Fret Tang Grinding Machine

[chinjazz]

Another update on this machine:

Because of the problems I showed above with the pink wheel wearing down quickly, I bought it a higher quality grinding wheel. This is a Norton MVBE series aluminum oxide grinding wheel, 3" dia x 1" wide, 60 grit, right out of McMasters catalog. It cost $12 whereas the pink wheel was $3.

I had to quickly machine up an adapter sleeve for it, got it mounted, and tested it out.

View attachment 4256789

So far, so good. It took about 2 seconds to grind off the tang of my usual stainless fretwire.

View attachment 4256790

Looks great Bruce!

 

[Bruce Johnson]

I wonder how a diamond coated drum would work for such a task?

In most cases diamond coated tools aren't supposed to be used for cutting steel. They will heat up and shed their diamonds. Diamond tools are intended for abrasive brittle materials like glass, stone, concrete.

 

[byacey]

In most cases diamond coated tools aren't supposed to be used for cutting steel. They will heat up and shed their diamonds. Diamond tools are intended for abrasive brittle materials like glass, stone, concrete.

My dad had some sort of drill bit sharpening tool with a diamond drum that seemed to hold up well. Just a thought.

However, I think my bits still cut better than his, and I still sharpen them by hand on the side of the grinding wheel.

I found your fingerboard slotting templates very interesting in the other thread.

 

[Bruce Johnson]

I did another upgrade to the Fret Tang Grinding Machine.

I was a little disappointed in the stone grinding wheels that I had on the machine before. They were wearing faster than I expected, which was messing with the cutting geometry of grinding the tangs.

So, I decided to take a different direction. I found that McMaster carried fiberglass-reinforced abrasive cutoff wheels in 3" diameter x 1/8" thick, 60 grit. Just the right size to fit this machine. And for only $2.75.

Here's the abrasive disk mounted in place of the white grinding stone. I machined up a new front cap for the arbor from 1" stainless.

And I moved the aluminum swinging arm over to line up the edge with the disk.

With the guard back on, a few quick tests on some stainless fretwire. Jescar 37080, the size I use on all my Scroll Basses.

It worked well. The 60 grit disk definitely ground the tang off quicker than the stone wheel, but the finish wasn't any rougher. And I was still able to feel when the tang was ground down to the underside of the crown.

I think the abrasive cutoff wheel is a good solution for a machine like this. It should last for many years with no real wear. And if it does ever wear down, it's cheap and easy to replace.

I've got a fret job coming up this week, a more complete test.

 

[Bruce Johnson]

I worked on the Fret Tang Grinding Machine some more today, tuning up the geometry and operation. I filed and refitted the little aluminum blocks on the holding arm that the fretwire slides under. And aligned the arm better with the cutoff disk.

I ran a few more test pieces, then ground the tangs on a whole set of frets for a bass that I'm working on.

With the help of my LED shop light, here's a better look at how the fretwire slips through the arm, and how the arm lines up with the cutoff wheel.

I hold the fret like that, seated in the notch and aligned with the edge, while I lift up the arm. The cutoff wheel grinds the tang down until the wheel contacts the ledge on the aluminum arm. I can feel it when it hits the aluminum, and I drop the arm down and pull the fret out. It takes about 2 seconds per fret end, 4 seconds per fret.

And there's the result. The tang is trimmed back 1/8", flush with the underside of the crown.

I can declare this machine Finished and Operational.

 

[Gilmourisgod]

Dang, that’s slick. I’m still rocking a Dremel cutoff wheel and file, low-tech style. Tedious.

 

[rudy4444]

Dang, that’s slick. I’m still rocking a Dremel cutoff wheel and file, low-tech style. Tedious.

You and a bunch more of us!

I thought that there was a topic that had a bunch of different "solutions" to fret tang removal shown. I like the jig setup that was sold by LMI and featured on Robbie O'Brien's Youtube channel, but I've just been too lazy to make one up.

My Dremel jig works acceptably well, but Bruce's machine is pretty tempting!

 

[Gilmourisgod]

My Dremel jig works acceptably well, but Bruce's machine is pretty tempting!

I'm not even doing anything that sophisticated, literally just hogging off the worst of the fret tang at the ends, and then filing the remainder flush. Good enough for my miniscule output, but obviously not too efficient. I don't even build often enough to justify even a set of those fret tang nippers.