A few new marking knives

Striking!

Stephen Shepherd in the State of Deseret

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question

Bill Tindal, E.TN

>would you describe how you grind the bevel (and keep it centered and symmetrical) and how is blade fixed (glued, wedged, ?)in the wood?

I have a short knife much like yours that someone gave me and I find it exceptionally handy. Would like to make a larger one.

Re: question *LINK*

Derek Cohen (in Perth, Australia)

>Hi Bill

I wrote a tutorial on building these marking knives a while back. Link below.

Long story short - the blades are epoxied into a slot and reinforced with a brass ferrule. I have made about 50 of these to date and, bar one where there was a flaw in the wood, they have all remained strong and performed beyond expectations in regard to downforce.

To get the double bevel on the blade, I use a jig to set up the side angle (50 degrees and bevel angle (30 degrees), then grind them on my belt sander. I finish the edges by freehanding them on a extra fine diamond stone. The edges are very durable and sharp. My current users have not needed to be honed in a year.

If you need, I can take some pictures of the jigs involved. Let me know.

Regards from Perth

Derek


A Knife for Marking Dovetails

Re: How thick is the blade?

arw01

>The blade looks thicker than I thougtht it would for the source item? Would you mind using a caliper and advising the thickness so I can scrounge a bit in my stashes?

Thanks

Alan

Re: How thick is the blade?

Derek Cohen (in Perth, Australia)

>Alan

No caliper to hand, but I know that the blades are a tad over 1mm thick (by 6mm or 1/4" wide) and 40mm long (from the ferrule).

Regards from Perth

Derek

Flaw? What Flaw?

Todd O. Cronkhite Maine Native, Presently Away

>that ain't no flaw mate, that's a natural decoration. I like it too, and try to work them into my ww'ing as well.

The awl blades are ground and hardened from concrete nails.

How in the Tasmanian Devil did you grind these round awls from concrete nails and make them so round? Must'a been big nails to start with. The concrete nails that I am familiar with a flat sided, are they round in Oz? Did you have to soften them first?

At any rate, I they look really nice, and I like your handle style.

T.O.

Todd & Derek

Tom Colligan

>Todd, you may be able to put the nail in an electric drill and touch it to a grinding wheel.

Derek, I just wish you could explain how you get the 50 and 30 degree bevels. Is it on the 1" belt sander? What would the jig be that you've settled on. (A picture would be great!)

Thanks so much, they look great! Tia, Tom.

Grinding the blades - a short pictorial tutorial

Derek Cohen (in Perth, Australia)

>Tom asked, Derek, I just wish you could explain how you get the 50 and 30 degree bevels. Is it on the 1" belt sander? What would the jig be that you've settled on. (A picture would be great!)

The main items are ...

... a prepared jigsaw blank (surface ground, polished and bevel outlines ground) ...

... a belt sander (with my grinding jig), 240 grit belt ...

... and a template for setting the bevel angles ...

This jig sets the projection for a 30 degree bevel edge on a 50 degree side angle, thus ...

This is now set up for the belt sander ...

And the final result looks like this ...

Now the blades are cut out (to a length of 40mm), and the bevels are given a final quick freehand hone on a extra fine diamond stone.

Give it a go!

Regards from Perth

Derek

Grinding an awl blade

Derek Cohen (in Perth, Australia)

>Todd, you may be able to put the nail in an electric drill and touch it to a grinding wheel.

Exactly.

Grinding blades for awls is the easiest thing in the world!

Cut off the projecting head of the nail and chuck the nail into your power drill. I use a disk sander but you can use a bench grinder as well. Now hold the spinning nail (hence the drill) against the spinning disk (or grinder wheel). Taper the nail until it gets nice and pointy.

OK, now you have a pointy and rough nail that is blue. I spin this again, this time against a deburring wheel to clean it up and smooth it down. You could also use very fine sandpaper.

Heat the last 1/2" of the nail red hot and quench it in water. You now have a rock hard edge that will scratch steel. Clean it up again. This time I polish it with Veritas green rouge. It comes up like chrome.

I leave the nail hardened in this state. It should not lose its edge, ever.

Regards from Perth

Derek

My personal favorite ones...

Scott Burr in Ben Lomond CA

>Are the Jarrah and Olive wood set. Very insteresting color and grain combonation. Well done.

now that is clever

Bill Tindal, E.TN

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Round concrete nails

Bill Houghton, Sebastopol, CA

>You can find them here at the upper end of the world too, Todd - my Ace hardware carries them, I imagine they have them in Florida too, and probably even in Maine.

Re: Round concrete nails

Todd O. Cronkhite Maine Native, Presently Away

>Thanks Bill, I've never seen round ones before, coarse, I never went looking for them either. I fiqured Derek must of either been starting with some humongus nails to be able to turn them round, or they had round concrete nails in Oz. I'll go look for some one of these days.

T.O.