Baby crib design start

Now that we have a starting point for the design, it is time to start gathering dimensions from the photos.   Traditionally, I have done this by printing photos at half or full sheet and then scaling it manually.  My goal when borrowing from an existing design is not an exact replica but rather using the original as a model to start for overall proportions.  I am not into doing reproductions. Additionally, in this case I am making improvements in the design.

First, I will note the major known dimensions. In this case it is overall height width and depth. This is done on each photo. Do not assume (or forget) that the scaling will be different in each  image.  Next the actual size in the photo for these is measured and the scaling amount calculated. I will normally do the actual measurements in mm to make the math easier (avoiding fractions). You can use a caliper or ruler – I like using a caliper.

I double check that the X&Y dimensions yield similar results.  If all you have is an angled or isometric view then this gets more complicated. Now I take measurements of measured features and do the math in a spreadsheet so I have a listing of my measurements and can easily double check for errors in case of a conflict.    I will also do the actual photo measurements in one color and the final scaled in another to avoid mix-ups

I will typically start on paper and make sure that the dimensions make some sense before transferring to Sketchup.

You can also import a photo into sketchup and then start drawing your components on top of it.  For rectilinear pieces it is better to use it to set a few lines and then draw as you normally would. Trying to match the photo underneath will otherwise lead to errors and out of parallel edges.

Here I have started with the curved end pieces. With the rudimentary curve drawing tools in Sketchup (arcs, lines and bezier curves) it took a lot of tries to get something that looked decent. I wish I could have gotten the NURBS lines to work which offer much more control.  At this point I will lay down a couple of lines to mark the lower rails and then hide the photo. So now I can move into 3D space.  each of the parts show becomes a component so I can mirror them for the other end and all of the modifications transfer as I work back and forth.

The top and bottom rails are then fit to the end posts.  Now I mirror the ends, and set them approximately the right distance apart. I am still not sure if the end top and bottom rails will fully or partially overlap the legs.

Next come the bottom rails and I then draw guide lines up the leg posts to show where the top rail should line up vertically and the  offset for the spindles from the inside edge.  The inside spacing is an important dimension as you are only allowed 28 +-5/8″ by CPSC guidelines so you don’t have too big a gap around a standard crib mattress.

The front top rail is next. It took a few tries to get something that is not too thick.  I may still make it a bit taller. Lets see after the rear top rail is in place. 

Now with the the back rail placed, and the frame colorized you can see the shapes better. I think it looks better with the taller top rails, but lest see what the girls say tomorrow.

Baby Crib Project

Baby Crib Project

My daughters, Jessie and Elyse, are both due at the end of March 2018. Jessie still needs a crib. So the question of: “What is the next project?” has been decided, and I have a rather short timeline. However, if push comes to shove, she can use the same cradle that she slept in as a baby that my dad made, while I finish the crib.    This is another project where I am following in my Father’s footsteps making things for the grandkids.

Basic requirements:

  • Solid back – avoid little fingers finding outlets and easier cleanup after dinner gets launched. Flat panel rather than raised panel per Jessie’s preference.
  • Adjustable mattress height
  • Convertible to a bed.  This will make it last, rather than be a 2 year item.   Appearance as a bed will take precedence over appearance as a crib.
  • Follow CPSC guidelines for safety.  This includes no cut outs – so much for Mackintosh style slats I had wanted to do on the CNC router (besides Teal and Jessie are not fans).
  • Design needs to complement the other furniture I have made for Jessie which is of a craftsman style and have the same finish

So we have been digging through many Google Images, Pinterest, LumberJocks and many other websites looking for ideas as a launch point.  There are a lot of ugly cribs out there! Besides, many designs that look OK as a crib  do not look very good as a bed.  On top of it you have the predominance of MDF and particle board based junk that is on most of the web sites.

Given that Jessie is expecting a girl, I was hoping for a sleigh crib / bed sort of design. However, many “sleigh cribs” have weird lumps for curves that seem to have been tacked onto an otherwise square leg. I want something that will be smooth and flowing.  Plus, this will give me another excuse to play with the CNC router. Although, a band saw and spokeshave or template and router would probably work well, too.  For Elyse’s queen size bed, the curves were laid out on a template and then pattern cut with a band saw and router.  Her bed (ca. 2009) is shown below.

Now, I want to do something that is more “organic and flowing” for the end posts rather than ending squarely at the floor.  This is a tall order for an engineering mind.

Safety

Much has been said about the changes in safety standards for cribs. The slat spacing requirements have changed, no more drop fronts (yeah!). However I was still worried about safety and started more research. The primary resources I used are:

Where to start?

After several evenings of web searches and IM messages back and forth with Jessie, a leading candidate for the basis of the design emerged.   It is the “Franklin and Ben Mayfair Crib”.   For an example see:  Mayfair Crib  This was the first site that it popped up on. Others sites list it as discontinued.

This is just a starting point. As on many projects, I will look at multiple designs and then take the pieces I like and modify for more robust construction and the techniques that I prefer.

Things I like in the design:

  • The outside sweep of the posts – especially the inward curving feet and no “lumps”
  • Curved top rails (teething deterrent). These will end up looking more like Elyse’s sleigh bed
  • Looks nice as a bed
  • Nearly solid back
  • Openings at the ends of the back panel

Things that must be improved:

  • Flat panel in back looks like it was tacked on
  • Lots of fasteners and holes showing
  • Flat inside edges of the legs when viewed from the side
  • Extra side and bottom parts hanging on when converted to a bed
  • Front bottom rail – likely will be removed as this will not be a day bed  but rather converted to a full size directly (pending approval)

So now I need to gather basic dimensions and start the new design.

Finishing Touches on the Dresser Project

Completion and Finishing Touches

Final Drawer Alignment

The drawers are inset by 1/8″. This is done by having them held in place with squares as shown or a wooden jig. It is important to have both front corners held in place at once as it is very easy to accidentally move the drawer while gluing and pinning the stop blocks in from the back. I prefer to use pins rather than brads to secure the blocks while the glue dries.   The blocks are rather small and brads will often cause them to split.  I also typically use thick superglue for this step.

Hardware installation

When marking the drawers for the hardware you can either make dedicated jigs or mark each drawer. For this I use masking tape and a fine point Sharpie. The reason for the sharpie is that no pressure is required and there is not a chance of a line telegraphing through the tape into the finish as with a pencil, especially for softer woods. Also if there is an errant mark on the drawer from the Sharpie, it is easily removed with xylene and does not harm the finish.

Note that I have also placed marks on the square so I have a firm reference and avoid mistakes.   For the vertical alignment I run the marker along with a square set tot the correct distance from the bottom of the drawer- direct transfer rather than more measuring.

Each of the kids wanted a different style of hardware.  Jessie selected glass knobs. These have screws permanently attached which are too long. Rather than measuring and marking each one individually, I made the spacer block shown below. This made the cutting much easier and helped prevent them from turning while cutting on the bandsaw. I plan to use this trick when cutting other screws on the bandsaw in the future.

Backs

The backs are covered with  1/4″ plywood. The oak plywood shown was actually quite reasonable.

The notches in the back are hand holds. They line up with the bottom of the 2nd row of drawer supports. Each is about 1.5×5″. This makes moving the dressers much easier, especially up and down stairs.

 

Tops

The tops are screwed on from below with #10 1 1/4″ flat head screws run up through the front and back rails.

Front Leveling Feet

When placing dressers against the wall on carpeting, they will typically lean forward. This is due to the rear feet being on the perimeter tack strip under the carpet. Adding screw in leveling feet in the front corners allows you to then raise the front until the back is again parallel to the wall.

Final results

Jessie’s

Elyse’s

Actually it is for Sawyer’s room. He sure seems pleased.

David’s

In this shot I am still waiting for the rest of the handles and next time I need to remember to dust before shooting photos.

Finished!

This has been quite the project and it is nice to have it completed. Now I just have 2 more deliveries to do and then straighten up the shop for the next project.

Staining the dressers

Finishing for “pop”

With the quarter sawn oak, I want to enhance the grain figure while also making the mix of white and red oak piece blend together.  Additionally the finish requests were for 2 different colors.  David and Elyse wanted a traditional Mission Oak style color and Jessie wanted a “Cherry” finish. This matches the colors of the beds and dressers I had made for them previously.   The technique borrows from one that I had learned from Jeff Jewitt of Homesteadfinishing.com at a Wisconsin Woodworking Guild class a number of  years ago.

Technique

The finishing schedule uses a base coat of dye, a barrier coat that locks in and protects the dye which is then sanded, a gel stain and top coats. I prefer to spray the finishes as the dyes can be tricky to do by hand  and it goes a whole lot quicker.  However if you are heavy handed with the coats they will tend to mottle. Go lightly and build gently – more coats is better than 1 heavy one.  RESIST the urge to touch up the dye. It WILL appear to be uneven when initially drying but trust that you have laid it on evenly ant it will turn out in the end.

For David and Eyse’s:

  • Transtint medium brown dye in alcohol (1 oz to 1 qt)  – 2 light coats
  • Blond shellac 1.5 lb cut – Zinsner seal coat dewaxed  diluted by 50% with alcohol.  Apply 2 light coats.
  • Sand 320 grit  – full scratch – no glossy spots
  • Minwax Bolivian Rosewood Gel stain. Wipe on, let sit 10 min and wipe off (hard)

After the shellac  (this was a bit heavy, leading to some splotching prior to sanding)

 

After Sanding . 320 grit full scratch.

After gel stain

For Jessie’s

  • Behlen Solarlux dye – Golden Fruitwood – 2 light coats
  • Garnet shellac (hock or shellac.com) 1.5 lb cut – 2 light coats.  Garnet shellacs vary in color a lot.  I use a “red” garnet vs a “brown” garnet
  • Sand 320 grit  – full scratch – no glossy spots
  • General Finishes gel stain – custom mix – 2 parts CandleLight to 1 part Georgian Cherry

For all

Apply finish coats  – typically 4 coats sanded after 2 coats and then final 2  – all sprayed

If spraying indoors in the winter I use General Finishes Endurovar Pre cat Urethane.  With 2 coats gloss and 2 coats satin. If you do all satin it will appear cloudy. All gloss and it is too shiny and I have not had great success rubbing this one out to satin.

If spraying outdoors I use Sherwin Williams Pre-cat Lacquer  Hand rubbed satin finish.   This stuff is wonderful.

Safety

All of these have some level of toxicity or at least particulate damage to your lungs. Spraying indoors is hazardous.  Any flammables (including alcohol) in the finish pose a fire and explosion hazard and lacquer certainly is a good way to make your house go “BOOM” which is why I only use it outdoors.     Relying on open windows or doors is not enough and in our wisconsin winters it is a serious problem (low temps and high winds on my west facing shop door).    For this project I was finishing while it was -5 to +8 F outside.

Wear a respirator and make sure the filter cartridges are fresh.  I sometimes forget with shellac and end up with a headache and decreasing finish quality during the session  – typically getting too heavy as the alcohol takes hold.  Not recommended. Water based finishes still have solvents in them and the particles are nasty lung irritants.   I also run a ceiling mounted air cleaner when finishing (box with a furnace blower and filters) which helps a lot.

Drawer ends

With the dovetail ends, the question arises of: “Where do you end the stain?”   Stopping at the edge of the top leaves light lines in what should be the shadows of the drawer edges and ruins the separation effect. Just swiping down the sides is ugly. Trying to stain all the individual dovetails is madness. So I mask off at the top of the dovetails and stop staining there. It makes for a nice transition.

 

All of the photos are without the final finish coats which will add yet more depth. However, I need to let the stain cure for at least 3 days and a few above zero days to apply the finish (to allow for reasonable ventilation).

Making the Dresser Tops

This time I am using White Oak veneered MDF that is 3/4″ thick. I ran a cross a deal on some sheets that were edge damaged at Alpine Plywood when I was picking up the plywood for this project. The wood figure is beautiful.  Something to remember is going to a commercial plywood vendor will get you stock that is an order of magnitude better than at the home improvement store.  At Alpine they bring the skids of stock to your truck on a forklift and help load it in. The only seeming downside is not being able to sort and pick your sheets, but overall, again compared to the big box stuff they are beautiful with thicker surface veneers, thinner core veneers (more plies) and fewer voids and without the typical “potato chip” shape seen at Home Depot in the winter.

The MDF sheets are very heavy – about 95lbs. So this required help to maneuver them onto the table saw.  Since I needed glue ready edges, the first piece was ripped about 3/4″ wider than required. Then I flipped it around and  moved the fence and take a second pass at the final width and remove the edge dings. I use this technique a lot with sheet goods as it is very hard to get a perfectly straight cut on the first pass out of a full sheet, especially with something as heavy as this and the edges are always somewhat damaged in handling.

The MDF edges need to be banded. I am using 1/4″ thick oak on the long edges. The long edges are simply glued on and clamped with cauls to hold them flat.  At times folks will wonder about the pile of narrow sticks (1-2″ wide I have by the jointer. They are used for edge banding and later for supports while spraying the finish.  David and I got all 3 of the tops glued up with the long edge bands on in the morning. However, I nearly exhausted my clamp supply in the process.

The edge banding was quickly trimmed flush with a 1/2″ laminate trim bit in my trim router. The keys to doing this well are:

  • Light weight router – I favor my old Porter Cable.  Larger routers have a tendency to tip and gouge the edge banding
  • 1/2″ flush laminate trim bit  with the bearing set to run about 1/8″ inside of the edge of the edge banding. Laminate bits typically seem to have have a very slightly oversize bearing to leave a little of the edge for clean-up by hand vs a template bit which is more often exactly flush.
  • Moving in sections about 2 ‘ long. Don’t try to do the whole 5’ length in one pass  – you are asking for divots. As you restart the pass, alwasy keep the router moving forward to avoid burning
  • Make sure the cord is clear of any obstructions. A cord catch almost always causes a downward tip and divot the edge banding. I drop the cord  down from the ceiling when doing this.

Then finish up by scraping the edge flush with a card scraper. Take off any glue along the joint as well. Doing this 2-3 hours after initial glue up is usually best. The glue is firm, but not yet rock hard.

Adding a slight angle in the direction of travel over the veneer towards the edge banding seems to minimize tear out.  Plus angling the scraper helps you scrape off any bumps in the banding due to glue blobs deflecting the router bit. Anything from 15-60 degrees can work.

For the “breadboard ends”,  2 1/4″ oak  pieces are glued on on using 3 biscuits per end. The biscuits help with alignment as the ends are only .005-.010″ thicker than the panel as well as adding some strength in case someone attempts to pick up the dresser by the top when moving it.  Pipe clamps are needed due to the length and as you can see I even had to extend them. I keep a variety of pipes and couplings on hand in the range of 3, 4, and 5′ long. This provides a lot of flexibility on larger glue ups.

Yes, there are burn marks on the edge banding where I changed grip on the piece as I ripped it (and it liked to cup as tension was released), these will come out in the finishing passes. Plus the front black pipe is actually kinked – not a figment of your imagination.

The ends are cut only about 1/8″ longer than the top is wide. What is the left end / rear edge as viewed on the bench has the end set inwards just slightly. This will allow for the first of the clean up passes on the table saw without catching on the fence.

Note the anvil on the floor below the bench. It is a good surface to pound out the biscuits. Old biscuits will swell due to humidity and this will hinder assembly.  A few taps with a hammer thins them back out, making the assembly easy again.

The top of the ends is nearly flush and just needs some scraping. Note how the scraper is angled and I also angle the stroke of the cut towards the end.  I often switch as needed between a push stroke or pull stroke (as shown here) with the scraper.  The bottom side of the end board still needs some planing as the end boards were slightly thicker than the rest of the panel. The reason for difference top vs bottom is using the biscuits. They are referenced to the top surface  when cutting the slots.

After scraping. Can you see the joint on the banding or end???

The bottom needs to be planed to thickness and then scraped. I made the ends about 0.010-0.20″ thicker than the panel.  Be careful to keep the plane blade only on the end. You don’t want to cut into the veneer , even though I am taking very fine shavings at this point.

Final scraping on the ends. At this point, angling the scraper is mandatory. If you simply scrape across the ends, you will end up with ugly tear out which will show up when you stain. Angle the scraper and direction of your cut into the end piece. These are much less prone to tear out than the veneer of the plywood. However adjust based on the wood you have and how it is behaving.

A side note on the trim routers. Several years ago I was teaching a class on inlay work and a laminate trimmer was one of the tools needed. There was a wide variety. However as we ran them we saw the old Porter cables (metal body) & Bosch Colts ran coolest. The Dewalts got quite hot as did the newer Porter cables (plastic body) .

 

Fixing some defects

Defects happen

With any project there will be defects to fix, for a variety of reasons. With the batch of drawers assembled there were a few that had some gaps in the dovetails. It appears that these were mostly due to cupping of the face boards due to the rapid humidity change. Here in Wisconsin, we were getting our first cold weather over the last month and this meant a drastic drop in humidity.  Some of the drawer fronts cupped unnoticed prior to cutting the dovetails. This lead to some gaps to fill .

When I was young, and learning woodworking from my father,  he would say “A craftsman knows how to cover his tracks.”  Often for small dings and gaps he would use elmers glue and sawdust. However these fixes had to wait a day to proceed with further work and often had nasty splotching when finish was applied.  Now we have better choices of adhesives but wood as the primary filler, whether as a powder, thin strips or veneer is still the primary component.

When fixing small defects like these, as well as corner chips, I typically use thin cyanoacrylate adhesive (super glue or CA).  The bottle of glue and squirt  bottle of accelerator are always at hand when sanding, planing and scraping the parts near the end of a project.

Filler materials

In filling the gaps, it is handy to have wood flour also known as sanding dust on hand. I have multiple colors of wood flour that I have collected over the years, notably: White ash, white oak, okoume, mahogany, cherry, walnut.   Each is a match to woods I have used. Here are a few of the choices on hand. The finest are from sanding, coarser are from the band saw.   To collect a given color based on your current project, clean the air filter of the shop vac well  and then attach the vac to your sander. With a random orbit sander you will have enough for many projects after wearing out a few disks sanding. Now you just tap the sawdust off the filter  onto a piece of cardboard or into your container.

Adjusting the color

When using wood flour, the material will often be a bit darker than the background wood. This is most noticeable with epoxies which also will add their own amber or reddish tint. To lighten the color, use some high density silica powder such as West Systems 404.  I often will use 1/3 as much as the wood flour to get a decent match.  If you only need a bit of lightening colloidal silica such as West Systems 406 will work. The wood flour and high density silica was used on almost all of the fillets on the inside of the boat: http://bronkalla.com/Interior_floor.htm . White coloring in the epoxy was used for the contrasting deck stripes: http://bronkalla.com/decking_fiberglass.htm

When you need something a bit darker than the wood flour on hand, powdered “earth pigments” provide the easiest answer. I have a set of powdered pigments that I got from Lee Valley a number of years ago but these no longer seem to be available.  The powdered pigments work well whether using super glue or epoxy.   I have heard of others using powdered tempera or milk paints as colorants but have not tried them myself.  When using epoxy, then you have added options of: Universal Tinting Colors (UTCs) such as Tints-all, Mixol or Transtint dyes.   Unfortunately the Tints-all tubes crumble / fracture after a few years.

Small and tiny gaps

For tiny gaps you have 2 primary choices. Ignore them and then fill after finishing with colored wax or use the sanding dust and CA method. For the sanding dust and CA, apply a small amount of CA into the gaps and then start sanding with your random orbit sander. The sanding dust will naturally fill in the gap and the glue will harden in the power. You may have to do this a few times. If you are overzealous in your glue application you will ruing the sanding paper in short order.  If there are mixed or contrasting woods, I will often sand from the lighter wood towards the darker.

Above is an example of some tear out that would qualify as a small gap. Certainly too small to insert a piece of wood as filler.

The wood flour has been applied. Ready for the CA.

Now the CA glue has been applied. I have tried to keep the overflow on the side plywood rather than the face endgrain as much as possible.

At first, the CA and wood dust mixture will seem dark. However, it is approximately the same color the surrounding wood will darken to once coated with a clear finish.

 

Medium gaps

Medium gaps (1/16″ to 1/8″) can be filled with solid wood, wood flour and glue or epoxy. It varies with the background and your schedule. Here are a couple of examples.

Sawing a solid wood filler. Wedge shaped pieces offer a better opportuity for a tight fit than straight. I like cutting shallow crescents out of matching stock as this gives a nice taper and 2 filler pieces from each cut. Remember you must visualize this from the standpoint of the end grain of the piece rather than the face. 

The  cut does not need to be very shallow. I am using a 1/4″ 3 TPI blade in this photo. Yes, the blade guard is way too high but it makes for a better photo.

 

Here is the piece inserted into the gap in the drawer and the glue applied on the plywood side. Adding the glue on the face side makes for too much CA in the end grain and potential splotches when finishing.

Cutting it off with a zero tooth set Japanese saw. These are GREAT for cutting off not only filler pieces but also bungs for screws and many other uses.  No scratching of the surface.

The completed repair.   Nearly invisible. If I had dug a bit deeper in the scrap bin I could have yet a better match.   (yes I have a split to fix to the right of it.)

Large gaps, knots and splits

This is really a category of its own, but with tinted and filled epoxy you can have spectacular results.

This really falls into more categories. Those that are irregular and need a liquid filler or those that are small and straight and can be patched with a matching piece of wood.  I will focus on epoxy filling.  The epoxy is mixed and tinted to match the gaps appropriately. Blue masking tape works well for dams to prevent the epoxy from running out. Careful application of heat with a propane torch brings the bubbles to the surface . However practice first on scrap!

Yes it is a big project when you have to crawl on it to sand it.

And who says finishing is not fun?

Here is the rustic ash table top (7 feet long) that had knots and cracks filled with tinted epoxy.  It nearly filled my shop as you can see tools nearby on both sides. Great fun!

 

Trimming and fitting drawers

Design and construction elements

This design uses “flush” drawers that fit closely into the frame. Final fitting is fussier than if you are using overlay fronts. The drawers need to fit allowing for wood expansion in the summer, yet have an even appearing gap around the front edge with respect to the frame.

There are several keys to making this work:

  • Having raised runners inside of the dresser. The runners tops are about 3/32″ above the bottom of the opening. With flat drawer bottom edges this distance will set the gap below the bottom of the drawer.

  • The sides and back are cut 1/16-1/8″ shorter than the drawer fronts. This means that when doing the final trimming you only have to plane the drawer front rather than all 4 edges. This also leaves a little extra gap on the sides to eliminate binding in the summer.

  • Drawers were calculated to be a 3/16″ narrower than the opening width including plus the over cut for the dovetails on the fronts. This means that when the faces have the dovetails trimmed flush they are nearly at the correct width.
  • The drawers and dresser frame must all be square. Any out of square makes for large gaps around the drawers or drawer fronts that won’t sit flush in the frame.
  • Making sure the seasonal wood expansion does not eat up all of the vertical gap and make the drawers stick. Using quarter or rift sawn wood minimizes but does not eliminate this problem.
    Fitting and trimming

For the final fit up, slide all of the drawers into place. With this technique, every drawer will have a distinct location unless your joinery has been absolutely flawless up to this point.  In addition, with this design the grain of the drawers flows across the front from drawer to drawer. This is your last chance to check that you have the placement correct. Some will not close and others will have uneven gaps.    On the back or bottom mark them as to their location (and in this case which dresser they are for as I am making 3).

Now you can trim the sides to make each drawer slide in smoothly with a good 1/8″ gap between the top of the drawer and the runner above. Next the drawer front is trimmed for height.  Push the drawer in too far and scribe with a pencil against the rail above the drawer aiming for an even gap of about 1/8″.  Now trim with the table saw (if the cut is straight) or hand plane to adjust for a slight angle or bow of the rail.  If you have a slightly bowed rail this will require trimming of the drawers above and below the bow. After a few trimming passes  the gaps top and bottom should be equal.

Now check that the drawer can be set in flush with the rails. The final stops will be set in place after finishing. At this point you simply want to see if the drawer face can be perfectly flush with the front. If not, then the drawer or frame is out of square. To address the problem. the back edge of the drawer sides must be beveled to allow for clearance around the rear frame and angling of the drawer so that the front can be flush. Alternatively the drawer front can be planed to adjust the fit. However, if done on the inner ends of the face, this will cause the grain flow across the front to not match as well.

Next is final adjustment of the side gaps. With plywood sides, this is not easily done in an invisible manner. If the side is a bit off, then there will be the layers of the plywood and the glue lines showing through. I prefer to avoid this. Scribe the sides as you did for the top, now take a sharp hand plane and bevel the side back from the line to the start of the dovetail.  This will leave an even gap as seen from the front.

Here is one of the dressers with all of the drawers fitted and ready for final sanding and scraping of the drawers and frame.

The sides and edges will be sanded and the corners broken slightly. The fronts are scraped to make the quarter sawn wood flakes really pop when the finish is applied.

Dresser drawers part 2

Lessons learned

With the first batch of the top drawers out of the way, it was now time to start on the rest of them.  These are bigger, and I had learned a few lessons from the first set of top drawers:

Consistency and repeatability are paramount.  This lead to fixture board end stop additions and minor redesign to remove most human error.    I had some sides on the first batch which did not line up perfectly and I was lucky to be able to fix the fit by sanding the backs of the drawer fronts.


After the first roughing pass, the new stop fingers had been “modified” due to the low Z axis clearance between cuts. 

Drawer and side thickness MUST be consistent.  This time all of the boards were drum sanded to the same thickness. It is surprising how much variation even a large well tuned planer has (mine is a 20″ Jet).  This made a big difference in the fit for the 18 drawers vs the earlier batch of 9. Planing single handedly does not help.

Scoring the faces of the sides to prevent tear-out is a must. The roughing cut sequencing of Joint Cam causes a lot of tear out. It would be better if the roughing cut was the same sequence as the finish / dovetail pass. However , scoring the face heavily with a marking gauge, largely mitigates the problem .

Fixture additions must account for bit profile differences between the roughing and finish passes. It would pay to run the finish pass air cutting to make sure the fixture fingers are not in the way or you could end up with a snapped bit or missed steps. I  had to trim back the corners by hand to allow room for the dovetail shaft.

The new LED light ring around the front of the motor nicely illuminates the work .

This shows the touch plate I use for setting the Z axis zero. There is something funky with the Mach4 CNC controller touch functions. I now repeat each zero touch to verify the value does not change. 

Now for cutting the dadoes and assembling the 18 drawers.

Dresser Drawer Construction

Building out the drawer boxes

There are many ways to build the drawers. I have settled on a particular technique for the furniture I build which provides what I think is a good combination of elegance, ruggedness and reasonable ease of building. This combines dovetails for the fronts, dadoes for the backs and bottom. The bottom is also completely captive which helps square up the assembly.

Sides and backs

Once the dovetails are cut in the sides and fitted it is time for the easier tasks. The first is to cut the dadoes in the sides for the backs. I typically set this up on the smaller radial arm saw using a 8″ Freud stack dado set. In this case the plywood is 12 mm thick which requires almost all of the shims in the set. The dado depth is just under 1/4″. I leave 1/4″ of wood behind it which makes measuring for the bottoms easier (outside box dim – 1/2″ = the bottom dimension).

I usually set a stop for the distance from the rear ends. Pay attention to the distance from the front. The dresser is just over 18″ deep and the drawer bottoms can reasonably be 16″ so you can get 3 pieces from the width of the standard sheet of plywood.

The backs are cut to length on the big radial arm saw, again using a stop.  When cutting the fronts and sides to width I cut 2 extra strips of plywood, ready for the backs. Plus the backs are shorter than the sides so I could re-cut some sides where the dovetails were messed up.

Dadoes for the bottom panels

These are cut on the table saw. The plywood I am using is 5.2 mm thick which is too far under the 1/4″ minimum of my dado sets. So this become a 2 pass cut on the table saw.

The key point in setting this up is that you want the dado ends to be under the side dovetail tails . This will completely hide the groove when viewed from the outside.  The photo below shows the alignment of the first cut which will be the top of the dado.

At this point there is a lot of time invested in the sides. Cutting the dado incorrectly will ruin a side. So I carefully double check the orientation of allof the pieces and stack them so they are ready to slide against the table saw fence.  This reduces the chance for error vs. “flipping on the fly”.

Once all of the sides, fronts and backs are cut make a few extra test piece cuts.  The alignment of the fence for the second cut takes a bit of trial and error until you get a good sliding, but not overly loose fit on the plywood for the bottoms.  I tend to re-use the test cut scraps multiple times.

Now adjust the fence, make the test cuts and test for fit against the plywood for the bottoms.  When making the cuts, be sure to hold with even pressure so that the piece does not ride up over the blade, reducing the depth of cut. I often will use a top feather board for this but skipped it this time, which resulted in some extra fine tuning at final fit-up.

Final fitting and assembly

I will completely dry fit assemble each drawer before gluing.  This gives me a final chance to fine tune the fit of the components. I can adjust the dados with a chisel but prefer a dado plane and side rabbet plane as shown in the photo below.  Scrape or sand off any marks on the inside faces of the drawers at this point as it is far easier now than when fully assembled.

If fitted properly the dovetails need no clamping. The only clamp required is for the backs. The drawers are all placed o stacked flat to prevent racking and are checked for squareness. A few taps with a mallet will usually fix any minimal out of square.  Look up and down the dovetails after assembly making sure the sides / tails are evenly inset for the full height of the drawer. The fronts will be trimmed flush with the sides after the glue dries.   I will clean up the glue squeeze out after a few hours. This makes the least mess.

So 9 drawers done, and 18 to go for the dresser project.

Dresser project – small drawer dovetails

Initial testing

One of the goals when making the CNC router was to be able to do general woodworking joinery including dovetails, sliding dovetails and mortise and tenon joints. The mortise and tenon capability was proven out when I did the blanket ladders.  The dovetails needed another project and the dresser project with 27 drawers is a perfect fit.

The CNC router was set up with a special base for the dovetails and the horizontal fences were CNC routed to final spacing in place (20″ apart) to match the vertical fences.

Over the last week I had prototype the joints using JointCam and using scrap pieces of plywood that were of the approximate thicknesses of the drawer fronts and sides. I tested both equally spaced and equal spaced dovetails and both turned out well after a bit of initial tuning.  Teal liked the equal spaced better and these could be done with both pins and tails in one pass so this was chosen.

Wood for the drawers

The drawer faces are white or red oak depending on the dresser . At this point I am doing the top row of smaller drawers.  The 3 top drawers for each dresser are cut from a single board so that the grain runs across the face of the dresser. If one is botched then all 3 are scrap.  So there is a bit of tension here with some nice pieces of quarter sawn white oak (big flakes) and near quarter sawn red oak for the drawers.

The drawer faces are approximately 3/4″ thick.  The drawer sides are 1/2″ nominal (0.47″ actual) baltic birch. I like the baltic birch plywood for drawer components. The even coloring and lack of voids make for nice side pieces.

Now for the “production”

The off cuts were again tested and everything seemed to work although the joints were a bit looser than expected from the earlier testing . Jointcam has a setting for adjusting the fit and this was used. New pieces tested OK so on to the real stuff.

At this point things fell apart. The router bit was progressively creeping out of the collet during the cuts. This was apparently exacerbated by the oak drawer fronts. I reduced the feed rates and increased the spindle speed but it was still happening. I tried a new dovetail router bit with a longer shank and really cranked down on the collet but it was still creeping out and then the shank of the router bit snapped just past the collet. Time for a beer (or 3) and think through the alternatives.

Plan B

There is not a lot of info on the net about CNC cutting dovetails. There are bits on commercial work where you cut everything flat and add a false front, but little on the trials and tribulations of doing this properly.  The JointCam info mentions the use of roughing and dovetail bits and passes but no guidance on when to use this vs single pass.  So after the beers and sleeping on it I decide to be conservative and use a roughing pass (straight bit) and finish pass with the dovetail bit but switching to a 1/2 ” shank dovetail in the hope that it would grip better. I had one more of each on hand – 1/4″ straight and 1/2″ 14 degree dovetail with 1/2″ shank.  As you can see from the photo below, the pieces are cut 2 at a time as right / left pairs.

Testing

Testing went well. However it is tedious as you need to do a bit change for each test (straight and dovetail passes). So by late morning it was a go for this method. Now I just had to make a new set of drawer fronts for the dresser that had them ruined in the first try.

I also found that while JointCam makes a scoring pass for the dovetail / finish bit, one is needed for the roughing pass on the plywood sides. The side faces tend to splinter easily.  So I took a marking / cutting gauge and scribed a line across each of the sides before routing. This contained the  splintering.

Production part 2

I did the drawer fronts first. These were labeled as to sequence on the dresser, inner face and top edge. The top edges were placed against the fences on the CNC router.

First pass for the stack of pieces was with the straight bit.  After all were run, I changed the bit to the dovetail (and it is nice to have a soft mat under the edge of the CNC to catch the dropped bits vs. the concrete floor).

Now that the fronts were done (pins) and they fitted reasonably well against the test sides it was time to do the sides (tails).  These were cut and after the first pair I test fitted them to the fronts. They were close but there was still some variation form one front panel board (set of 3) to another. One small adjustment of the fit clearance (-.001 to +.004″) was made in JointCam for the sides to match the fronts. At this point the sides are labeled right and left (blue tape on the rights) and for each dresser set.

Video of the CNC router cutting the joints is here: Dovetail cutting

Final fitting

There was still some tweaking to do. One set was still tight even with the +0.004 correction. These pieces were tight and had a gap at the end of the tails. So I took this set of 3 to the drum sander. I took off about 1/64″ on the inside face and everything fit nicely.  So now I have the 9 drawer faces and sides fitted up and ready for the dadoes for the bottom and backs.