With everyone getting stuck up and all sensitive about sharpening and what not lately I figured what better time to have yet another sharpening related post – so here it is – my way – at least nowadays (it keeps evolving as the years go by and getting better and better for me).
I keep hearing about the marvels of water and oil stones all the time, and always wanted to “be there with the best”, so at some point I got a couple of arkansas stones – a hard , and a black which according to the specs should have taken me from my diamond stones shine to a higher level only heard about in legends… unfortunately it just didn’t happen to me, and the results I am getting from these are subpar to my green super-fine diamond stone which gives me a much higher shine. maybe its because I’m not using “proper” honing oil? it’s possible… but I digress. My point being that I simply went back to my tried and trued method of giving me a super sharp edge.
My setup involves 2 steps:
Step 1: Flattening the Back with (3) Diamond stones
I got this set of DMT diamond stones from Rockler when I was in my early years of woodworking as a rough shaper for edge tools, but for some reason I find that I don’t have a need to go beyond these as “rough” as they may be:
I go through the 3 stones until I get mirror finish on the backs, and then move on to step 2 (who would have thought). as some would say – I am not anal about the backs – which I will get to later on this post showing what I mean, and showing the reason…
Step 2: Setting the bevel and polishing it up using Slow wet grinder
I picked this Scheppach grinder up on CL some years ago for a good price, but even new (same as the grizzly) it doesn’t break the bank, and has been performing great everytime I use it:
It’s easy to use, does a good job, grinds cool and cannot screw up the blades. Once the bevel is set and the bevel and back meet at a proper edge, I switch to the polishing wheel freehand (although you can swap the toolrest and use that as well) and let the bevel ride on the wheel from it’s heel (so that if anything gets rounded – it’s the non crucial part of the bevel) and bring the blade up to have the entire bevel ride on the wheel to give it a nice mirror finish.
at that point – I take the blade back to the highest grit diamond stone, and give it a light treatment on the back to remove any burrs from the grinder.
and I’m done. can shave hairs off, and slice end grain – makes me happy.
can I do better? I’m sure I can
But this is fast, efficient, and I don’t have the feeling that I need to do better, so I leave it at that.
Now… why did I come to this?
I know a woodworker that goes through some health issues, and decided to donate my set of German chisels to him to help bring up the moral. that meant I am chiselsless. as life would have it, the same day, someone posted a set of chisels for sale, which I promptly went for. the chisels arrived today quickly and well packed. Unfortunately I believe that someone tried to sharpen them but possibly didn’t go about it properly.
This is pretty much what prompted me to post as someone posted a day or 2 ago about how not anal he is about the backs of chisels which I didn’t realize why he posted it as I don’t know anyone who IS anal about the backs of chisels, and most anyone I know including myself only flattens the front of the back (confused much?), but looking at these chisels, it seems like someone actually went through the trouble of trying to flatten – the entire back of the blade.
The problem with doing so (unless you are using a surface grinder), is that it means you will have to remove ALOT of material which not only will take forever, but also requires a lot of energy invested into it, and worst – it adds quite a bit of chance to round over the backs at the edges because there is much friction between the sharpening medium and the metal which can cause it to lift, or twist out of flat. which is what I assume happened here. the entire backs received a flattening treatment but the edges were all rounded off making it almost impossible to properly get a sharp edge out of these.
I flattened the front 1” or so of each chisel and you can see the “previous” scratch marks visible on the entire back, the “new” scratch marks I made trying to flatten only the front, and the sliver of previous scratch marks on the edge of the back as it was rounded over and is now a “low spot” which makes it almost impractical to flatten the back of the chisel where it matters – at the edge:
- the obvious – grind the front of the blade back to remove the rounded over area completely – reestablish the bevel from scratch
- The rule trick – use a thin metal rule to raise the blade at the other end so that it is slightly tilted towards the edge. you will not get a “pure” flat back, but this will help by flattening ONLY the leading edge of the blade which reduces the amount of metal you are removing.
- elbow grease – keep on flattening the back until you level it off with the low spot (rounded over edge).
I chose a combination of #3 and #1. I gave the backs a bit of an extra work to get down and closer to the low spots on the fronts, and then reground the bevels which I believe were originally set at 20 degrees to 25 degrees and ground them back a bit to remove that front lowered edge.
2 hours later, I had all 7 chisels razor sharp and ready for work.
here you can see the backs where it’s pretty visible how far back I flattened them as opposed to the original attempt to flatten them completely:
the only area that matters – is near the cutting edge, the rest of the back can be “somewhat flat” but it isn’t critical to have it completely flat.
the bevels (I did grind the 1” chisel at 35 degree, and then decided to grind the rest at 25… I will need to redo it’s bevel at some point for more paring operations):
and the cutting edge on the bevel side where you can see that the majority of the bevel is left “rough” as it doesn’t do the actual cutting and does not need to be all that polished. just like the back side, it’s only the edge that really needs to be flat and polished:
So that’s my take on anal and lenient. be mindful of what’s important, and don’t sweat the rest – same with all cutting tools, and same with hand plane soles – they don’t all have to be completely flat throughout end to end. only the critical parts/areas need be flat and sharpened (in blades) to the best of your ability (the more the better of course).
Hope this was helpful as a lesson, or tip, or an eye opener to some of you, or at least entertaining to others :)
-- ㊍ When in doubt - There is no doubt - Go the safer route.