Making a Graf Blade

April 8, 2010

A couple months ago I pulled my graf machine and went to sharpen it. I quickly snagged it on the sandpaper, tearing out a huge chunk of the center of the curve, rendering useless. When I took it to David’s shop to sharpen it, I promptly found that it was too small to sharpen again, to which David responded, “Guess it’s time to make a new one!” So I learned how to make Graf machine blades. The gist of it is:

1. Buy a piece of soft steel stock at the hardware store. I can’t remember the exact measurements of the piece of steel but if anyone really wants to know, I’ll look it up. (a trip to McFadden Dale hardware store)
2. Cut it into two inch pieces. (2 mins)
3. Bolt the piece of steel into a vice or clamp. Use a drill press with a 1/8 mill cutter to cut out the approximate shape of the top slot (7 mins)
4. Use a 3/16 bit drill to drill a hole in the middle of the piece and then use the same size mill cutter to lengthen the slot (5 mins)
5. Use metal files to get both slots the correct shape (15 mins and a blister on your right index finger)
6. Take the piece of steel to a grinding stone to start giving it a rough curve. The main purpose is just to get steel off so you don’t spend hours grinding it by hand. Dunk in water periodically to keep the piece of steel cool so it doesn’t burn your hands. (5 mins)
7. Sand both sides down a lot with 300 then 600 grit sand paper, then move to jewelers 3G and 4G sand paper. Sand at least one side so that it no longer has a single scratch in the surface (which can eventually become a flaw in the burr/curve if you leave it in there long enough), and has a nice shiny mirror finish. (15 mins, and a painful elbow)
8. Test to make sure everything fits into your graf machine, because the next step is the point of no return. (once the blade is hardened, it’s super tough to sand/file more metal off of it. (2 minutes)
9. Buy several containers of 30 weight motor oil and put in a resealable bucket or jar. Light a blowtorch with M.A.P.P. gas. Using a coat hanger, dangle the rough blade on the end of the coat hanger for at least five minutes (the back side facing toward the blade) until it becomes molten red hot. Then dunk in the oil and let cool for five minutes. (11 minutes)
10. Sand all of the carbon off of the new hardened blade. Repeat steps 7 and 8 if desired, holding the blade in the flame for a longer period.
11. Grind the blade to match your guide and your machine now! (countless hours of frustration, a very finite amount of hair being pulled out, and a pot of gold at the end of the rainbow… somewhere…)

My first batch was 8 blades and a few of them turned out okay, a few were junk and a few were mediocre at best. The hardest part was just getting the measurements exactly right, such as the piece of metal between the two slots, the length of the middle slot, etc. The second batch of 6 went really well, and David took 5 and I kept 1 for my machine. The deal was that David would show me how to make the blades and let me use his tools, but I would have to make him a few blades.

My first Graf blade, pre-hardened

So the lesson learned was that making a graf machine blade was NOT fun, hurts your elbow and back and everything in between, and it’s best to find someone else to do it for you!


2 Responses to “Making a Graf Blade”

  1. I wish I had seen this blog before. By the look of your blade (identical to mine), my old klunker might be a Graf. does it have 4 bolts and 4 allan screws under and a double-wedge for the thickness adjustment? Is it a real pain to recalibrate (say, if you accidently dropped it on the floor)?

    I understand and support your reasons for not making reeds commercially anymore: very unforgiving, oboe reeds and people. What specific area of doctoral studies? Best of luck: I’m sure you won’t need it!

    • cooperwrightreeds said

      Hi Robyn,
      Sorry I didn’t see your note sooner. No allan screws, although they could have been added later. Yeah, Grafs certainly are a pain to fix. I just pulled my blade a month or so ago and am just getting it back in form.

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