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Yonico 12" radius router bit test


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A few years ago, someone made a router bit to put the radius on a fretboard. It was WAY out of my price range, so I didn't bother looking into it. Last year, I found another company on Amazon that makes one: Yonico.  I'm confident that it's Chinese, but I can't confirm it. It's been in my list for quite some time, but I had no readon to get it as I haven't been making anything for a while. Then the price dropped from $25 to $12.50. Well, that's that!



So there I was this morning, out in the garage, making a router table jig/sled. I was going to make it a box, but I didn't have enough screws. I was quite proud of myself for changing directions into this....



Then I started messing with it and remembered why it HAS to be a box. 





I scrounged some more screws and now we have a box. A little time wasted, but life goes on.

I took down and sorted through my pile of fretboard blanks and picked out a couple I was willing to sacrifice in the name of SCIENCE. I wanted to see 1) how well it worked, and 2) can I slot the board first. I decided on these two boards for 2 reasons. 1) I don't trust a glued board to take the potential stress of a truss rod adjustment, and 2) if the slotted board splinters, zebra is about as splintery as it gets, so it it doesn't splinter, we're good to go with just anything.

Also, here's my feet. We can't go through a whole build (or whatever) without seeing my feet. It's just some sort of law of the universe. Best not to fight it.



First off, let's test with some scrap, just to get the feel of it. I have some leftover test pieces from a cedar chest I made this past Winter. That'll do!




Ya gotta stick it to the sled with double sided tape. A slow pass through the table and here we are...



I only did one side of it, just to get the feel. It seems to have done it well enough. Let's try it with the maple/walnut board.

Reading up on it, you should use a fence with it. The bearing is only supposed to be useful on the 1st pass. When you flip it over, the bearing will be riding along the part that already has the radius routed away, thus making it unevenly routed. THIS is why the sled HAS to be a box. Once you center the board on the face, you can flup it over and rout the other side of the board without moving anything.  Being kind of a cheapskate and never having bought a proper fence for my table, a 4x4 and clamps make an excellent substitute.



The first thing I discovered is that you're likely to get a little chip out on the end as it enters the bit, so leave a little length on the board, just in case it damages the end beyond reason.



One pass later and here we are. I'm not sure if you can see it in the pic, but there's daylight between the bit and the board with the sled firmly against the fence. This is why you're supposed to use the fence, as I already described.



Making a pass on the other side and this is what I ended up with...



There are parts the bit never touched, and the second edge is thicker than the first. I had set the bit so that the highest point of the cutting edge was along the center line I put onto the sled. Well, seeing as this is all experimental test pieces, I ran it again on the 2nd side without the fence. This put the bearing against part that already had material removed, making the 2nd side deeper.... but the 2nd side was thicker with the fence, so what the hell.



It turned out OK. 

Now, it's ENTIRELY possible that setting the bit a tough higher MIGHT have had a different outcome. What I DO know is that doing it without the fence left the board pretty close to even.

So does it route it perfect? Of course not!, However, I am satisfied that if you spend a few minutes with a proper radius block, it'd be perfect. So the bit will save anyone a HUGE load of time & labor by doing all the hard work for you. You'll just have to add the finishing touches. Technology yet again makes out lives easier.

On to the slotted zebrawoodboard!

That one didn't turn out as well.....





Clearly, that didn't go quite as well as the unslotted (mostly) maple board. The 1st pass wasn't bad, but the 2nd was a disaster. Could it be grain orientation? could it be that zebra is chippy? The only other slotted boards I have are an ebony one and a jatoba. Jatoba is significantly harder than zebra,... and damn near anything else you'll come across, and I'm willing to sacrifice it to find out, so let's go!




The jatoba DID have a little bit of chipping, but it didn't tear out in the fretboard area as the zebra did so badly. At this point, I believe the chipout is due to the fret slots. One more experiment will tell the tale.....  An unslotted black palm board. It's pretty splintery, as it's a grass, not wood. If IT chips out, it's from the wood. If it doesn't chip out, the the chips are being induced by the bit catching on the edges of the slots, just like it did when the maple board entered the bit.







So the conclusion is:

1) The bit works just fine, especially considering it's price.

2) You'll need a sled to feed it into the bit.

3) You are best advised to slot the board after it has been routed.

4) You want a little extra length to account for end chipout.


I hope this helps!

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I can confirm... yonico is def chinese.  that said... they are really great bits... been using them for a while.  You wouldn't expect them to last like whiteside and they don't... but when they are new they sure cut like whiteside.  I would wager they last longer than the bosch or other "mid grade" bits.  

cool thread and a lot of detail there... I do mine by cnc now but had considered this route a while back... I'm guessing this will be a very useful thread for many.  cudos.

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