WB8NBS

NBS
This Blog will document projects I have
in progress or completed. You can search for my
handle on Flickr, Facebook, YouTube, or Picasa
for photos. I will link some of those here.

House for a Homeless Stanley

This page documents a White Oak  box I constructed in early 2011 to house a Stanley 45. It features a wood spine designed to hold the plane securely in place which I will describe in some detail.

As far as I can tell, this particular 45 dates from the late 50s. Almost new!  It was a Christmas present to myself. Actually, I already had a 45 but dropped it onto the concrete garage floor. In a fit of despair, I bid on this 45 on EBay and won.  Meanwhile I was able to repair the cracked main stock on the first 45 so now I have two of them working.

Neither came with an original box which was likely cardboard anyway. Hence this project.  Guess I will have to build two of them.

The first photo shows the plane side of the spine. The peg at left hooks the front of the skate on the 45. The plane then is lowered till the skate sits on the horizontal wooden ledge. Three magnets grab the main stock skate while the bottom of the wooden fence sits on a thin strip of Oak underneath the spine.

Finished Box Spine

Finished Box Spine

 

A Stanley 45 has sort of a turned up nose on the skates. That fits under the peg.  The flat strip of Oak under the Rosewood fence is necessary and is cut away at the front because the front tip of the fence pivots down a bit while hooking the plane under the peg, and needs additional clearance there.

Hooking the Skate Under the Peg

Hooking the Skate Under the Peg

 

The main stock side of the oak spine has to be relieved to accommodate the slitter stop and the depth gauge and there was minor chiseling near the dowel to get everything to fit.

It was my goal to not have to disturb the planes settings just to put it away in the box. Usually that succeeds, though the fence does have to be close in and in the higher of it’s two positions.

Main Stock Side of the Spine

Main Stock Side of the Spine

 

This is the “new” Stanley 45 plane nestled in it’s docked position. It’s snug and the magnets hold it down pretty well.

On this plane, the tote and fence are Rosewood but not the fence knob.  Stanley stopped using Rosewood about 1960, so this plane was probably made during that transition. The 45 was not made after 1962. I have not yet attempted to de-rust or otherwise clean this plane. Its clean enough to use. I’ve made a lot of Eleven Grooved Boxes with the two 45s.

Docked

Docked

 

Box joints for this project were cut with my lead screw box joint fixture, which is documented elsewhere on this Blog.  Grooves for the top and bottom pieces were cut with a Lee Valley Box Slotting bit  which works really slick.  It cuts a 1/8″ slot so needs two passes to get the 3/16″ groove I needed.  The July 2008 issue of  “Wood” magazine had an article (“Box-Slotting Bits”, Page 24) on using this bit, but unfortunately, it does not seem to be accessible on line. You just set up the slotting bit in a router table, dry fit the box with strap clamps, then set the box over the bit and run it all around the inside.

The next photo shows completed sides and bottom with inside components attached. There is a double grooved block on the bottom which holds the longer set of rods. Button magnets keep the rods in place and there will be more button magnets inset in the bottom to retain the two removable depth stops, and the cam. I made seperate thin sided boxes to hold the cutters, these are screwed in place along the sides.

Box Dry Fit

Box Dry Fit

 

And this is the Stanley 45 nestled in its new home.  I should have made the box a quarter inch longer, had to relieve the panel on the right side to allow the tote to seat all the way. The sliding top fits well enough that the plane can’t move much once the box is closed.

Dry Fit with Stanley

Dry Fit With Stanley

 

I did the glue up in the house as the garage was so cold that PVA wouldnt work.

About 120 box joint pins have to be coated with glue and the whole thing assembled at one time. I use Titebond 3 extend which has a long open time. You get at up to 15 minutes but that still means careful preparation and rehearsal is needed to get the thing together before the glue sets up. 15 minutes is used up very quickly.

I did stain all the interior surfaces prior to glue up as it would be difficult to get into all the corners later. Also liberal use of masking tape inside and out to control glue squeeze out.

On removing the clamps I noticed the box had racked a bit.  Next time I will use strap clamps with corner cauls on the panels. It will be much easier to check for and correct errors.

Clamp Time

Clamp Time

 

The box is finished and assembled.  It has had one coat of straight Minwax Golden Oak stain, two coats of 50/50 Golden Oak and Watco Natural, and a final coat of Watco Natural alone. After the Watco cures, everything gets several coats of paste wax.

You can see the cutters inserted in the two side boxes, long rods stowed at bottom left.  The cam and one of the depth stops are tucked away at top left, and the tongue stop stuck to a magnet at bottom right. Button magnets work well to control those little parts.

Finish Applied

Finish Applied

 

This is the docked position of the plane.  One of the medium width cutters is installed to check the fit and you can see the skates hooked under the dowel at the front.  Later I learned to store the cutters pointed end down. Please don’t ask how I learned that.

Stanley in New Home

Stanley in New Home

 

All the White Oak material was obtained from inch thick cutoffs. It was resawn on my table saw, thicknessed to 3/8″ using a lunchbox planer, and glued up into panels.

The lid slides in a 3/16″ groove which was made with the box-slotting bit. There is a 3/8″ inch radius sanded on the rear corners of the top plate to match the size of the slotting bit  A small lip at the front of the lid gives a better purchase for the brass latch.  The box bottom has a similar design.

That brass latch was way more trouble that it was worth….

All the Parts

All the Parts

 

The box can now be considered finished.  I let the finish cure for a few days then applied several coats of  Butchers Bowling Alley Wax.

Final dimensions are 6 3/4″ x 7 1/4″ x 11 1/2″.

The Money Shot

The Money Shot

 

It’s now May 2012 and I  finished a box for my second Stanley 45.  This one is made of Jatoba – a hard tropical wood with twisty grain which makes it a real pain to smooth out.

Jatoba Box

Jatoba Box

 

The second box is pretty much identical to the first but is 3/8 inch longer.  Please Don’t Ask Me Why the first box is shorter.  Also I made the cutter holders longer on the right side, and used more magnets in the long rod holder.

Second Stanley At Home

Second Stanley At Home

 

This Family Shot shows the new Jatoba box next to it’s older White Oak brother.

Two Stanley 45 Boxes

Two Stanley 45 Boxes

 

Automating the Box Joint Jig Lead Screw

I constructed an Arduino based controller to automate the carriage on my lead screw Box Joint Jig which was originally inspired by Matthias Wandel at woodgears.ca. Interestingly, Matthias added automated operation by a laptop to his design at the beginning but later removed the function in favor of multiple wooden gear sets. My jig was manual at first and automated later after I kept losing count of the crank turns

See this WordPress Blog entry on construction of my Box Joint Jig and also this Blog entry on some of the applications.

A video of the development breadboard in action is at www.youtube.com/watch?v=6Zz1fGDO5jw.

A video of the controller installed on the jig and working is at www.youtube.com/watch?v=URk4qYnEWgI

I used an inexpensive DC motor driven with a Polou MD01B H bridge, and added position feedback to the lead screw. This gear drive motor from All Electronics (DCM-697), was intended for actuating automotive power seats.  I sawed the shroud off the connector housing so I could use standard push on terminals.  The mounting base is a bit of hardwood flooring rounded out to fit the motor and hose clamped on. I can loosen the clamps and slide the motor to align the sprocket and adjust the chain.

Modified Power Window Motor

Modified Power Seat Motor

 

This shot shows how the lead screw shaft has been cut and ground down to fit the "D" shaped hole in the drive sprocket.

Window Motor Shaft

Seat Motor Shaft Ground Down

 

Two 24 tooth sprockets from All Electronics (GR-100).  They don’t come with a cap for the shaft collar so I made some from a piece of aluminium. Normally they have a “D” shaped hole. The sprocket on the left has it’s D intact – it will go on the motor shaft. The sprocket on the right has it’s D filed out round so it can clamp on the 3/8 threaded rod that drives the Box Joint Jig.  I have since replaced the motor side sprocket with a 42 tooth part to speed up the carriage motion.

24 Tooth Sprockets

24 Tooth Sprockets

 

Photo of the first test bed.  Power seat motor on left, Pololu motor driver (MD01B) above that, protoboard in the center and Arduino on the right.  Two buttons on the protoboard run the motor either CW or CCW.  The amazing little Pololu board has a VNH3SP30 H bridge chip which is less than 3/4 inch square but can switch 30 amps!

Bare Test Bed

Bare Test Bed

 

Since the motor is a simple series type, I need a way to inform the Arduino how far the shaft has rotated.  An optical sensor could be used but then there would be sawdust issues. Instead I use a Hall Effect sensor and permanent magnets.

This is the prototype position disc. It will go on the jig’s lead screw.  Quarter inch button magnets are coupled to six penny nails to focus the magnetic field and pressed into slots sawn in the disc.

Prototype Feedback Disc

Prototype Feedback Disc

 

Here the magnets and nails have been epoxyed and a coat of varnish applied.

This was intended to be a prototype but performs well enough that it probably will be the final.  The disc is 3 inches in diameter and will be taped directly to the motor sprocket for software development purposes.

Trimmed Magnet Disc

Trimmed Magnet Disc

 

Detail of the disc edge showing one of the six penny nails sawn off and filed flush.

The Hall Effect sensor (SS441A from Jameco) gives a clean transition when placed about a quarter inch from the edge of the disc. NO bounce observed (Yay!) so I can easily code an interrupt driven counter. Eight steps per rotation on the 16 TPI shaft will give a resolution of  0.0078125 inch at the carriage. One – One Hundred Twenty Eighth of an inch.

One of the Magnetic Poles

One of the Magnetic Poles

 

Since this is the Breadboard phase of development, I thought it appropriate to mount the parts on a real board.  At this point the motor software is done but the menus are not. A video of the development breadboard in action is at www.youtube.com/watch?v=6Zz1fGDO5jw.

Clockwise from the top:
– Chain and sprocket for the lead screw
– Sensor disk temporarily on motor
– Motor and mount screwed down now
– Hall Effect sensor glued to a stick
– Stick clipped to mount so its adjustable
– Arduino clone board
– 16×2 LCD display
– PWM pot (not used, will be removed)
– Proto board with LEDs and buttons
– MD01B motor driver

Final Development Breadboard

Final Development Breadboard

 

Here is the box I selected to hold the completed controller.  It is a standard electrical box from Lowes, but it has a bump out on one side that forms a nice surface on which to mount button switches. The lid of the bump out is molded as part of the box. You fold it over and it snaps on. You can do this about 3 times before the plastic hinge breaks off so plan the layout carefully beforehand. 30 Cubic Inches sounds like a lot until you start stuffing cables in there.

I amputated the 8 penny nails and mounting ears.  LCD and LED indicators mount flush on the top where the AC receptacle would normally be.

Electrical Box

Electrical Box

 

I think the box has enough holes now….  Putting the controller hardware into the box is more complicated than it seems. Just the box itself needs wires from two buttons, power switch, 12 volt feed, motor feed, two limit switches, and the Hall Effect sensor.

Outside, a blue Euro style block is glued on for the Hall and limit wiring, Two pin Molex connectors added for the 12 volt leads.  The box material is soft enough that it cuts easily with a utility knife.

Box With Wiring

Box With Wiring

 

Here is the Pololu MD01B motor driver in it’s new home. Have to use plastic screws because the plating around the mounting holes is electrically hot (why??).  This small sheet of aluminum fastens inside the box via the two countersunk holes visible just above the buttons in the previous photo.

Pololu MD01B Mounting

Pololu MD01B Mounting

 

The Arduino clone processor is mounted on the opposite side of the aluminum plate.  Four analog inputs and 12 digitals are cabled out.

Arduino on Mounting Plate

Arduino on Mounting Plate

 

Four LEDs and the 2×16 Liquid Crystal display are mounted on a piece of plexiglass cut to fit the top opening of the box.

Leds are:
slewing left
power on
hall sensor (added for coolness factor)
slewing right

Display Panel Front

Display Panel Front

 

This is the display panel seen from the bottom.  Four 2 wire connectors for the LEDs and a 10 wire cable for the LCD display.

The small connectors are salvaged from PC front panel displays, the multi wire connector is sawn off an IDE hard drive cable.

Display Panel Rear

Display Panel Rear

 

I used a Radio Shack PC board to make a central interconnect for all the buttons, limit switches, LEDs, Hall sensor, LCD display, and processor.  There is a 5 volt regulator for the logic side, pullup resistors and LED dropping resistors.  This cries out for a printed circuit board but since I’m only building one of these, it will do as is. I would have to work through this stage to design a PC board anyway.

Interconnect Board

Interconnect Board

 

Made a drawing of the interconnect board so I could remember where things plug in.

Interconnect Board

Interconnect Board

 

Final mock up to test wiring. All this has to go into the blue electrical box. Found two LEDs functionally reversed. One of the cool things about the Arduino is the pins are software defined so that took maybe a minute to fix in software. The 5 volt regulator got too hot for comfort so in a last minute change, I moved the regulator chip over onto the aluminum sheet – even more wires!

Final test Before Assembly

Final test Before Assembly

 

Well it does all fit, though it’s a PITA to find a place for all those wires.  This shows the completed controller connected to the breadboard motor mount having just made a 128 step (1 inch) simulated slew, sixteen revolutions of the sensor wheel.  Those two microswitches will be limit switches on the jig, and I will use an inline fuse in the 12 volt feed, couldn’t find room inside.

Testing Controller on the Breadboard

Testing Controller on the
Breadboard

 

This shows the motor screwed to the end of the jig, two sprockets, and #25 chain. These parts came from All Electronics.

It sticks out more than I hoped.  Maybe need some kind of guard to keep fingers out of the chain.

Motor as Mounted

Motor as Mounted

 

I made a small L shaped plywood structure for mounting the controller on the box joint jig.  The mounting is tall enough to protect the sensor wheel assembly and the right limit switch.

Controller Mounted on Box Joint Jig

Controller Mounted on Box Joint Jig

 

Mounted the left hand limit switch horizontally. It is very exposed so I cut off most of the actuating lever and made a guard out of aluminum.

Left Limit Switch

Left Limit Switch

 

This photo shows the sensor wheel mounted on the lead screw shaft. The Hall Effect sensor is epoxied into the small wood block just right of the wheel.  It gave me grief, it didn’t work!  After a lot of experimenting, I determined the Hall sensor is only sensitive on one side. I had glued it into the block upside down.  Turned it over and success!  You can also see the right limit switch mounted vertically.

Sensor Wheel

Position Sensor Wheel

 

I set the controller to slew sixteen inches. Ran it up and back about ten times, it always came back to the exact same spot.  Takes more than a minute to go 16 inches.  I will look for different sprockets to speed it up. The motor has plenty of torque, I put most of my weight on the carriage and it didn’t slow down a bit. I’m using an XBox power pack to supply 12 volts, it’s easily up to the job, but wish I could figure out how to get it up to 15 volts.

A video of the controller installed on the jig and working is at www.youtube.com/watch?v=URk4qYnEWgI.

Sixteen Inch Setting

Sixteen Inch Setting

 


Completed Box Joint Projects


 

A Roy Underhill Memorial Tool Tote.  About 30″ long, 9″ wide.  The yellow pine does not seem to take an oil finish well.

The box (finger) joints all cut on the automated lead screw jig.

Yellow Pine Tool Tote

Yellow Pine Tool Tote

 

Another smaller tool tote done on the automated jig. This example in Cherry.

Tool Tray in Cherry

Tool Tray in Cherry

 

These boxes made for my two Stanley 45 Combination Planes.

House for Homeless Stanleys

House for Homeless Stanleys

 

I made this to hold a small Variac transformer. Keeps my soldering iron at just the right temperature.

Variac Box

Variac Box

 

This Walnut, Butternut, and Oak box was made for my Brother-in-Law.

A Box for Johann

A Box for Johann

 

 

Compound Angle Box Joints

This is a practice piece for a larger project.  I wanted to make a tool tote like the one Roy Underhill carries in the introduction to “The Woodwright’s Shop”.  There is a description of the tray in Roy’s book “The Woodwright’s Apprentice”. His example is butt jointed and nailed together, but I thought it would be nice to do the tray with box joints and glue.  Thus started a journey into trigonometric hell.

Practice Piece

Practice Piece

 

The sides of this piece are 15 degrees from vertical (75 degrees from horizontal) which is close to Roy’s slope of 1 1/2″ rise over 5 1/2″ run.

The only other reference I had for compound joinery was a section in Tage Frid’s book “Tage Frid Teaches Woodworking, Book 1: Joinery” on hand cutting dovetails in a similar situation. Not for the amateur woodworker and difficult to follow.

Other references may be available – Google is your friend.

Strange things happen when you slope the sides of a box.  All the angles change and the side edges are no longer parallel.  People who install crown moulding are familiar with this.  I used the Butt Joint calculator at www.pdxtex.com/canoe/compound.htm.

To get the side and bevel angles needed for the project. It is easier for me to think of these angles as offset from vertical (90 degrees) so I entered 75 degrees as the side slope.

Compound Angle Calculator

Compound Angle Calculator

 

The table saw has it’s blade tilted to the calculated bevel angle (3.84 degrees) and the miter gauge tilted to the calculated side end angle (14.51 degrees from 90 or 75.5 degrees).

Cut the first edge with the miter gauge in the left hand gauge slot. It helps to label the faces as the small bevel angle is small and not obvious. The narrower face goes towards OUTSIDE of the pyramid. For my right tilt saw, the piece being cut off in this photo has it’s INSIDE face up in this photo. The next piece, on the left of the blade, has it’s OUTSIDE face up in the picture.

Compound Cut

Compound Cut

 

Now rotate the miter gauge 180 degrees and put it in the right hand slot. Flip the board over and make the second cut. The piece being cut off now has it’s INSIDE face up.

This method does not waste any wood, but every other piece has it’s face side reversed which may be a concern if you’re matching grain.

After all the pieces were cut out I ran them through the saw a second time with a stop block clamped to the miter gauge to ensure they were all the same width.

The final step in fabricating the four sides is to tilt the saw blade to the slope angle (15 degrees in this case) and bevel the top and bottom of each piece. I used the table saw fence to guide this, but watch out for kickback.

Second Compound Cut

Second Compound Cut

 

If the butt joint angles are cut correctly on the table saw, a straight edge held parallel to the top or bottom will show no gaps across the junction of two sides.

Joint Alignment

Joint Alignment

 

To dado angled box joints exactly parallel to the slanted top and bottom edges, the work pieces have to be held in the jig in the position they will occupy in the finished assembly.

I made two complimentary spacer blocks, one for the right edge of the work piece, and another for the left.  I first glued up a 3 inch thick blank from four pieces of 1×6 pine. This was trimmed and planed square.  Then I laid out the lines for the necessary slopes all the way around the block.

Angle Block Layout

Angle Block Layout

 

The next corner of the block.

I found it was easier and more accurate to lay out the lines by calculating and measuring rise over run rather than use a protractor.

Second Side of Angle Block

Second Side of Angle Block

 

This is the opposite corner of the block.  The layout lines go all the way around.

I made several of these blocks before I got the angles dialed in right.

Third Side of Angle Block

Third Side of Angle Block

 

The fourth corner of the prepared block. The next step is to slice the block along the layout line.

Fourth Side of Angle Block

Fourth Side of Angle Block

 

A Sketchup model of the jig spacer block.  Angles for this 15 degree project are 3.8 degrees on the long side, 14.5 degrees on the short edge.

The dimensions shown are approximate due to Sketchup limitations.

Sketchup Screenshot

Sketchup Screenshot

 

This shows me and Henry Disston dividing the block along the layout line. It’s easier than it looks.

For a good example of how to do this see www.pbs.org/woodwrightsshop/video/2800/2810.html where they slice veneer off a walnut block by hand sawing.

Splitting the Angle Block

Splitting the Angle Block

 

Here the two halves of the block have been smoothed, and pegs added so they will plug into my box joint jig.

Note the orientation. The block on the left will go against the jig on it’s square face. The block on the right plugs into the jig on it’s sloping face.

Two Setup Blocks

Two Setup Blocks

 

A view showing how the sloping faces of the spacers lay against the jig. One spacer tilts out 3.8 degrees and slopes 14.5 degrees left, the other tilts in 3.8 degrees and slopes 14.5 degrees right.

Side View of Spacer Blocks

Side View of Spacer Blocks

 

The dado stack has to be tilted to match the side angle. This aligns the slot with the top and bottom surface of the work piece. For this 15 degree side slope project, the angle is 14 1/2 degrees off vertical.

An additional complication is, now that the dado is angled, the slot will be slightly wider than the stack width. Box joints depend on the slot being exactly the same width as the pin, so the pin size has to be increased to match. For this 15 degree project, I added 0.012 shims to the dado stack and increased the pin cycle by 1/16 inch. It came out pretty close.

Wixey out the Angle

Wixey out the Angle

 

Finally the jig with spacer is ready for duty. Here one of he blocks is plugged into the lead screw jig carriage, the work piece and a backer board are clamped to the spacer and I am pushing through the dado.

Note the masking tape throat plate. The jig itself provides a throat for the Dado set, the tape just keeps down the sawdust.

Clamping the work piece at the necessary angle is difficult. I used tapered shims to get a straighter purchase for the clamps.

Clamping the Workpiece

Clamping the Workpiece

 

Since the stacked Dado set cuts a square bottomed slot, but the edge parallel fingers require a trapezoidal hole, there is a small triangle of material that must be removed from each of the slots by hand.

Here I am knifing the edge of the triangular area.

Knifing the Slots

Knifing the Slots

 

The small side of the triangular areas can be sawn.

Sawing

Sawing

 

One of (many) practice pieces showing the small triangular area at the top of each slot that must be removed. Here I have defined the triangle using a straight edge and utility knife, also the small side has been cut with the dovetail saw.

DSCF0324

 

Now to remove the waste from the triangular area with a paring chisel.

It might be possible, if thinner stock is used, to build a fixture and do the clean out with a 14 degree dovetail router bit. If I had to do a lot of these I would investigate but it doesn’t take long with a sharp chisel.

Paring the Slots

Paring the Slots

 

Not a bad dry fit.  The material is cupped a bit which left some spaces but I think it will pull together with sufficient glue clamps.

The sloped sides are going to be a problem on the glue up.  I will make some 15 degree cauls to keep the clamps from sliding off, also will use strap clamps.

Practice Piece

Dry Fit Practice Piece

 


Finished Compound Angle Projects


 

This is the finished Roy Underhill Memorial Tool Tote created with the compound angle box joint jig.

First Tool Tray

First Tool Tray

 

Close up of the compound miter box joints on one end of the tool tote.  I don’t have all the cool hand tools Roy has so this project was built with machines.

Corner View

Corner View

 

Detail showing how the handle is mortised into the end pieces. Just like Roy’s.

Handle Detail

Handle Detail

 

This is a smaller tray in Cherry.

Tool Tray in Cherry

Tool Tray in Cherry

Lead Screw Box Joint Jig


Jig Construction


There is an excellent woodworking site at woodgears.ca.  Matthais Wandel documents projects beautifully.  I was inspired by his box joint jigs, in particular the video at the end of woodgears.ca/box_joint/jig.html though I thought the gear part was overkill.  The premise is to use a lead screw to position the board while cutting the slots.  The usual technique for finger joints is to use an indexing pin on a sliding sled.  The problem with that method is any error in spacing between the pin and the blade will be cumulative, if you  cut 10 pins and they are each off  by 2 thousanths, the last one will be off by 20 thousandths.  The lead screw should be more accurate, it’s easy to cut multiple pieces at once, and quite large stock can be handled. This fixture will easily handle four inches of material stacked up.

This is the jig mounted on the table saw. It is 11 x 40 inches, will be able to handle 18″ stock in a single pass. Material for the miter slot rails is plastic coated MDF.

Box joint jig and table saw.

BoxJjoint Jig and Table Saw.

The lead screw is 3/8″, 16 Threads Per Inch so one turn of the crank advances the carriage exactly 1/16 inch. In the photo, the block on the right end is fixed to the carriage and has a T-nut to engage the rod. The doubled block also has a T-Nut but is floating (not attached to the carriage). Springs between the fixed block and the floating block take up any backlash in the lead screw. The rest of the blocks support the carriage face and also protect the threaded rod.

Lead Screw

Lead Screw Nut Anti Backlash Springs

At the crank end, a soft rubber washer provides tension on the rod to eliminate backlash at that point. The rod protrudes an extra inch so I can use a 9/16 socket in a drill to rapidly slew the carriage back to the end. 18 inches times 16 TPI is a lot of cranking.

Lead Screw Crank

Lead Screw Crank

This shot shows how the carriage is mounted on two full extension drawer slides, one on top, one on the rear. Each has a maximum travel of 18 inches, and since they are mounted at opposite ends, when one is at maximum extension the other is at minimum extension.

I was surprised at how rigid this was.

Lead Screw Extended

Lead Screw Extended

This is the other end of the fixture. You can see the rear mounted drawer slide. I will be cutting a port for the shop vac in the end piece as soon as I figure out how to couple in the hose.

Keeping sawdust out of the ball bearing drawer slides may be a problem. I have an Aluminum extrusion modified to slip over the rear slide for protection.  In practice, sawdust has not been a problem after adding the shop vacuum coupling.

Left End of Box Joint Jig

Left End of Box Joint Jig

This is the face of the carriage. Also shows the board added across the front of the sled for stiffness, and you can see the two runners fitted in the saw’s miter gauge slots.

Front View of Box Joint Jig

Front View of Box Joint Jig

You can cut all four sides of a box and stack the pieces in the fixture. There’s two clamped up in this photo. If you do all four at once you need to offset two of them by the width of the slot. See the video on Woodgears.ca.

Normally you need a sacrificial backer board between the carriage and the stock because the slot in the jig gets too big.

Box Sides Set Up for Cutting

Box Sides Set Up for Cutting

These were cut on the jigs maiden voyage. Actually the second try, I screwed up the first set. The material is half inch MDF left over from another project.

Part of planning a box joint or dovetail project is figuring out the pin width that leaves a good half pin on the ends. Clearly that didn’t happen here, but it works OK just looks odd.

Four Box Sides Ready for Assembly

Four Box Sides Ready for Assembly

The box joints fit well though a hair loose. These are half inch pins, two 1/8 chippers in the Freud Dado set. A perfect fit would require narrowing the dado set a few thousandths but it’s good enough as is.

Dry Fit

Dry Fit


Completed Box Joint Projects


Toy Box for the Granddaughter

This is wood salvaged from an old Pine table, had a nice patina even after planing off the epoxy paint.  About 24″x15″x12″.

Toy Box

Toy Box

Toy box opened. Spring loaded holder upper gadget from Menards.

Toy Box Open

Toy Box Open

Box joints are half inch pins, one inch pitch. The banding top and bottom was fitted, then cut with one eighth inch box joints. Biscuits reinforce the banding.

It was quite an effort to glue this up. I did all four corners at once with slow setting Titebond which gave just enough time to get every clamp I own on the box.

Toy Box Detail

Toy Box Detail

 

 

Garden Planter Frame

The previous owner of this house had made a planter box from treated 2x12s around a back yard tree. The tree grew and pushed the box apart so I replaced the planter with a larger box made of Cedar.

I used box joints with half inch pins to assemble the new planter. The new box was more than four feet on two sides, I had to move the table saw to the driveway because the boards clamped to the carriage hit the roof trusses in the garage.

Cutting Fingers for Planter Box

Cutting Fingers for Planter Box

Each side was formed from two 2×6 Cedar boards. Two opposite sides had one 2×6 ripped in half so adjacent board seams don’t line up when assembled.

One Completed Edge

One Completed Edge

I assembled each pair of sides and bored a 3/8 hole all the way down through the pins. Then I inserted a 12 inch long galvanized nail to hold the joint together at each corner. There is no glue.

Corner Detail

Corner Detail

The final assembled planter. Under the dirt I put 4 inches of gravel inside hoping it will drain better and last longer.

Planter Installed

Planter Installed

Notes on the Roubo Bookstand

A Roubo Bookstand is made from a single piece of wood. It opens as pictured or folds flat. The design is actually much older than Andre Roubo (he wrote in the 1770s), it is a traditional form for supporting the family Quran.  Searching the Internet for “Roubo Bookstand” will keep you busy for many hours.

Here is plate 331 from Roubo’s book.

Plate331

Plate 331 from “L’Art Du Menuisier”

 

The project is based on a “Woodwright’s Shop” episode from season 31, 2011-2012. Many thanks and credit go to Roy Underhill. You can view it here or here  and you should to fully understand the material in this post as I won’t show steps here that duplicate Roys.  There is a downloadable plan here.

I’ve made this my hand tool project for 2014 and done several in soft wood for practice. In this web page I document methods and tools, especially where they differ from Roy’s.

I used construction grade 2x4s or 2x6s for practice pieces. The 2×6 version makes a fine Roubo IPad stand, the 2×4 size makes a dandy Roubo stand for a cell phone.

Roubo Tablet Stand

2×6 version Roubo Tablet Stand

 

Roubo Book Stand

2×6 version with a 7 inch tablet in place

 

I use this stand every week watching “Ask an Engineer”.

2x6 Stand with Nine Inch tablet

2×6 Stand with Nine Inch Tablet

 

I don’t own a smart phone but I borrowed one for this photo of the 2×4 version.

2x4 Roubo Cell Phone Stand

2×4 Roubo Cell Phone Stand

 

In the the next picture you can see two modifications I made to Roy’s plan. Both changes make the stand sit more upright making reading easier, and less likely to tip over. I shorten the front feet about 25%, and also inset the hinge pockets a bit, 3/32″ on this one inch thick stock. That keeps the stand from opening to a full 90 degrees.

Roubo Bookstand

2×6 Roubo Ipad version

 

In this page, I’m making a pair of cell phone sized stands from a 14 inch piece of Red Oak.

The hinge pocket inset requires angling the chisel when chopping out the pockets. I draw layout lines tangent to the hinge barrel circle just as Roy shows in his video, then add lines inset 3/32″ towards the center line.  1/16″ pilot holes for starting the saw cuts that define the hinge barrels get drilled along the inset line, not on the tangent line.

Modified Layout

Hinge shoulder position is changed

 

Here I have drawn a line from the inset to the barrel tangent. The pocket must be chiseled out along this angle, about ten degrees.

Angled Cut Line

Angled Cut Line

 

With the hinge layout complete, the next step is to saw down between the individual barrels. I tried Roy’s modified hack saw blade but got poor results so I acquired a jewelers fret saw. The problem is, these saws have a fairly narrow throat so can’t be used here in the normal way. I had to turn the blade 90 degrees so the fret saw could be held sideways.  The nose fitting on this saw can be rotated a quarter turn, but the handle clamp is fixed. I found however, that I could clamp the blade in a sideways position.  If you look closely below, the blade teeth are pointing towards the top of the photo, not out.

90 degree fret saw

Modified fret saw

 

So now the fret saw can be used off the side of the work, though it still has to be carefully supported at both ends of the blade. There is enough range to cut hinges in the 2×4 or 2×6 version but I’ll have to get a bigger fret saw for larger stands.

In the photo below you can also see half inch deep cuts across the end grain to start the lengthwise ripping that ultimately separates the two parts of the stand. These initial cuts were done with a Tom Fidgen-esque kerfing plane.

Cutting Hinge Pocket Slots

Cutting Hinge Pocket Slots

 

This Red Oak example is laid out two up. A pair of bookstands will be cut from a single long board, Roy mentions Roubo’s writing on this in the Woodwright’s episode – “to avoid the great loss of wood”.  The two tall back sections are laid out overlapping and separated with a frame saw after removing part of the overlap.

My frame saw is a Craftsman originally intended as a wall decoration. I bid on it in a moment of weakness and seriously regretted when UPS dropped it off. The blade was coarse with way too much set. I have since changed to a nicer blade cut from an old rip saw, and made special blade supports to use with this project. At this stage I will saw down to about a half inch from the hinge layout, leaving enough wood to absorb the stress of chiseling hinge pockets.

Frame Saw in Use

Frame Saw in Use

 

You can see in the photo above that the frame is held at an angle so it’s behind, not directly over the cut. I have made steel blade supports and twisted them 15 degrees. The modified saw works well and produces a fairly clean, straight kerf with not too much effort, even in this hard wood.

Angled Frame Saw Blade Bracket

Angled Frame Saw Blade Bracket

 

The result after separating the pair of blanks and shortening the part that will form front legs.

Two Roubo Stands

Two Roubo Stands

 

I chose to lay out the top and bottom curves at this time. This can wait until the stand is officially open but is easier while the blank is still a solid block. I use three templates, one for the top curve, one for the rear foot ogee, and a shallower ogee for the shortened front foot.  The templates have half the desired curve. The vertical edge is aligned along the stands center line, half the curve drawn, then the template is flipped and the other half traced. Symmetry is assured. I added masking tape in this photo so I could draw with a Sharpie for the camera.

The top and rear leg profiles can be cut at this time with a coping saw but the front leg profile has to wait until the stand is fully open.  I’ll wait and cut them when I need a break from chiseling.

Ogee layout

Ogee layout

 

Chopping out the ten hinge pockets is done per Roy’s brute force method – firmer chisel, followed by paring chisel, followed by sharp knife.  The inset hinge shoulders mean there is less room for the chisel but it can be done. In the next photo I am using a small bevel gauge to help guide the chisel to the necessary 10 degree angle.

Chiseling hinge pockets

Chiseling hinge pockets

 

After all ten pockets are cut, the last half inch of the dividing wood must be removed. Roy called this “going flat” and he clamps the piece in an end vise. I only have an iron shoulder vise so that’s where it goes. I found clamping a pair of hardwood blocks at the hinge tangent line makes it easy to tell when to stop sawing.

Sawing the Final Half Inch

Sawing the Final Half Inch

 

After an hour and a half of tweaking, paring off spots that were binding it finally opens all the way. It helps to open it as far as it will go then hold the saw kerf  up to a strong light and look into the hinge pockets. You can see places that are not completely separated or are binding.  Don’t use force, the wood will splinter. Just work with it gently until both parts are moving independently.

In this photo you can see another Secret Weapon. Utility knife blade that have the corners cut off. These are tough enough to be pounded into the hinge pocket with a ball peen hammer.

Finally Open

Finally Open

 

I’ve been cleaning up the saw marks with a low angle block plane or my trusty Stanley 5 1/4  followed by coarse sandpaper but on this hard Oak I used a card scraper after the plane. Because the stand doesn’t open to a full 90 degrees, planing these surfaces is hard on your knuckles.

When the stand is opened, it will sit on just the inside edges of the feet so its a good idea to bevel them.  It’s also a chance to tune the feet to eliminate any wobble.  My procedure is to clamp the stand upside down in the vise, then plane a few strokes on each corner with a slicing motion. The plane has to be long enough for the bed to rest on the opposite foot for reference, so I’m using the 5 1/4 in the next photo.  Check the stand often on a flat surface to see if you’ve eliminated all wobble.  For extra credit, tape a sheet of sandpaper to a flat surface and slide the stand across it a few times.

Beveling the Feet

Beveling the Feet

 

I like to stain Oak projects with Minwax Golden Oak. That will be followed by three coats of Watco Natural applied with my sandpaper spit shine technique, then paste wax.

First Finish Stain

First Finish Stain

The Eleven Grooved Box – Tools Update

I have an improved fixture for making Eleven Grooved Box splines.  Roy Underhill’s video shows the spline blank placed in a grooved block. Then the blank is planed to size with a block plane.  The problem is, this eventually cuts some off the top surface of the grooved block causing the splines to come out too small. Then the splines won’t do their job well and look terrible.

My improved method has three secret weapons:

  1. A Kerfing Plane to make the blanks
  2. A modified Dado plane with skewed blade
  3. A sizing block with a channel to guide the modified plane

Secret Weapon #1

Tom Fidgen, in his book “Unplugged Woodshop” describes a kerfing plane. You can get parts to build one from Bad Axe Tool Works. Toms kerfing plane looks a lot like a stair saw with a fence, you can see it on his web site.  My version is made from a vintage plow plane and a blade cut from an old rip saw. It’s easy to cut  a tempered saw blade. Just score it on both sides with a Dremel grinder and cutoff wheel. Put the blade in a vise and flex it, it will break along the score line.  The next problem is drilling holes in the hardened blade. It will wreck a conventional twist bit, but I had good luck with carbide tipped masonry bits.  First, center punch the hole positions well, drill a pilot hole with a 1/8″ masonry bit, then finish with another masonry bit sized to fit your screws.  Use plenty of oil while drilling.

 

Kerfing Plane

Kerfing Plane

 

This old plow plane has an inch or so of the adjusting threads stripped so I added a spacer block to the fence to skip over the bad spot. The next photo shows the kerfing plane making 5/16 inch deep slots in the end grain of a Walnut scrap. The modified plane is accurate enough that I can easily slice four spline blanks from this 7/8″ thick bit of wood.

Kerfing plane in use

Kerfing plane in use

Now that three kerfs are cut, use a backsaw to cut the four spline blanks free. I kerfed both ends of the Walnut scrap while I was at it.

Cutting the spline blanks free

Cutting the spline blanks free

The end result after a bit of block planing to remove saw fuzz. Eight spline blanks ready to be trimmed to size.

Walnut splines

Batch of eight Walnut splines

Secret Weapon #2

I always had trouble using a block plane to trim the blanks. The plane would sometimes catch the blank and break it. Since these are planed across grain, then on end grain, the plane has to be held at a skewed angle. That makes it awkward and even easier to damage the sizing block.  I have a “vintage” 3/4 inch wide dado plane with a good skewed blade. That would do a nice job on the cross grain blank but would certainly tear up the sizing block. I thought about how a shooting board constrains the blade with the small bit of iron sole below the blade. A dado plane has a full width blade so that won’t work, but the solution I’m using adds outboard hardwood skates to the plane. These will stop the cut at the appropriate depth if I make a runway on the sizing block. The skates are made from a strip of Maple hardwood flooring sliced in half down the middle, then clamped onto the dado plane.

 

Modified Dado plane

Modified Dado plane

This photo is an end view of the modified plane. You can see at the bottom where the Maple has been thinned to 1/8″ on each side to form skates. Skate may not be the best term as these are used as guides and as a depth stop. They are adjusted to be even with the sole of the plane.

This outrigger skate technique would also work with a shoulder plane. Or you could make a wider sizing block and just use a block or smoothing plane, in which case you wouldn’t need the skates. The iron on either side of the blade would serve the purpose.

Modified Dado plane

Modified Dado plane

 Secret Weapon #3

For the modified plow plane to work, we need a sizing block that has a channel to guide and stop the skates. I made this on the table saw using a stacked dado blade set. The wood is from a backyard Apple tree, very hard. In this photo you can see the profile, wide channel for the plane on top and bottom, a groove for trimming thickness on the top, two grooves (with slightly different depths) for trimming width on the bottom. I cut the thickness groove a little too deep so it is shimmed with Post It note paper.

Spline sizing block

Spline sizing block

The other end of the sizing block has a stop screwed on. It’s removeable to make it easier to recut the grooves if necessary. Both ends are drilled to accept the stop. The sizing grooves are not centered so moving the stop to the other end from time to time will help even out wear on the dado plane blade.

Sizing block removable stop.

Sizing block removable stop.

Using the jig is a simple matter of clamping the block in the vise, inserting a blank in the groove and go to it.  Always plane the blank to proper 1/8″ thickness first and turn the blank over a couple of times so both sides are dressed. Here you can see how the channel in the sizing block is guiding the plane. The cut stops when the skates hit the bottom of the channel.

Thickness planing a spline blank

Thickness planing a spline blank

Coming out of the first step we have a blank evenly thicknessed to an eighth of an inch.  Also in this photo you can see the port sawn into the side of one maple skate to allow shavings to exit.

Spline planed to 1/8" width

Spline blank planed to 1/8″ width

The sizing block is now rotated in the vise so the quarter inch deep grooves are up. The thicknessed blank seats in one of the grooves where it can be trimmed to exactly a quarter inch width.

Width planing a spline blank

Width planing a spline blank

This final photo shows the completed cross grain spline accurately sized to 1/8″ thick and 1/4″ wide.

Finished splin

Finished spline

These three Secret Weapons work really well and make spline production easy.

Fun with Vectors

Recently on the Workshop88 mailing list, there was a discussion of things that could be shown at the STEAM fair (STEAM stands for Science, Technology, Engineering, Art and Math) at Glen Ellyn Public Library March 8.  Jim Williams said an oscilloscope is a good thing to generate interest.  I added the link to the oscilloscope vector Christmas tree that made the rounds two years ago. That was such an intriguing hack that I built it immediately. It requires only four parts besides the Arduino and the scope.  Arduino does not have Digital-Analog Conversion hardware but the mega328 chip can do Pulse Width Modulation and johngineer uses that capability, integrating the pulse train in an RC network for his Christmas tree. Here’s the tree on my ancient Kikusui 5630:

Vector Christmas Tree

Vector Christmas Tree

Many people commented in johngineers blog and offered other vector images.

The possibility of an analog scope demo at the library set me to searching the internet for other interesting vector applications.  I found this Youtube video encouraging, and there are a number of vector clocks out there.  Then I found a page from hudson at the NYC Resistor makerspace site discussing vector generation on the AVR chips. That post mentioned the Hershey simplex fonts, with a link to a discussion and code. That implementation appears to be very old as the ^ (circumflex) symbol renders as an up arrow and that change was made to the ASCII character set in the sixties. It’s a proportional font and there is a column for the character width.

I decided to try implementing the Hershey font using johngineers simple RC integrating network.  After some manipulation and scaling the font table I was able to display single characters entered from the serial port of the Arduino:

Vector display "at" sign

Vector display “at” sign

This is the absolute worst case glyph, uses all 56 vector pairs.  One problem with vector fonts is the more vertices, the longer it takes to render the character.  A problem that is exacerbated by the RC integrating network.

Some of the Hershey characters have skips indicated by a -1,-1 XY value pair. For example, the equal sign is rendered as two disconnected lines. A skip indicates that the vector trace needs to be turned off while moving to the next point.  Fortunately my old oscilloscope has a Z axis input and by using a third Arduino digital pin, I was able to easily implement blanking.

Here’s a picture of the Arduino showing the two integrating networks.  The black wire goes to ground. My scope’s Z axis is connected through a third 10k resistor.

Arduino with X and Y integrating networks, and Blanking lead

Arduino with X and Y integrating networks, and Blanking lead

I found the Arduino quickly runs out of memory when you’re dealing with a 95 x 112 array so I had to learn how to force data into the flash program space using the PROGMEM keyword.  I found an example that did almost exactly what I needed to do.

I’m old enough to remember Don Lancaster’s TV Typewriter. I thought it would be an even more interesting display if I could get multiple characters on the scope. So much programming and debugging later I have that working.  I only made a 2×5 display as it’s just too slow.  Filling all ten vector characters with the worst case @ sign takes close to a second to write the screen, but normal text is easily readable.  Here is a group of letters:

Vector display of letters

Vector display of letters

and here is the number display:

Vector display Numerals

Vector display Numerals

Displaying multiple characters also requires blanking the trace between glyphs.

The Serial debug console that comes with the Arduino IDE can be used to enter text but a character-at-a-time terminal program works better. I use Minicom.

Note the rounded parts are much brighter than straight lines. This again is because there are more closely spaced segments and therefore the curves are painted more slowly.  Also note some characters are distorted, like the seven above.  I think this is because he RC integrating network continues to integrate the previous move while the next move is being generated. The first character position in each line is particularly subject to this distortion because the beam has to move a large distance from the last character.

The NYC Resistor page implementation does not use Arduino PWM, he uses an R-2R ladder DAC. This would be a great improvement from my simple RC network as all the delays in the sketch needed to wait for the RC network could be removed.

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