Is a flat platen or a disc better to sand the ricasso and flats above the hollow ?

[LARRYZ10]

I know some knife makers sand out the ricasso and flats above the bevel with a disc instead of a flat platen after heat treat for a high polish finish and then finish the hollow grind on the wheel up to and including 2000 grit. I have been using a platen after heat treat first and then take the scale off and finish and thin the edge of the hollow with a wheel and several belts. If the disc gives a better finish then how do you hold the blade perfectly parallel to the disc. Also, do you change the sandpaper grits on the disc four or five times for one blade? Am I missing something? Some of the disc users get a beautiful high polish on their knives with crisp edges that I admire. Any opinions from you guys who do the high polish finish from time to time? Larry Lehman

 

[AVigil]

Have you tried using belt grease on the disc to finish the ricasso?

 

[A C Richards]

Disc will give you a much better FLAT surface on your ricasso. As for how, put it against the disc and hold it precisely how you expect it. Not trying to be flippant here it just takes practice. Once you get good you can keep it within .001. Now I take mine to 400 grit on the grinder and then finish by hand. Yes you change paper often on the disc using feathering disc adhesive. I use a torch to remove the disc, just warm up the paper a bit and it peels off cleanly.

 

[LARRYZ10]

AVigil, I have to confess that I do not know what belt grease is . Do you use it on your disc to keep it from grabbing. And also for the guys that do use a disc do they slow the disc way down to start the sanding of the ricasso. I would just hate to sand the thing so that one edge is thinner than the other. I will give it a try. I use a disc with 320 grit to flatten my bolsters for a tight fit but it is easy to start them against he disc before turning it on. Thanks, Larrfy

 

[LARRYZ10]

Chuck, I have been using 3m spray adhesive and just peeling the paper off and cleaning with acetone. Is the "feathering" adhesive a better product and where do I find it to give it a try? Thanks, Larry Lehman

 

[AVigil]

AVigil, I have to confess that I do not know what belt grease is .

Here it is http://www.formaxmfg.com/coated-abrasive-grease-sticks

You apply it to the belt or disc. It helps the disc from loading up and gives a nice finish

 

[kc custom]

Feathering disc adhesive,- get your ricasso fairly flat do your hollow grinds and after
you have the hollows cleaned up do your final on the ricasso. This is really going to
tell you where your grinds and plunges need work. Assuming you are using a disc on
the flats.
Ken.

 

[silver_pilate]

For that last bit where things are getting really clean, place the work on the disc before you turn it on. Unfortunately, my setup doesn't make this easy, but I've used a helper to throw the switch for me, and I've considered adding a foot switch to get the job done on my own. I also have my disc motor on a hinged mount that allows me to position it on end with the disc horizontal or on it's side with the disc vertical. I have an easier time working on bevels with the disc vertical, and I typically work on flats with the disc horizontal.

--nathan