Violin Forum/Message Board

DonLeister · Posted: Sat Jun 22, 2013 8:39 am Post subject:

This is my version of Michael's system, his tool rest isn't straight at the wheel, it has a cutout where the tool rest goes up each side of the wheel an inch or two. I think Lee Valley or Veritas used to sell them.
That's pretty much everything, what you see there. Go from the grinder to the Japanese stone, it's really fast and a lot of control.

For scrapers I have a disc sander with a very fine psa disc on it with chrome oxide green compound with a 50 degree fixed rest on it and from that I go to the Japanese stone using a 45 degree wooden block you see in the picture so it only hones the leading edge.

kjb · Super Member Joined: 06 Feb 2013 Posts: 385

good idea cliff, I still am looking to better my gouge sharpening system.

Don nice setup, what is the width and grit of the stone you use?
I think I have the same tool rest
, from an old harbor freight wet stone system!

ctviolin · Posted: Sat Jun 22, 2013 2:04 pm Post subject:

Andres Sender · Posted: Sat Jun 22, 2013 3:13 pm Post subject:

DonLeister · Posted: Sat Jun 22, 2013 10:32 pm Post subject:

I'll have to check the number on the wheel, it cuts fast and wears faster than what I see on run of the mill bench grinders.
I salvaged the tool rest from my old underpowered delta wet grinder. I found the grinder(s) at a flea market/junk store. I think most of them have small arbors so you have to make a bushing to get a wheel on there.

Yup, CT, the grinder works really well as long as you have a decent tool rest.
Credit goes to Mr. Darnton for sharing his set up years ago.

DonLeister · Posted: Tue Jun 25, 2013 9:54 pm Post subject:

Here is what I have on my grinder. I think tihe letter I following the number 120 indicates the friability of the wheel which is important in that the wheel is not super hard and wears away faster than a hard one, but it exposed fresh sharp grit so it cuts quickly and so the tool does not get hot as easily.

kjb · Super Member Joined: 06 Feb 2013 Posts: 385

thanks

John Schmidt

For grinding a 6 mm wide blade with a 20 degree or less point angle, I have found that I can attach the blade to a 5 foot wood stick. A steel post is in the lower end. This post sits in a hole in a plywood board on the floor. With this set-up, I can easily grind this blade. Of course the grind has a tiny arc, radius 5 ft. But this is not a problem. This knife is good for f-hole eyes and possibly bridge work. I use a green 60 grit Zirconia belt on my 1 x 30 belt grinder. If you are light on the pressure, the blade stays cool.

How do the rest of you grind this kind of narrow blade?

I developed my version of a honing jig which works very well. The basic idea is found here

The two circles are NIB magnets. A very short video of its use is here. http://www.youtube.com/watch?v=4zM9bZF1LR8

kjb · Super Member Joined: 06 Feb 2013 Posts: 385

a short video is worth a thousand words thanks

John Schmidt · Posted: Sun Aug 25, 2013 10:56 am Post subject: knife jig update

Update on my sharpening discoveries -- not NEW discoveries for the world, but NEW TO ME:

I have spent more time with the sharpening jig and the 16,000 grit Shapton stone.

---- My sharpening standard on the "thread test" thread test is now 65 grams instead of the previous 75 grams. The thread is 40wt rayon. Steve Elliott changed, and therefore I followed suit.

---- After using the O-1 blade until somewhat dull, I can now re-hone with about 10 strokes on each side. This takes very little time, as required by you violin makers who are well-trained.

----- One does not need a microscope to see the edge. A good 10x loupe will work. But light and geometry are critical. I use a bright craft lamp, sitting on the table in front of me. The room is dimly lit, so that the under the table area, toward the floor, is relatively dark. Hold the loupe close to your eye and look at the edge. When you rotate the knife just right, you can just barely see the bright edge against the dark background.. If you now dull a section and look again, you will clearly see the difference between the sharp and dull section.

What's the advantage of a jig like this?

1. The exactness of the grind is much less critical. In fact, as long as the grind is below a certain angle, like 25 degrees, you can adjust the edge angle as you wish.

2. Less grinding skill is require for newbies to sharpening.

3. This jig really works!!!

BTW, I learned that before each use of the Shapton stone, it should be cleared of residue by wiping it with a 5 micron SiCarbide paper and washing in water.. Or another Shapton or Japanese stone.