Re: Marking Knife Assembly - Lots of *PICS* *LINK*
William R. Duffield, on the Cohansey
>Noah,
I was wondering if you could post a close up picture of the recent marking knife you made.
For starters, here's an enlarged photo of three, quite different, marking knives I've made to date.
The one in whose construction you are interested is on top. Length overall = 5 5/8". Diameter = 5/8". Material cost was pennies. The two below it use Hock O1 shivs and are thus quite expensive. I also had to pay for the wood for both of them, cocobolo for the MK I and manzanita for the MK II.
Here is a closeup of the head of the Loxahatchee Toolworks Mark III Marking Knife.
Any details about how you fit the blade in the handle would be much appreciated...Also, any detail about the threaded insert...
Background information on this marking knife, including hardware specs, can be found here: Re: Sort of like the Veritas Marking Knife
For starters, you need to drill two concentric holes in the end of the handle blank. The smaller diameter, longer hole should match the diameter of the saw blade, and the larger shorter one should match the specs on the threaded insert.
Next, install the threaded insert in the handle blank. The following photos show the curly walnut stock rough turned before doing everything else, but this preliminary step is not necessary, unless you are looking for a just-so piece of wood. You will need to make a mandrel, using a long bolt and two nuts, jammed together, matching the internal threads of the TI. The next photo shows (from left to right) the constuction of the mandrel, the TI installed in the handle blank, and the worn out Bosch jigsaw blade I used (with the teeth ground off and new cutting edges ground in), with a TI slipped over it.
Next, chuck the mandrel in your favorite brace, and thread the insert onto the mandrel. A three jaw brace works better than a two jaw or four jaw brace. Drive the TI about half it's depth into the handle blank. It should be obvious at this point whether you drilled the holes deep enough. With a quick snap, unthread the mandrel from the TI. If you start to back it out slowly, it is more likely to turn the insert out with it. I install the TI with the screwdriver slot in, since I'm not planning to ever remove it from the handle again. Note that the screwdriver slot in a TI is for removing it, not for installing it. Walnut is not very tough. This makes it good for carving, but it also means you may have problems threading the insert, especially in end grain. I have had to resort to epoxy to hold the TI in place. You might want to practice on scrap before ruining your handle blank. Firm, even pressure is required when driving it in place, even more so than driving phillips head drywall screws into oak. Do not over torque it.
Next, remove the mandrel from the brace, and put it in your Jacob's chuck, and mount that in the headstock of your lathe.
Thread the TI and handle blank back onto the mandrel and bring up the tailstock.
With a file, turn the exposed threads off of the TI. Then, turn the handle. You can start with a square or octagonal blank. Sand the handle, polish the ferrule, and finish the whole thing. Part off the handle, back off the tail stock, and sand and finish the end of the handle.
Snap off the shank of the jigsaw blade, and using your favorite adhesive, mount it in the handle.
Also, if you could possibly provide how you might attatch the blade without using epoxy. (You mentioned that you thought it may have been a poor choice, I am assuming for ease of blade replacement.)
My only concern with the epoxy was that the saw blade is pretty soft and awfully short, and therefore a lot of resharpening might prematurely age it. It is just a cost/benefit thing: How much time should I spend making a handle, if I'm going to wear out the non-replacable tool in a relatively short time? The problem with any liquid adhesive is getting it all the way to the bottom of the hole, and forcing the air out. I followed Gougeon Brothers recommendation of injecting it with a hypodermic syringe, filling the hole from the bottom up, and thereby forcing all the air out. The acetone I used to get the excess epoxy out of the syringe dissolved it, the cup it was soaking in, and the blue Scott shop towel I used to clean up the mess. Pick your syringes carefully.
I haven't tried any of the following alternatives: I think hot melt glue could be used, and subsequently resoftened for blade replacement with much less danger of ruining the handle with too much heat. I'll bet hot hide glue would work, too. Heat up the ferrule before you pour either one in. If I were desperate for a knife in a hurry, I might even try Zap-a-Gap (thick CA). I think a couple of square toothpicks, one jammed in on each side of the blade, would hold well enough, especially if you gave the blade a couple of turns after trimming them flush to seat them a little deeper.
I've also been toying with the idea of turning a fancy wood handle that I can glue an aluminum x-acto blade holder into, and maybe another matching wooden sleeve to go around the x-acto collet collar.
Can't wait till 5 Barns to learn to make a mallet..really not sure I can wait
Making a carver's mallet is easy. Just install a big hunk of wood on the lathe between centers, and turn away everything that doesn't look like a mallet :^)