Rules of thumb for the plane/chisel 'Sharp test'

[transatlantic]

A good magnifier and good light is an excellent way to see if you have a crisp edge. If you struggle to see the 'shiny edge' that Chris describes, try a magnifying glass or 2 pairs of reading glasses at the same time. You will clearly see whether the edge is crisp or not.

Sorry - what I meant was that I believe I have a crisp edge as I don't see the reflection of light caused by a dull or rounded edge.

 

[transatlantic]

I'm using a guide. Not the fancy veritas one, just the basic one.

Are you absolutely certain the blade is held squarely in the guide? I have a basic one right here next to me. It's a Screwfix jobby and no matter what I do with it, it wont hold a blade square in the horizontal plane. This one is basically junk as it results in all my chisels/plane irons having an angled cutting edge.

Not saying this would definitely cause the problem you describe, but with limited clearance in the mouth, it will cause problems.

I believe so yes, as I am using a small highly accurate engineers square to test the blade after sharpening.

 

[bugbear]

A good magnifier and good light is an excellent way to see if you have a crisp edge. If you struggle to see the 'shiny edge' that Chris describes, try a magnifying glass or 2 pairs of reading glasses at the same time. You will clearly see whether the edge is crisp or not.

Seconded - a 5-10 times magnifier can be most instructive on what's happening to an edge.

BugBear

 

[Graham Orm]

A good magnifier and good light is an excellent way to see if you have a crisp edge. If you struggle to see the 'shiny edge' that Chris describes, try a magnifying glass or 2 pairs of reading glasses at the same time. You will clearly see whether the edge is crisp or not.

Sorry - what I meant was that I believe I have a crisp edge as I don't see the reflection of light caused by a dull or rounded edge.

Then if as you say you have flattened the back, in my opinion your blade is sharp. I read somewhere in the thread that you haven't given much attention to the flatness of the sole. It's particularly important in front of the mouth. The problem is that this part of this particular plane is designed to adjust, so to guarantee a flat sole as with a fixed mouth plane is nigh on impossible.

However, it might be worth marking the sole up with a marker pen in a criss cross design, wind the blade right back and give it a rub on some 120 paper. You will see where any concave areas might be.

 

[Mr T]

Skip the 4.5 and go for the 5.5, it's got more momentum than a 4, 4.5 or 5.

Chris

 

[transatlantic]

A good magnifier and good light is an excellent way to see if you have a crisp edge. If you struggle to see the 'shiny edge' that Chris describes, try a magnifying glass or 2 pairs of reading glasses at the same time. You will clearly see whether the edge is crisp or not.

Sorry - what I meant was that I believe I have a crisp edge as I don't see the reflection of light caused by a dull or rounded edge.

Then if as you say you have flattened the back, in my opinion your blade is sharp. I read somewhere in the thread that you haven't given much attention to the flatness of the sole. It's particularly important in front of the mouth. The problem is that this part of this particular plane is designed to adjust, so to guarantee a flat sole as with a fixed mouth plane is nigh on impossible.

However, it might be worth marking the sole up with a marker pen in a criss cross design, wind the blade right back and give it a rub on some 120 paper. You will see where any concave areas might be.

I shall take a look into that.

I picked up a magnifying glass so I could take a look at the edge as advised, and noticed little dings/dents, i.e the edge wasn't flat. So I ran through the sharpening process again and took another look. Now the edge was perfectly flat - not dings or dents. I then took a number of swipes with the plane on the same pine wood (no knots). Having looked at the edge under the magnifier after, there were dings and dents again! .. I've run through the above several times, and I get the same result Is this normal? .. I was expecting to see a rounded edge after use, not an edge with dents.

So now I'm wondering if maybe I have sharpened the edge to something less than 25 degrees, perhaps introducing an edge that is too weak? Unfortunately I don't have an angle measure tool, but will look into getting one soon.

 

[AJB Temple]

Getting back to the basics of sharpening, have you made sure there is no wire edge / folded over micro bevel? Have you flattened the back of the blades well as sharpening the bevel side?

I test plane blades after stropping, in the same way as knife blades: hold up a piece of paper and cut down from an edge. No tear and no pressure. It's good enough if it will do that. You will know for sure it is sharp.

Then follow the guidance already given (and in numerous threads here) on setting the blade correctly.

 

[bugbear]

I picked up a magnifying glass so I could take a look at the edge as advised, and noticed little dings/dents, i.e the edge wasn't flat. So I ran through the sharpening process again and took another look. Now the edge was perfectly flat - not dings or dents. I then took a number of swipes with the plane on the same pine wood (no knots). Having looked at the edge under the magnifier after, there were dings and dents again! .. I've run through the above several times, and I get the same result Is this normal? .. I was expecting to see a rounded edge after use, not an edge with dents.

If nothing else, you've demonstrated how useful a magnifier is when diagnosing sharpening issues!

BugBear

 

[Jacob]

......
So now I'm wondering if maybe I have sharpened the edge to something less than 25 degrees, perhaps introducing an edge that is too weak? Unfortunately I don't have an angle measure tool, but will look into getting one soon.

Everybody has an angle measuring tool (a brain). 30º is a gradient of: slope = twice the height. Just practice freehand on paper, or cut out an equilateral triangle - the corners are 60º so halve that etc. It's worth just getting familiar with easy angles. Grinding angle is just a bit less than 30 so thats no prob, and so on.

 

[AJB Temple]

If you have a bevel gauge or a combination gauge, that is enough for checking angles. Otherwise bolt two pieces of wood together and use that with a protractor. Of just mark it on a piece of paper and hold the edge against it.

 

[John15]

Has anyone mentioned a micro back-bevel

John

 

[Jacob]

I can see this one is going to run and run!
One very neat way of checking your planes performance is to try it out on the edge of a straight grained but very thin board say 4 to 6mm thick. It should be instantly obvious which parts of the blade are cutting or not, and how tidy the shaving is shows how sharp it is.
If it all seems OK try on thicker board edges but reduce the set for a finer cut.
It's generally more about fiddling about, trial and error, rather then finding "an answer" to "a question".