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post #1 of 21 Old 07-24-2011, 04:15 AM Thread Starter
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This is harder then it looks.

I keep blowing bowls to pieces. I don't want to sound like I have a huge ego or a swell head but I usually pick up on stuff quickly and master most things I try. So that's why this is driving me crazy with turning bowls. I get really close then bam pieces everywhere.

I posted pictures of my first bowl (Oak) rough cut and then again when I broke it. I glued it up and I'm almost finished but it broke like 2 more times. It will require a lot more sanding but I will be happy just to finish it since it's the firth one.


My second one (Oak) exploded into so many pieces I never did find half the pieces. The third one was almost as bad.

My forth bowl (also Oak) has a hole that was hidden in the block and a crack (flaw) that was there when I started. I wanted to try and turn it without filling them but that wasn't working so they were both filled with epoxy and coffee grounds. I started turning it again and I found another crack so I'm filling it with epoxy also.




My fifth bowl was Red Cedar it started out about twice the size it ended up because I found a hidden bad section of wood. I had it really close to finished and it broke in half. I'm gluing it and trying to finish it also. It's a learning experience but also a matter of pride, I can't let this beat me. I know I have issues.


I'm pretty sure I'm probably going to thin (about 3/16) the good news is on the ones that broke the thickness is uniform through out.

Could the type of wood be giving me problems?

Am I right about the thickness being a problem?

I'm thinking I need to resharpen my tools when I get close to finishing so I can get a cleaner cut and need less sanding but I'm not sure that's what is breaking the bowls.

Any suggestions will be appreciated. I'm using free wood for the most part for practice and I would like to get this down so I can try some nicer woods. I have some Ambrosia Maple, a Cherry and Maple logs just waiting to be turned.
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post #2 of 21 Old 07-24-2011, 04:37 AM
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Quote:
Originally Posted by rrbrown View Post
I'm thinking I need to resharpen my tools when I get close to finishing so I can get a cleaner cut and need less sanding but I'm not sure that's what is breaking the bowls.

Any suggestions will be appreciated. I'm using free wood for the most part for practice and I would like to get this down so I can try some nicer woods. I have some Ambrosia Maple, a Cherry and Maple logs just waiting to be turned.
I haven't tried turning a bowl yet. I may just do that before I die though. So I'm just guessing here that there are probably places in the grain that give way. Could be too dry and brittle. Could be a fault that starts along the grain that gives way. And/or dull tools, as we know sharp ones cut with less effort. I found this out turning newels and balusters.








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post #3 of 21 Old 07-24-2011, 05:06 AM
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That's the cool thing about turning, you never know for sure what's inside. Razor sharp tools, and a little patience will get you through. The next one may be a beautiful specimen, turning with zero problems.

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post #4 of 21 Old 07-24-2011, 06:23 AM
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Hereabouts, I am known as 'Mission Control'. This is not because of my superb turnings, rather it is because I am constantly launching pieces of wood across the yard. All of my online mentors tell me that I need to find someone to help me learn...my problem is there is no one nearby to take lessons with. Our last turning club died due to lack of interest. So I'll keep on trying(and launching) 'til I get it right. I do have some pretty firewood though

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post #5 of 21 Old 07-24-2011, 08:44 AM
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This is only my observations and may not be accurate at all.
I canít tell the diameter from the pictures but most of mine I turn for use. I typically leave the walls 1/4Ē thick or on a large bowl (12Ē or better) up to 3/8Ē.

It may be the picture but on the second bowl the tenon looks very long and with a very steep dovetail. I use a Nova chuck and on their jaws they say not to cut a dovetail for a tenon/spigot. Your chuck may require something different.

It appears you have a lot of chatter near the rim on the third bowl. The thinner the more chance of chatter. If you donít, you may want to work down the inside in steps. Work down the first inch or so to the thickness you want, and then go to the next section. You wonít be going back to first area so cut it as smooth as possible. This will help a lot because you will not be working in an area subject to a lot of flex since you still have most of the support in the bottom.

As far as the breaking, it could be the wood, but it could be that you are getting too much of the wing into the wood. This assumes you are using a bowl gouge.

When I have turned cedar it tends to be brittle and even if dry warps easily with heat. I suspect the cedar bowl had so much chatter it finally tore itself apart and may not have been a catch.

As other suggested, you can check here to see it there are a local AAW club near you. http://www.woodturner.org/community/chapters/LocalChapters.asp
If not, maybe your local woodworking store (if you have one) may know of someone to give you some hands-on help. Just a couple of hours may be a big help. In lieu of that I suggest Lyle Jamiesonís DVD Bowl Basics Ė The Easy Way. It is a two DVD set and very informative, almost a school teacher style.
I didnít see a forum here for selling items but many woodturning forums do. I still have my Jamiesonís and still refer to it but I have resold other DVDs for 2/3 of the price within a few days. To me a few $ sent on instruction is just as important (or more so) than spending another $200 on chucks, chisels, etc.

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post #6 of 21 Old 07-24-2011, 09:09 AM
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I would like to try a bowl one day soon also but just haven't had the want bad enough to try. I was told the tools didn't need to be razor sharp, just grinding them was good enough. I thought that was kind a strange but then I am not real experienced at turning either.

I was told turning green wood was easier also, I can see where that might be true.

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post #7 of 21 Old 07-24-2011, 10:28 AM
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Rich, it's been my experience that when a bowl explodes like that there was usually a catch involved. I don't want to sound like I'm bragging, but in 4+ years of turning I've only exploded about 4 bowls. I've had 2 more just fly off the lathe. Every single time it was due to a catch. A momentary lapse in concentration and the gouge angle turned just a few degrees and then BANG! There is no problem turning thin, as I've seen turners (much more experienced than I) turn bowls so thin you can see light through them. You do need to slow down and take much lighter cuts. You probably need to turn down the speed of the lathe a little as you get thin, as it may be distorting the wood a little. It might also be species related. I've not turned oak or cedar. Try some maple or cherry...very forgiving woods to turn, especially green. As to tool sharpening, I touch up my gouge several times usually when doing a bowl that size. I also use a big heavy scraper for the final cuts on the inside.

Hope this helps and keep at it. You're doing well as I really like the nice continual curve you're getting on the outside of your bowls already...that took me about 6 months to get down.

That bowl was perfect right up until that last cut...
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post #8 of 21 Old 07-24-2011, 10:53 AM Thread Starter
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Thanks for all the replies. I do have someone local to help but it's hard to get our times together sometimes. He jokingly yet seriously says he not an expert and that his way isn't the only way. I'm looking for others input because there are always more then one way to do things.

The one with the epoxy fill is like 8", the others are probably like 4" inches. The cedar started at 8" and quickly went down to the smaller size.

I will have to try cutting the walls a little thicker and have more patients with my cuts using sharpened tools. I will go over my technique with my local friend and see if I'm doing everything correctly. I think the chatter is probably happening for a few reasons. Two thin of walls, to short of a tool rest and possibly the way I'm holding and/or presenting the tool.

Is Turning segmented bowls easier then turning from a solid piece of log? Minus the making of the segments.
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post #9 of 21 Old 07-24-2011, 12:50 PM
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Blowing up a bowl is almost always due to tools or technique - dull tools, improper presentation of the tool to the wood resulting in a disastrous catch, or an improperly held blank (allowing it to wobble).

You can also turn the walls TOO thin, resulting in weak walls which flex and wobble and break easily.

Very seldom is it the wood - even the rattiest wood full of holes and inclusions can be turned if enough care is used. Witness the number of beautiful bowls turned from Buckeye Burl and other wood with lots of voids, or look at the various types of winged bowls where the turner was cutting mostly air. These are all examples of catches and bowl explosions just waiting to happen, yet literally hundreds of these bowls are turned every day by turners around the world.

Keep your tools sharp, learn the proper way to use them, and keep on tryin' . . . it DOES get easier.
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post #10 of 21 Old 07-24-2011, 01:00 PM Thread Starter
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See the wood flexing when it's thin could be the problem or at least one of them. I will slow it down towards the end and see if that helps. I'm pretty sure the presentation is right but I will watch it. Seems like it the wood flexes some that could be giving me the chatter because it happens when I'm just about finished usually around that 3/16 thick wall. I thought the tools were sharp but maybe just a quick touch up when I slow the speed will help.

Thanks for the advice.
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post #11 of 21 Old 07-24-2011, 01:02 PM Thread Starter
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Originally Posted by fgvanatta View Post
Blowing up a bowl is almost always due to tools or technique - dull tools, improper presentation of the tool to the wood resulting in a disastrous catch, or an improperly held blank (allowing it to wobble).

You can also turn the walls TOO thin, resulting in weak walls which flex and wobble and break easily.

Very seldom is it the wood - even the rattiest wood full of holes and inclusions can be turned if enough care is used. Witness the number of beautiful bowls turned from Buckeye Burl and other wood with lots of voids, or look at the various types of winged bowls where the turner was cutting mostly air. These are all examples of catches and bowl explosions just waiting to happen, yet literally hundreds of these bowls are turned every day by turners around the world.

Keep your tools sharp, learn the proper way to use them, and keep on tryin' . . . it DOES get easier.
Welcome to the forum and thanks for the advise. You should get an intro posted and maybe post some pictures of your work in your albums because we like pictures. You also should list your location in your profile. It makes it easier to help or relate to a post if the location is known.

Last edited by rrbrown; 07-24-2011 at 04:23 PM.
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post #12 of 21 Old 07-24-2011, 02:49 PM
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Rich -

I'm wondering how you sequence the work, and whether doing things in a different sequence might reduce the odds of the pieces breaking up on you.

The lady who taught me said to completely finish (including sanding) the outside before doing any of the inside.

Then work down from the rim of the bowl, in bands of between one and one and a half inches; supporting the outside of the bowl with one or two fingers of the hand nearest the cutting edge of the gouge to try to dampen vibrations, cut to desired thickness, and sand.

Repeat, working down the inside of the bowl inch at a time, avoiding going back up to the previous band(s) except to blend the previous one into the freshly cut band.

This is to give the part you're working on as much support from the wood closer to the headstock as possible.

HTH

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post #13 of 21 Old 07-24-2011, 03:02 PM
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I also only turn from free logs, and frequently get cracks while the bowl is in progress. As I'm turning a blank, I'll stop and inspect for cracks every now and then, and if I see one starting, I'll drop some thin CA on it and let it dry for a while before I resume. For larger cracks (up to maybe 3/16"), I'll soak it with thin CA to strengthen the parts of the crack that I can't see, then fill it with thick CA. I use CA simply because I haven't bothered to buy any epoxy.

Since you're using free logs, I am curious as to how long you've let the logs dry before you try turning them. Drying bowl blanks seems to be something to master on its own, regardless of your proficiency at turning.

Also, what speed are you using to turn these bowls? The bigger the bowl, the slower the RPM.

I got into turning because I liked the idea of being able to start a session with a blank, and have a finished product in a few hours. In the three years or so that I've been turning, I've learned that you can make a fast bowl, or you can make a fine bowl. It'll take many more years before I get to the level of making a fine bowl fast.
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post #14 of 21 Old 07-24-2011, 04:32 PM Thread Starter
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Rich -

I'm wondering how you sequence the work, and whether doing things in a different sequence might reduce the odds of the pieces breaking up on you.

The lady who taught me said to completely finish (including sanding) the outside before doing any of the inside.

Then work down from the rim of the bowl, in bands of between one and one and a half inches; supporting the outside of the bowl with one or two fingers of the hand nearest the cutting edge of the gouge to try to dampen vibrations, cut to desired thickness, and sand.

Repeat, working down the inside of the bowl inch at a time, avoiding going back up to the previous band(s) except to blend the previous one into the freshly cut band.

This is to give the part you're working on as much support from the wood closer to the headstock as possible.

HTH
I pretty much do the same thing minus the sanding part.

Quote:
Originally Posted by b00kemdano View Post
I also only turn from free logs, and frequently get cracks while the bowl is in progress. As I'm turning a blank, I'll stop and inspect for cracks every now and then, and if I see one starting, I'll drop some thin CA on it and let it dry for a while before I resume. For larger cracks (up to maybe 3/16"), I'll soak it with thin CA to strengthen the parts of the crack that I can't see, then fill it with thick CA. I use CA simply because I haven't bothered to buy any epoxy.

Since you're using free logs, I am curious as to how long you've let the logs dry before you try turning them. Drying bowl blanks seems to be something to master on its own, regardless of your proficiency at turning.

Also, what speed are you using to turn these bowls? The bigger the bowl, the slower the RPM.

I got into turning because I liked the idea of being able to start a session with a blank, and have a finished product in a few hours. In the three years or so that I've been turning, I've learned that you can make a fast bowl, or you can make a fine bowl. It'll take many more years before I get to the level of making a fine bowl fast.
The oak was turned green and boxed in shavings until they quit losing weight.

Speed is around 600 to start and up to maybe 1300 by finish. all subject to change by how it feels.

As I said earlier I think the chatter was coming from the wood flexing as I got thinner with the wall. I will slow it down some. I will dress the tools at that time to make sure. I'm also going to listen and check for cracks as I go a little more often, just to be safe.

Last edited by rrbrown; 07-24-2011 at 05:31 PM.
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post #15 of 21 Old 07-24-2011, 05:29 PM
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Sound like you are doing everything right. Here is nice article on avoiding catches.

How to Avoid a Catch
https://www.lylejamieson.com/instruction-classes/documents/AAWArticle-FearFactor-Winter06.pdf


FIVE WAYS TO AVOID A CATCH
https://www.lylejamieson.com/instruction-classes/documents/5%20Ways%20to%20Avoid%20a%20Catch-March1996.pdf


Cannot comment on wood because not seeing what you are.

Last edited by wildwood; 07-24-2011 at 05:50 PM.
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post #16 of 21 Old 07-24-2011, 06:02 PM
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Something else you may want to check...snug up your jaws every now and then. The vibration from cutting may loosen up the jaws a bit. Even in metalworking.

That's why it's better to use a chuck with no tommy bars. Gives you a better 'feel', while you are tightening the jaws.

Harrison, at your service!
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post #17 of 21 Old 07-24-2011, 06:13 PM
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I would like to try a bowl one day soon also but just haven't had the want bad enough to try. I was told the tools didn't need to be razor sharp, just grinding them was good enough. I thought that was kind a strange but then I am not real experienced at turning either.

I was told turning green wood was easier also, I can see where that might be true.

Yep, in the olden days; an old pro would take great care in sharpening and honing the cutting edges. Using slipstones to get a polished, mirror like finish on the gouges. Slip stones were also used to polish the inside flutes of gouges.

With todays better quality grind stones, honing isn't usually necessary. That's another reason the old timers cherished their tools, and kept them in immaculate condition. Done right, the cutting edge lasted a whole lot longer between grinds.

When you're out flea marketing, you may find ancient gouges that look polished. That's when steel was steel.

If you are in a hurry while turning, just touch the edges up on a grinder. Good to go.

Harrison, at your service!
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post #18 of 21 Old 07-24-2011, 11:42 PM
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Olden days

Quote:
Originally Posted by H. A. S. View Post
Yep, in the olden days; an old pro would take great care in sharpening and honing the cutting edges. Using slipstones to get a polished, mirror like finish on the gouges. Slip stones were also used to polish the inside flutes of gouges.

With todays better quality grind stones, honing isn't usually necessary. That's another reason the old timers cherished their tools, and kept them in immaculate condition. Done right, the cutting edge lasted a whole lot longer between grinds.

When you're out flea marketing, you may find ancient gouges that look polished. That's when steel was steel.

If you are in a hurry while turning, just touch the edges up on a grinder. Good to go.
Olden (golden?) days? My warranty ran out at 40.

FWIW
I had the same problem with exploding wood bowls when I was younger and just beginning. Watching an old timer, I learned to sharpen frequently when getting the bowl pretty thin 3/8 to 1/2. One mistake I used to make was a tendency to put more pressure on the tool when the chatter started. That may be OK, but if your tools aren't razor sharp during this phase, you are flirting with disaster. Make sure that your tools stay sharp, and teach yourself that if you are starting to put excessive pressure on the object, your tool is dull.

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post #19 of 21 Old 07-25-2011, 02:16 PM
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Something else you may want to check...snug up your jaws every now and then. The vibration from cutting may loosen up the jaws a bit. Even in metalworking.

That's why it's better to use a chuck with no tommy bars. Gives you a better 'feel', while you are tightening the jaws.
Huh? I don't understand that. Most of my chucks have tommy bars, and I feel that they give me a better "feel" for how tight the chuck is on the spigot; with the key chuck i lose that feel - probably due to the torsional leverage.

JMO.
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post #20 of 21 Old 07-25-2011, 02:49 PM
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It must have further stung to receive a caged bird from Roger as a symbol of how he wanted her all to himself. It was at this point that Joan began to question the rules.
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