bevel burnishing?

[Jeremy Pyatskowit]

I've recently experienced the bevel of my gouge burnishing the bowl when making finish cuts. How do you balance the speed for making clean cuts with not burnishing? Or is the burnishing not a problem.

[Steve Schlumpf]

Jeremy - make sure your gouge is sharp - then take light cuts. The burnishing is caused by the pressure you exert while 'riding' the bevel. Believe it or not - you don't need that much pressure to keep the gouge cutting.

[bob svoboda]

Good advice from Steve. You could also consider grinding a secondary bevel to diminish the area causing the burnishing.

[Roger Chandler]

+1 for the secondary bevel. I grind the heel on my bowl gouges now, and it makes a huge difference! No more bruising rings from the heel!

[Don Geiger]

If you are using a jig to sharpen your gouges, you can grind the heel of the bevel very easily with great repeatability by simply adding a block to your V-notch. I cut a triangular shaped block of wood and faced it with Corian (1-1/4" thick overall). I added two rare earth magnets the the lower facets of the triangle to hold the block down into the V-notch. Place the new V-block into the V pocket of your sharpening system and then place the stem of your sharpening jig in front of the block. This moves the stem forward 1-1/4" and presents the heel of the gouge to the wheel.

I recommend first grinding away 50% of the original bevel. Once you get used to using a narrower primary cutting bevel you can increase the relief bevel even more.

I reserve my double-beveled gouges for use when making the inside finishing cuts on open bowls. I have two double-beveled gouges; one at 70 and another at 85 degrees.


Don Geiger

[Jeff Nicol]

Jeremy, The thing about the term "Rubbing the bevel" should really be called "FLOATING the bevel" because you really don't want the back of the grind to really rub continuosly along the cut. Also the way the tool is sharpened can help with how the tool cuts, for instance if you use a jig most always the contact to the grinding wheel is always the same and a concave area is created between the cutting edge and the heel leaving a space of air. So when you address the wood beginning with the heel or the facet from the grind until you roll the tool to begin the cut the tool is actually rubbing on the wood. But once the cut is picked up the only part that is truely touching the wood is the cutting edge. This is where the secondary bevel comes in handy as the cut and the rubbing are virtually simultaneous thus leaving little or no burnishing. But if you are sharpening by hand what happens to a lot of wood workers is that they tend to just sharpen the cutting edge and do not have a continuous gind from edge to heel which will create facets and high spots that will touch the wood at the same time the edge is cutting in turn leaving the deep burnished marks, so this needs to be checked to make sure the grind is true or the heel is ground with the secondary relief grind. If you are using a belt sander to sharpen the grind is flat and the secondary bevel (Very small) is almost a necessity.

Lots of info but hope it helps you find the best method to keep the burnishing from appearing and using 40 grit paper to remove them!

Have a great day,

Jeff

[Jeremy Pyatskowit]

Thanks for all the great advice, it sounds like the secondary bevel and less pressure is what I need.

[Dick Wilson]

Jeremy,

I presume you are referring to the inside of a bowl because that is where 99% of the burnishing marks appear. In my experience you cannot sand them out unless you spend a lot of time with your 40 grit tool. The only way to get them out is with a gouge. Above Don referred to grinding the heal of the bevel back. The end result is what I learned as a "micro bevel". I have a dedicated bowl gouge with a micro bevel. I very seldom grind to sharpen. I hone it. I use my micro bevel gouge to make the last pass and I am talking about a 1/32" cut. The bevel is only about an 1/8" wide. I get very nice results without burnish marks.

[Nathan Hawkes]

Ditto what Dick said. The gouges that I use for finish cuts have even less of a bevel, just over 1/16". It definitely cuts differently than gouges with a larger bevel, but with practice, the finesse you can achieve with very fine cuts is unmatchable with any larger of a bevel.

[Jeremy Pyatskowit]

You mean I need to tell my wife I need more gouges? :)

[Dick Wilson]

Blame it on me, I have thick skin, besides, she can't reach my throat:D

[David E Keller]

You mean I need to tell my wife I need more gouges? :)

I'd tell your wife that you bought more gouges... Better to ask for forgiveness than permission.

[Nathan Hawkes]

I don't want to get you in trouble! It is easier to ask forgiveness, but grinding back the bevel is very simple. Plus, if you don't like it, or you think you've ground it back too far, all you need to do is sharpen it a couple times and the bevel gets larger each time.