little elm bowl

[Raul McCai]

Finally and I mean Bloody Stinkin' Finally. I got my DC all hooked up and finally my lower back is not killing me so much I can't stand in place I hurt it last may. First time I could stride like a person was mid September. Anyway, enough whining.

An elm fell (Siberian Elm) from a windstorm a while back and I just left it - it's still alive and green. This is one of the many bowls I expect to harvest from it.

http://i1002.photobucket.com/albums...tle elm bowls/20161018_162200_zps8mqiwtdh.jpg

http://i1002.photobucket.com/albums...tle elm bowls/20161018_162155_zpsy9hxcnwi.jpg

http://i1002.photobucket.com/albums...tle elm bowls/20161018_162144_zpsbemp6cei.jpg

It's still rough.
I didn't give a lot of thought to this one. I just grabbed a hunk of log some 8 or 10 inches diameter and split it and chucked it. It's still green and I'm really close to finished dimension. I got it wrapped in plastic wrap just playing around to see what happens overnight.

The knots are not being my friends. The only siberian elm I've chucked up before has been dry and man oh man that lumber is dusty as all get out. So this'll be a learning experience.

I've worked a lot of this local Siberian Elm. Ht dries like a trooper very little warping and checking machines like - - well it's really sweet - and I think is just a gorgeous wood. I made Five of these boxes fer the womin folk a while back http://s1002.photobucket.com/user/zydaco/library/The Shop/A box?sort=3&page=1

 

[Dennis J Gooding]

Raul, I suggest that you consider uploading your images directly to the AAW Main Forum. I for one, found difficult to navigate the site that you referenced.

 

[hockenbery]

@Raul McCai It would be a lot easier to follow with photos in your post.

Pretty good for your first bowl.

When I rip the whole round to make my blanks, I cut parallel to the bark an Inch from the pith.
I'm guessing you got a catch on the pith to beak it. If it were not in the blank you won't break it.

Practice practice practice
Have fun

 

[Mike Johnson]

I was driving through a neighborhood and spotted a freshly cut tree and had to stop and pick up some crotch pieces.
Forgot how much of a pain green elm wood is to cut and process into bowl blanks and spindle blanks.
You can quickly gum up the drive sprocket and bar with long shavings cutting green elm.
You spend a lot of time cleaning the chainsaw when processing elm wood compared to many other wood species.

 

[Raul McCai]

THERE~!!! Maybe I'll remember how to insert an image. for next time.

Meanwhile I chucked up another hunk of elm log and even though it's entirely unnecessary I just had to whip out that Cobra style Hollowing system I made last winter - - this is it's very first use. I found the shielded cutter head to be a tad large for this small diameter. It's made from 5/8" rod stock so it's a tad big for little work but I just had to ( lets see if I can post a You Tube video)
This was the first post if the thing.

Here I am using it for the first time

and here

 

[Mike Johnson]

Raul,

I tried your last two video's and they come up as private.

 

[Raul McCai]

Raul,

I tried your last two video's and they come up as private.

Hmmm Shouldn't be. Maybe it's because you tube was still processing them? The first one is about a year old.

 

[Barry Crowder]

They're showing private for me, as well. Go into video manager for your channel in YT. Check the icons on the right next to the video. Should have a globe icon for public, not a lock icon for private.

 

[Raul McCai]

Thanks. It's all my fault for being a technical doofus. I never actually "published" them.

 

[Bill Boehme]

Looks like there is a lot of vibration in the cutter. The tool might work better if you progressively work from rim to center in stages. Once a section is done and thin, don't go back for "one more pass". A bowl gouge. Would be quicker and easier and have a pleasing smooth flowing continuous curve from rim to center.

 

[hockenbery]

When you develop techniques size matters.
Some Techniques that produce results on small bowls will be disappointing on larger work.
Like Bill said a bowl gouge will leave a better surface and be much more efficient.
You can reduce vibration some on your hollowing rig by working over the tool post instead of on the edge of the tool rest.

This is a clip from a demo showing how I use a gouge to hollow a small bowl.

View: http://www.youtube.com/watch?v=flw8LwQqGQU

This same technique will work quite well on a 20" bowl.

 

[Raul McCai]

Bowl Gouge, ok. I have Irish grind gouges. I built that Franken Hollower to compensate for my lack of skill inside the voids. I catch the tool like crazy. Sorby has a really simple rest that projects into the void maybe I'll make one of those and give the gouge another shot & pay more attention to the angle of the tool.

 

[Leo Van Der Loo]

The tool the OP uses is better used in endgrain IMO, for sideg-rain I would use a bowl gouge

 

[Bill Boehme]

The tool the OP uses is better used in endgrain IMO, for sideg-rain I would use a bowl gouge

That was my thought also. Of course it can also be used on side grain hollowforms, but you need to go slower with lighter cuts to reduce vibration.

BTW, welcome to the AAW forum. I recognize your name as one of the long time regulars across the creek.

 

[hockenbery]

Bowl Gouge, ok. I have Irish grind gouges..... I catch the tool like crazy. .

@Raul McCai
Working with a mentor will eliminate years of frustration and advance your skills rapidly.

Catches occur when the wood can drive down onto the the tool.
Most common reasons are incorrectly ground gouge, tool rest too low, flute angled too high. Taking too big of a cut.
1. The cutting edge of the gouge must be a continuous convex curve wing end to wing end. Flat is ok.
Dip is not ok. Hold edge on a flat plasticfrom wing to wing. The edge should touch at one spot all around. If light shows between too spots grind the high spots on either side,

2. I like the tool rest set so I am cutting at center with the tool handle parallel to the floor. This enables me to cut to the bottom center of the bowl with a swing of the tool.

3. Point the flute at 3 o'clock entering the bowl. Then roll it up to 2 o'clock or maybe 1:30. This is what I do in the video. Avoid the advanced cuts with flute higher the until someone teaches them to you.

4. When you first start hollowing take smaller cuts. 1/4" -1/2 inch of wood removal per pass.
1/4" is best until you get experience and you get twice the experience with 1/4" cut as you get with 1/2" cuts. Float the bevel over the surface. Grinding the heel off the bevel helps keep the bevel on the wood and reduces bevel drag.

I recently saw a tip attributed to Glenn Lucas. Draw a line in the bottom of flute with a red sharpie.
If you can see the line while turning you are likely to get a catch.

Have fun. I like the robust J rest for working inside large bowls

 

[Raul McCai]

thanks for the info. I think you mentioned mentoring once before. No one is ever going to teach me anything first hand. It's just not in the cards. I watch videos on the web. There are no turners around me, I don't know any one with a lathe, The nearest putative turner's club is - - well it's a journey. I was thinking of attending the Segmented Symposium in Beantown but my back wasn't letting me travel.

My "gouge grind" is exactly as the grind was on my gouges that came from Tompson. I built a version of the Tormek and it does it for me.

I must confess: I got Thompson's bottoming gouge and haven't figured out how to use it. Every time I pick it up I catch it.

I've found that very small cutting tools ( 0.187" to 0.250" dia) mounted to stout shafts of 5/8"dia., tend not to catch and yet I can wast away enormous amounts of material rapidly. Well, I'm sure they catch, but the "catch" is small so it passes without notice. The tool isn't mounted on an angle (it's flat to the work) so it doesn't get driven into the work the way a gouge can when presented poorly. I grind em to cut on the sides and face.

I try to rub the bevel when I start a cut: still working on developing the proper habits. The wood Lathe is unlike pretty much every other thing in the shop. It's a whole different set of skills.

 

[Leo Van Der Loo]

OK so I looked at your video again, #2 this time, and I might be totally wrong, but it appears to me that you are using a ring cutter that is shielded, held upside down, with your lathe turning in reverse ???, I mean clockwise facing the bowl.

Am I right ????

 

[hockenbery]

thanks for the info. I think you mentioned mentoring once before. No one is ever going to teach me anything first hand. It's just not in the cards. I watch videos on the web. There are no turners around me, I don't know any one with a lathe, The nearest putative turner's club is - - well it's a journey. I was thinking of attending the Segmented Symposium in Beantown but my back wasn't letting me travel.

You list your location as nj. There are lots of AAW members in New Jersey. If you want to send me your address in a pm I can find out if any AAW members are close to you.

My "gouge grind" is exactly as the grind was on my gouges that came from Tompson. I built a version of the Tormek and it does it for me.

Most gouges are shipped with a rough profile not a finished profile. I think Thompson puts a rough profile on. You might consider tuning it up a bit. Although it may be usable as received you can improve the profile.

I've found that very small cutting tools ( 0.187" to 0.250" dia) mounted to stout shafts of 5/8"dia., tend not to catch and yet I can wast away enormous amounts of material rapidly. Well, I'm sure they catch, but the "catch" is small so it passes without notice. The tool isn't mounted on an angle (it's flat to the work) so it doesn't get driven into the work the way a gouge can when presented poorly. I grind em to cut on the sides and face.

. The small scrapers are an old style turning tools that can be quite effective. MyronCurtis
and quite a few other turners use these small scrapers quite effectively. These can drive into the wood if you drop the handle too much. Keep level that are sort of catch proof and as you pointed out.

I try to rub the bevel when I start a cut: still working on developing the proper habits. The wood Lathe is unlike pretty much every other thing in the shop. It's a whole different set of skills.

You can't use turning tools like you would use a chisel to chop a mortise.

 

[Bill Boehme]

OK so I looked at your video again, #2 this time, and I might be totally wrong, but it appears to me that you are using a ring cutter that is shielded, held upside down, with your lathe turning in reverse ???, I mean clockwise facing the bowl.

Am I right ????

I think you are right, Leo. I looked at them a couple more times and I also noticed in the second video that the tool shank from where it sits on the rest back to elbow is not in line with the cutting tip. So, turning in reverse and the twisting force on the shank both contribute to vibration.

Raul it looks like you're about 60 miles from the nearest turning club. Here in Texas, that's like going to the grocery store.

 

[Tom Gall]

There are no turners around me, I don't know any one with a lathe, The nearest putative turner's club is - - well it's a journey.

Raul, I see you're from NJ. Where do you live? There are seven AAW chapters in NJ and the state isn't that big. Even if the meeting site(s) are too far for you to travel, I'm sure a member or two can be found near your location. Are you a member of the AAW? If so, go to the website and find the chapter locations and contact information. If not, maybe I can help you in that regard.

 

[Owen Lowe]

OK so I looked at your video again, #2 this time, and I might be totally wrong, but it appears to me that you are using a ring cutter that is shielded, held upside down, with your lathe turning in reverse ???, I mean clockwise facing the bowl.

Am I right ????

Yeah, I don’t know if it’s clockwise or just the video syncing…
Assuming the wood is spinning in the conventional direction, I do think:

• The lathe speed is too fast;
• The tool is too low (you can see this when he crosses the bottom center of the bowl);
• The wood has visible cracks.

Raul,
The combination of speed, tool height, and increased flexing of the wood due to pith cracks is not doing you any favors. I’ve used the Pro-Forme shielded ring cutters on bowls with no problems — very much the same approach and cutting action as a bowl gouge — so I don’t think that is a big factor here. I think if you raise your cutting edge above center height you'll see great improvement. You also might want to explore a gradual hollowing of the interior so that the bulk of the wood remains while working from the rim to the center. Once you get an appropriate wall thickness you don’t revisit that section other than to lightly blend.

 

[Raul McCai]

OK so I looked at your video again, #2 this time, and I might be totally wrong, but it appears to me that you are using a ring cutter that is shielded, held upside down, with your lathe turning in reverse ???, I mean clockwise facing the bowl.

Am I right ????

Well no. The reason it looks upside down is an engineering /design decision I made when I built that tool. I put the screws that connect the knuckle as well as the screw that holds the hood in place under the tool so that the threads were cut in the parts of the tool that face up. So the lathe is running in the normal direction the little round carbide insert is facing up. If I ever build another, I'll use left handed threads. One flaw in this design is that the rotational force on the knuckle in normal use tends to cause the screws to come loose. To solve for this I had to add a specialty locking washer to it after the fact which meant I had to re spot face the seats 0.090" deeper. I would link you to the photobucket page where I have images of the construction pictorially but photobucket won't load today.

I'm still of two minds about the whole adjustable knuckle thing. I sort of wonder if a couple of variations of the bent bar tool might be every bit as functional as a knuckle system.

 

[Raul McCai]

I think if you raise your cutting edge above center height you'll see great improvement. You also might want to explore a gradual hollowing of the interior so that the bulk of the wood remains while working from the rim to the center. Once you get an appropriate wall thickness you don’t revisit that section other than to lightly blend.

Thanks I'll look into that.

EDIT:

Raised the shielded cutter above the CL That made a real difference~!!

 

[Bill Boehme]

Raul, I see you're from NJ. Where do you live? There are seven AAW chapters in NJ and the state isn't that big. Even if the meeting site(s) are too far for you to travel, I'm sure a member or two can be found near your location. Are you a member of the AAW? If so, go to the website and find the chapter locations and contact information. If not, maybe I can help you in that regard.

Anybody is able to use the club locator. You do not need to be an AAW member. From the home page go to Services > Resource Directory > Find an AAW Chapter or click here.

 

[Leo Van Der Loo]

Yeah, I don’t know if it’s clockwise or just the video syncing…
Assuming the wood is spinning in the conventional direction, I do think:

• The lathe speed is too fast;
• The tool is too low (you can see this when he crosses the bottom center of the bowl);
• The wood has visible cracks.

Raul,
The combination of speed, tool height, and increased flexing of the wood due to pith cracks is not doing you any favors. I’ve used the Pro-Forme shielded ring cutters on bowls with no problems — very much the same approach and cutting action as a bowl gouge — so I don’t think that is a big factor here. I think if you raise your cutting edge above center height you'll see great improvement. You also might want to explore a gradual hollowing of the interior so that the bulk of the wood remains while working from the rim to the center. Once you get an appropriate wall thickness you don’t revisit that section other than to lightly blend.

Hi Owen, it’s been a long time exchanging info, if you do recall that is.

I was not basing my thought on the last bit of the slowing down bowl, as yes it could be video/light syncing, but on a couple other things, the overhang of the cutter that sits on top of the shield, you can see the opening of the cutter where you can see the shavings shoot out upwards.

But maybe I’m blind, I do agree with the tool sitting too low if oriented the right way,

 

[Bill Boehme]

Cutting below center on the interior definitely not good. As far as the direction of the shavings, I have a Rolly Munro guarded cutter for my boring bar and that is the way that the shavings exit ... there's no other way that they could go. If I didn't previously mention it, the tool shank needs to be inline with the cutter tip. This is why hollowing tools have a goose-neck shape. Otherwise there is torque that goes back to whatever is holding the tool shank ... an elbow type tool in this case. Even if there is very little free play at the elbow, there is still plenty of compliance between there and the cutter tip to cause vibration. Having the tool shank inline with the cutter would effectively remove much of the torsional contribution to vibration.

Regarding cutter height, cutting exactly on the centerline is the neutral stability position and generally safe for both inside and outside.¹ Basically, you want to have the cutter height so that the wood is moving away from the edge and not tending to drive deeper. This means that on the interior of a bowl the tool needs to be on or preferably above centerline. On the exterior it would be just the opposite with the cutter at or below centerline. This is a simplified description that is easier to see with scraping tools or cutters that are horizontal. In the real world, experienced turners can make cuts that appear to disregarding Mother Nature and getting away with it. In actuality, the cuts are safe, but it takes some experience to reach the point where you can safely use the tool on the hairy edge of a massive catch. You will have that "aha moment" where you can intuitively use the tool to make nice shavings without catches².


¹ An engineer might think of it like being right on the jω axis of a stability diagram ... safe, but right on the edge of bad things.
² I don't have catches, I'm just practicing to show beginners how a catch happens. That's my story.

 

[Gretch Flo]

That's my story.

And I suppose you're sticking to it????!!!!!! Gretch

 

[Leo Van Der Loo]

Cutting below center on the interior definitely not good. As far as the direction of the shavings, I have a Rolly Munro guarded cutter for my boring bar and that is the way that the shavings exit ... there's no other way that they could go. If I didn't previously mention it, the tool shank needs to be inline with the cutter tip. This is why hollowing tools have a goose-neck shape. Otherwise there is torque that goes back to whatever is holding the tool shank ... an elbow type tool in this case. Even if there is very little free play at the elbow, there is still plenty of compliance between there and the cutter tip to cause vibration. Having the tool shank inline with the cutter would effectively remove much of the torsional contribution to vibration.

Regarding cutter height, cutting exactly on the centerline is the neutral stability position and generally safe for both inside and outside.¹ Basically, you want to have the cutter height so that the wood is moving away from the edge and not tending to drive deeper. This means that on the interior of a bowl the tool needs to be on or preferably above centerline. On the exterior it would be just the opposite with the cutter at or below centerline. This is a simplified description that is easier to see with scraping tools or cutters that are horizontal. In the real world, experienced turners can make cuts that appear to disregarding Mother Nature and getting away with it. In actuality, the cuts are safe, but it takes some experience to reach the point where you can safely use the tool on the hairy edge of a massive catch. You will have that "aha moment" where you can intuitively use the tool to make nice shavings without catches².


¹ An engineer might think of it like being right on the jω axis of a stability diagram ... safe, but right on the edge of bad things.
² I don't have catches, I'm just practicing to show beginners how a catch happens. That's my story.

Bill al the foregoing showed that I wasn’t familiar with the Rolly Munro tool, as I assumed it was a ring tool, similar to a Termite tool, I just now googled “Rolly Munro woodturning tool” and saw how that tool is made and works.

Maybe I should have looked that up first, sorry for that, the other part of holding the tool too low of course still stands, it would also have the heel run into the wall, especially in a smaller turning )

 

[Bill Boehme]

The Rolly Munro carbide cutter has a raised edge like the Hunter tools which means they are very sharp and very good at slicing wood. Without the guard they couldn't be used with a captured bar type of hollowing tool. I haven't used a Hunter tool, but I suppose that they could be used like a hook tool for hand held hollowing. I've used a hook tool enough to be barely proficient and appreciate that they aren't very forgiving.

I like your new avatar, Leo. Looks like you're enjoying a refreshing glass of Kool-Aid.

 

[Mike Johnson]

More like most likely one of the following......it's all good.

• French Beaujolais
  
• Italian Chianti
  
• Cabernet Sauvignon
  
• Australian Shiraz
  
• French Bordeaux
  
• Merlot

 

[Raul McCai]

as I assumed it was a ring tool, similar

Well it is sort of a ring tool; Just not hollow. I used a round carbide cutter in mine

Just not a hollow ring . The "Ring" such as it is is a raised edge on the round carbide cutter. The shavings are supposed to slip down into the circular depression in the cutter and up out of the tool. I find that wet shavings can get stuck necessitating that I clear the tool.

Fuzzy photo from the underside showing the slot used to adjust the hood

 

[Leo Van Der Loo]

Well it is sort of a ring tool; Just not hollow. I used a round carbide cutter in mine

Just not a hollow ring . The "Ring" such as it is is a raised edge on the round carbide cutter. The shavings are supposed to slip down into the circular depression in the cutter and up out of the tool. I find that wet shavings can get stuck necessitating that I clear the tool.

Fuzzy photo from the underside showing the slot used to adjust the hood

Raul looks like a well made tool, and I would consider using a tool like that in a hollow form if I ever would make one, with bowls my tools are bowl gouges and spindle gouges on spindles and endgrain turnings also.
Thanks for showing the pictures

 

[Raul McCai]

milli grazi.

 

[Owen Lowe]

Hi Owen, it’s been a long time exchanging info, if you do recall that is.

I do remember, yes! Your name didn’t register from long ago - I was thinking you were a regular in my circle! When you noted the above it all became clear once again.

 

[Gerald Lawrence]

[QUOTE="hockenbery, post: 118181,
Most gouges are shipped with a rough profile not a finished profile. I think Thompson puts a rough profile on. You might consider tuning it up a bit. Although it may be usable as received you can improve the profile.

Al, Thompson gouges come ready to use and his grind is closer to a traditional grind it seems to me . I have kept the original grind on my 5/8 and I really like it. I do not think beginners should get too involved in changing the grind on tools til they get more training and experience. The discussion of grinds and angles always amuses me as "no one is going to change their opinion of what is best to use" , so why do we spend so much time on it. Best to say "this is what I use for best results".

 

[hockenbery]

[QUOTE="hockenbery, post: 118181,
Most gouges are shipped with a rough profile not a finished profile. I think Thompson puts a rough profile on. You might consider tuning it up a bit. Although it may be usable as received you can improve the profile.

Al, Thompson gouges come ready to use and his grind is closer to a traditional grind it seems to me . I have kept the original grind on my 5/8 and I really like it. I do not think beginners should get too involved in changing the grind on tools til they get more training and experience. The discussion of grinds and angles always amuses me as "no one is going to change their opinion of what is best to use" , so why do we spend so much time on it. Best to say "this is what I use for best results".

Good to know the Thompson gouges come ready to use.

About any grind on a gouge will work as long as the cutting edge has a continuous convex profile. Flats are ok. Dips in the profile makes the tool catch or not cut.

When I do classes and workshops for "experienced" turners, I see quite a few gouges with dips in the nose or on the wing. The owners of these tools get an immediate improvement in their turning when I put one of my tools in their hand. Then we tune up the student's gouge and the students sharpening technique.
The " oh wow" in those students is amazing to watch.

 

[Bill Boehme]

.... I do not think beginners should get too involved in changing the grind on tools til they get more training and experience....

I agree and I think that it is because beginning turners are full of enthusiasm about this very addictive hobby and wanting to soak up as much information as they can in as short a time as possible. It's not uncommon for a beginner to say that they want to buy a boxed set of cheap tools so that they can:

1. practice sharpening, and
2. try different grinds to see which one works best for them.

Basic sharpening can be learned in one easy lesson and then exposure to some special sharpening techniques that they might find useful. Your observation about changing grinds is right on the money in my opinion. My observation is that a beginner frequently uses every tool as a scraper and really needs more experience as you said.

....The discussion of grinds and angles always amuses me as "no one is going to change their opinion of what is best to use" , so why do we spend so much time on it. Best to say "this is what I use for best results".

I think that the discussion usually arises when a newbie asks, "what grind is best". I think that it is a natural question to ask. Why do we use this grind or that grind? How do they differ? Am I using the wrong grind? If I change this other grind will I stop getting catches? Everybody has their favorites and wants to share it with the newbie. Announcing that a certain topic has been discussed enough and will no longer be discussed ain't gonna' happen. A newbie today doesn't know what topics were discussed ad nauseum years ago. A forum is a place for sharing ideas, opinions, and information. Woodturning today continues to evolve and Internet discussion forums are a part of that evolution. My perspective is that these discussions are a good thing.

 

[hockenbery]

I agree keep things simple for beginners. I reccomend beginners take a basic bowl class and use whatever grind they learned in that class until they get pretty good with it before experimenting with other tools and grinds.

However many of the participants in the forum are past the beginner stage.
The various gouge grinds determines what the tool can be effectively used for.

One of the benefits of local chapters is seeing different people demonstrate. Over time members get exposed to a variety of tools and techniques. Many chapters have workshops and mentoring sessions to provide hands on experience and opportunities to experiment. Over time everyone develops their own preferred tools and techniques.

 

[Raul McCai]

"what grind is best"

In the end aren't they all just hammers? ;>p

 

[Mike Johnson]

A bigger hammer is the solution most of the time if you can't locate the finesse.

Now where did I put that finesse?