The final product

Published on February 9, 2011 in Finishing and Jigs and Fixtures. 2 Comments Tags: , , , .

v\

The "flag", laid out on an offcut from the turning

The last step was to make the “flag” that signifies an 8th note in musical notation. I actually didn’t care about the musical timing, but needed the flag to hang the note on its stand.

I bandsawed off a slice from that large bulge I originally turned on the bottom of the blank, drew the flag, then scribed a line on the right, where the tenon would begin. Scribing this way keeps the wood fibers from fraying at the cut line, giving a clean cut. I scribed both sides.

Cutting the tenon on the flag

I cut out the flag and tenon area on a scroll saw, then mounted the piece on a horizontal router table to cut the 1/8″ thick tenon. Here you see it elevated on a scrap, secured by clamps. A 1/2″ spiral straight router bit comes in from the right, held by the horizontal router. The router table allows me to set a depth of cut, then move the workpiece horizontally to cut one side of the tenon. The router is held on a plate attached to a 16TPI threaded rod. Once I’d cut one side of the tenon, I just turned the vertical control handle 10 turns, to raise the router by the diameter of the bit plus the 1/8″ thickness of the tenon.

With the tenon cut, I carved a slight flat around the mortise on the stem so the flag would sit flush, then glued it place. I sanded everything, applied three coats of shellac, then waxed and buffed the note.

The note on its stand

Finally, I brazed together some cold-rolled steel—1/8″ rod and 1/8″ x 1/2″ flat stock, into a musical “staff”. I attached the staff to a steel plate at the same angle the note hung at, sprayed everything with black lacquer, and the project was complete.

I’ll mention in passing how handy it is for woodworkers to have a bit of metalworking capability. Brazing is easy (like high-temperature soldering), strong, and can be done with a MAPP gas torch in your driveway. It let me make a light, strong stand in scale with the note—something harder to do with wood, which isn’t as strong in small sections.

From a pile of parts to a jig

Published on February 5, 2011 in Jigs and Fixtures and Routing. Closed Tags: , , , .

The parts, ready for assembly

Here’s the pile of parts, waiting to become a jig. That loop in the front is 1/4″ threaded rod that I bent into a semicircle and covered with vinyl tubing. It’ll help secure the router in place, along with the knob at the back of the picture (which threads into a hole on the side of the router casting).

I inserted the carriage bolts and drew them up to bite into the melamine, then secured them with nuts. Nuts and washers near the top of the bolts support the top plate which holds the router.

Setting the height

Here’s the jig with the router in place. I set that height gauge on the left to the distance between the table that will support the router jig and the centerline of the lathe spindle. Now, it’s a simple matter to adjust the nuts up and down on the bolts until a bit chucked in the router is at the spindle height, and the router is level. The digital protractor in the foreground helped with the leveling.

The jig at work, cutting a mortise

It’s time to try it out! Here you see it in place on a plywood table that’s mounted on the lathe ways. I’ve clamped stops to limit the width and depth of cut, and chucked a 1/8″ spiral bit into the router. The note, not yet fully carved, is held in place on the lathe.

Here’s a close-up of the action.

Here you can see details of what’s happening at the business end of the router. Once that mortise is cut, I can carve the rest of the note so the stem flows smoothly into the body, and make a “flag” that plugs into the mortise. See it in the next post.

Starting the jig

Published on January 30, 2011 in Jigs and Fixtures and Machines. 5 Comments Tags: , .

Drilling the melamine

I built this device using scraps of melamine-coated particle board, a flat, low-friction material that’s perfect for jigs.

My design called for two plates, separated by the 3/8″ bolts and nuts shown in the previous post. To drill bolt holes that line up in the two plates, I attached them together with a couple small pieces of double-stick tape, then set the drill press fence and stops so I could drill all four holes.

Above you see the bottom of the jig, which sports four large counter-bores (holes that don’t go through) to accommodate the heads of the carriage bolts, so they won’t drag on the table as I move the jig around. I drilled them first, using a 1″ Forstner bit which drills a flat-bottomed hole.

Forstner bit speed table

A lot of people run Forstner bits too fast, then wonder why they burn the wood and won’t hold an edge. The table at the left came with my set, and it shows that I should run the 1″ bit at around 800 RPM. When I did, it cut smoothly, with no burning.

Forstner bits leave a tiny pit in the center of the hole, and I used that to line up for drilling through both plates with a 3/8″ bit to accept the bolts.

Backer blocks eliminate chipping

Melamine is very brittle, but when I set the drill for the right speed (about 2100 RPM on my machine) and backed up the cut with scrap wood, I got the clean exit holes you see at the left, with no chipping. Note that there is some fraying or chipping around the edges of the plate. This surface faced down when I cut it on the table saw, and I didn’t take the time to set up a zero-clearance throat plate on the saw (it’s just a jig, after all). Therefore, as the blade teeth exited the cut, they pulled a little of the brittle melamine away from the core. The throat plate would have taken care of that. Covering the cut line with masking tape can also help.

Next, assembling and adjusting the jig.

How to hit the high notes

Published on January 27, 2011 in Jigs and Fixtures, Machines and Woodturning. 3 Comments Tags: , , .

I belong to a woodturning club, and each month we have a President’s Challenge project, to get us to stretch a bit and try something we wouldn’t normally do. This month’s challenge is “Stemmed”.

The note at an early stage, on the lathe.

I think one of the secrets to success is to figure out what everyone else is doing and don’t do it. In this case, I’m betting a lot of people will turn goblets or pieces of fruit. So I wanted to make a musical note.

I mounted a 3″ diameter chunk of osage orange between centers, and turned the stem down to 5/16″ using classic spindle turning techniques. I left a large round piece at the bottom. At this stage, it looked rather like a top.

The next step was to mount it sideways, gripping that large round section between centers. Then I could turn the section down to become the body of the note. I had to turn very carefully, because that long, thin stem whips around in an almost invisible arc. I turned left-handed so I could cut in close to the stem while keeping my hands clear. You can see the note body (that ball on top) is complete, and I next have to remove the rest of that big wooden round. I’ve remounted it along the original turning axis for the photo.

A Porter Cable trim router is the right size.

Now’s the interesting part. I want to attach a “flag” to the stem, like a musical note would have. That means I need to cut a 1/8″-wide mortise in the stem to accept the end of the flag.

I had a little trim router perfect for the job. But I needed to be able to move it in a controlled way along the centerline of the turning. Time to make a jig.

Here are the guts of the jig.

I started with some scrap melamine-coated particle board, 3/8″ carriage bolts, nuts, and washers. Carriage bolts are nice for jigs because once their square shoulders bite in to the wood, they won’t rotate as you tighten bolts on them. By building the jig as a base and elevated platform, fastened by bolts, I eliminated the need for precision cutting and tricky measurements of router bit height. This jig would be adjustable! (That also means I can adapt it to other routers when this one dies.)

Next—turning that pile of stuff into a jig.

A comment on comments

Published on January 10, 2011 in Uncategorized. 2 Comments

I appreciate the comments you send in, and especially questions that suggest directions for future posts. My goal is to build a woodworking community here, and have some fun at the same time. Unfortunately, we bloggers get bombarded with spam comments, which the botnet managers hope I’ll be sleepy enough to approve so they can get a shot at you, my reader.

Here’s how I protect our community.

I use a spam filter to weed out link-choked “comments” so you and I don’t see them. I vet the rest. A lot of those are schemes promising webmasters “…huge amounts of traffic…” or “…make thousands by doing hardly any work.” I got three of those this morning. Peace was just a click away.

The rest of the spams are generic nonsense in broken English. How about, “I think everyone will really like to study this write-up once more & once more and am quite sure that most vsitors of this page will come here once more in future.” (sic). These try to get you to click on their URLs, which take you to sites that try to sell you something. They never relate to the article to which they’re responding. Click. They’re gone.

Finally, there are questionable ones that might be just pats on the back, but don’t mention anything specific about an article or about woodworking. I’ll usually post those if they show a person’s name. Otherwise, they go.

That’s it. Please comment. Please don’t spam.

Fixing the Beall Collet Chuck

Published on January 1, 2011 in Machines. 10 Comments Tags: .

The problem, explained in the previous post, was that the cap for the collet chuck was improperly machined, so it had a ridge of metal inside that would push the collet off center before it was clamped down. The solution, just as it would be for a wooden cap, was to turn away that ridge without damaging the precision surface that touches the collet.

Collet cap mounted in a three-jaw scroll chuck.

The necessary turning didn’t demand precision. The ring just had to be turned away. So I mounted the cap on a metal lathe in a three-jaw scroll chuck. This chuck centers work within a few thousandths of an inch, and that was adequate for this job.

I wanted to be able to reach into the cap with a cutting tool, hooking around the threads and cutting away the ridge beyond them, toward the headstock.

The boring bar, ready to go to work.

Fortunately, I had just the tool for the job—a 1/2″ boring bar with a carbide tip brazed on the end. That tip reached a little beyond the bar’s side (toward the camera in the photo), enough to clear the threads and cut the ridge. I mounted the bar in a quick-change tool holder, then measured the tool holder’s position when the bar was just past the ridge, but not yet contacting the precision taper which holds the collet in place.

The final result – no more ridge interference.

After that, it was a simple matter to spin up the part and carefully advance the bar into the collet cap, cutting away a little at a time until the ridge was almost gone.

Here’s the final result. You can still see the remnant of the ridge, but it’s now concentric with the tapered hole, and it’s cut back far enough that it no longer touches the collets as I tighten them up.

What a difference! The properly machined cap pushed the collets in tightly without tilting them. Runout at the collet went from .007″ before to about .0005″. Of course, a metal lathe made the job easy. Otherwise, it would have meant a trip to a machine shop. Shame on you, Beall, for letting this part out the door in the first place.

The moral of the story? Check your tools before you blame yourself for problems. Even good quality gear from reputable manufacturers can have problems.

Don’t trust anybody!

Published on December 29, 2010 in Machines. 4 Comments Tags: .

All right, that’s harsh. But sometimes we blame ourselves for bad results when the fault lies with equipment we just assumed was fine.

I’ve been working with my home made rose engine lathe, learning what it can do. Rose engines (more about them in the future) are slow at removing wood, so I hand-turn blanks to roughly the right shape on my traditional lathe, then use the rose engine for final shaping. To get the best possible registration as I move work from one lathe to the other, I got a Beall Collet Chuck to hold the blanks. Collets are more precise than scroll chucks.

Or, are they?

I chucked a walnut rod into the Collet Chuck and turned it round, then moved it to the rose engine. There was .007″ of runout! What’s up with that?

I know, 7/1000 of an inch doesn’t sound like much. In fact, noted turner John Jordan once told me that runout like that makes no difference at all. But I’m using the rose engine to cut through walnut walls only .014″ thick, to reveal white maple inside. It’s an sgraffito technique (where you cut through one surface to show a surface beneath). .007″ is half the wall thickness, and quite noticeable indeed. The pattern was obviously wider and deeper on one side of the piece than the other.

A collet chuck with runout problems

Time for some detective work.

I first assumed I must have turned the piece carelessly. So, just to be sure, I put the Collet Chuck back on the lathe and chucked a piece of 1/4″ drill rod in it. When I measured the runout with a dial indicator, it was .007″. You can see the setup at the left.

Here's the problem!

I took the Collet Chuck apart and looked at the pieces. These chucks have precision spring collets, held in a tapered hole by a screw-on cap that forces the collets to move into the body and tighten up, rather like router collets. When I turned over that cap, here’s what I saw.

The collet cap in my hand has a tapered opening that bears on the collet, forcing it into the hole. But this cap must have been machined near quitting time on Friday afternoon. Note how there’s a ridge of metal just inside the rear hole, and it’s off center! That meant the collet would be pressed into the chuck body only on one side of the top, virtually guaranteeing it would seat off-center.

Isn’t that often the way it goes? Halfway into a project, we have to stop and repair the machine or build the fixture to make the next step possible. Coming up next, fixing the problem.

Time for some alcohol

Published on December 23, 2010 in Finishing. 8 Comments Tags: .

Posting’s been slow of late—not because of alcohol, but from a combination of the usual holiday madness and the labors in launching a start-up company. But presents are wrapped, the PowerPoint file is saved, and I have a few minutes to tell about an interesting finishing solvent. (BTW, I’m just a satisfied user. I have no connection to the company.) I used this on the leaf plate mentioned in the last few posts.

White lightning shellac solvent

Tools for Working Wood’s wholesale division, Brooklyn Tool and Craft (BT&C), recently introduced a shellac solvent that’s 99.5% ethanol (drinking alcohol), with a little bit of rubber solvent as a denaturant.

So what, you say? Well, if you’re a fan of shellac finishes (as I am), you’ve probably used hardware store “denatured alcohol” to thin your shellac or dissolve the flakes; typically Kleen Strip’s S-L-X brand. However, BT&C’s product, while admittedly harder to find, has some advantages.

First, there’s safety. Read both Material Safety Data Sheets (MSDS). Of course ethanol has its hazards, but they’re more to do with inebriation than casual exposure. Observe the cautions on the label and MSDS, but it’s a pretty safe solvent. S-L-K’s Denatured Alcohol, on the other hand, is 50%–55% methanol, a more dangerous alcohol which can cause severe central nervous system reactions, according to its MSDS. BT&C’s shellac also has a flash point about 12 ºF higher than S-L-K’s, giving a little more explosion safety.

Second, there’s a usage advantage. I used BT&C’s alcohol to dilute shellac both for spraying and French polishing. Confirming what the manufacturer claims, my coats seemed to dry harder and faster than the same shellac thinned with the S-L-K product.

You won’t find this stuff in most hardware stores. However, it’s available on line at www.toolsforworkingwood.com, and also at Woodcraft stores. Give it a try and see what you think.

The end of the autumn (leaf, that is)

Published on November 23, 2010 in Finishing and Woodturning. Closed Tags: , .

Some of you’ve wondered if I went to sleep or moved away. It’s been days between posts. But actually I’m working with a little start-up, planning their marketing. And, like all new companies, it takes a lot of time. Plus, the holidays are starting to take their toll in tasks.

this spot of end grain created some finishing challenges.

Anyway… I sprayed several coats of amber shellac on the leaf plate, but the blotch in the photo, where a branch passed through the plane of the plate, absorbed finish unevenly. The result was a dull spot. Fortunately, since I used a shellac finish, the solution was ready at hand—French polish.

French polish was probably the first gloss finish, before the age of sandpaper. It’s achieved by applying lots (and lots) of super-thin coats of shellac to a piece. It’s very labor-intensive, so it’s rarely used anymore, but it’s a quick solution to problems such as this.

I put three cotton balls in the middle of a small, lint-free, cotton rag. I poured a little clear shellac into them, then twisted the rag tightly around them to make up a “rubber”. I took care that the bottom was smooth, without wrinkles. Then, I put a drop of oil on the bottom of the rubber, which was just damp with shellac.

Here’s the leaf plate wearing its final finish.

Now, using a motion like an airplane landing and taking off again, I “touched down” on the spot and glided off again, let it dry for a moment, then did it again and again (and a lot more). Each time, the spot got a little glossier. Finally, the sheen matched that of the surrounding area, and I could let things dry for several days.

Coming back to the piece once it was thoroughly dry, I did my favorite final rubout. I rubbed the piece with 0000 steel wool, using paste wax as a lubricant. I let the wax harden for half an hour or so, then buffed the surfaces to an even, satin sheen. Now the plate’s on the shelf, ready to be a Christmas gift.

The colors of autumn

Published on November 7, 2010 in Finishing. 9 Comments Tags: , .

Airbrushing with transparent acrylic paints.

Raw wood doesn’t look much like autumn, and I deliberately chose birch for this project to provide a neutral canvas. I’d previously dyed the wood with yellow water-based dye, and now it was time to add the subtle color gradations of falling leaves.

I wanted the grain and woodburning to show, so I chose transparent acrylic airbrush paints. I could build them up in layers to get the color effect I wanted, and an airbrush would let me place the colors precisely.

Airbrushing in process

I mixed each round of color, then diluted it 50% with airbrush diluting medium so I could build layers more slowly. I began spraying green around the edges of the leaf, overlaid with redder and browner tones toward the center. I used the original photo of the maple leaf to guide me, but tried to capture its feel rather than copy it slavishly (which I couldn’t have done). The photo shows the leaf partway through this process.

Amber shellac—the next stage

When I was done airbrushing the leaf had lots of color, but it looked a bit garish. It needed mellowing, and my favorite solution in situations such as this is amber shellac. I cut Zinsser’s amber shellac 50% with BT&C’s excellent anhydrous alcohol (more about this in a future post), then sprayed seven coats with the detail gun you see in the picture. The result was a deep, mellow amber cast that blended the airbrush colors and looked like autumn.

But the finish wasn’t done yet. That pesky knot with its uneven gloss will be dealt with next post.