Lampshade- how to proceed

[dickhob]

Need some advice. I was turning birdhouses from ~7in green limbs and having some problems hollowing ~7in deep. I was not happy with the inside finish on the forms. Too rough and difficult to get a smooth finish using a gouge or a hunter osprey (thanks John Lucas- I’m working on it).

At the AAW symposium in FL, I had purchased a hook tool from Andre Martel. Gave it an initial try, and stored it in a drawer. Last week I started searching youtube and vimeo for hook tool videos. Found a few. I pulled out the Martel hook and proceeded to hollow 6.5 x 6.5 x ~1/4 vase from a semi-green pine log- with knots. The hook was not sharp, but it did a promising hollow vase. Further searching for some “how to sharpen” type videos allowed me to put on a respectable edge.

Had a really good time getting the vase down to a little less than ¼”. The videos have inspired me to attempt a lampshade thickness.

I’d appreciate some thoughts on how to proceed. The form seems to have dried out pretty well. I’m thinking of sanding the INSIDE and soaking the INSIDE with a generous coat of tung oil or Tried and True oil. I think the tung will penetrate better, but I’m not locked in as yet. Then i plan is to gently shave the outside to a final transparent thickness, sand and apply a finish oil to the outside. Per an Andre Martel video on Vimeo, I’ve reground a 3/8” bowl gouge to a 65 deg spindle roughing gouge shape. I’m planning to wet the outside surface and proceed to thin down the surface. I’ll use a lamp on the inside to get a consistent thickness.

Any comments or suggestion would be much appreciated.

Dick Hob

 

[Donna Banfield]

Dick, I've never watched Andre demonstrate, so take what I say as my own personal experience. Turning something translucent (very thin) is usually done by shaping the outside first, and then using a light source placed on the outside, hollow out the interior, working down the wall an inch at a time until you reach your final wall thickness, and using the amount of light coming through as your thickness gauge. Once you achieve your desired wall thickness on that inch, you move down another inch. And never return to 'touch up' where you've been. Peter Bloch, who turns lamp shades, does it that way, and JoHannes Michelsen, who turns the original Range Rider Cowboy hats uses that same technique. When I am turning a green end-grain vessel or side grain bowl once to final thickness, that is the order in which I do it, as well.

 

[dickhob]

donna
I've turned shades the way you describe, but I found it interesting that Andre turned to final thickness on the outside with the light on the inside.

https://vimeo.com/82587061 check his video around 1:23:00 where he shows this. I think it's worth exploring. I'm not sure where I picked up the 65deg straight SRG grind, but I know I saw it and again it seems like it's worth a try.

I didn't make myself very clear. I want to oil the inside before turning the final thickness in hopes that I'll be a surface with an underlying base that is not so dried out and therefore will be less prone to cracking or worse.

 

[Bill Boehme]

Once wood as dried, I don't think that you are going to be able to make it as easy to turn or as translucent as green wood.

 

[john lucas]

Well you have a host of questions. I'll first answer what I'm familiar with. The Hunter tools will cut as clean as the Hook tools tools and don't need to be sharpened and don't clog. I played with ring tools and hook tools a lot before the hunter's came along. The Osprey may not be the best tool for the job of thinning to a transparent look. I find scrapers much better for this. The Hunter #4 used with the cutter facing the wood does a good job of shear scraping. A negative rake scraper also does well. Before I started using those I used a bowl gouge shear scraping with the wings for my final cuts to thin out the piece to translucency.
Donna said it. I have only seen people who turn really thin do it from the inside. That's doesn't mean you can't do it from the outside. I will have to play with that sometime. The forces against the cutter would be different when turning from the outside vs inside so there could be some advantages but I just don't know. Like I said all the people I've seen who turn really thin do it from the inside. When I took a class with Frank Sudol we would turn the outside a little and then turn the inside to final thickness and then turn the outside some more. This was on 14" deep extremely thin vessels and you had to leave the mass on the outside to reduce the chatter.
The guys I see who do this turn far less than 1/4" thick. 2mm or slightly less than 1/8" is the goal.

 

[Dennis Weiner]

If you haven’t seen Andre Martels video on end grain turning it’s available from woodworkers emporium or from Andre himself. This video tied all the loose ends of the process. The outside of the Form he uses a bowl gouge with a wings vertically ground. He brings to final thickness with this tool cutting with a beautiful finish like a skew but with the versatility of negotiating curbs. The video is in French but english is dubbed in. Once you get past that, the video was worth waiting 10 years for. I would also start on the next piece. Also when possible, Stay away from knotty pieces when using a hook tool.

 

[hockenbery]

With thin end grain turnings a couple of things to keep in mind

Hollowing first has three advantages
1. The wood Is less likely to crack with less than delicate hollowing
2. Much easier to see the light from the outside
3. Most people have more control on the outside turning to the light thickness

Using a light works much better on wet wood since the fiber optic properties of the wood will pass the light.
Dry wood has to be paper thin to pass light
Light colored woods ( cherry, maple, box elder, sycamore, camphor....) are easier to use with light.

I’m a big believer in building a foundation of experience before tackling a new project.
I often turn prototypes of new pieces for me so that I appreciate the challenges of various steps.

Turning small natural edge goblets 3” diameter and then 7” diameter natural edge vase will give you experience in hollowing endgrain and shaping the outside with a light

 

[john lucas]

I have used the same technique you mention Andre uses with a bowl gouge and vertical wings but do it on the inside. The advantage of the flute up vertical wing cut is it puts very little pressure by the bevel on the wood so it reduces chatter tremendously. Does take skill to keep from getting a catch.

 

[dickhob]

Once wood as dried, I don't think that you are going to be able to make it as easy to turn or as translucent as green wood.

That's why I was planning on giving a soaking coat of oil on the inside to provide a bit of moisture/lubrication.

I've got it in my mind that using the 3/8in SRG ground to 65deg would not be so aggressive as to blow the vase up.

Maybe I should should oil the outside too and then reduce the thickness.

This is really an experiment. It's not going to kill me if it doesn't work out as intended.

 

[dickhob]

Well you have a host of questions. I'll first answer what I'm familiar with. The Hunter tools will cut as clean as the Hook tools tools and don't need to be sharpened and don't clog. I played with ring tools and hook tools a lot before the hunter's came along. The Osprey may not be the best tool for the job of thinning to a transparent look. I find scrapers much better for this. The Hunter #4 used with the cutter facing the wood does a good job of shear scraping. A negative rake scraper also does well. Before I started using those I used a bowl gouge shear scraping with the wings for my final cuts to thin out the piece to translucency.
Donna said it. I have only seen people who turn really thin do it from the inside. That's doesn't mean you can't do it from the outside. I will have to play with that sometime. The forces against the cutter would be different when turning from the outside vs inside so there could be some advantages but I just don't know. Like I said all the people I've seen who turn really thin do it from the inside. When I took a class with Frank Sudol we would turn the outside a little and then turn the inside to final thickness and then turn the outside some more. This was on 14" deep extremely thin vessels and you had to leave the mass on the outside to reduce the chatter.
The guys I see who do this turn far less than 1/4" thick. 2mm or slightly less than 1/8" is the goal.

I just bought the osprey 2 weeks ago, specifically to get a clean cut on the inside of bowls. It has worked well on dry wood, but really clogged up on this wet pine. It got the job done, but very slowly and did not leave a smooth surface. I just can't buy another tool right now.

In the past I've done thin wall vessels using bowl gouges and scrapers as you and Donna described, and was able to get down to ~1/8in.

As I mentioned, this is largely an experiment. I want to get familiar with the hook tool, the Hunter osprey, and turning final thickness from the outside.

I had a pine log on the shop floor and started messing with it- knots and all. I know I'm not doing myself any favors by turning this wood, but I started it and would like to see it through. If I can pull it off, it just might be a reasonably nice piece.

 

[dickhob]

If you haven’t seen Andre Martels video on end grain turning it’s available from woodworkers emporium or from Andre himself. This video tied all the loose ends of the process. The outside of the Form he uses a bowl gouge with a wings vertically ground. He brings to final thickness with this tool cutting with a beautiful finish like a skew but with the versatility of negotiating curbs. The video is in French but english is dubbed in. Once you get past that, the video was worth waiting 10 years for. I would also start on the next piece. Also when possible, Stay away from knotty pieces when using a hook tool.

Thanks for the video info. I'll check it out.

I maybe gave a poor description on the 3/8in bowl gouge as a SRG shape. A vertical wing is clearer.

 

[dickhob]

With thin end grain turnings a couple of things to keep in mind

Hollowing first has three advantages
1. The wood Is less likely to crack with less than delicate hollowing
2. Much easier to see the light from the outside
3. Most people have more control on the outside turning to the light thickness

Using a light works much better on wet wood since the fiber optic properties of the wood will pass the light.
Dry wood has to be paper thin to pass light
Light colored woods ( cherry, maple, box elder, sycamore, camphor....) are easier to use with light.

I’m a big believer in building a foundation of experience before tackling a new project.
I often turn prototypes of new pieces for me so that I appreciate the challenges of various steps.

Turning small natural edge goblets 3” diameter and then 7” diameter natural edge vase will give you experience in hollowing endgrain and shaping the outside with a light

This piece is 7in deep and 6.5in wide. I was just trying out the osprey and hook tool, and the project kind of evolved to where it is now.

I did turn the outside shape first. For me, it feels a lot easier to use the outside shape to gauge the inside walls. Got it to just under 1/4in without resorting to scrapers (which I frequently use). The lampshade is an afterthought and "design enhancement".

This fits very well your prototype category. A real lampshade would be much bigger.

 

[Dennis J Gooding]

Another consideration regarding inside vs outside cutting for final thinning is that, depending on the depth of hollowing, your hands or your face may be in the line of fire if things go south.

 

[hockenbery]

I did turn the outside shape first. For me, it feels a lot easier to use the outside shape to gauge the inside walls.

I always find it somewhat uncomfortable/unnatural to hollow first but I do it on endgrain when I want a thin wall.

There is no right or wrong with order of outside or inside first.
Choosing which is a series of trade offs

Almost all bowl,and hollow form turners turn,the outside and then hollow the inside to match the outside.
Most often Norfolk Island Pine is turned endgrain with the out side being turned first because the turner wants control of where the knots go on the form’s surface.

Most goblet turners hollow the cup first then use the hollowed opening to locate the top of the stem and cut to turn the ousdied an

Turning the inside first is really hard the first few times you do it. It is sort of turning In the blind. With a goblet or a vase it is helpful to have a template.

 

[john lucas]

The Osprey is not a good tool for hollowing inside. You don't say whether you are using it flat as a scraper or tilted as a bevel rubbing tool. Flat as a scraper it will not leave as good a finish. I prefer to use the Hunter #5 for hollowing by tilting it to the left at about 45 degrees. It will clean up the bottom as a bevel rubbing tool and you can clean up the side with the cutter facing the wood and do a shear scraping cut. The shear scraping is how I get really thin walls. I cut with a bevel rubbing tool as long as I dare and then switch to shear scraping. I don't do a lot of really thin wall vessels so my skills aren't quite there although I did a small bowl the other day and got the walls to about 2mm while rubbing the bevel on my Henry Taylor tool with the Batty 40/40 grind. I was using the flute up left wing cutting method.

 

[Dennis Weiner]

FYI

This is a 5/8 Robert sorbey u bowl gouge repurposed/reground. I use it on the outside of an endgrain piece. It’s wings are presented to the wood at about a 40/45 degree angle just like a skew. Finishes like glass. I learned this from AM video.

 

[dickhob]

I always find it somewhat uncomfortable/unnatural to hollow first but I do it on endgrain when I want a thin wall.

There is no right or wrong with order of outside or inside first.
Choosing which is a series of trade offs

Almost all bowl,and hollow form turners turn,the outside and then hollow the inside to match the outside.
Most often Norfolk Island Pine is turned endgrain with the out side being turned first because the turner wants control of where the knots go on the form’s surface.

Most goblet turners hollow the cup first then use the hollowed opening to locate the top of the stem and cut to turn the ousdied an

Turning the inside first is really hard the first few times you do it. It is sort of turning In the blind. With a goblet or a vase it is helpful to have a template.

Like I said, I've always hollowed the outside shape and then do the inside. For endgrain hollowing from a log, I assume you get a round surface before going to the inside. I can't imagine trying to hollow inside on an out of round/unbalanced form.

A goblet makes sense- I hollow barbell rattles this way. But a larger endgrain hollowing seems to me to need a balanced form before proceeding to the inside.

 

[dickhob]

The Osprey is not a good tool for hollowing inside. You don't say whether you are using it flat as a scraper or tilted as a bevel rubbing tool. Flat as a scraper it will not leave as good a finish. I prefer to use the Hunter #5 for hollowing by tilting it to the left at about 45 degrees. It will clean up the bottom as a bevel rubbing tool and you can clean up the side with the cutter facing the wood and do a shear scraping cut. The shear scraping is how I get really thin walls. I cut with a bevel rubbing tool as long as I dare and then switch to shear scraping. I don't do a lot of really thin wall vessels so my skills aren't quite there although I did a small bowl the other day and got the walls to about 2mm while rubbing the bevel on my Henry Taylor tool with the Batty 40/40 grind. I was using the flute up left wing cutting method.

John- you're trying to bankrupt me and cause disruption in my happy home life! I thought about consulting with you before I bought the osprey- hind sight is 20/20.

I ended up using the straight flute bowl gouge followed by a 1/2 spindle gouge with a Batty 40/40 grind. Turned out pretty well. Pics to follow.

 

[dickhob]

Another consideration regarding inside vs outside cutting for final thinning is that, depending on the depth of hollowing, your hands or your face may be in the line of fire if things go south.

I know you guys probably don't consider 7in as deep, but when you have a 6in or less open end, at my present skill level, it can get pretty exciting. Working on the outside is still challenging and a whole lot more comfortable.

 

[hockenbery]

Like I said, I've always hollowed the outside shape and then do the inside. For endgrain hollowing from a log, I assume you get a round surface before going to the inside. I can't imagine trying to hollow inside on an out of round/unbalanced form.

A goblet makes sense- I hollow barbell rattles this way. But a larger endgrain hollowing seems to me to need a balanced form before proceeding to the inside.

You are quite right. I don’t do large endgrain bowls except an occasional Norfolk Island Pine but it is too messy for me to turn often.

I haven’t done any vases larger than 10”diameter. Don’t do many of those.

On a thin walled vase what I would do is not touch the first inch of the eventual rim to leave bark all around.
turn a cove as the under side of the rim and turn the rest to a cylinder to balance the weight.

Reasonably balanced weight wise I then shape the rim leaving it about a 1/2 thick with the curve I want.
Hollow it out with a curved bottom and make the side wall curve into the curved rim.

Rough shape the vessel leaving the walls a 1+thick at the bottom. Turn the rim to thickness until then if it is an 1”8 the light woods will show light and I turn the rest of the outside matching the light to same color yellow.
( here we avoid White light because white light is air - bright yellow is thin - amber is thickmatch with the smaller tools.
As I come along the bottom I go for yellow as it is straight endgrain and passes more light. I measure her too.

Jimmy Clewes does a vase on one of his videos. Don’t think he uses a light in the video.

 

[Charlie Knighton]

Well.....back in '10 I attended the campus where I attended rotation by Larry Hasiak titled "Hollowing the low tech Way" he mounted hf wood with a face plate......he would alternate turning the outside then the inside to final thickness on the hf....working top to bottom .he never remounted the hf.....very impressive......also saw Rudolph Lopez,
Al H., Dale Nish, Alan Leland, Nick Cook,
& Michael Mocho.....

 

[Raul McCai]

https://vimeo.com/82587061 check his video around 1:23:00 where he shows this. I think it's worth exploring. I

Oh my. thanks for that. I've struggled with a source for a good hook tool I got one from Germany made of cobalt HSS ( m2) but IT's not shaped hike his. I want to try his. I notice his handle is about 46 feet long.

 

[john lucas]

the Osprey is one of my favorite tools. Possibly not the best for what you are describing here but I use it for finishing cuts on a lot of things.

 

[dickhob]

OK guys- Here is the final product.

I saturated the both inside and outside with 50% tung oil, then proceeded to finish turn on the outside. Had the speed way down because of the warped surface and procedded very slowly using my new ground 65deg straight wing bowl gouge. (I'm probably going to regrind to other angles) I finished the surface with a 1/2in 40/40 spindle gouge, and sanded to 320.

My final wall thickness is 5/32-1/16. Considering the wood and the knots, I'm happy with the result.

Mama saw it and now she wants a base. My daughter says if I want to find a home for it, she has one.

Thank you all for your advice and suggestions. I think I have something to change my avatar.......

 

[john lucas]

Good job.

 

[Donna Banfield]

I agree, Dick. That's a great job. For someone who was just 'seeing where it was going to take you', you did quite well. I hope that you continue to explore this area. You seemed to enjoy it, and your first one looks great!

 

[Raul McCai]

Way Cool~!!