Help using Bubble Jig.

G

Gaelic Blades

Joined
Jan 27, 2016
Messages
8
Started making my first few knives and I'm using a Bubble Jig. My bevels keeping coming out like this. The bevel on one side of the blade is higher than the other. I've been trying to keep the same pressure on both sides and obviously doing the same angle. Could this be my grinder? Any help is greatly appreciated.



 
It looks to me like you're putting more pressure on your left thumb and index finger while you're holding the tang with your right hand.
 
You are the "grinder"

It is not the machine, it is how you are applying the pressure and the position when you grind.

Chem blue that blade, scribe where you want the grind height, then start at the edge and work the grind up to the line. That way you will know where you are at on both sides.

Also use a tool rest to rest your pressure hand on to give you some stability.
 
If you have not scribed a center line it's possibly you are going over center on one side. If you are centered then make sure when you set your angle of the bubble that it is set off the platen not off the table, as the platen may not be perfectly plum. Aside from that the device is pretty simple and I have not had issues with mine. The other thing is to watch that the bubble block is aligned properly on the clamp. If it's crooked when you stick it on the angle is not the same
 
My grinder tends to vibrate a bit when I first make contact which sends the bubble all over the place but it clears up after. I've fought with the grinder and vibrations since I put it together. I just figured a little vibration is going to happen no matter what I do.
 
There are many small variables. You will find its always on one side. Just increase pressure along the spine, let the bubble drift up against the black line.

The way the clamp grips the steel and how even in thickness across the blade.

You will find after a few more blades this will even out. Get in the habit of holding the clamp up to the light and sight thru the clamp ends and down along the edge with your naked eye, it will help you with keeping the grind even.


Fred
 
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