LumberJocks

How not to #1: Turn a Bowl

  • Advertise with us
Blog entry by scottb posted 10-09-2007 12:53 AM 4926 reads 0 times favorited 12 comments Add to Favorites Watch
no previous part Part 1 of How not to series Part 2: make a five board bench »

The first in a, likely, long educational series, teaching by example. Poor example. Deliberately. If we don’t try (and fail quick) we may never learn how to proceed. Or reasons why the tried and true, really is.

Several months back (or more) I saw some experimental turnings of Hilary Pfeifer's made from several layers of perforated hardboard, laminated into a block with woodglue. Inspired (and knowing that common wood glue would be brutal to keeping your chisels sharp) I took a bunch of clapboard scrap, and glued it up using hide glue, and set it aside. I also ordered a big ‘ol jug of epoxy to try that out too.

Never knowing quite what I would do with a laminated chunk of glued, pre-primed cedar, I set it aside and awaited inspiration. Today it struck me, figuratively speaking, in the car.

I have never tried any hollow turning. I’ve also never tried turning any laminated material. So why not take a shot at making a laminated bowl? I might get a neat looking cedar bowl to post. It’d smell great, AND id get to try my hand at making my own jigs turn with.

Since I’m still waiting for Santa (or preferably Birthday) Claus to bring me a four jaw chuck, I dreamed up, then tried my hand at making a “four screw” chuck, that would allow me to make a bowl – first by hollowing out the inside, and then flipping it, and using a second jig, along with the tail stock to hold it in place to shape the outside.

First step: creating a wooden face plate by putting a recessed bolt though a counterbored hole in 1” thick ply (two layers of 1/2 inch screwed together with strips added to the bottom to keep the tips safely buried.

Second step: squaring up the laminated block, and mounting it – as centered as possible with screws through the back of the face plate into the corners of the block.

Third step: securing the bolt in the jacobs chuck of my shopsmith. (moving the tool rest into place, making sure everything is safe and secure, etc…)

Fourth step: Firing up the lathe and pretending I knew how to turn a hollow vessel. I’ve seen plenty of demos and articles, so I actually had a pretty good idea of what to do.

The turning was easy, and I knew that as long as I kept my gouge withing the “visible” middle portion of the square block of wood – and avoided the blurred corners – I woulnd’t hit the screws and would avoid any nasty surprises.

Torn.
I don’t think that all the clapboards (if indeed any of them) were cedar – didn’t get that nice smell, and the tear out was as horrible as any pine turnings I’ve ever practiced on, depite going as slow as possible. The glue didn’t really have as negative effect on the process of turning as my sharpening skills (or lack thereof) did. Sometimes I get a good enough edge and have a fair amount of success, though most of my smooth edges so far have been the result of improper use of the skew and parting tool, and lots of sanding. – only used the gouges today.

and wobbly,
The bolt wasn’t aligned at a perfect 90 through the faceplate which the turning clearly shows. The bolt/washers appears to have sunk into the plywood unevenly when tightened. The wobble was slightly obvious in the blur of turning, enough to have the tool cutting air during 1/2 of the time when defining the rim of the bowl.

but secure.
I was keeping very careful to avoid the square edges of the plate and block, and never even came close to the embedded screws – which cracked the block – they still held very securely. I should have predrilled being so close to the edges of a soft wood.

If I try this method again, I’ll square up the faceplate before I mount anything on it. I could sacrifice my aluminum sanding disk, or I could glue up the base, or use mdf so I can turn it flat. I’ll also try NOT using such a soft wood, or laminated anything for the turning stock for the first trial runs.

Not much to show for my afternoon, but I sure learned a lot, and am motivated to try even more new (and perhaps even unconventional) things.

The moral of todays story:
1. Try ONE new thing at a time
2. Always use SHARP tools. Get, or make the proper jigs.
3. Don’t be afraid to walk out of the shop with nothing to show for your time.

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/



12 comments so far

View mot's profile

mot

4911 posts in 3499 days


#1 posted 10-09-2007 01:16 AM

I’ve had to embrace moral #3 many times. Great story! Do you have all the skin on your knuckles still?

-- You can discover more about a person in an hour of play than in a year of conversation. (Plato)

View Karson's profile

Karson

35035 posts in 3863 days


#2 posted 10-09-2007 01:28 AM

Great Blog Scott.

#3 Yes, #2 Yes #1 No. Try as many new things as you can.

Karson

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia karsonwm@gmail.com †

View scottb's profile

scottb

3648 posts in 3790 days


#3 posted 10-09-2007 01:52 AM

re: knuckles – yep (for know) they appear intact. I successfully fought the strong urge, to feel the turning while moving.

re: #1… using cooking as an analogy, I’m trying to say, don’t swap margarine for butter, banana for canned pumpkin, applesauce for eggs, and milk & vinegar for sour cream and still expect something similar to gramma’s good old banana bread. Might be fine, or might have been better with one less substitution – but which one? Back to the drawing board!

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/

View Karson's profile

Karson

35035 posts in 3863 days


#4 posted 10-09-2007 02:52 AM

Good point. Scott.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia karsonwm@gmail.com †

View scottb's profile

scottb

3648 posts in 3790 days


#5 posted 10-09-2007 02:54 AM

That’s all I’m saying, otherwise, I totally agree.

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/

View SteveRussell's profile

SteveRussell

101 posts in 3423 days


#6 posted 10-09-2007 03:16 AM

Hello Scott,

Sometimes you bite the wood, sometimes the wood bites you… There are numerous ways to turn a bowl without a four jaw chuck. One tried and true way is to use a glue block and a faceplate. You can mount the faceplate on the top of the bowl first, profile the outside and then turn a spigot/boss on the bottom of the bowl and sand the outside.

Flip the bowl around and run your screws into the waste section on the bottom of the bowl and hollow the interior, adding fine details. When you’re satisfied with the profile, sand the interior. Part off the bowl where it meets the faceplate (above the screws) and then rough turn a jam-chuck that will fit your bowl rim out of 3/4” plywood, which is screwed to the faceplate.

Reverse turn the bowl using your jam chuck and the live centre. You can turn everything but the small tenon/boss where the live centre is inserted into the bottom. Finish this off the lathe (pare it off with a small Japanese pull saw, or similar) and sand the last area by hand, or use a small high speed sander with a foam sanding mandrel.

It’s a lot of back and forth, but it works… I’m lucky or lazy, take your pick, as I have 8 chucks, each with a different jaw set attached so I don’t have to spend time changing the jaws. You can however, turn all the bowls you want to without ever using a chuck. There are many other ways to turn a bowl without a chuck. If you give me an idea of what type of turning tools you have, I’ll be happy to help. Take care and all the best to you and yours!

Steve Russell
Eurowood Werks Woodturning Studio
The Woodlands, Texas

-- Better Woodturning and Finishing Through Chemistry... http://www.woodturningvideosplus.com

View scottb's profile

scottb

3648 posts in 3790 days


#7 posted 10-09-2007 05:15 AM

Thanks for that Steve. I’ve seen a screw going into the waste portion of the interior, but didn’t see how to flip it around. Thanks for that Eureka! moment.

For the time being, I’m finding my way around with an original model shopsmith – the 1952 ER. I have a couple of centers for the tail stock – live and not, #2 MT, and a couple stardard drive centers for the 5/8ths spindle.
for chisels, I’ve got a few old, but good tools. a big skew, couple of gouges, spindle and larger, no big roughing gouge. that, and a parting tool. No proper lathe tools came with the shopsmith, just picked up a couple of the centers and tool rest on ebay. No screw chucks, or proper faceplate. – save the 10” one for the shopsmiths sanding disk mode.

I imagine I can chuck a lag bolt or similar into the jacobs chuck to use as a screw center?

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/

View RobS's profile

RobS

1334 posts in 3769 days


#8 posted 10-09-2007 04:12 PM

hmm, I bet I could still eat oatmeal out of it…

Thanks for the lesson.

-- Rob (A) Waxahachie,TX

View scottb's profile

scottb

3648 posts in 3790 days


#9 posted 10-09-2007 09:48 PM

sure – about 1/4 cup at a time!... Mmmm, think of the new flavor combinations! Maple & brown cedar, apples, cinnamon and apple, maple walnut, maple maple mo maple, banana fanna fo fample me mi mo maple.

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/

View SteveRussell's profile

SteveRussell

101 posts in 3423 days


#10 posted 10-09-2007 10:28 PM

Hello Scott,

Jacob’s chucks are not really designed for bowl turning. The forces created during bowl turning can be significant and a regular Jacob’s chuck (with Morse taper fitting) would probably fall out of the spindle, causing you to engage in what we call the “Quick Foot Bowl Dance.”

The only way to safely use a Jacob’s chuck without a tailstock support when turning heavy items, is to use one with a draw bolt. The draw bolt runs through the headstock spindle and is secured on the other end of the spindle with a nut. This draw bolt works to prevent the MT from loosening during turning or drilling operations, when the Jacob’s chuck is mounted in the headstock.

Even if you have the draw bolt style of Jacob’s chuck and it’s properly secured, the lag screw would probably slip in the jaws when you were making heavy cuts, like during the roughout phase. I think the least expensive way to get you into bowls would be to buy a simple faceplate (you can get aluminum ones for $25.00 (£13) to fit your lathe from Craft Supplies USA) and use the technique I described in my earlier post to turn your bowls.

Steel faceplates are also available, for a wee bit more money. A better, but more expensive option is to get a combination faceplate/wood screw. This is a two part fixing that can be used as a regular faceplate, or a faceplate/wood screw combo. To use it without the wood screw, you simply remove the housing for the screw, leaving you a regular faceplate.

Wood screws are a nice way to begin a bowl, you simply drill a hole in the top of the bowl and screw the blank onto the screw. The faceplate acts as a backstop for the top of the blank. Once you have turned the bottom of the bowl, you remove it from the screw centre and use the faceplate to secure it into a waste area on the bottom of the bowl. (You could also glue an additional piece of scrap hardwood to the bottom and when the glue has cured, screw your faceplate into the new waste area).

Then, you complete the top of the bowl and when you’re finished, you part it off above the screws and reverse it onto a jam chuck to finish the bottom. Combo faceplate/screw centre chucks are about $69.00 (£34) in a size to fit your lathe. You might be able to find some used SS accessories as well. I see ads for chaps selling SS from time to time, so that might be another option.

Some turners get plate steel and weld the correct sized nut onto the back, making their own faceplates. If you have metalworking skills, this is not that hard of a project. You have to relieve the interior female threads for a small distance, so it fits your spindle correctly and it really needs to be balanced for smooth operation. In addition, the holes on the underside (where it will be fastened onto the blank) should be relieved with a chamfer. This relief allows the green wood fibers to move up a wee bit (as they always do), and still give you a flat mating surface on the blank face. The top holes can also be chamfered if desired, depending on the type of wood screws you will be using.

One last note, if/when you decide to get a faceplate, do NOT use sheetrock screws to secure your blank onto the faceplate. Sheetrock screws cannot take the forces that are generated during faceplate turning and will usually break, usually at the worst possible time, giving you an opportunity to practice your quick foot bowl dance. Use only strong steel wood screws to secure your faceplate. I like the square headed screws for smaller blanks and I use regular lag screws for larger projects. Take care and best wishes to you and yours!

Steve Russell
Eurowood Werks Woodturning Studio
The Woodlands, Texas

-- Better Woodturning and Finishing Through Chemistry... http://www.woodturningvideosplus.com

View Zuki's profile

Zuki

1404 posts in 3540 days


#11 posted 10-09-2007 11:26 PM

I never really thought about #3. I normally feed a little disappointed when I leave the shop with nothing accomplished or not as much accomplished as I anticipated.

I will keep it top of mind.

-- BLOG - http://www.colorfulcanary.com/search/label/Zuki

View scottb's profile

scottb

3648 posts in 3790 days


#12 posted 10-10-2007 02:17 AM

Even more helpful info Steve! Thanks.

Oh, #3 is a struggle Zuki. I hate spending time at ANYTHING and having nothing to show for it – even if it’s something I’ve never done before. I tend to never get done as much as hoped – I set the bar kinda high – either as a challenge, or more likely, wishful thinking.

-- I am always doing what I cannot do yet, in order to learn how to do it. - Van Gogh -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com