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August 2008: Inside This Issue

Welcome to all of our new U.S. and International subscribers and thank you for joining us! This is the twenty first edition of Lathe Talk, a free monthly newsletter (e-zine) for subscribers of Steve Russell’s "Woodturning Videos Plus" woodturning website. This newsletter will be delivered on or about the fifteenth of each month to the email address you indicated on your sign-up form. All back issues of this newsletter are available to subscribers here.

Lathe Talk will offer tips and tricks to make your woodturning easier and more productive. I’ll also show you ways to save money in your studio, so you can stretch your hard earned money. In addition, we will periodically offer subscribers only specials on our videos and e-books. If you like this e-zine, please do a friend and me a favor by forwarding it to them. If a friend DID forward this to you and you like what you read, please subscribe by visiting our subscription page.

We've Reached A Milestone: I'm proud to report that we now have more than 50 free original articles available in our woodturning educational libraries. We will have lots of new features that will be coming online in the next few months, so check in every so often for the latest updates. To expand our free educational libraries even further we're adding two new libraries, a Tool Reviews Library and a Woodturning Multimedia Glossary Library. We are also going to expand our free Video Tips Library, with additional video segments on different aspects related to woodturning.

New Distribution Date For Lathe Talk: Starting with the next issue (September '08), Lathe Talk will be emailed to all subscribers on or about the 15th of each month. This move will allow me to schedule numerous production deadlines in my studio throughout the month, instead of having all of them coming due at or near the first of each month. Thanks!

New "Tool Reviews" Library: We're adding a brand new feature library "Tool Reviews" to our website that will feature in-depth reviews and "First Looks" from a professional woodturners perspective on machinery, tools, products, finishes and equipment that are important to woodturners. Glitzy sales brochures and snazzy flash videos on manufacturer websites might look nice, but what happens when your new tool or product arrives on your doorstep? Does it really work as advertised? We hope this library will become a valuable resource for you when researching new woodturning tool and product purchases.

New Multimedia Glossary Library Coming Soon: Another new feature library that is under construction is our new "Woodturners Multimedia Glossary." This glossary will feature words and phrases with definitions, as well as photos, drawings and video clips to help clarify the meaning of the words. In addition, I plan to incorporate regional and country specific phrases where possible, as well as slang words to further illuminate specific entries.

My goal is to build the best multimedia glossary on the Internet for woodturners. This will be no small task getting all of the pages coded, as well as shooting the photos and videos. Since this is such a large project, uploading will be performed in several stages. The first section of the glossary will be online in the next few weeks, followed by additional sections and multimedia segments over the next few months.

We will be adding new words in the future once the initial glossary is available, as well as new features to make it easier to use and access. My ultimate goal is to have a 1,000-word glossary available within two years. If you have any suggestions for words that you would like to see added to the glossary, please email me at steverussell2436@comcast.net

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Please help us to share this valuable learning resource with other turners in your woodturning clubs, associations, or on your own woodturning website links page.

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Additional $10.00 Discount off Our Volume I and II e-Book and DVD Video Super Combo. From now until the end of August 2008, you can save and additional $10.00 off the current sale price of $50.00 on any Volume #1 and 2 e-Book and DVD Video Super Combo set ordered from our website. With this special sale, your price will be $40.00 (plus taxes if you live in Texas) plus postage. The regular price of this combo is $70.00.

In the Volume I e-Book, oil and wax finishes are thoroughly tested and the proper use of wax emulsions and boiling to reduce drying defects (part one) are covered. Turning projects include writing pens, inlay items, letter openers, magnifiers and more. Safety and turning techniques are also included. Volume I articles include over 93,000 words and 500 pictures.

In the Volume II e-Book, topics include how to find free wood, drying green wood, processing logs and perfecting various finishes. Sharpening your turning tools, shear scraping, resharpening bandsaw blades and boiling to reduce drying degrade (part two) is covered. Volume II articles include more than 60,000 words and 450 pictures.

In the Volume II DVD Video, I demonstrate all the steps necessary to turn an elegant writing pen. Steps include blank selection and preparation, gluing, drilling, milling, mounting, roughing, finish turning, sanding, multi-step finishing options, assembly and more. More information on this e-Book and DVD Super Combo pack can be found here.

To access this special offer, enter the coupon code 2344 on the shopping cart page in the coupon box area. Click the "recalculate" button and your discount will show on the screen. Offer ends August 31, 2008 at 12:01 midnight, CST. Additional subscriber only discounts and specials will be offered in future editions of Lathe Talk.

Kelton curved neck profile scraper with handle

Overview

One of the more common turning tools in a woodturners toolbox are scrapers. Most of us own the usual compliment of straight and round (bull-nose) nose scrapers and perhaps a left/right skewed scraper. While traditional scrapers like these are commonly used by woodturners, few own or use profile scrapers.

Profile scrapers are specially shaped and ground scrapers that are designed for specific cutting tasks, like creating back cuts (an under cut on the inside of a bowl or other form) on bowls and platters, or working on the shoulder area on hollow forms. While there are many different ways to accomplish almost every task in woodturning, using profile scrapers is at times, an easy and fast way to get the job done.

An Undeserved Reputation

Various Kel McNaughton curved profile scrapers

Scrapers have a bad reputation with many woodturners. I've heard many horror stories through the years of turnings that were ruined, or damaged by the use of a scraper. I've also heard turners say that scrapers are an "Ill wind that blows no good" and only tear the grain, making the surface worse than when you started. Still others say that cutting is always better than scraping, so why scrape at all?

The fact is that scrapers have a bad reputation for sure, but it is largely undeserved. Using any tool improperly can result in torn grain, or surface damage. When used properly and with a fresh edge, scrapers are as useful as any other tool in your inventory. When used in a sheer scraping mode (with the cutting edge held at a sheer angle of approximately 45 to 55 degrees), scrapers can leave the wood surface smooth enough to start sanding at 320-grit, substantially reducing your abrasive protocol.

For additional information on using sheer scrapers, click here.

On dense exotic hardwoods (like Violet Rosewood for example), scrapers can actually produce a better surface off the tool than a gouge, an undeserved reputation indeed! However when used improperly, a scraper can be your worst nightmare. It can tear and mangle end grain fibers and even produce peck out on the surface of the wood. Most of the problems I see with my students when using scrapers centres on not keeping the edge sharp enough, or improper presentation of the tool on the surface of the wood. Luckily, both of these problems are easily remedied.

Two different ball-end profile scrapers from Kelton Tools

Profile scrapers offer a much easier way to produce certain finishing cuts like back cuts on rims, or relief cuts under the shoulder of a hollow form. Regular scrapers like flat, round-nose, or left and right skewed scrapers are usually too large to do any tight quarters work. Even if a traditional scraper can fit inside the opening on a project, it may not have the right profile shape for intricate profiling operations.

In addition, regular scrapers usually feature a large sharpened surface, which may make the cut too aggressive on thin walled projects, whereas profiled scrapers typically present a much smaller sharpened edge to the wood, allowing light cuts to be taken with ease. Also, the unique shapes of some profile scrapers allow for easy access in difficult to reach areas, where a regular scraper could never reach.

Types of Profile Scrapers

Large and small skewed end profile scrapers from Kelton Tools

There are many different types and sizes of profile scrapers available including numerous curved and bent shapes, ball-end, ball on post, left skewed, teardrop, square, straight-end and pointed. If you need a custom profile shape that is not available, you can easily take an unused straight edge scraper and grind the exact profile you need using a bench grinder. Final shaping can be completed with shaped abrasive cutters mounted in a hand held rotary tool.

Using Profile Scrapers

Upper: Henry Taylor Tools profile scraper;
Lower 3: Kelton Tools micro profile scrapers

Most wood surfaces can be improved if the scraper is held at a sheer angle of 45 to 55 degrees in use, instead of laying the scraper flat down on the tool rest. Depending on the specific shape of the scraper and the clearance around the tool, this presentation may not be possible. If the scraper must be used flat on the tool rest, raising the handle slightly so the end of the handle is higher than the sharpened edge is preferable over a flat presentation of the cutting edge to the wood.

To see two short video segments on sheer scraping the outside and inside of a bowl, click here.

The Importance Of Frequent Sharpening

The number one problem I see with my students when using a scraper is not sharpening the edge frequently enough. Scrapers that are used straight off the grind stone (no honing) feature a tiny burr on the cutting edge that does the cutting. This tiny burr does not last very long and must be refreshed frequently during use.

Just like any other cutting edge, as the edge begins to wear, the quality of the cut degrades. If you're using a scraper with a dull edge, chances are very good that you will experience torn grain or other surface damage. By keeping this edge frequently sharpened, you substantially reduce the chances of compromising the surface quality of the cut.

How often should you resharpen the edge? That depends on the quality of the steel in the scraper and the type of wood you're turning. As a rule when working with a typical M2 HSS scraper, I refresh the edge after every 25 – 30 seconds. Yes, you read that right, every 25 to 30 seconds! Scrapers work best with a freshly sharpened edge. If you get in the habit of refreshing the edge every few seconds of use, the quality of your cut will be dramatically improved.

If you're using a scraper made from one of the longer wearing exotic steels like powder metal steel or cryogenically treated steel, you can get a little more life from the edge. If I'm using a cryogenically treated M2 HSS, or a powder metal scraper, I typically refresh the edge after every 45 to 50 seconds.

For additional information on cryogenically treated turning tools, click here.

To Hone Or Not To Hone

I usually use scrapers with the burr intact (straight off the wheel, no honing), unless I'm working with a very dense exotic timber. In these cases, I use a fine credit card size diamond hone to remove the burr completely before use. To remove the burr, simply lay a diamond hone flat on the top of the scraper and lightly rotate the hone over the sharpened edge in a circle. It only takes a few seconds to remove the burr.

Remember if the burr is left intact, the cutting edge will be more aggressive. If the burr is honed away, the cutting edge will be less aggressive. If your scraper is somewhat grabby in use and you're using a freshly sharpened edge, with the tool held in the correct cutting position and you're working with a dense hardwood, try honing the burr off and see if that makes the cut more controllable. With some timbers, having no burr at all is just what the doctor ordered.

Experiment a bit with leaving the burr on and taking it off. There is no real hard and fast rule here regarding the burr, since the timber you are working with at the moment, as well as the thickness of the walls on your project, both tend to influence your decision.

Overview

Many years ago when I first opened my studio, I was finishing the bottoms of my bowls and platters using time-honored fixings like jam chucks and friction chucks. These fixings worked fine, but they were just too slow in a production environment where time is money. When I used the tailstock for extra support, I would have a small nub left in the bottom that required finishing off by hand, requiring even more time and labor.

As my business began to grow rapidly, I knew I had to find a better and faster fixing for finishing off that allowed more throughput and less wasted time. I decided to invest in a set of jumbo jaws (also known as "Cole" jaws by some manufacturers) for my large Vicmarc scroll chuck. I heard good things about them from some friends and was eager to give them a go.

Jumbo Jaws

Front view of my wooden faced jumbo jaws. When
closed, the outside diameter measures 19".

Jumbo jaws are large aluminum wedge shaped plates that attach to a scroll chuck just like a pair of jaws. My jumbo jaws measure 19" when fully closed and are mounted onto a large 5.25" Vicmarc heavy-duty, four jaw scroll chuck. Each jaw plate is drilled with numerous holes that are threaded to accept retainer bumpers that screw into the holes. These bumpers grip the rim of bowls and platters, allowing you unfettered access to the bottom of the piece for finishing off the bottoms.

The advantage here is that since there is no tailstock needed, you can complete the sanding and finishing on the lathe, without having to complete a supplemental hand sanding operation to remove the tiny nub left by the tailstock centre point. Great idea right? Well yes and no… As I began to use my jumbo jaws, I noticed that the retainer bumpers did not always provide as secure a grip on the project as I would have preferred.

When you're working on any project, especially one that will sell for a few thousand dollars, the last thing you want to happen is for the piece to come out of the chuck and hit the floor, or get launched into the stratosphere. Down in Texas, we call this kind of an unintended result a "Flier." I asked around and found out that many other turners also felt that the manufacturer supplied bumpers were not the best they could be. Some thought the design of the bumper was to blame, others felt that the bumpers were just too hard and would not grip curved rims very well.

One of my friends suggested I replace the original bumpers with better quality rubber bumpers, like the kind sold for lab use as a stopper for test tubes. I tried this option and while it did seem to grip the projects better, it did not give me the kind of reassurance I was looking for when working on up-market projects. What I really wanted was some type of adjustable friction, or jam chuck. One that would be easy to custom fit for each project and would be reusable. Yes, I wanted to have my cake and eat it too! I also wanted seconds and a large cold glass of milk to go with my cake.

Problems, Problems

With the jaws fully extended, the outside
diameter measures approximately 22".

Necessity being the mother of invention led me to experiment with different ways of securing projects onto my jumbo jaw plates. I liked the idea of having a large set of jaws on my chuck that I could use for finishing off, I just wanted a better way to secure the projects when turning the bottoms.

I experimented with using strapping tape in conjunction with the test tube bumpers. This worked better than using the bumpers alone, as the tape offered a little bit of extra protection that the project would stay in the chuck. I also experimented with using wrapping plastic (like the kind sold to wrap pallets or boxes for shipping). This type of plastic sticks to itself, but not anything else so there was no residue left on the surface of the project like would sometimes happen when using tape. This worked well with bowls, but not as good with thin platters since there was not much depth for the plastic to grip.

Down but not out, I thought that cork might offer a good solution, but it would need some type of a stiffener in the core to prevent gross deformation when the project was secured in the chuck. Corian scraps were everywhere in my studio, so I turned a set of bumper cores with inset rims. I then glued a regular wine bottle stopper cork to the turned Corian core.

The Corian and cork bumpers were drilled and counter bored to accept the manufacturer supplied bumper screws. This modification worked well on most projects, but it still took a bit of time to move the bumpers around for each project and then secure them onto the jaw plates. In addition, some projects featured rim designs that did not allow a secure fitting with bumpers. Although I had a very good set of bumpers now, they fell short of what I really wanted.

Problem Solved

This view shows the jumbo jaws slightly
opened, ready to turn the recess.

Undaunted, I kept experimenting until I decided to attach wooden faces to the front of each jaw. Ka-Ching! The wooden faces act much like an adjustable friction chuck and are a fast and easy way to fix items on the chuck for finishing off. The wooden jaws are made from a soft hardwood like Poplar. You do not want to use a dense hardwood, since this may damage the rims on softer hardwood projects when secured in the chuck.

For making the wooden faces, I use a S4S (surfaced four sides) Poplar plank that is 2.0" to 2.5" thick. This makes it easier to mount each segment on the jaw faces, since the mating surfaces are flat. You can use one of the Jumbo Jaw plates to make a template for cutting the four jaw face segments on the bandsaw.

Back view showing the large aluminum jumbo jaw plates.

For securing the segments onto the jaw faces, I use hardened steel woodscrews. These are secured at the edges of the inner (near the mounting screws for the jaw plates) and outer rims into the existing drilled and tapped holes. Once all four faces are mounted and secured, I turn on the lathe and true up the outer rim and the face of the wooden segments so the chuck will run true. At this point, the chuck is ready for use.

Using Wood Faced Jumbo Jaws

This 13" white ash salad bowl is mounted in
the jumbo jaws to complete the bottom.

To attach a project like a bowl or a platter to the wood jumbo jaw faces, open the jaws up slightly, say ¼" to 3/8" and turn a recess that will fit the outside rim of the project. If the bowl features a beaded or other decorative rim, the recess should accurately match the shape or design of the rim. This will insure that the wooden jaw faces grip the rim of the project evenly.

If I prefer a jam chuck type of fixing (a scrap piece of wood mounted onto a faceplate or chuck, turned with a protruding spigot to fit the inside wall of the project), I simply turn a spigot on the face of the jaws. Since the jaws open up in four pieces, the spigot acts like an adjustable jam chuck and allows for slight variations in the size of the spigot.

Platters can also be mounted in
the jumbo jaws for finishing off.

When used with a recess as in the earlier example, the turned recess also opens up, allowing for full contact on the outside of the rim just like you would have if you turned a traditional jam chuck (scrap wood mounted on a faceplate or chuck and turned with a recess to match the rim of the project).

To prevent any marks on the rims of your projects, simply line the inside of the recess with paper towels before inserting the project and tightening the jaws. Think of this as a faster way to make friction or jam chucks. When the chuck jaws are secured, the jaws close slightly for a friction mounting, or expand slightly for a jam chuck type of mounting and grip the project very securely.

Side view of Pecan crotch platter ready for finishing off.

If desired, the tailstock can be used for the main finishing cuts for extra safety. Once the bottom is nearly complete, you can remove the tailstock and finish off the nub left by the tailstock live centre. At some point, you will need to replace the wood faces on your jumbo jaws, as the wood faces will eventually get too thin to make new recesses, or spigots. Replacing the wood jaws only takes a few minutes and you're good to go again.

Limitations In Use

Side view of jumbo jaws showing 2.5" thick wooden faces.

Since the wooden faces are attached to the jumbo jaw plates with wood screws, you lose some capacity with the jaws since the area around the screws must be avoided. This however, is a small price to pay for the versatility of using this fixing. If the jaws are over tightened, you may damage the rim on your project. If the jaws are not tight enough, your project may come out of the chuck and become damaged.

While this fixing is not perfectly suited to every situation or project, it does offer a fast and easy way to mount some projects on the lathe for finishing off. It has worked so well in fact, that I have used this method for finishing off my production bowl and platter bottoms for the last twelve years. During that time, I also experimented with several other fixings for finishing off, but I always preferred using my wooden jumbo jaws to any other method.

Cautions

Small bowls like this 7" Elm bowl can also
be finished using the wooden faced jumbo jaws.

As with any one-sided fixing (jam chuck, vacuum chuck, friction chuck etc.), there is always a danger that you may get a catch and pull the piece from the chuck/jaws. I have not found this to be a problem, since you should always take light cuts with sharp tools when finishing off. In addition, you should always reduce your lathe speed down when working with one-sided fixings.

Close-up view of the small 7" Elm
bowl mounted and ready for finishing off.

For extra security, you can easily add some strapping tape, or shrink wrap around each jaw and across the project. I have used this technique on a few pieces that featured lots of negative space around the rim and on a few whose profile required a supplemental fixing due to the shape of the rim. It worked very well and offered an extra measure of confidence when working with these special situation projects.

Final Thoughts

Recently, I have begun experimenting with using a vacuum chuck on some projects, instead of using my wooden jumbo jaws. While the vacuum chuck excels at some fixing situations, it is not the best for every situation or need. Like everything else in woodturning, you need several tools in your toolbox so you can choose the one that best meets your needs on the specific project at hand. For me, that means that my trusty set of wooden jumbo jaws will be getting new Poplar faces soon, and I will continue to use them for the bulk of my finishing off needs when working with bowls and platters. When my jumbo jaws do not offer the best solution for the project, I can always use my vacuum chuck, or perhaps go "old school" and use a good old fashioned jam chuck, friction chuck, glue chuck, tape chuck, or maybe even a pressure chuck. You can never have too many options in woodturning!

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Steve