Continuing tool sharpening questions...

Dave I use a 6" Delta grinder and it works fine. In the directions that comes with the Wolverine it says to elevate the grinder an inch for 6 inch grinders. Take a look at the following link to see what they mean. There is a picture of a grinder, jig and platform for the jig.

Where are you. I'll give you a deal on mine.

Bob Darrah West Linn, Oregon

Dave

I use a 6" hi speed grinder and actually prefer it over the 8" or other slow speed grinders. I recently replaced my chinese made grinder with an Ebay special Ryobi 6" thinline. I have the Wolverine and like the way the bevels turn out on the 6 - it seems that the 8" grinders do not produce as pronounced a concavity as the 6" on the bevels. The Wolverine jig is the way to go - if only for the ability that it gives you in making the grinding process a simple, predictable and repeatable one. That is the purpose of any jig - to simplify or make consistent.

When grinding, make sure you take a moment to look at the bevel against a stopped wheel (in Profile), adjust the platform or slider so the entire bevel is in contact with the stone. That will produce an unfaceted bevel, which will make your cuts smooth and the tool a pleasure to use.

Ray

I think there's much too much emphasis on bevel "facets" which may well represent less than .001 in surface deviation and yet be visible because of a slightly different grind angle. That's well within the compression distance for even seasoned wood. It's the edge which cuts, and with a skewed cut, even that's an average.

I'm with you George. I used to free-hand and frequently had more than one bevel. I now use a Wolverine for consistency and the grind certainly looks prettier but IMO the multi-bevels were not the cause of any degraded cutting performance. Billh

Dave, I have a 6" Delta from Lowes. It came with one white alum. oxide and one grey wheel (as well as a light and a wheel grinder used to shape the wheels).

For gouge sharpening I use a Sorby fingernail profile jig. This was easily set up and does provide a consistency I have yet to be able to achieve freehand.

-Kevin

Geo

I think that many people have trouble with multifaceted bevels which round over the cutting edge and cause the turner to alter their angle of approach to the wood and makes the cutting edge of the tool efficient in a very small section of the edge. A clean, concave bevel and consistently sharp edge is preferred. So I advocate looking at the profile of the tool against the wheel everytime the tool is dressed.

Ray

Is that pronounced concavity a good thing, Ray? I always understood it was undesirable, but perhaps I was misinformed. The books I have seem to imply that concavity should be minimized.

Max

I think you see more of a problem than actually exists. You're describing a dulled edge, which can be produced equally as well in a smooth-looking grind.

Judge your edge by the work it does.

Apologies. Now that the second cup is down and the adrenalin rush of the first run complete, I realize that you sharpen with a jig. If so, you certainly should visually inspect the grind for consistency of the _edge_. Other than a constant pattern will indicate an incomplete grind and possibly a dull edge.

For those who do not use jigs, it's not really meaningful. The edge is tested with the thumbnail or, as I prefer, the work, then taken back to the wheel if proven inadequate. The angles in a turning are so complex, in my opinion, that even if they vary on the tool in minor degree - for instance, having been altered by honing, they make only an academic difference, the material being imprecise in its own right.

If the cutting pressure is minimal and the shaving smooth-edged, it doesn't matter how you ground or honed the tool.

This is a topic often discussed as well. I'd suggest you take a look at

Max

If you look at the work we do, you will note that most of it is round. so if the bevel is alos rounded - concave- the bevel will sit on the wood better so when the handle is lifted the edge wiil make contact in a more complete manner than if the edge were made up of 1000 facets

Ray

This makes sense.

I went to an 8" grinder to accommodate the larger wheels based upon my interpretation of what I was reading. But many herein use 6" grinders (which I also own) with apparently good results and no problems. Guess it's a non-issue. So why do the instructional books make such a big deal of it? The implication is that if you don't have 8" wheels, or larger, you might as well take up knitting baby blankets in lieu of turning.

Max

This seemed intuitive to me, even after reading the oft-repeated behest to get a grinder with larger wheels in some of the instructional books.

Also see George's explanation and my response. So I rephrase the question: why is such a big deal made about larger-wheel grinders? I've seen the work of many of you herein, and frankly I doubt if bevel concavity plays much of a role pro or con.

Max

Hey, everyone's gotta have an opinion. Some are based on discovery, like math computations or scientific experimentation, some on experience, either personal or vicarious, without attempt at explanation. Some are just the way "Personality X" does things, and s/he's a recognized turner.

Doesn't matter how you get the edge, matters how you employ it.

I think Ray's sort of tweaking you and me with his "round" reply. If you know your geometry, you know that two points define a line. If those two points are the heel of your bevel and its edge, the only thing they can do is slide along that line. To cut below the line, you need to lift the heel. Same for a convex arc, where it would be impossible to cut anything smaller than the radius of the wheel that ground the bevel while maintaining full contact.

Then there's the concave....

Which is why "rubbing the bevel" doesn't mean at right angles to the edge, but along it, where the depth of cut is more or less the same height above chord you calculated, and a gouge with its swept and curved edge can take a shaving which curls with little shear, and twists with more, while referencing on the concave face of the cut.

Bite the bullet and buy yourself a Tormek and a couple of their jigs and forget about how your going to sharpen your chisels. If you don't have the cash go through some of your junk that you don't want and put it on EBay and you'll get enough cash to buy it. That's what I did.

It was most kind of you to include yourself in the above reply, but I was the one who bit. Or perhaps Ray simply limits himself to 6" bowls. :-)

Max

Perhaps I "protesteth too much." I actually get fine, usable edges with my

Max

Well, I imagine some of you good folk will get a laugh out of this, but I get my best results from a 3" wheel in a little bitty 10,000 rpm grinder that also came with a strop and a flex shaft (ala Dremel / Foredom) from an ACO hardware store for about $40. ALL a lathe tool should ever need (unless deliberately changing its form, as I have done to a couple of tools) is a little teeny tiny touch-up of maybe .010" - .020". This is easily handled in one or two passes on my 'toy' grinder.

All the leather strop seems to do is make the bevel shiny while destroying the edge. I use the flex shaft with a cut-off wheel to sharpen my pen mill.

Since I only have one stone and a wire wheel mounted in my 6" grinder, it is pretty much impossible to keep it in balance so I reserve it for rougher jobs such as reshaping or knocking rust / dirt off things.

Keeping the stone nearby and dressed is pretty important. You will get much smoother cuts from a wheel that is balanced on its shaft and not bouncing the tool all over while you are trying to maintain contact. And you will be better able to keep the edge sharp if the grinder is only a step or two away. Mine is on a table directly behind me as I work on the lathe. Being only a single step (literally) away, it's no big deal to turn around as soon as I notice that the edge is dulling a little and just hit the stone a little. Thirty seconds later I'm back to work.

And that's key to being productive and enjoying (safely) working with wood. A person who doesn't want to stop to sharpen a tool because 'it takes too long' will lose far more time and more than a little material while placing himself and all around him at personal risk than someone who says 'my tool is getting dull; I'll pause for a moment to sharpen it' before the thing gets so dull he can't push it into the material hard enough to get it to 'cut'.

Bill