New turner/with a question

[alex carey]

My buddy came over and did some turning today, the wood is from a pear tree his dad cut down a few weeks back. Or at least I think its pear. Didn't finish it today, just roughed it out. I do all of the finishing cuts and he does most of the shaping and hollowing. Hes still in beginner mode but learning quickly

I'm having trouble teaching him how to properly hollow a bowl, I am trying to teach him to do long cuts all the way from the outside to the center, ya know, just one continuous motion for a clean cut, but he seems to prefer using a round nose and hollowing that way? Generally I will guide the back of the tool while he uses the gouge, any pointers on teaching? Hes definitely better then he used to be, I think perhaps teaching him how to sharpen will give him an idea of how to use the edge of a tool? He was definitely starting to get the ideas down as you can see. Thoughts?

[alex carey]

more pictures

[Jeff Nicol]

Alex, The first thing I see is that the tool rest is a little high, as in one of the pictures he is actually using the tool with it over and down into the bowl to make the cut. This is not a good thing as a catch could be nasty! I think there are any number of ways to get the inside of the bowl out, and it is really what the turner is comfortable with. Most of the time I will make a small cone in the center close to a depth that I want and then cut to that depth with progressive cuts toward the rim, as I most always turn the green wood thicker to allow for drying and warping to be returned later. If I am going to finish the bowl then I will cut the cone in the center then make cuts so that I will end up with an inch or so down from the rim to the center. This way there is plenty of wood to support the bowl as you do the finishing cuts to the thickness you want the walls of the bowl. Then work your way down the side of the bowl cutting from outside wall to the center blending the finished cuts at the wall for your final thickness. This way there is always enough mass to cut into and when you are working in the bottom of the bowl you have less leverage against the chuck or faceplate. I believe that Stuart Batty and Mike Mahoney do a video of them showing both basic ways I just described, so that would be a great teaching tool for you and anyone you know who is interested in turning on the lathe.

Good luck and it is great to have friends who show interest in your hobbie!

Jeff

[Harlan Coverdale]

Good on you for teaching your buddy, but I'd encourage him (and anyone else) to wear face protection all the time, not just when the bark is flying. I'm guessing he hasn't been hit. Yet. You're actually more likely to blow one up when you're doing the finishing cuts at higher speed than low speed roughing cuts. As I think you can recall, getting hit can really mess up your day.

That's some pretty wood he brought over, though. I hope the bowl finishes out nicely.

[Steve Schlumpf]

Alex - teaching is a little harder than it looks...... and you find you have to think through everything that you know in order to be able to explain it so someone else can understand. Good experience for you!

I agree with Jeff - the tool rest is to high. Also, judging by all the ridges inside the bowl, your student is not rubbing the bevel and mostly using the nose of the gouge. Course, using the nose of the gouge with a high tool rest is almost going to guarantee catches! Another thing that leads to ridges is pushing the tool through the wood and not allowing the tool time to cut. Once you have the bevel rubbing and a slight forward pressure - you should have continuous ribbons coming off the gouge and a smooth surface to prove that you are doing everything right.

Everyone turns a bowl a little differently. I personally like the method that Bill Grumbine uses in his DVD 'Turned Bowls Made Easy'. If you have the DVD - it explains everything.

Have fun teaching - it can be a very rewarding experience!

[Jake Helmboldt]

Alex, others have pointed out the obvious (tool rest, bevel rubbing). I think the key to teaching anything, whether differential equations or turning a bowl, is to facilitate the "student" understanding what is taking place.

I think if you can show him the mechanics of the bowl gouge and how the cutting edge, wings, nose/bevel, angle of attack, etc all come together to make the tool work he will grasp what he needs to do with it (along with understanding how it doesn't work, i.e. catches or results in discontinuous cuts by using only the nose).

For the record I never did fully grasp differentials because the female Woody Allen I had for a professor couldn't articulate what was happening, only the "steps" to solving the equation.

[Bernie Weishapl]

I agree with the rest. I think Bill Grumbines and Mike Mahoney's DVD's would answer a lot of his questions. I also agree with Harlan that a face shield is in order. About the first time he gets a broken nose or stitches it will definitely get his attention.

[Michael Mills]

Hi Alex,
I am only at the stage of budding amateur myself but..
Stance – for a good demonstration watch Richard Raffans Wood Turning dvd
Pic 1 – Straddling the lathe, I assume one foot is not even on the floor, a pull cut will be a lot slower but I think a lot safer in this case.
Pic 3 – Can he shift his weight from foot to foot? Looks like he would have to lean forward and back instead of side to side but it may just be the picture.
I agree wholeheartedly with a good face shield. You are not using this speed (I hope) for roughing out but the following does show the potential for a mishap. However the blank being turned does appear to be quite a bit larger than 10 iches.
Assume a 10" diameter bowl at 1,000 rpm
What is the speed of the outside?
10 X 3.14 (pi) = 31.4 inches circumference
31.4 X 1,000 rpm = 31,400 IPM (Inches per minute)
31,400 X 60 minutes = 1,884,000 IPH (Inches per hour)
1,884,000 / 12 = 157,000 FPH (Feet per hour)
157,000 / 5280 = 29.73 MPH
Finishing at 3,000 rpm?..about 90 mph.
For a 14" bowl increase 40%, or about 125mph.

Mike

[alex carey]

We only roughed it out yesterday and its still connected to the faceplate, for the initial roughing out I had him wear face protection but once it was round I let him take the facemask off. I wasn't too concerned because we were only turning around 4-500 and we never went thin with it, we kept it about an 1 inch thick.

I agree the tool rest is a too low and I take blame for that, if I had been turning it would have been higher, I foolishly was trying to read my logic book and at the same time teach. I probably wasn't as involved as I should have been. I more pointed him in the right direction in the beginning and then every now and then interjected when my book was getting covered with dust and not ribbons.

The reason there is one picture with the tool so low is because he was having a lot of trouble with the center of the bowl.

I agree with you Jake, teaching him what is happening is probably a good idea.