Chisel edge crumbling
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Hi,
I have a set of cheapo Stanley chisels.
I’ve flattened and sharpened them as best I can using Paul’s method, and they worked really well when shaping Spruce for a saw horse.
However, after one saw horse top the edge of the chisel is crumbled.
Does anyone know why this might be? Spruce is soft, so I expected the edge to stay good long beyond this job. I don’t get the shine on the cutting edge that Paul does, so perhaps I’m not sharpening them properly?
Thanks
Darren.
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You must be logged in to view attached files.24 October 2016 at 3:08 pm #141861Well unfortunately cheapo is probably the key word here. If it was me, I would grind some of the chisel edge away. I think you have to get rid of that edge. It could be the construction process of the tool or other reasons but you have to get rid of those nicks and that edge. The steel could be fine behind that edge. I hollow grind my chisels. Of course you have to be careful that you don’t overheat it. Its possible to do it with out a grinder but will take you much, much longer.
I have seen that on other chisels, a tool maker basically said its due to the uneven heat treatment the thin material at the cutting edge recieves when they are being tempered/heat treated. I have seen this with moderately priced Sorby chisels I own. After a few sharpenings you get to good metal. I would continue using them and see if they stop fracturing like that after a few sharpenings, if they don’t, then I would look at better chisels like Narex.
24 October 2016 at 10:19 pm #141876I think, you should spend some time removing all the machine marks near the edge. The machine marks weaken the surface and increase friction. I am not sure, if they directly affect the stability of the edge, but indirectly, they will, because you need more force to cut.
And if the upper portion of the edge doesn’t just look rusty, consider using a little bit of oil for protection.
Dieter
Hi,
Thanks for the suggestions.
I spent an hour this evening grinding the edge down and carefully honing it to the correct angle.
It looks much better now.It worked really well, and in fact was so sharp I didn’t notice it slice through my finger (twice). I only noticed when I realised there was blood smeared on the saw horse I’m making…
I’ll keep an eye on the chisel as I use it. Based on this experience I think I need to grind them all down a bit and put a new edge on each one.
Thanks again,
Darren.
Dieter,
The marks near the edge aren’t machine marks, as I had previously ground all of them out.
I think a secondary problem I have is with my EZE-LAP diamond stones.
I got a polished finish as I moved through a new coarse stone to an old coarse stone, and on to a fine stone. When I tried finishing off on my “super fine” stone I got a lot of new scratches in the face of the blade.
It may be that the Super Fine stone might not have been worn as much as the others, so my fine is really super super fine, etc.
Now of course I’m wondering if I mis-labelled “fine” and “superfine”, and I’m finishing off on the wrong plate…
Darren.
24 October 2016 at 11:59 pm #141883just flip the stones over they should have the grit written on the back in black ink
25 October 2016 at 12:01 am #141884On the plus side, cheap chisels are great for learning to sharpen because you have to go back to the stone so often!
I started out with the cheap, heavy butt chisels with the poly handles you get at the big box store. They were on hand in the toolbox, so that’s what I used. I literally could not get through chopping the waste for a single dovetail in soft pine or poplar without having to go sharpen up. They were bad.
Hi Eddy,
These just had a colour swipe on the back, black for coarse, red for fine, blue for superfine.
I realised it was wearing off, so put a new mark on the back with a coloured Sharpie and wrote what grit the stone was.
It’s possible I switched fine and superfine, although I don’t *think* I did.
Darren.
If it’s a new diamond plate it’s likely not broken in yet, just sontinue to use it and the stone will even out. There should be some indication on the stone itself to identify what grit it is. You never mentioned a strop, the leather strop with polishing compound will refine that edge.
Hi,
I am using a leather strop and green compound. I’m giving it 30-40 swipes.
I can see it is polishing the very edge of the blade, but not the main face.
I don’t know if that is due to my technique with the stop, or because there are too many scratches in the face when I start stropping.
Darren.
25 October 2016 at 1:19 am #141889My friend realized he had the extra course diamond plate instead of a course. He noticed it written on there. You could have them “out of order”. It is hard to tell. I had a similar issue with my new Ashley Isles chisel. Guess the fractured edge happens with a new tool.
On a related note, I tried Pauls method of sharpening but it never worked for me. I tried it for a year. Maybe it was because I use oil stones. If you aren’t happy with your results over time try another method.
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