sharpening angles

[Jacob]

ok .....I have read all the posts so 25 to 30 degrees looks like the way to go .............but you have now ground the angle and honed it to razor sharp using said angles

how do you know you have ground/polished these angles spot on ...do you check them with a protractor or is it really trial and error
i.e. its not cutting well so i need to redo .......

before any one jumps in I am not de crying anything just curious to how you know

ok Dave :wink:

If you are doing it freehand it's useful to have a visual guide like CC's above. Mine's a wooden wedge cut at 30º. Have it alongside your stone as you hone. You soon get used to guessing it close enough.
Or you just do it by eye - 30º is a 1 to 2 incline (1 vertical, 2 up the slope) or half an equilateral triangle, so it's not hard to visualise.
The main thing is to avoid raising it with every honing.
The second main thing is to get a burr right across the middle. The middle gets most wear and so tends to be the last bit to get re-sharpened and is easily neglected.

 

[CHJ]

Before I acquired a fancy bevel gauge I made up a couple of these simple check tools, in fact they still get the occasional use if the sticky label has rubbed off the odd turning gouge that has not seen the grinder for some time and the old memory bank has lost the reference.
Stuck onto some stiff card or thin ali sheet or brass if you want to be posh they don't take more than a few minutes to clean up with a fine saw and needle files.

Link to PDF Version

 

[bugbear]

Perhaps it might be more appropriate to say grind at about 25 degrees, and hone at about 30 degrees - a degree or so either way on either grind or hone angle isn't too much of a problem.

To check the angle, there are many ways. You can buy some quite nice brass gauges (Richard Kell makes a good one), but mine is just a piece of cardboard about 3" x 2", with notches about 3/4" deep cut in the long sides at the different angles (mine does 20 degrees to 40 degrees by 2 1/2 degree increments, so 9 notches in all), and the relevant angle marked against the relevant notch in pencil. Took about ten minutes to make, so if it falls apart in a year or so, I'll just make another. I sharpen freehand, so it's easy to just hold blade and gauge up to the light, and offer the two together to see where I'm at.

Some people prefer to hone with a jig (by the way - the only 'right' way of sharpening is the one that works for you, irrespective of whether it works for anyone else), and to set that up, you could use something similar - a set of cardboard angle gauges to set the tool in the jig.

However, the main point is to sharpen until the tool feels sharp and does what you want it to - exact angle isn't critical.

Agreed - but hitting the same angle every time is helpful, even if it happens to be 26 (or 24) not your notional target 25. This reduces the amount of metal you remove, saving time and paid-for tool steel. This is easily achieved using the common-and-cheap Eclipse jig and a projection gauge bashed together from scrap. Quick, easy, accurate, sharp.

BugBear

 

[Digit]

I'll stick my oar in and point out that theoretically the cuting angle would depend on the material being cut! If we are gonna maintain a single angle for all materials it might as well be the size of your hat!

Roy.

 

[Teckel]

I was never one for worrying about angles. When stones dont bring up the keen edge it goes to the grinder and then back to the india and then the fine stone. Job done.
Also give your chisels a quick rub after you use them on the fine stone. That way the edge lasts longer...and it only takes seconds in the evening to do this. :wink:

 

[Digit]

Exactly!

Roy.