Knife Making:

M knife is here:

New line of CPM-3V violin knives is here!

See below.Violin makers need sharp tools. The highest quality blades are required.  For an introduction to blade making, Navaching is  good place to start. David Tseng, a violin maker in Winnepeg, has been making blades out of A2 steel. He leaves them untempered. You can investigate A2 steel at Crucible Steel. The temperature before quenching is 950 C. This is a bright yellow heat. I water quench.  Also, the steel should be wrapped with stainless steel foil to keep out oxygen and other gases. A supplier I have used with success is Flatground.com and amtektool.com.

Oct. 23, 2009

A2 steel blade, 1/16" x 1/2" x 6 inches was placed in Stainless foil and heated to 970 C for 5 minutes in kiln. It was then air cooled with air blast from a vacuum cleaner. Resultant knife seems very sharp. I would liked to have done 30 minutes of "soaking" at 970C, but it did not work out. I wonder if soaking is necessary.

June 7, 2011

Comment by Steve Davis on the hard O-1 knife I made for him:
"Oh yeah, the knife! Have only run it over a several thousand grit ceramic stone maybe 4 or 5 times since you sent it to me. Couple of light passes. And that after carving a couple of necks. Yesterday evening I was using it to shape a replacement corner. No chipping or tear-out. Nice continuous super thin clean shavings." Steve
p.s. the corner was baked to match the wood color, so should have been extra crumbly. Nice knife!

August 26, 2011

My new line of violin knives will be available soon. Introductory price is $20.00!  These knives are of CPM-3V steel. Steve Elliott has tested this steel and found it to be superior to A2 cryo blades in toughness and durability.  His results can be found here. Thanks Streve!  My own tests agree with Steve's.  I tested M2, A2 cryo, O-1, "gold blades," and Swedish steel blades. Here is Steve's chart:

Sept. 21, 2011

The knives are now available. I have only 27 left (Sept. 22, 2011). Place your order by sending an email to me, please.

email: jpschmidt44@gmail.com

October 5, 2011

Sharpening notes for CPM-3V violin maker knives: Since I don't have one of the sharpening machines, I use a large 12 mm thick glass plate. Sharpening angle is 30 degrees. I use Silicon Carbide wet/dry automotive finishing paper to start.

This gives an edge that will cut through 40wt rayon thread with 50 gram weight attached.

October 7, 2011

And now I have an important discovery. I can use the following procedure:

Furthermore, if you can place the blade in the jig in the exact same way each time, you can hold the strop angle constant. There will be no "round-over" and you can get many stroppings before going back to the 3 micron diamond paste. Repeat, theoretically MANY STROPPINGS, like maybe 20.

October 12, 2011

Stropping with the 0.5 micron diamond paste on mylar gives an edge that will easily cut through the thread at 50 grams. Under the microscope this edge, at 200 power, looks like this:CPM3V_05micronpaste200xThe edge is clearly visible, and obviously not perfectly sharp. I want to be able to SEE the difference between this edge, and the duller one, obtained by 0.5 micron paste on cast iron.

Next is a 60x view of a well-stropped edge, sharp at the 50 gram level. Marks are numerous, but the edge cuts very well.

60xwell_stropped

 

Nov. 2, 2011

Testing of O1 process:

November 12, 2011

Mason Freeman liked my O-1 knife:

"John, The knives arrived and I had a chance to use the 1/2" blade and I love it! I reground it with a curve towards the tip and it works great for fitting bridge feet. Do you have any plans to make a 1/4" blade? I would definitely be interested in picking up 1 or 2 in that size if you ever decide to make that size."

Bill Yacey liked my CPM-3V knife:

"Hi John, I had an opportunity to give your knife a good workout, and I am really pleased with it. I was shaping the heel of the neck I've been working on, and it holds an edge really well; the maple cuts like butter. I wonder if you could make a couple more for me, specifically for purfling. I'm thinking they should be single bevel, one left and one right hand. They should probably be also be made from narrower stock, perhaps 3/8 inch wide, rather than the 5/8 like the one I have now."

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