It’s a bit intimidating to me.

[Alan Weinberg]

I’ve turned pieces up to 14 inches. Big difference in 20 inches. Big piece of Norfolk pine. Took bark off with a chisel and mallet, then was able single-handedly to wrestle it onto the lathe, a PM3520. Biggest dimension was just shy of 20 inches but it still wouldn’t turn. Had to trim one side w a chainsaw. Now it turns but I haven’t turned on lathe yet. Trying to mount courage.

 

[Alan Weinberg]

More

 

[Kevin Weir]

Looks like a challenge. Good luck and have fun.

 

[Vincent Vogel]

Stand off to the side where your on/off switch is and start at a very slow rpm and speed it up slowly. When it starts to vibrate a little back off some and start turning. Just take it easy until you get the feel of it. You have a heavy piece of wood there. Once you get it round it will be fine. You probably want to turn from the headstock towards tailstock so you have access to your off button. I've turned pieces that diameter on my old lathe outboard but only 2 1/2" thick. That piece looks to be about 10" thick or so.

 

[Jerry Bennett]

I agree with Vincent except keep the speed really slow and clunk clunk until it gets close to round. That much eccentric weight can be a problem.

 

[Paul M. Kaplowitz]

I have turned literally hundreds of bowls up to 36'' in diameter. Let me offer some suggestions. Your face plate is too small. If you are going to turn a 20'' heavy piece of log I would use an 8'' or better 10'' face plate. The holes in the face plate should be large enough to use 5/16 x 2 1/2 '' lags. I don't have a tailstock on my VB 36 and in 30 years have never had a problem with the blanks mounted this way. See the picture on the left.

 

[Richard Coers]

No difference than small bowls, except time. A good coring system saves a lot of that time. I would have turned between centers to flatten the face so the faceplate laid flat.
Here's a stack of 18" finished diameter bowls. I made 24 of these for one patron.

 

[Alan Weinberg]

Thanks all. I have a second switch to turn off lathe and I turn left handed. Biggest face plate I had, 2 1/2 inch screws. Coming round slowly.

 

[Alan Weinberg]

Lathe turning at 315.

 

[Tim Hunter]

Can you take heavy cuts continuously, or do you have to cut a bit then wait for it to speed up then cut again?

Tim

 

[Alan Weinberg]

Update—lathe slows w heavy cuts. Sharpening often. Up to 400

 

[Alan Weinberg]

Ready to turn around ! It went well.

 

[Michael Anderson]

Looking good Alan!! Love the progress pics. Can’t wait to see more 😃

 

[Alan Weinberg]

Looking good Alan!! Love the progress pics. Can’t wait to see more 😃

Thanks all. Hollow to 2 inches tomorrow. Covered w plastic for the night. I’m tired.

 

[Alan Weinberg]

I have turned literally hundreds of bowls up to 36'' in diameter. Let me offer some suggestions. Your face plate is too small. If you are going to turn a 20'' heavy piece of log I would use an 8'' or better 10'' face plate. The holes in the face plate should be large enough to use 5/16 x 2 1/2 '' lags. I don't have a tailstock on my VB 36 and in 30 years have never had a problem with the blanks mounted this way. See the picture on the left.

You are far more experienced than I. I have only turned for 19 months, 150 bowls. So this was a huge challenge that really taxed me.

 

[David Wyke]

Thanks all. I have a second switch to turn off lathe and I turn left handed. Biggest face plate I had, 2 1/2 inch screws. Coming round slowly.

I turn left handed also. It works great for staying out of the line of fire. Once I get the piece balanced I will switch to right handed for the final cuts. I had to train myself to turn right handed. Looks like you’re making great progress on this bowl!

 

[John K Jordan]

You probably want to turn from the headstock towards tailstock so you have access to your off button.

I see Alan beat me to it. A remote emergency kill switch in a magnetic box can be positioned anywhere on the front of the lathe where it can turn off the lathe with a touch of the upper leg.

I also believe it’s best to learn to turn equally well with either hand.

JKJ

 

[Kent Reisdorph]

Big blanks are a different animal, aren't they (for us relative newbies)? The largest I put on my lathe was an 18" piece of highly unbalanced walnut I roughed out for a twice-turned bowl. I think I spent about an hour on that blank at 250 RPM.

 

[Wyatt Holm]

I have turned a few 20 to 22" they aren't too much different than a smaller bowl, just takes longer, much longer. A 20" takes me twice to three times as long as a 14".

 

[R Henrickson]

I have turned a few 20 to 22" they aren't too much different than a smaller bowl, just takes longer, much longer. A 20" takes me twice to three times as long as a 14".

Simply a matter of geometry. A 20-22" diameter bowl would have 2-3 times the volume of a 14".

 

[hockenbery]

Simply a matter of geometry. A 20-22" diameter bowl would have 2-3 times the volume of a 14".

My observations on timing are slightly at odds with using just volume for open bowls.

I find hollow forms are closely linked to volume than open bowls. For spherical hollow forms a 10 D takes 8x longer than a 5 D

I find open bowl timing to be more related to the diameter and the area of the opening than the volume.
A 10 D takes more like 3- 4x longer than a 5D

With bowls taking a 1/2” shaving it takes 5 cuts to hollow a 5” opening 10 cuts hollow a 10” opening.
last 5 cuts on the 10” opening are twice as long in distance as the first 5.

With hollow forms time goes way up with chip removal. When I hollow 3” ornament balls - I don’t have to stop for chip removal since the feed out from the tool.
With a 6” I have to stop a lot to remove chips


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