Couple Questions on gouges and grinds...

[Corey Hallagan]

The other day while making my first little turning I had a problem with the spindle gouge catching as I mentioned in my post with the photo. I think this was a result of several things but I was sharpening my roughing gouge and parting tool and got my gouges out.

You know I bought a set of spindle gouges in 1/4, 3/8, 1/2 and 3/4 sizes. Actually I have 2 of the 3/8 gouges just alike. These are from PSI. Anyway, besides the probem with the endgrain, I really had a problem with these 2 gouges now that I think back to get them to cut anything on the spidle part of the project in turning the profile. I just couldn't get those gouges to do anything, so I grabbed my 1/2 and it worked just fine. Also have a sweet little 1/4 spindle gouge that worked beautifully down in those tight coves etc.

So I was comparing these and I find that the angle on the 2 I couldn't get to cut anything was very stubby where the 1/2 and 1/4 angles were much much longer. The stubby ones also have the wings stick right up there where the other two have the wings ground back not sticking up.

When I got this set none of them were very sharp. I sharpened them all with a couple very light passes and put a sharp edge on them but didn't alter the factory grind which I was happy to have achieve that level where before I trashed them with a heavy hand and thru my originals away.

So, am I right do these 2 gouges need to be ground to match the profile on the others that I really like and they work good for me?

Thanks all,
Corey

[Ken Fitzgerald]

Corey..... My spindle gouge 3/8" IIRC........has a finger nail grind to it. I'm not sure what the angle of the bevel is but I could measure it. With the fingernail grind, the sides of the bevel at the flute flair back towards the handle a little. I can go check one of the books I have and check the actual angle on the gouge itself.

I know this....my bowl gouge had the original factory grind on it ...it's a Robert Larson 3/8".....It's bevel and shape looked more like the grind on a roughing gouge. I touched it up and found I was getting a lot of catches when I was practicing on some pine. So....I broke out the book...watched the Oneway Wolverine videos...spent some time until I got an Irish/Ellsworth/side grind on it. There was no comparison to the way it cut then. I think in both cases, having the "corners" of the flute ground back away from the frontal working portion of the gouge made the gouges catch less and cut better.....Remember this is coming from a newbie.....but an analytical newbie......

If you'd like I can measure the angle of the bevel on my spindle gouge and I can tell you what angle the authors of the 2 books I have recommend for the bevel on a spindle gouge.

Good luck Corey!

[Corey Hallagan]

Thanks Ken, that would be great. I guess I can measure fairly closely ( don't have a bevel guage) on the ones I like how they cut too!

corey

[Jeff Farris]

While I am a whole-hearted proponent of side grinds and fingernail grinds, in following this forum for several weeks it sure seems to me that you guys are trying to solve all your problems with a grind, when it reads like many of the problems are tool presentation.

If you can't control a straight ground gouge, you will be hard-pressed to control a side ground gouge.

Just to make sure that some fundamental ground has been covered, let's examine what might -- I said might -- be going on in Corey's problem -- and some from other recent threads.

The gouge needs to be presented to the wood in three steps each and every time a cut is made. First, set the tool on the tool rest, then place the back of the bevel on the stock, and finally raise the angle of the tool slowly until it starts to cut. At that point the bevel is rubbing and you have control of what is being cut. If you just drop the gouge on the tool rest and stick it in, you are scraping, not cutting and you have almost no control, lots of catches and ragged torn surfaces -- even if the edge is razor sharp.

Catches and tears usually come from one of a couple of mistakes. In Corey's case with the gouges with the sharp corners, my guess is that he was not riding the bevel and he got the corner of the gouge close enough to the stock to get caught. That happens often when cutting coves and trying to work "uphill". In cutting a cove, work from the large diameter on one side down to the middle, then make a cut from the other side of the cove at the large diameter down to the middle. That way you are always working downhill and never uphill.

Corey asked about bevel angle and shape. Theoretically (and practically) you can get a reasonably good surface finish on your stock with any bevel angle from 30ish to 70ish as long as you keep the bevel rubbing. Any grind shape (side grind or straight grind) will work if you keep the corners out of the cut. Longer (30ish) bevels give you a larger bearing surface, and therefore are a bit easier to control. I have my spindle gouges ground at between 30 and 35 degrees. The milled gouges (cut from round bar stock) have fingernail grinds and the forged gouges (hammered from flat stock) are ground with a relatively straight across grind. My roughing gouges have a straight grind with about a 65 degree bevel angle, to hold up to the impact of high speed stock removal of square corners. My bowl gouges are ground at between 45 and 60 degrees, with my favorite being a Robert Sorby 1/2 inch bowl gouge with a 55 degree bevel and about 5/8 inch back grind.

Now, at the end of this post, I want to talk a little about the fourth paragraph and how it relates to sharpening. The mantra of "tool on the tool rest, heel of the bevel on the wood, and raise the angle 'til it cuts" is how Nick Cook and Rude Osolnik taught me to turn. Often where I see folks stray from the path is when an edge is less than optimal. They will try to follow the rule, but when the bevel is rubbing, the cut ain't happenin'. That is because the edge is not sharp OR the edge might be sharp, but the bevel has too many facets too close to the edge and the bevel that is rubbing is not the one that the "edge" is attached to. So most folks, without thinking about the fact that the edge might be gone (or mis-shaped) continue to raise the angle until something starts coming off the stock. Well, at some point, if you keep increasing the angle SOMETHING is going to start coming off. But if that happens past the point where the bevel is rubbing, you are scraping (or beating) the wood off -- not cutting.

If you raise the angle and the stuff that comes off the stock is a shaving, then your edge is sharp, the geometry is correct and the bevel is rubbing. If you raise the angle to the point where you think the bevel should be rubbing, but you don't get anything coming off and you bring the angle a little higher and start getting dust instead of shavings, stop, turn off the lathe and walk to your grinder (hopefully a TORMEK grinder -- shameless plug over ) -- something is wrong. Either the geometry is off or the tool is dull. Once you have some serious hours at the lathe under your belt, the first will be unlikely -- you'll know the geometry by then. Trying to push things too far and get a few more minutes from a dull tool is a rookie mistake that you will eventually learn to avoid, too.

Hopefully Corey and everyone else can benefit from my ramblings. I just think that the direction a lot of discussions take leads us away from fundamentals, when that is where most of the problems can be solved.

Oh, one last point (I promise). Maybe as a result of learning to turn while demonstrating tools, I had a valuable opportunity that a lot of folks seem to miss. Please, please, please don't try to learn to turn with a "project" in mind. Mount some stock and turn it into shavings -- all of it -- down to a toothpick. Then do it again, and again, and again. Don't worry about what you turn, worry about HOW you turn. Be proud of your shavings, not your turnings. After hours and hours (and a half a cord of firewood ) you can start thinking about project oriented turning.

[Ken Fitzgerald]

Corey............I measured my spindle gouge and it measures at about 35 degrees. Keith Rowley in his book Woodturning - A Foundation Course suggests a 35 degree bevel. Good luck Corey!

[Corey Hallagan]

Thanks Ken, I appreciate it.

Jeff, thanks for your comments. I understand what you are saying, however I know the tool was sharp, it was very sharp, but I could not get the darn thing ( neither of them) to cut on the spindle, that is what concerns me. I am pretty decent making beads and coves on spindles etc. and making the spindle gouge do what I want, but I just could not get these two to cut. Ther bevel does not have multiple bevels. Maybe I need to give them another try before I mess with them and be sure that the bevel is rubbing etc. My 1/4, 1/2 spindle gouges make nice cuts very easily.. rub bevel, raise heel and cut. thanks for the help, I will pay more attention to what is going on with it. I am not a fan of regriding everything that is for sure.

Corey