Turning green blanks

Re: Turning green blanks

robo hippy

Well, best bet for learning is to find the nearest club. All clubs have mentors, and you can't beat hands on sessions. Next would be You Tube videos, and there are lots out there. I have a bunch up and I mostly turn green bowls to final thickness. John Lucas, a regular here has a bunch up as well.

The roughing gouge is now referred to as a spindle roughing gouge, or SRG. They are not intended for roughing out bowls.

robo hippy

Re: Turning green blanks

jim breeden

A spindle roughing gouge should never be used to rough out bowls, as the tang is to weak to take the abuse, and has a great possibility of breakage. If all you have is a crack, consider yourself to be lucky that it did not separate while turning.

A tenon is more secure

david

...you don't have to ask me how I know that. If you absolutely need to have a recess, make it a deep one.

Re: Turning green blanks

John K Jordan

cameron,

The roughness and tearout you mention concerns me a little. Unless the wood is punky (partially rotted) you should be able to get clean cuts on almost any green wood, including oak.

As I see others have mentioned, what is generally called a roughing gouge is not the thing to use on face work (bowls). Not only will it beat you to death and often leave a horrible surface it is just plain dangerous. The tang is too small. Many people have broken the tang and thrown the gouge and some have been hurt. I think another problem is the shape of a roughing gouge presents too much edge to the wood at one time.

A good bowl gouge (ground with swept-back wings) is far better and will give a clean cut. A lot of people use a scraper to hollow bowls and then clean up with a bowl gouge. I personally don't like to see any tearout even at the roughing stage. If you get tearout with a bowl gouge perhaps it needs to be sharper. You should also be able to get a clean tenon if the wood is good.

Some people lay something to cover the bed the lathe (an anything else that will rust) to protect it from wet oak shavings. Oak is one of the worst.

JKJ

Re: Turning green blanks

cameron

Was just using the spindle rougher on the outside if that makes a difference but the point is taken and it has been retired (why I just bought a bigger bowl gouge.) This part of the log has some color variation so it might be a bit punkier then the rest, this was an old tree that had a significant hollow portion from about 3 feet under ground extending up about 15-20 feet. I like the coloring contrast but its pretty soft in places and really wet, the end grain sections in these spots are not clean, even with a freshly sharpened tool...

Re: Turning green blanks

john lucas

Smoothness is not critical but I do it just to learn about the wood and how it cuts. I have been using a Hunter Hercules for my roughing. It roughs very fast, is extremely tough and reduces the beating your shoulder takes when roughing. I had always used a 1/2" or 5/8" bowl gouge before and still do quite often simply because that's the tool I'm used to.

What I try to do on green roughed out bowls is to not leave any sharp corners. Those tend to loose moisture faster and start cracking.

Re: Turning green blanks

cameron

I bought a Hunter #5 at Christmas but so far it seems like it is not very good for roughing, course I don't have much time in it and assume I am light on technique...

Re: Turning green blanks

John K Jordan

I like the #5, but if you get a chance, you won't be sorry to pick up the Hercules. It, the Osprey, and the odd-shaped Clewes Mate are amazing to turn with. I used the Mate yesterday turning a spindle of very hard persimmon (in the Ebony family) and it worked well, both in the bevel-cutting for planing cuts and scraping modes for tight coves. The cutters on all of these are angled for easier control.

I use the smaller Hercules on a lot of spindles and other pieces, including the colored acrylic - leaves a smooth surface that needs very little sanding.

JKJ

Roughing is the perfect time to practice

Dick Coers

If you get tear out while roughing, you'll likely get tear out when finish turning. Dry wood does not turn easier than wet. Keep working on the rough outs until you get a good quality cut.

Re: Turning green blanks

John C Lucas

The Hunter #4 and #5 are not for roughing and should never be used with the cutter flat. I use those tilted to the side in a bevel rubbing cut. They are fabulous for cleaning up the inside of boxes or cutting the bottom of steep sides bowls. The Hunter Hackles and Osprey have the cutters tilted down at 30 degrees and can be used just like a scraper or they can be tilted and used in a push cut just like a bowl gouge.

Re: Turning green blanks

Barry Irby

A tenon is better than a recess. On big bowls and especially on oak it will warp. Cut it over sized and plan to return it later, after it drys and warps. Leave a center mark in the bottom of the bowl. When you come back to re-turn the bowl you can jamb it against the face of the chuck and the inside bottom of the bowl to re-turn the tenon.

You mentioned 15 to 18" diameter bowls 1" thick. I suspect that is not thick enough. If you get the kind of warping I have seen with oak, it may elongate enough to not be able to get a round bowl out of it. I think a 10 or 12" blank should be at least 1" thick and an 18" bowl should be close to 2" thick. I have found you can make the bottom an 1" thick and "flare" the thickness as you approach the rim. That is gradually and evenly increase the thickness from the bottom to the rim. When you remount these, start very slowly. They will be crazy out of balance, specially on a ten inch deep bowl. At that point the bowl will be an oval and you will be cutting the inside out of the narrow part and the outside "tips" off the long points to get back to round. I had a few that were warped so badly I could not get a circle out of them. I partially turned them on the lathe, widening the inside and shortening the points until I was as close as I could get and maintain decent thickness and hand and power sanded the rest.

Glad you retired the Spindle Roughing gouge. May have saved you an injury. I use and like a Bowl gouge with an Ellsworth grind. The shaft is 5/8". I have no experience with the other tools mentioned but would try them if I were going to turn lots of bowls. Mike Hunter and Doug Thompson are true benefactors to the turning community.

Practice, practice, Practice. Time on the tool counts. Join a club, get a mentor. Two hours of good instruction can save you a year of struggle.

Try turning some green to finish. They warp, sometimes in wonderful ways. Sort of organic. You either like them or you don't. Tremendously easier than twice turning them.

Re: Turning green blanks

robo hippy

The tenon vs. recess debate has popped up continually ever since I first got on the forums. I discovered a long time ago that they both work well AS LONG AS THEY ARE MADE CORRECTLY.... The correctly part is huge. I have made just about every mistake possible in my journey through the wood lathe, and if you have a failure, there are reasons, and if you learn how and why, you can solve the problems. Making a recess deeper does not make it stronger any more than a longer tenon makes that one stronger. Check out my clip about mounting things on the lathe, under robo hippy on You Tube...

robo hippy

Re: Turning green blanks

cameron

Thanks for the tips, I'm running a very heavy 1" so hopefully it will be ok but I'll make sure to make them closer to 2" here on out. I've got a ridiculous amount of these logs dumped in my driveway so I've got a to to practice on...

Re: Turning green blanks

don stephan

Never made a twice turned bowl, but I've read more than once a suggestion to leave the wall thickness 10% of the overall diameter. If I remember from Bruce Hoadley's "Understanding Wood," the ratio of tangential to radial shrinkage is 1.6 so don't skimp on the wall thickness.

Make some smaller bowls to practice and develop technique. 6" diameter quarter cut oak bowls are wonderful for breakfast cereal, snacks, candy, and more.

Re: Turning green blanks

Hugh Buttrum

I am with Robo on this one........find the nearest club and find someone there who will talk to you. They will help you. Find Anchor Seal also. Write the date and the wood species on the roughed out bowl for future reference.

After you use your bowl gouge and rough out about 100 bowls.....you will like it a lot.

Hugh

Re: Turning green blanks

George Balock

Cameron,

A lot of great advice here. The only thing I would add is that I use a 1/2" spindle gouge on the outside of my bowls (rough or final turned) to get rid of any tear out. Typically I will use the gouge turned on its side and the handle as low as possible. The shavings I get off of it are incredibly fine. Keith Tompkins recommended it in a thread about three years ago and I've been doing it ever since.

George

Re: Turning green blanks

john lucas

A pull cut with sharp wings does wonders but it depends on the shape of the gouge which affects the shape and sharpness of the wings. U shaped gouges tend to have thinner wings that become more acute when grinding. V shaped gouge can be less acute although usually more acute than the tip of the typical grind on gouges. For example my V gouge the nose angle is about 55 degrees which is fairly blunt but will turn most things I do. The wings on that gouge are much sharper and for that reason a pull cut at a steep angle usually gives a cleaner cut.

My Stewart Batty grind is on a U shaped gouge but because of how he grinds it the entire edge is 40 degrees. That is the advantage of his grind in that you can cut with any part of it as a push cut and get the same sharp cutting angle.

I have an older gouge that I made a special grind just for my mirrors and the nose angle is closer to 35 degrees and the wings are very thin and really sharp. This gouge is what I call a really thin U shape which helped the wings get that sharp. A pull cut with those wings which I grind really long gives a very clean cut. That long straight edge is also very good for shear scraping.

Re: Turning green blanks

Hal Taylor

Cameron, if you are getting a lot of tear out you may have dull tools. Sharp tools are a must. Also, careful attention to making a tenon (or recess) is essential. If not done properly the blank can fly off causing much damage. And of course, as others have said, find a club or experienced mentor.

The more you practice, the ........

JamieDonaldson

...luckier you become!

Re: Turning green blanks

Peter Hyde

Cameron,

I always use Johnson's Paste Wax on my lathe ways. Apply it with a non abrasive scotch brute typ pad, wait for 10 minutes then buff. Lasts for hours and no rust at all from wet wood. Might need a couple of applications during a day of rough turning

Usual rule of thumb for wall thickness is 10% of diameter.

Re: Turning green blanks

Brad Vietje

Welcome to the addiction, Cameron!

Sharp tools are only 1/2 of the issue. The other half is -- probably 25% each -- tool presentation, and direction of cut.

By tool presentation, I mean bevel supported, and NOT scraping. Even a super-sharp tool can leave a ragged mess if your technique is lacking. If you imagine the tool cutting, there should be no air space between the spinning wood and the bevel of the tool. You will often see turners on YouTube or other videos using a bowl or spindle gouge with a substantial gap in there, so they are sorta cutting and sorta scraping; the cut would be better if they eliminated that air space. that does not mean pushing the bevel against the wood -- it should barely touch it.

Direction of cut matters a good deal on softer, green wood. On a side-grain bowl, the best cut on the outside will be from the foot (tenon) up and out to the rim of the bowl, and on the inside, from the rim down to the center of the bowl. When turning end grain (vase, box, etc...) those rules are reversed.

I'm glad John pointed out no sharp edges. Its a very good idea to bevel every corner in rough turning, as sharp points dry out real fast, and cracks are likely to get a start.

How smooth should they be? I'd take this as a great opportunity to practice getting the best cuts you can, but unless you are leaving a real mess, it actually matters very little. I find that coarse, grainy and stringy woods like Red Oak and White Ash usually cut fine across end grain, but sometimes fibers pull out on the side grain. That will happen a lot less -- only rarely -- when the wood is dry, as those fibers are held in place much better.

Safe spinning,

Brad Vietje

Newbury, VT

Re: Turning green blanks

Brad Vietje

Watching Reed's videos is a great idea. The key is that a tenon not be too tall - you don't want the tenon touching the jaw bases, and you do want the tops of the jaws to have good contact with a flat turned around the tenon (well, technically a spigot, but who's counting).

Safe spinning,

Brad Vietje

Newbury, VT

Re: Turning green blanks

Dick Hines

I rough turn most of my bowls. I soak the tendon with thin CA. If you get to heavy handed you can pinch the tendons off.

I also make the tendons larger than I would a dry piece. This gives my some stock to true up the tendon when it dries.

Re: Turning green blanks

Don Evans

Cameron:

Regarding your rust or potential rust problem on your lathe...

If u have places with rust starting then purchase a product called 'Rust Free', it will turn rust oxide (rust)

into ferrous oxide which is black therefore stopping the rust immediately.

Here is a link where you can order or just read about it:

http://www.woodworkingshop.com/product/tb00008/

I have no stake in this, Just FYI. This product is phosporic acid but it is pure, if you purchase the acid at local hardware it will probably not work as well because it is probably watered down too much.

Just follow directions in washing it up when done treating with it.

Wear eye protection and "nitrile" gloves, ones at local drug store work great.

Where are you located, perhaps we can suggest a local club for you?

Don