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Hardening the Steel

Hardening the Steel

OK - I'm not a blacksmith or anything like it... but hardening this type of steel is quite easy to do.  While I use a gas forge:

For tools this size, it's easily done just as well with a MAPP gas torch.  You only have to worry about the business end of the tool - the rest of it (what's under the handle) doesn't require any sort of hardness past what it already has.  Incidental hardness won't hurt it, and neither will leaving it annealed.    After it becomes cherry red, and reaches the "Curie Point" (where it loses any magnetic qualities), quench it in oil.  Any oil will do, I use vegetable oil in a coffee can.

When cooled, temper the steel by sticking it in an oven set at 450 degrees for an hour.  This should give the blade a hardness of about Rc60 or so...

A black coating covers the steel when you are finished heat treating the blade, but comes off easily with a deburring wheel - or sandpaper if you don't have one of those:

Putting it Together.

Now you are ready to assemble the whole affair.  Well - OK - not quite.  Since it's a bit easier to get into the corners, now is a good time to work on the bevel of the knife a little bit, before you put it together.    Not that it will be a big deal later, but its just a bit easier to do it now:

I don't sharpen it completely - it won't cut paper - because I don't want to cut myself somewhere in the assembly process.  Final sharpening can wait till the whole affair is assembled.  Speaking of which, that can start, if you have done all of the shaping you need to do to the scale before putting it together.  One example might be ramping the edge of the scale down near the business end of the tool, something you can't do after it's together  without a good amount of difficulty.

Now that we are there - it's time to put the rivets into place.

It's a simple process, really - it's just putting the outer sleeve in first, then placing the blade and opposite scale into place, and hammering the rivet into place:

Here's where you find out if you didn't have the right size hole.  Too tight, and either it won't go in or crack the wood, or too loose and and it won't hold it tightly enough.

 

Finishing Up

Now that the tools are assembled, it's time for a little quality time with the sander, rounding off the sharp edges.  Some of this is better done before the blade is installed, and some is better done afterwards.  It's up to you when each shaping step is important - just use common sense in how you approach it, and learn from the mistakes made... and you will do fine.  I actually was shaping the handle all the way through the process...

By far the easiest finish is a little boiled linseed oil followed by paste wax.  You can add as many coats as you feel necessary to get the sheen you want.  So - here they are in all their glory:

Nothing spectacular, but still make for some good, functional tools without spending an inordinate amount of time on them putting them together.

From there, the screwdrivers are ready to use:

For the knives, a little time with some oil stones, sharpening them the same as you would a pocket knife (with a double bevel) is required to get them into shape.  Some people might prefer a single bevel for a marking knife, but I would encourage them to give one of these a try.  If nothing else, they are good for carving the wheat into the handles you area making for all those backsaws you are making, right?

Comments

Comment: 
<p>That&#39;s a great post. &nbsp;I recently started to play around with carving, so making a few Murphy knives would be pretty fun. &nbsp;I&#39;ve been looking for rivets and didn&#39;t know that Lee Valley carries them.</p> <p>Thanks for the write up and info!</p>

Comment: 
<p>Thanks, VC!&nbsp; It&#39;s one method - there are several.&nbsp; I think a &quot;Murphy&quot; knife is just a little different in that its&#39; tang isn&#39;t the full width of the handle (inserted into a slot in the back of the handle&nbsp;rather than between two halves) and it shape is much more amorphic than these - but the same basic steps to making one like that would apply - post a photo of one you&#39;ve made&nbsp;when you get it done if you want!</p> <p>&nbsp;Leif</p>