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Thread: First go at a chisel
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10th October 2016, 07:49 PM #16Senior Member
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Hopefully I'm allowed to post links. This is my FB page... uploading pics to tapatalk is a nightmare! They're all there if you're inclined to have a look.
https://www.facebook.com/VicarForge/...92097317608339
Thanks for the interest.
Matt
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10th October 2016 07:49 PM # ADSGoogle Adsense Advertisement
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11th October 2016, 01:15 PM #17
Hi Matt
That is a very beautiful chisel.
Your father will no doubt be very proud of his accomplished son.
By the sound of things your father is likely to use it for paring and so he might find a primary grind at 25°, or even a little less, more useful than 30°
Out of interest how did you heat treat the steel
One point, as far as I know, Damascus steels vary in hardness and elasticity between the light and dark bands of metal. If this chisel were to be used for heavy chopping, you might find that the edge is very prone to chipping in line with the bands.
With your next chisel, you may wish to have the bands running close to parallel with the back of the chisel.regards from Alberta, Canada
ian
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11th October 2016, 03:23 PM #18Senior Member
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Hi Ian,
Thank you for your feedback. You are absolutely right that 25 degrees would have been more appropriate. I figured that since I'd finished and etched it I would sent it to him and he can regrind if he wishes to adjust the bevel.
I have a digitally controlled Heat treat oven (basically a knife kiln) that allows for very accurate temp controls, and quenched into a commercial heat treatment oil (haughtons k quench).
The two steels are almost the same, very small differences in composition and slightly more nickel in 15n20 gives the contrast, but heat treatment is the same for both steels so they should perform the same.
While Damascus should essentially be one piece of steel I agree that there is an increase in risk of delamination with that orientation. My next chisels will be Damascus on top of a monosteel to gain both performance and appearance.
Greatly appreciate the time you took to respond. Hopefully you an provide some critique on the next ones also.
Cheers
Matt
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11th October 2016, 03:40 PM #19
dredging my memory of metallurgy, and comments by other blade makers, my understanding is that at the level of the crystal structure within the metal, the difference between the two steels is sufficient to cause a problem.
Paul Williams who was the person behind the Academy Saw Works blades -- which unfortunately are no longer available -- told me once that the steel he favoured behaved differently depending on whether, when sharpened, the edge was parallel to or across the direction of rolling. The issue related to how the marstenite and austenite crystals broke off as the edge wore.
with your steels, I suspect that the crystal structure difference may be sufficient to be a problem. With a knife, micro fractures along the edge probably enhance it's performance as a cutting tool. From what I know, the same is not true for a plane or chisel blade.regards from Alberta, Canada
ian
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11th October 2016, 05:19 PM #20Senior Member
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There you go. I have to admit my understanding of the finer details of metallurgy are not there at all and your information is probably bang on.
Hopefully laminating a top of Damascus will alleviate that issue and be a functional tool
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