Hi everybody,
I am planning to try to make my own marking knife using one of Ron Hock’s 1/4 inch marking knife blades and a small block of ebony. I have a couple of ideas on how to do it and I want to make sure that I am on the right track. Any advice or alternate methods would be appreciated.
Method 1: Square up the ebony block. resaw it down the middle and joint the faces flat. Use a 1/4″ router bit on a router table to rout a recess in the blank (I haven’t decided whether to resaw 1/4 inch off center and make the recess on one face or to resaw down the middle and make a small recess on both faces.) Once this is done I plan to glue the two sides together with a brown paper in the middle so that they can be easily split once I finish turining them. When the turning is completed and the blanks are apart I will epoxy the blade in and glue the sides back together.
Method 2: Same as method 1 except instead of gluing the sides together with brown paper between I would glue the knife in before turning and place a large cork over the sharp edge during turning.
At the moment I am leaning towards method 1 but I am sure there are multiple ways to do this. Please let me know if you have any advice. Also I have not completely decided whether or not to place a brass ferrule on the end. It doesn’t seem like it would be completely necessary for this application. Any advice on that aspect would also be appreciated.
Thanks,
Phil
Replies
How about method 3?
Glue the wood around the blade, and instead of a cork make a 'scabbard' the same way as the handle with a slightly looser fit, unglued to the blade of course, and turn as a whole between centers. When your done, your marking knife is protected when you put it away or need to take it somewhere. You can make up a prototype of wood scraps (substituting wood shaped like the blade for the Hock), to work out the details and refine the design.
I like method three... I like to turn the pieces before I do the blade fitting. I split the scabbard part with a knife, mark the profile of the blade and carve it out. The handle I predrill for the tang and then seat hot, melting it into the resins of the wood. You could do it the same way as the scabbard and just epoxy it in also. If carefully fitted I find the scabbards will stay in place even when carried in my pocket for months and years. Be really careful of interior squeeze out when you glue up the scabbard sections... keep the glue applications very thin and applied to both sides. Then clamp tightly. Do several test fits on the scabbard carving and keep the fit extra tight as the glue line and burnishing from wear will loosen it just a little. Sounds a lot harder than it is... try it!
agomega,
I used method one on Thursday...kinda. I recycled a portion of a planer blade into a turned handle. The resawing went fine as did the brown paper glue up and the turning on the lathe. It was a pain getting a good grip on the turned handle to remove the brown paper so I could re-glue. Also, I chopped out space for the blade after I removed the brown paper.
After reading this thread I may go down to the shop and do it again. I'd try to glue once and cover the exposed blade during the turning. I suppose that would eliminate the possibility of a ferrel..
Phil
The method for constructing a marking knife really depends on the tools you have available, and what the knife will be used for. A knife to score lines deeply, or used to cut like a chisel will be very substantial and quite different in construction from a knife used to mark inside dovetails. The latter will use a much thinner blade. Where the former may be held in a palmar grasp, the latter could be held like a pencil.
Here is a tutorial on building a marking knife for dovetails.
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First of all, I have a very basic lathe.
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The piece at the end is removed later and shaped it by hand. The woodis Jarrah.
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The ferrule and blades are purchased as follows. I can get two knife blades from each jigsaw blade. The end cost of a knife blade is about $2. The ferrule probably ends up about 50c each. These costs are what one might expect for making a run of 10. If one were to do this on a large scale, it would be better to source the raw material elsewhere than Bunnings!!
The teeth of the blades are ground off on my belt sander, the faces are flattened and smoothed, then polished on waterstones. Emphasis is given to keeping the back area under the bevel flat. The bevels are ground on the belt sander, then honed by hand .
To install the blade, a kerf is cut, first with a thin Japanese saw, then widened on my LN dovetail saw (for which the marking knife is designed - same width blades). The body is drilled for the tang. The pieces are pushed together (usually a tight fit), then epoxied.
A few measurements: the ferrule and the tang are each 5/8" deep. This should be plenty support for the blade. The blade is 1 1/4" long (above the ferrule) and about 1/4" wide. The body of the knife is 6" long.
Regards from Perth
Derek
Edited 8/20/2006 7:48 am ET by derekcohen
Derek,
Your tutorial was very interesting and I like that method a lot. I have also seen other methods which are very similar. The problem that I have is that the hock blade is shaped very differently from one of the homemade tang type blades. The hock blade is 7 inches long and 1/4 inch thick all the way back. I guess I could reshape it similarly to the knife in the picture, but I wasn't sure if it was supposed to go into the handle as a whole piece.
I guess another option could be to glue it between two knife scales and hand shape the handle. I am basically just looking for different ideas on how to handle the hock blade specifically. I plan to purchase some annealed O1 steel and a propane torch and hand shape and temper some blades myself to try out a few of the other methods that I have seen which are similar to the method in your tutorial.
Thanks,
Phil
The hock blade is 7 inches long and 1/4 inch thick all the way back.
Oops Phil - I was thinking that it might be 1/4" wide!
Regards from Perth
Derek
Sorry, I meant 1/4 inch wide. It was too early in the morning when I wrote my earlier message. The blade is only 1/16" thick.
Phil
Sorry, I meant 1/4 inch wide. It was too early in the morning when I wrote my earlier message. The blade is only 1/16" thick.
Phil
That is about the same as the blade I make for the marking knife I have shown you. I made the one below today for a friend. The wood is Sheoak.
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Regards from Perth
Derek
That's a pretty cool tutorial, Derek. Thanks. I'm going to have to make one (or two!) of those, despite already having a marking knife or two.
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