Crib – End rails and slats

Slat Fitting

The curved end rails made for some interesting routing for the mortises.  The slats were inserted into the bottom rail mortises and aligned behind each of the mortises. Then pieces of blue masking tape were used to mark the length to the bottom of the rail and the angle. An additional 1/2 inch was added to arrive at the final length.

The router was set up with a fence to guide the cuts and keep them centered.  However the direction of the plunge for the mortise is perpendicular to the bottom edge at that point. The ends of the mortises are then not parallel with the slat edges.  There are then 2 options:

Chisel the ends to be parallel with the slat ends. This is very hard with a  small gouge in the Oak.

Bevel the edge of the slat to approximate the angle of the slot end. This is FAR easier.

Below you can see the end rail and one of the slats. The slot nearest the slat has some small burn marks, so you can see the direction of the plunge. The end of the slat has been trimmed to length and the right end beveled to roughly match the mortise end. 

One final test fit with all of the slats in place.

Next step was rounding and beveling of the edges of the legs and rails.

Now on to the finishing.

Crib – Planing and Plasma

Completing the rails

Today’s tasks included completing the front and back top rails and making the bottom plates that fasten the ends to the front and back .

The top rails needed to be transformed into the sleek shapes in the drawing. This meant making the under-hanging lip, adding it to the rail and the generating the sweeping curve of the rail top.

The underhanging lip is a 1/2″ thick semicircular segment which is then glued to the rest of the top rail. To safely and accurately make a shape like this you must start out with a larger piece, shape the edge and then rip it off.  Below you can see the stock being run through on the router table with a 1/2″ radius round over bit. The fence is set flush with the front edge of the router bearing. The fence is needed as the bearing of the router bit will not be landing on un-cut stock  and it provides the needed support for the cutting depth. The feather boards  help to both guide the stock and keep my fingers clear of the spinning router bit.

 

After the profile is cut with the router, it is then ripped off on the table saw.

This profile was the glued on to the top rail. You can see it as the bulge in the lower left of the rail as seen below. The drawing of the rail end was the printed out square with the end and with no perspective in Sketchup. This was then printed life size (which took several tries). The print out was the cut out and placed over the ends of the rails and the outline traced with a  sharpie.

The corners and excess were then saw off on the bandsaw and table saw. At this point the goal is to have a rough approximation of the curve which is ready for hand shaping.   The bandsaw with the table tilted offers a safer alternative to the table saw when there is a small land / support area under the base of the stock and the cut has no support directly underneath it.   Be careful here, greater overhang under the cut can fling the stock or break the blade if you lose control.  In retrospect a feather board behind the blade would have been a good idea here.

Now comes the exercise part.  There was a LOT of hand planing required to get to the final profile. Remember this is Oak.   It took just over an hour to plane the rails and another 1/2 hour of sanding and touch up planing.  I started with a #6 plane set for a fairly aggressive cut.   The shavings piled up quickly and my heart rate rose as well.  I think I was excused from skipping my usual workout on the elliptical (the shirt did not stay on long after this photo).

When planing a curve like this, you start out with the facets cut on the saws approximating the curve. With the plane, you basically bisect each facet, adding new ones and incrementally going from a rough set of angular faces to an ever better approximation of the curve. The sound of the plane and touch of your fingers guides where to make each cut, angling each one differently than the prior one.  After planing, then the sanding starts with 80 grit cloth backed paper on a long stick.

Side brackets

The next step was to start cutting the brackets which hold the end pieces to the legs. I wanted to minimize the visible hardware on the final bed, sacrificing a bit on having more hardware showing on the crib. The ends are held on with 12 gauge steel plate brackets (about 0.1″ thick) . The brackets are cut out with the plasma cutter (much more fun than a saw).

The brackets are then drilled to 1/4″ for the screws and then the locations are marked with a transfer punch. The holes are drilled and brass threaded inserts are screwed into the wood.  Below you can see the frame with the bottom bakets in place and ready to start making the top end brackets.

 

Crib – Headboard

What will become the headboard of the bed is the tall / wall side of the crib. This week we have sanded all of the legs and rails and spindles.

The headboard has three flat panels. They are glued up from two 5mm  (not quite 1/4″) thick sheets of oak veneer plywood.   The front facing side has the same quarter sawn white oak veneer as the dressers and the back side is  rotary cut white oak .  I did change form 2 panels to 3 to accommodate the size of the plywood off cuts from the dressers and in the end, I do think it looks better with 3 than with 2.

The panels were glued together with TiteBond Cold Press veneer glue and placed in the vacuum press to cure.   Vacuum time was 1.5 hours. They were then left in the bag for another 3 hours  and then removed and placed on stickers to dry further. This is critical. If you simply take the pieces out and lay them on a flat surface they will cup badly due to the moisture leaving faster via the uncovered top.  

The top rail assembly for the back was similar to the front with the dado (facing right) cut prior to assembly.

 

The Workmate is the handiest way to hold an assembly like this.  The top and bottom rails are placed first and the gap measured (at least twice) and then the length including depth of the dadoes is added prior to cutting all of the pieces to length. The dividers have tenons on the end and dadoes on the sides, so the panels are retained all around. The end gaps are 2″ to conform to safety standards.

Next comes test assembly of the footboard and shaping of the top rails

 

 

 

Crib – Rails and slats

Rails and Slats

Today we were mortising the crib side rails and slats. The lower rail mortises were done on the CNC  router.  Overall, there are 50 mortises to cut for the slats.

The front rails are 5″ tall and the end rails are and 6″ tall. So these had to be clamped upright to the  left pf the main work area on the router top. A new fence was made on the left edge of the work area to support the rails in the vertical position.  The fence was made from some 2×2 scrap stock. Once drilled and bolted in place, the router was used to cut the left face so that it was perfectly aligned with the router Y axis and exactly plumb.

As you can see clamping the ends is quite easy.  This is adequate for the crib end rails but not enough for the long front rail.

The front rail is about 53″ long and needs some support in the middle.  There is no good way to add a conventional clamp  as  are used on the ends.  At this time, the router does not have enough vertical travel to clear clamps placed over the top of the boards and there is always the fear of a crash with a misplaced clamp. So this was solved by taking a scrap of 3/4″ plywood and sawing it into a pair of wedges. These are placed between the stock and the side rail. A few taps with a hammer, and the wood is secured.

Here you can see the front rail clamped in place ready for the cuts.

Top end rail mortises

The top end rails need to be done conventionally with a plunge router and fence. However the start and stop points for each mortise need to be transferred to the parts.  However they are curved and there is a 6.5″ rise from the front edge to the back. Armed with a dimensioned drawing and a cutting mat, the parts were aligned to the grid of the cutting mat and a 1-2-3 block was then used as the vertical guide. A block of wood would work as well, but the mass of the metal block made things easier.  Here the leading edges of each mortise are being transferred.

The mortises now need the trailing edge marked. This is easily done by aligning one of the slats with the leading edge mark and then bringing the 1-2-3 block up to it and then making the mark.

The slats are 0.5×1.75″ and the corners are rounded over with a 3/16″ radius. This is done at the router table, which is an extension of my table saw.  Feather boards are placed to guide the cut (fewer ripples) and protect Teal’s fingers. After the photo Teal tucked the ties of her sweatshirt in.

Top Rails

The front and back top rails are curved as can be seen in the end view below. The rails start as a rectangular piece of stock 1.5×3″. 

The first task is to cut the tenons on each end. This is done at the radial arm saw with a dado blade.  An end stop is set for the length of the tenon and they are cut in 2 passes as you can see below where I am cutting the second pass.   Having the digital readout on the height adjustment greatly  speeds  up the setup.  The next step is cutting the bottom bevel which is at 38.5 degrees.

The bottom piece of the rail is 3/8 x 1 1/4″ and the mortises are again cut on the CNC router. However at that point the stock was left thick for added stability and rigidity and then after they were cut the stock was ripped to the 3/8″ final thickness.

Here the bottom piece is being glued to the rail. Note the off cut form the angle is being used to provide a grip for the clamps. It is lightly tacked in place with super glue (and some slipped).    This is another case where using many clamps with light to medium pressure works better than a few clamps with high pressure.

 

 

Crib – Construction Start

Return to the shop

The last few weeks were taken up with vacation and conferences. So there has been no progress on the crib. Teal and I had brought in the last of the wood from the shed, but it was not thick enough for this project and has to wait for another project.  This was the last of the Wisconsin Woodworker’s Guild Logfest hauls that I had set up to air dry. At its peak, it was over 1300 board foot of lumber,  which has now been reconstituted into many pieces of furniture for the family and friends.

Saturday

So yesterday we set off for Kettle Moraine Hardwoods which is our local lumber mill.  They had a nice selection of thick Red Oak (5/4 and 8/4 – 1.25-2″ thick) and we picked up some Hard Maple and an Elm slab for future projects, as well.

Once home, it was time to surface the boards on the jointer and planer and then cut them to rough length in preparation for sending them to the CNC router. At this point, there was a minor design change as the thick stock for the legs was completely cleaned up at 1.86″ vs the 1.5″ I had in the design. So we decided to go with thicker legs.  However, this leads to more work as I did not have a router bit that would cut deep enough, which will be detailed later below.

I fired up the computer for the CNC router and some problems arose. I had not used it for ~2 months and only had the windows 10 logo showing for 45 min. At this point, I rebooted again and it came up in a few minutes. However, Mach 4 which is the CNC controller software for the router had a whole series of errors when starting, and was unusable. Most of the plugins would not work. So I restored it from the backup copy, restarted the PC again and it started to work. However, in testing, many of the configuration parameters were missing including “little things” like the home switches and control for the spindle. Digging through my notes for the configuration values, I got it running again. Now, thoroughly annoyed, it was time for a reward of our home brew Imperial Stout which is now ready for consumption.

Sunday

After re-zeroing the CNC router it was time to set up the first part and make a test run.   The crib end top rails were chosen as they are the smallest parts and least costly in case of problems.  The 8/4 stock for the leg pieces was over $150. Making wach leg approximately $35-50, so I was not going to try those first.

So the stock is clamped on the CNC router and you can see my “cheat sheet” where I have printed out the outline and marked the distances from the near end for the various clamps.

Next you can see the cut under way. At this point I have left off the dust shoe, so there are chips EVERYWHERE.

Now the top rail is completed and vacuumed off.

Another shot in progress, looking down with the dust shoe in place.

With the top rails successfully completed, now I move on to making the legs.  One of the front legs being cut.  In order to prevent the part moving I used not only the 5 clamps shown but also some small strips of double stick tape which help reduce the part sliding under load immensely. With this CNC router, the limitation on cutting speed is not the machine, but the ability to clamp the work and avoid it slipping under the cutting forces. Cutting speed was 100 inches per minute, 18,000 RPM at 1/4″ depth of cut with a 1/2″ 2 flute carbide end mill.

Set up for one of the rear legs – 43″, 110 cm long. Not your ordinary tabletop CNC router. . Note the beautiful curl figure in the stock. Later, you will see how I make this “pop” when finishing.

The other back leg ready to cut

This is why I use wooden clamps. Just a minor nick this time.   These are shop made on the CNC router.

Another look at the scale of these cuts and the finish off the CNC router. This was without a reverse last pass as I don’t (yet) have a router bit long enough to do so and that would look even better.

Here are the legs off the CNC router. As you can see I was not able to cut all of the way through. The depth of cut was limited to 1.5″ based on my largest end mill / router bit. So now they need to be run through the band saws and then flush trim routed.  The end curves are too tight for my big band saw (24″ with 1/2″ resaw blade ) and need to be run through my small one (12″ with 1/4″ skip tooth blade).

Bandsawing the excess off the legs on the 24″ band saw.

Flush trimming off the excess. The holdfast works great to clamp irregular stock like this. Teal also assisted in taming the work. The Oak is a bit unruly.  I often had to reverse directions to minimize tear out.  This means taking climb cuts which try to throw the work and router around.

 

First dry fit test. Not bad.  The cross pieces will be flush with the upper / inside edges of the legs in the final assembly.

The CNC router made this work feasible in a few hours. Otherwise I would have had to make templates, band saw to size and flush trim through several steps. I had done a similar project with curved legs – Elyse’s Sleigh Bed.  This is MUCH easier and with less chip out to fix.

Movies of the CNC router at work

The first part  is without the dust shoe (chips Everywhere) and the second part is with the dust shoe in place (much neater) .