Flat grind on bowl gouge

[Jerry Lear]

Flat grind on bowl gauge
Is there an advantage having a flat grind versus a concave grind on a bowl gouge.Sorby pro edge vs grinding wheel.Need to make a decision to buy a sharpening system

 

[hockenbery]

Hi Jerry,
Some people allege it is so. I don’t.
A micro bevel is for all practical purposes a flat bevel.
So you can get the advantage if it were to exist by adding a micro bevel.
When sharpening just touch up the micro bevel 3-4 times then grind the main bevel to keep the micro bevel short.
There is definitely an advantage to having a short bevel on some cuts
Less bevel drag. Easier to turn a concave

 

[Zach LaPerriere]

Al is right. A microbevel is a huge improvement for most tools. Less bevel drag also makes sense, though I can't say that I noticed.

I have two grinders set up with CBN wheel and a Sorby Pro Edge. The Sorby is AMAZING for removing steel fast. Much faster than a 60 grit CBN, which is about as course as they practically go. But I found that I wasn't using the Sorby much, so I put it back in the box.

One small bonus to a concave edge (even microbevel) is in honing: much less to sharpen. I don't hone very often on gouges but I did notice a difference between the concave and flat bevels.

I also prefer sharpening on a grinder with CBN wheels, but that might just be that I learned on a grinder. Sure seems like the Sorby is huge in England and many people prefer it.

 

[john lucas]

I use a micro bevel on my tools. I believe it reduces catches. A few months ago I sharpened another bowl gouge with just one bevel. I switched tools every cut so I could learn the difference. You can actually hear the difference. The cuts were pretty much the same. Difficult ult to say if there was less criticism ton but based on the sound I would say yes. I do think the micro bevel is less catchy. I sharpen the tool.using a wolverine jig. I sharpen it, then move the jig forward in the Oneway V arm. Grind again so most of the bevel is gone leaving the micro bevel. I also grind off the heel of the bevel so all of my tools.

 

[Zach LaPerriere]

John—You are absolutely correct. A microbevel is MUCH less catchy. I have tried to demonstrate a catch, and with a microbevel it takes some effort! You have to really do something goofy to get a catch with a microbevel. I think it's wise to learn on a full bevel, but not much reason to stay with it. You can grind the secondary with a 60 grit and then the possibilities just open up from there.

The flute-up interior cut that Al mentions frequently is much improved with a microbevel.

Microbevels are the future of turning.

 

[RichColvin]

Flat grind on bowl gauge
Is there an advantage having a flat grind versus a concave grind on a bowl gouge.Sorby pro edge vs grinding wheel.Need to make a decision to buy a sharpening system

Jerry,

I have been using a Tormek for years, and it of course makes a "hollow" grind. The truth of the matter though is that the hollowness of that grind is pretty small. Page 14 of the Tormek manual has this page.

​

CBN wheels on 8" grinders are probably similar.


I have heard from wood carvers that this does matter. But, my humble opinion regarding wood turning tools is that the hollowness of the grind matters far less than the sharpness of the tool.

Kind regards,
Rich

 

[Dave Bunge]

I use a micro bevel on my tools...I do think the micro bevel is less catchy. I sharpen the tool.using a wolverine jig. I sharpen it, then move the jig forward in the Oneway V arm. Grind again so most of the bevel is gone leaving the micro bevel. I also grind off the heel of the bevel so all of my tools.

John, I use micro bevels too, maybe more accurate to say mine are mini bevels, about 1/16" wide.

Rather than moving the Wolverine jig arm forward, I put a small square of 3/4" wood in the V-arm pocket. This moves things forward so you can grind off the steel below the mini bevel. But the V-arm stays put so you don't have to move it back for the next time you sharpen the bevel. Just remove the piece of wood.

You can also use thinner pieces of wood to get more gradual change of the angle next to the bevel.

This is not my idea, but something I read on one of the forums years ago. It's quick and easy and works well for me.

Dave

 

[hockenbery]

John—You are absolutely correct. A microbevel is MUCH less catchy.

You guys are right on that. The micro bevel introduces a slight convex to the bevel edge where the micro bevel ends.
A catch happens when the wood can drive onto the tool.
As the wood begins to drive onto the tool edge the convex will try to turn the edge out of the cut
The concave will try to turn the edge deeper into the cut
The effect is that there is a tiny bit of auto correct with the micro bevel which can prevent some very minor catches from growing out of control. While the concave makes the mistake a tiny bit worse.
Poor tool presentation will still get catches regardless of the grind.

Jimmy Clewes and others use a convex bevel on the skew with beginners.
Johannes Michelson’s grind is convex and all micro bevel - also less catchy the most grinds

 

[John Jordan]

A majority of turners, use a decent grinder, typically with a wolverine/varigrind system, and CBN wheels are becoming common. There's a good reason for this-its hard to beat. Not that the belt setup won't work, but you won't find many folks that would trade. The wood won't care if the bevel is flat or hollow ground, functionally its the same. I've been in hundreds of shops, only seen a few belt setups, and they were typically unused. as there was a grinder as well.

John