may live near another member who would be willing to help you in person.

My chisels are set up at at a few different angles. (surely some here think me a nut case)

For paring, a shallow angle, 15-20º, works well for me. It is also likely to need refreshing more often.

For chopping 30º works fine.

Most of my chisels have a single bevel. My mortise chisels may have a secondary bevel.

Many have suggested using equipment you may not have.

Don't run out and buy something just yet.

One way to use what you currently have is instead of trying to set the chisel to a particular angle try setting it to the angle it already has.

I've done this by using a flat surface and holding the chisel's bevel flat on the surface. Then positioning the guide (sled holder whatever) to hold the chisel at that angle.

The goal is to remove as little metal as needed to get a sharp edge.

Later when you have more experience you can work on getting exact angles or regrinding the angle.

jtk

[Edward Weber]

Tim, don't worry about the factory spec.

Don't worry about the "right angle."

There is no "correct angle."

It might help if you included your location in your profile. You may live near another member who would be willing to help you in person.

My chisels are set up at at a few different angles. (surely some here think me a nut case)

For paring, a shallow angle, 15-20º, works well for me. It is also likely to need refreshing more often.

For chopping 30º works fine.

Most of my chisels have a single bevel. My mortise chisels may have a secondary bevel.

Many have suggested using equipment you may not have.

Don't run out and buy something just yet.

One way to use what you currently have is instead of trying to set the chisel to a particular angle try setting it to the angle it already has.

I've done this by using a flat surface and holding the chisel's bevel flat on the surface. Then positioning the guide (sled holder whatever) to hold the chisel at that angle.

The goal is to remove as little metal as needed to get a sharp edge.

Later when you have more experience you can work on getting exact angles or regrinding the angle.

jtk

I totally agree and put myself in the same camp. 20 for paring, 25 for general and 30 for chopping or repeated striking.
Different chisels and their uses require different cutting angles to be the most efficient.

[Jim Koepke]

I totally agree and put myself in the same camp. 20 for paring, 25 for general and 30 for chopping or repeated striking.
Different chisels and their uses require different cutting angles to be the most efficient.

There are three chisels in my kit that are for a specialized use. They are ground at 90º. They work kind of like a one toothed float.

jtk

[David Carroll]

If you are going to use the sled regularly, and if you feel confident that you can repeatedly set it up the same way, accurately, then I would set it at 25-degrees on your sled and grind away until you regrind the entire bevel. Your angle will wind up somewhat less than 25-degrees, but no matter. There's no magic to 25-degrees, it's just a reasonable compromise between a very shallow and sharp 20-degree bevel and a more obtuse and sturdy 30-degree bevel.

DC

[Robert Hazelwood]

It's kind of silly for the manufacturer to state a specific sharpening angle. It depends on the use, the users technique, and the properties of the steel. Could be anywhere from 15 to 40 degrees, but most often between 30 and 35 for me.

Anyways you need to figure out what the current angle is. Use a protractor or slowly increase the angle of your jig until you start to get contact at the cutting edge. You might find the factory grind is too obtuse to be usable- sadly its not uncommon. I wouldn't want the primary bevel to be over 30 degrees in any case. If it is, you'll need to remove quite a bit of material off of the bevel.

If you don't have a grinder, the way I suggest to do this is to get a decent length of coarse sandpaper (60 to 100 grit) and stick it on a hard flat surface - could be a table saw top or jointer table, cutting board, etc. It doesn't need to be perfectly flat for working the bevel side. Use a honing guide set for something a bit less than you want your final sharpening angle to be- I recommend 20 to 25 degrees - and grind away using long strokes. This will go much quicker than using diamond plates, and will keep your plates from wearing out too quickly.

Keep grinding and checking the new flat surface you're creating at the top of the bevel. Check that you are not grinding it at a skew - if you find that you are, compensate by applying pressure to the side with more metal remaining. Use the whole bit of sandpaper and change it every 5 minutes or so of grinding - it dulls quickly and will cut much slower than fresh paper. Once the flat reaches the edge you are done with grinding. Now you can reset your guide for your actual sharpening angle (I recommend 30 degrees to start) and take it to the stones. You should be able to raise a wire edge almost immediately.

You might also find that the back needs work as well. If its more than can be quickly honed out using your stones, then I suggest again using the coarse sandpaper. But take more care to find a flat surface- I like to use a granite surface plate. Small imported ones from Grizzly, Woodcraft, etc. are not too expensive and are nice to have around.

[Tom M King]

These make it easy to not only get the angle you want, but it's exactly repeatable every time. Back when I had helpers, I would hire illiterate people that no one else would hire. The last two, working together, could almost read a tape measure. They had no trouble sharpening chisels good enough to suit me, which is Really sharp.

[Jack Dover]

How do you make sure a chisel in a red jig stays square? I have a similar Veritas guide (not manufactured anymore) and I like it because it holds a chisel better than a side clamping jig, but setting and keeping it square to the edge is pretty much impossible.

[Tom M King]

The red jig doesn't hold anything square. I would never sharpen the narrow chisel in it with that jig, but just grabbed what was close at hand to show that any chisel can be set in any jig with them. That red jig is an old Record, and just has a ball for a roller. It works good for irons with short radiuses like Scrub plane irons, or 8 to 10 inch radius Jack plane irons. I have no idea when they stopped making it.

I don't think I own any jig, including the old ones that I rely on to keep the edge square. Even that Veritas jig, which is rarely used, keeps the cambered roller on it. I don't think it's been used since I made those setting jigs, and that was in 2015 or 16. I had a helper that could use it as it came when sharpening with oil stones if we were using a microbevel, but no microbevels since back then either. The picture is the day I stuck those jigs together back then. There is another now with 18 and 27 degree angles.

As far as grinding angle, for us it's just to get the bevel out of the way. I don't worry about, and have no idea what they are exactly-mostly just done by eye. My helpers could never sharpen anything by hand alone so we don't depend on a hollow grind to register on a stone. We hollow grind because the grinder has round wheels.

The edge bevel is what we use those setting jigs to get. There is nothing to fumble with or repeat exact setting on, so they are foolproof. We just sharpen flat bevels with no microbevels, so the edge bevel can take over as much of the ground bevel that it likes until there is edge damage. Only with edge damage will the cutter revisit a grinder.

My plane irons have not visited a grinder in years.

[David Carroll]

I've had the old clamp on top veritas sharpening jig since they were first introduced, mine has the old block with different angles, before they switched to the hex (or is it Octagonal) wheel design.

I struggled for years with the jig trying to keep chisels, particularly narrower ones square. I had a tendency to favor one side, which would cause the blade to drift and pivot toward the right (in the jig). Once I realized this, the cure was to sort of pretend the jig wasn't there and use a light touch.
I keep my eyes and my focus on the edge being ground, keeping it square with my body and hand positioning and letting the jig set only the angle of the bevel. It isn't a mindless activity it requires a fair bit of attention. Eventually I got the hang of it, and retrained my body to apply even pressure.

I bought the new(er) Mark II jig, but it had way too much gizmosity (in my opinion) and used it once, then sold it.

I rarely use the old jig nowadays. The only time I use it regularly is with my LN No. 9 which I use for shooting. That iron wants to be dead square and with a very shallow grind and microbevel.

Jack Dover: I now use a very shallow angle (less than 20-degrees) and a convex bevel on a lot of my bench and paring chisels. I've been experimenting with this for years now, and so far I am convinced that there is some value there, when freehand sharpening. If you do dig out the Hasluck book (which one?) to find the article by J.D. I'd be interested to read his criticism of the technique.

DC

[Patrick Varley]

All, I'm struggling to learn to sharpen my chisels.

I purchased GREBSTK 4PCS Professional Wood Chisel Tool Sets Sturdy Chrome Vanadium Steel Chisel, 1/4 inch,1/2 inch,3/4 inch,1 inch which are supposed to have a Sharpening angle of 25 degrees.


I have tried everything from wet stones, to diamond plates and now trying the scary sharp float glass + sandpaper solution.

I have a sled that allows me to set the angle accurately. I set that to 25 degrees, but only the very back top the chisel blade is making contact.

https://www.dropbox.com/s/7mrfhpp939...21.00.jpg?dl=0

I increased the angle to 30 deg and that helped a bit, but I'm nervous to get off the factory spec.

How do I get the front of the blade to contact? I know I could keep sharpening for a _long_ time and the chisel would eventually sharpen at that angle.

Thanks for any help.

Tim

https://youtu.be/GN4yr7vp4I4

I'd recommend watching some additional videos on sharpening. There are a million. But one key is understanding the idea of "primary" and "secondary" bevel. The factory bevel is probably somewhere around 25 degrees (though the exact number isn't necessarily important). The secondary bevel is what actually does the cutting (and more specifically, the edge between the secondary bevel and the back, both of which need to be flat, is what does the cutting), and many people will set that around 30 degrees.

If you don't use a secondary bevel, then yes, you have to get the whole primary bevel honed evenly. Not just on setup, but every time you sharpen. That's why the secondary bevel is helpful, as you only have to hone the first few millimeters of the blade. If you set it up this way, then you'll only have to regrind the primary bevel if you damage/chip the edge significantly and have to grind back the tip to repair it.

[Dave VanDewerker]

The chisel looks to be a hollow grind, ground on a wheel. When you then sharpen the chisel on a flat stone the edge will only contact the stone at the top and the bottom. The chisel is sharp in your pic, just use it, the cutting edge is only where the two surfaces meet, not all the way up the slope. After you use the chisel and sharpen it a few time the two contact points will get closer and closer until they meet and you have a flat surface, that will not make the chisel any sharper.

[roger wiegand]

Start on a powered grinder or sander to set the starting angle (a slightly concave cut will make your hand sharpening easier as only the front and back edges of the bevel will contact the stone. Yes, you just need to remove enough material to establish the primary bevel. It will take a long time by hand, be pretty quick on the grinder. Once that's done resharpening will be fairly quick work.

Only some chrome vanadium steels are high speed steels with heat resistance sufficient to turn red without losing temper so I'd treat them as if they are not, keeping them cool enough during grinding to avoid bluing of the edge.

A jig like the Veritas one makes keeping a constant angle much easier when hand sharpening.