Railroad Spike Mortise Chisel

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Blog entry by bobasaurus posted 11-15-2011 05:05 AM 6881 reads 2 times favorited 7 comments Add to Favorites Watch

I managed to get hold of a couple neat old railroad spikes, and thought maybe I’d try turning one into a chisel. I know they are made of really soft steel that’s not really suited for tool making, but the novelty of the idea was too great to resist. First I removed the many decades of rust using a wire wheel on my grinder, then brought the freshly shined spike into work with me. Taking some time in the evening, I made good use of the machine shop at work to mill flat three of the sides and make the primary bevel (~35 degrees). After a bit of honing on my oil stone at home, I ended up with this fine creation:

(Note my poorly-made secondary bevel… I need to work on my sharpening skills). It seems to work, though the edge was slightly degraded just from chopping this test mortise in cottonwood. Next time, I’ll have to make one out of good tool steel. Still, I can’t help but like this thing :) .

Edit: here’s a couple more pics:

-- Allen, Colorado (Instagram @bobasaurus_woodworking)

7 comments so far

View PurpLev's profile


8535 posts in 3641 days

#1 posted 11-15-2011 05:15 AM

cool idea and execution. I wonder what steel this is. any idea (looks like low carbon steel)? I just wonder if it’s worth/possible trying to harden this thing.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Blake's profile


3443 posts in 3867 days

#2 posted 11-15-2011 05:53 AM

Yeah, you could temper it with a blow torch and quench bucket. Look for a tutorial online (probably on youtube).

...Thats a GREAT idea though!

-- Happy woodworking!

View Mark Shymanski's profile

Mark Shymanski

5621 posts in 3705 days

#3 posted 11-15-2011 06:21 AM

+1 for hardening it. You’ve got nothing to lose and you may wind up with a novel chisel.

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

View bobasaurus's profile


3431 posts in 3177 days

#4 posted 11-15-2011 06:26 AM

After talking with my father who makes jewelry tools occasionally, I’m reasonably sure that this thing is made of mild steel or some similar alloy with not enough carbon content to temper, though I could give it a try.

Edit: Now I’m not so sure… I found this website:
That indicates that spikes marked with “HC” do have enough carbon content to temper. Mine does have this marking, along with an “R” above it, so this might be doable.

-- Allen, Colorado (Instagram @bobasaurus_woodworking)

View Dennisgrosen's profile


10880 posts in 3108 days

#5 posted 11-15-2011 04:04 PM

that spike does look good as a cheisel :-)
thanks for sharing … I too say harden it you have nothing to loose
even the slightest hardening will give you a better tool


View CaptainSkully's profile


1596 posts in 3551 days

#6 posted 11-15-2011 05:56 PM

You can infuse a higher carbon content into the steel, but that would require building a coal forge. That’s a very sexy chisel nevertheless…

-- You can't control the wind, but you can trim your sails

View PurpLev's profile


8535 posts in 3641 days

#7 posted 11-15-2011 06:03 PM

you can infuse higher carbon content into the steel but this will only be on the surface and is only used as a ‘finishing’ technique (case hardening – blackening) and will not really make the steel any harder to be used as a cutting tool.

however, if your spike is marked with HC (high carbon) then it may just have enough carbon in it to harden it. you’ll want to harden it (heat it up to cherry red for a few minutes, then quench quickly in oil/water, may need to do this twice or more) and then temper it by heating it up to straw color (lower heat), keeping it there for a minute and then quenching it. this will soften it up a tad bit otherwise the hardened steel will be too brittle and can shatter when used as is. look up ‘steel hardening’ and ‘tempering’

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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