Dining Table Miscellany 2

October 15, 2012 in Furniture, Tips & Tricks | No comments

A couple more bits and pieces…

Fixing dents and chips

The longer a project sits around the shop, the more likely it is to get bumped, dented, scratched, etc.  My dining table sat for several months while I contemplated the binding problem and worked on other projects in the shop and the yard.

Dents are relatively easy to fix as long as they aren’t too deep or in end grain.  They can be steamed out without too much trouble.

Chips are another issue.  When I got back to work on the dining table and started re-sanding the leg/apron assemblies, I notice that there was a large piece missing from one end of one of the legs.  One corner had chipped off, about 1/4″ x 3/8″  x 2″.  This was no dent; it was gone.

I used a block plane to remove the rough surface and create a flat surface for the patch.  The patch was chosen from some leftover leg material (never throw away offcuts until the work is delivered!).  I glued it in place and, because it was an irregular shape placed on an angle, “clamped” it in place with rubber bands.

I forgot to take a  before photo, but here are photos of the fix in work and the completed fix.  The color match will come in a couple of months as the cherry ages to that wonderful orange-red patina.

Custom hardware

There’s not much hardware required for this table, but what is needed is not readily available.  I had to make it or repurpose something else.  I needed two of each of the following:  hinge pins, pin plate (into which the hinge pin is inserted and rotates), washer, and stop plates (which stop the table halves from extending too far when opened).

The plate pieces are 1/8″ brass; the hinge pin is a pin with a head on one end.  In order to obtain the pins and the material for the plate parts, I purchased a pair of solid brass door hinges.  The hinge pins worked without modification.  The other pieces were cut from two of the four hinge leaves.  I used a hacksaw to do the cutting and my disc sander to do the shaping and fine tuning.  Some silicon carbide sandpaper completed the task.  Here’s a photo of the completed parts.

And here are the parts modeled in SketchUp.

And, an update:  I’m currently applying finish to the table.  It’s coming along slowly and I expect to have it completed in the next couple of weeks.

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Dining Table Miscellany

October 3, 2012 in Furniture, Tips & Tricks | 2 comments

Some random thoughts on the dining table project…

Hinges

The leaf must be hinged in its midsection in order to be stored under the top.  I don’t want to see the hinge when the leaf is “deployed,” so it must be hidden when open.  The only hinge of which I’m aware that meets this criteria is a Soss “Invisible” hinge.  There are other manufacturers, like Sugatsune, but the Soss version is the easiest to find.  It comes in two flavors, surface-mount and barrel.  Paul Schürch uses the surface mount version; Michael Fortune uses the barrel version.  I went with Fortune’s suggestion and, in doing so, I think I discovered why Schürch uses the surface mount.

I used the surface mount Soss hinge years ago and found that it was easy to install as long as you created the properly sized stepped-depth mortise.  A plunge router and fence or jig makes it possible.  The barrel hinge only requires a hole to be drilled.  Easy, right?  Yes and no.

The hole is metric, so I had to purchase a 16mm drill bit.  Not a problem; I ordered it, along with the hinges, from Lee Valley.  The challenge comes when you install the hinge into the hole.  It’s a tight fit!  Some sanding on the hinge barrel made things a bit easier, but it was still difficult to remove the hinge.  I was concerned that if the hinges were too tight, I would damage them on removal.  Too loose was not an option, so I opted for a snug fit and only one removal and replacement cycle for test purposes prior to the final installation.

It has worked out fine, but now that everything is together and I’m putting finish on the parts, it’s a bit of a hassle working around the hinges.  The surface mount hinges may have been a better option.

Marking part locations

When creating a project with multiple parts that are removed and replaced multiple times, it becomes necessary to mark part locations and orientations.  I prefer a marking process that cannot easily or accidentally be removed, so marks made on the surface of the parts are not an option.  The method I like involves a Phillips screwdriver and a hammer.

On a surface which will be hidden when the parts are assembled, I punch a small “X” in a corner of the part.  I do the same on the mating surface, in the same location.  When assembled, the X’s meet.  If there are two similar parts, I’ll use two X’s on one of the interfaces to further define the configuration.  See the photos below for an example.  These are the hinge blocks in one half of the table leaf.

Sliding Parts

In order for the two halves of the table to extend out from the inner apron assembly, I created a tongue and groove system.  With sliding wooden parts like these, harder woods work best.  The dining table inner apron is cherry, so the groove material was a given.  I could make the tongue from a different material, so I chose hard maple.

I very carefully milled the parts as straight as possible.  I used my router table to make the grooves in the inner aprons and used a feather board to ensure accuracy.  I milled a 1/16″ deep groove on the inside of the outer aprons to locate the maple tongue.  I made the fit of the maple in the groove with about .005″ clearance to ensure a sliding fit but not much sag when the table was open.  The fit in the 1/16″ groove was snug.

To create a smooth surface, I put a thin coat of shellac on the sliding surfaces, smoothed them with 0000 steel wool, and waxed them.

I was excited but apprehensive when I did my first test run.  I was concerned that the vertical loads on the slides might cause binding of the tongue and groove.  I won’t try to describe the details, but if you look at the video you can see that the vertical force of the legs causes a rotation force on the outer aprons relative to the inner aprons.

The binding was bad.  The table halves would stick and bind and not move smoothly at all.  I was really bummed.  I tried increasing the clearance between the parts a little, but that didn’t help.  I was so discouraged, I put the whole project on hold (which largely explains the lapse of blog posts this past year).

By the end of summer, I couldn’t put it off any longer.  I dusted off the parts and took another look.  I stared at the offending parts, the tongue and groove, the built-up gunk that was created at the sliding interface.  Then, it hit me.  The problem wasn’t the design, it was the finish.  Shellac has lousy heat resistance.  When I slid the table halves apart, the shellac heated up, melted, and then stuck to itself.

I did some light scraping and sanding to remove the shellac, then applied only wax.  I re-assembled the table and…it worked great!  Like it was on rails.  Like I had ball-bearing slides installed.  What a relief.  I was back in business.

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Table Leaf Alignment

September 26, 2012 in Furniture, Jigs & fixtures | 1 comment

Table pins are used to align the two halves of the dining table.  I have used wood pins in the past, but both Michael Fortune and Paul Schürch describe using metal pins, so I wanted to give them a try.  I checked out the pins available from the local Rockler and Woodcraft, and decided the pins from Woodcraft would work best.  The Rockler pins, although they were solid brass, were poorly made and didn’t fit well together.  The Woodcraft pins, apparently from Hafele, are shown in the photo.  They are plated steel, but nicely made and most importantly, accurate.

The pins are installed in four holes across the width of the table.  Three would normally be enough, but since the leaf is in two pieces, I wanted two pins in each half.  Per the Michael Fortune article in Fine Woodworking (July/August 2011), I made a jig to drill the 5/16″ holes.  The jig is shown in the photo below.  Note the blue tape on one end of the jig and near the edge of the table.  The tape was used to orient the jig and ensure I didn’t turn it around during the drilling operation.

The jig is aligned by sighting through one of the holes in the center.  The reference on the table half is a pencil line located at the center.

On the leaf, the joint line is the reference.  (The leaf is split into two halves; see this post for a photo/video)

Here’s a photo from below, showing the business portion of the jig.  The holes in the jig, through 1 1/2″ of hard maple, are used to guide the 5/16″ drill bit.  It’s really important that the holes in the jig are parallel to the face of the table top, since the jig is used from both sides to drill the mating parts.

It all worked out great.  With the pin hardware installed, the two table halves went together and aligned perfectly.  The leaf also went into place just fine, with the top surfaces all coplanar.

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Loose Tenons

September 21, 2012 in Furniture, Joinery | 2 comments

I’m a big fan of loose tenons.  Because I have a slot mortiser, they are usually quicker to create than traditional tenons.  I still use traditional tenons when the situation calls for it (haunched tenons, for example), but my first choice is loose tenons if everything else is equal.

In traditional tenon joinery, the mortise is typically made a little longer than the tenon is wide.  The terminology gets a little confusing here, since mortise length is the same as tenon width (and mortise width = tenon thickness, and mortise depth = tenon length).  The “slop” in traditional mortise-and-tenon joinery allows for wiggle room to get the aprons aligned with the tops of the legs.

Of course, the width of the mortise and the thickness of the tenon have to match, but I’ll get to that in a minute.

Here’s a photo of the mortise in the apron.  I have marked out the ends of the mortise using a combination square, referenced off the top edge of the apron, as described here.  Note that I have carefully cut the mortise right to the layout lines.

On the legs, things are a bit different.  The layout lines are in the same relative locations, but this time I cut about 1/32″ past the lines.  Why?  Because my tenons, which will be glued into the aprons in the next step, are cut to fit the apron mortises with no gaps, ensuring their precise location.  The 1/32″ overcut on the legs ensures that I will have the wiggle room I need later to align the aprons with the leg tops.

If both apron and leg mortises were overcut, the tenon may end up in the wrong location on the apron and not give me the adjustment necessary for alignment.  Here’s the leg mortise below.

And here’s a photo of the tenon in the apron:

The thickness of the tenon is, of course, very important to the strength of the joint.  A few thousandths thick or thin can be an issue.  What makes this tricky is that the mortiser bit cuts differently in end grain than it does in face grain.  The face grain mortise is almost always slightly larger than the end grain mortise.

To accommodate the difference, I mill the tenon material thickness to fit the face grain mortise (in the leg).  I aim for a snug fit, but not so snug that it won’t go together with glue.  I’ll surface the stock in my planer and use a handplane to fine tune the fit if necessary.  I then cut the tenon stock to final width, round the edges on my router table with a quarter-round bit, and cut to length on the table saw.  They are too thick, however, to fit correctly in the aprons.  I fix that by sanding half the face of the tenon on a MDF board that has a half sheet of 120-grit sandpaper glued to it (a handy thing to have around).  I also chamfer both ends of the tenon on the sandpaper.  The tenon now fits nicely in the apron and can be glued in place.  I know this sounds like a lot of steps, but it goes very quickly once you figure it out.

Here’s a photo of the setup for cutting the tenons to length.

This is a handy setup for cutting small parts to length.  It’s not safe to use a stop in this situation, as the cut parts would be trapped between the stop and the blade.  Instead, the length is indicated by the end of the 1/4″ MDF.  I just position the end of the MDF relative to the blade, clamp it in place, and locate the tenon material by eye.  If I want more accuracy, I can hold a temporary stop in place against the MDF end, locate the stock, remove the stop, and make the cut.  Easy-peasy.

Here’s a photo of all the apron and leg parts.  The #7 parts are the end aprons, which at the time had not been cut to length.  Those lengths could not be determined until the side aprons were located on the center apron assembly.

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Planer Tricks

September 16, 2012 in Furniture, Jigs & fixtures | No comments

Yes, it’s been a while since I posted.  I know some of you have been sitting on the edge of your seat wondering where I’m at with the dining table.  :-)  Well, it’s almost done, so I guess I should catch you up on what has happened in the interim.  If you need a refresher or are new to the blog, click here to see what’s happened so far.

The aprons are tapered across their width.  In order to do that, I created a sled for my planer (Robland XSD jointer/planer from Laguna Tools if your curious).  The sled is a piece of 3/4″ veneered MDF (left over from ???), about 4″ wide.  I cut the taper on one face by tilting the blade on my table saw and ripping the MDF.  I couldn’t rip the whole surface, so I just cut about half of it; see the photo below.  I cut a small rabbet on the uncut edge and glued in a small strip to continue the support.  If I remember correctly, the strip was then trimmed even with the angled cut using a handplane.  On the thin edge of the sled, I glued another strip to locate the apron parts along their edge and keep them parallel to the sled.

Back at the table saw with the blade tilted as before, I ripped the aprons to start the taper.  I then used the sled on my planer to complete the process.

When using a sled on the planer, a stop is necessary to keep the stock from sliding off the sled.  Counter-intuitively, the stop goes on the front of the sled, not the back.  The feed rollers in the planer are pushing the stock forward, which would tend to push the stock off the front end of the sled.  I just pin-nailed small strip there to keep the stock in place.

Note that I have carefully marked the parts so that I can keep track of their orientation.  Each side apron is cut in half due to the two halves of the table being separable.  I wanted to have the grain continuous through the seam, so it was important to remove the material from the correct face, and remove the same amount of material from that face.  The arrow in the first photo shows which face is out and which edge is up (the face arrow was cut off when the piece was planed).

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Danish Cord Stool

March 25, 2012 in Furniture, Small projects, Uncategorized | 1 comment

The student woodworking club at Cerritos College, where I teach, invited a local furniture maker to teach a class on Danish cord seat weaving.  David Johnson, of Sidecar Furniture, taught the class.

I have always admired Danish cord seats.  Danish cord looks great, with a clean, airy feel.  It’s lightweight, very strong, and comfortable.  It’s one of those things that I’ve wanted to do for a while and had planned to incorporate into a set of dining chairs.  (If I ever complete the two I started a couple of years ago, the remaining four will have Danish cord seats.)

We had to bring something to weave and the suggested project was a stool based on one of David’s designs.  Tweaking things a bit to suit my taste, I used cherry for the wood and flared the legs a bit.  “Gumby” legs, as David put it.

The first part of the class was Saturday, March 24; it continues on the following Saturday.  I’ll be camping in Death Valley next Saturday, so I had to hustle through the first day to make sure I could complete my project without further instruction.  By the end of the day, I had completed the “spokes,” as David calls them, and was ready for the weave (I don’t remember David’s term for that – weave may or may not be correct).  The actual terms are warp and weft, but that’s too confusing.

The process is not very hard, but it is a bit tedious and time-consuming.  The best way to do it would be to put on some music and get into the rhythm of it.  It took me a day to make the stool, an hour or two of finishing spread out over several days, and a long day to weave the seat.  David says he can do a seat and a half in a day.  With that in mind, the whole project could be done in a weekend if you used a quick drying finish.

I was really happy with the end product.  My wife loves it too.  Thanks to David for a great class; I’m sorry I won’t be there next week to pick up on any extra bits of wisdom I’m sure he’ll deliver.

 

Dining Table Legs

January 7, 2012 in Furniture, Jigs & fixtures | No comments

I’ve already discussed laying out the mortises on the legs, but I forgot to discuss the creation of the legs.  So, let’s go back in time a bit and see how that was done.

I started with my SketchUp model.  I drew the legs in the model using the BezierSpline plugin.  If you use SketchUp you need this plugin.  It’s awesome.

I printed out the leg profile at full scale, which spanned three pages.  I carefully taped the pages together and, to my surprise, had a very nice drawing of the leg.  I would normally do this by creating a full scale drawing using ship’s curves, etc, but I was very pleased with this method.  Here’s a (blurry) photo of the drawing.

I took this drawing, laid it on a piece of 1/4″ Baltic birch plywood, and transferred the lines to the plywood by poking holes through the lines on the drawing.  I then connected the dots with the aforementioned ship’s curves.  The template, or pattern, was then cut out and the curves smoothed with a spokeshave and curved sanding blocks.  (In retrospect, I should have just glued the drawing to the plywood.)

Next, I created a pattern routing jig.  I use a large custom end mill for this type of pattern routing and the jig must be very sturdy to take advantage of the process.  This is not the place for double-stick tape.

Here’s a photo of the setup:

There are two jigs necessary for the process, and both faces of each jig are used to get all four edges of each leg.  It’s a rather complicated process which, in retrospect, was overly complicated for just four legs.  But it gave me four virtually identical legs.

I start the pattern routing process by using the 1/4″ template to trace the profile onto the stock.  In this case the material was 12/4 cherry, since the total width of the flared legs is 2 3/4″.  When tracing, I’m careful to draw the pattern about 1/16″ oversize on the edges and 1/8″ oversize on the ends.  Two opposite faces are then rough cut on the bandsaw.

The two bandsawn faces are shaped first, with the other faces left flat.  The template is then used again to draw the profile on one of the shaped faces, and the bandsawing and pattern routing is repeated.  This time, however, the leg requires extra support, as shown in the photo above.

Finally, the legs must be cut to length.  Since I know they are 1/8″ oversize on each end, I start by cutting 1/8″ off one end.  It was easy to start at the top end, since it has two adjacent flat surfaces where the aprons attach.  The photo below shows the setup for cutting the bottom end.

Note the spacers taped in place to get the correct configuration.  The tape on the end of the leg is there to prevent tearout on the backside of the cut.

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Mortise Layout

December 24, 2011 in Furniture, Joinery | No comments

I typically use loose tenons for mortise and tenon joinery.  I find them to be much faster than a traditional M & T, plus it’s much easier to get accurate shoulders.  I use my Inca slot mortiser to cut the mortises.  It’s fast and simple to set up and it cuts a mortise in about a minute.

To lay out the mortise on the leg, I start by drawing the profile of the apron.  In this case, the outer face of the apron is angled.  I could get the angle from my drawing, but I prefer to get it by eyeballing what looks good as I draw it on the leg.  This angle will become the actual angle on the apron.

Once the apron profile is drawn, I draw the mortise.  I typically leave 1/2″ of material at the top of the leg, but in this case I cut it to 3/8″.  Because of the stresses on the legs and aprons as the table is expanded, I wanted all the glue surface I could get.  Smaller than 3/8″ could result in failure of the short grain at the top of the leg, so I rarely go less than that.

The photo below shows the layout.  Note that I only draw the complete layout in one location.

The other locations are only marked for the length of the mortise.  Why?  That’s all I need.  When I use my slot mortiser to cut the mortises, the height of the mortise above the table is fixed by the machine.  Once set, it’s the same for all of the cuts, so why waste my time marking more than I need to?

To maintain accuracy, I mark the mortise lengths using a combination square.  I use it like a depth gauge, with the head resting against the top of the leg.  The END of the blade is set to mark the lengths.  Once set for a given distance, I mark all the legs AND all the apron ends.  That way, every mortise is in exactly the same spot relative to the top of the legs.  Here’s an example of the apron end layout (this isn’t an actual apron).

Note that when marking the apron ends, the head of the combo square is only used to reference from the TOP edge of the apron.

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DT Inner Apron continued

December 23, 2011 in Furniture | No comments

I’m back at work on the dining table.  I didn’t get much work done during the fall semester, and even less blogging.  It’s time to get caught up on the blog and back to work on the table.

The outer apron assembly, which includes the legs, is guided along the inner apron assembly by maple guides.  The guides, about 5/8″ square, are attached to the inner face of the outer aprons.  Grooves routed along the outside of the inner aprons locate the guides.  If that’s clear as mud, perhaps these drawings will clear things up.

I was concerned that the outer apron assemblies might bind when being pulled out, so I added center guides to minimize this.  The center guides also act as stops to prevent the outer aprons from getting pulled off the table.  The stop feature will be accomplished by attaching a brass plate on the inner end of the guide.  If you click the upper picture you can just make out the stop in the enlarged pic.

Due to the relatively small size of the closed table and the width of the leaf, which has to store between the center stretchers, there wasn’t much room for everything to fit.  Some careful planning was required.  The end of the center guide, when the table is closed, barely clears the center stretchers.  When open, the stop actually moves past the inner face of the inner apron.  To make this work, I needed to rout a mortise into the inner apron surface.  A detail is shown below.

The depth of the mortise was determined using my SketchUp model.  When the table is closed, there is 1/4″ clearance between the stop and the outside face of the center stretchers.  When the table is open, there is 1/4″ clearance between the edges of the leaf and two halves of the top (not shown in the pics above).  Because of the tight clearances, I was very careful about getting the model right.

Cutting the mortise was straightforward, but I wanted to make sure both portions of the mortise were concentric.  I carefully laid out the cuts and then clamped the apron into my slot mortiser.  I used a 3/8″ bit to rout the through portion, then changed to a 3/4″ bit to rout the shallow part.  I set the stops on the mortiser to maintain a consistent length.  Here’s the setup for the second cut.

The remainder of the material was removed using a sled on the table saw.

I started out this process thinking I would use a hand-held router and guide bushings to cut the mortise.  After starting down that path, it quickly became apparent that it was far more complicated than necessary.  The slot mortiser was by far the better solution.

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Cutting Large Holes

December 15, 2011 in Jigs & fixtures, Tips & Tricks | No comments

Did you ever need to drill a large hole for which you didn’t have a drill bit?  Up to an inch, a twist, brad-point, or Forstner bit will work.  One to two inches?  Forstner bit.  Two to four inches?  Forstner bit also, but these are uncommon and expensive.  Four to eight inches?  Somewhere in there you can use a router and circle jig.  Hole saws can work in some cases, but they don’t leave a very clean hole.

I recently ran into this problem.  I’m updating my Inca slot mortiser fixture and needed to cut an accurate hole to hold my Porter-Cable 690 router motor.  The hole required is 3 1/2″.  I could buy a $30 Forstner bit, which I would use once and probably never use again.  (Okay, if I had purchased it eight years ago this would be use #2, but you get my point.)

Starting with the end in mind:  My goal is to create a pattern to use with a router and pattern bit.  I want a pattern, or template, with an accurate 3 1/2″ hole in it.

To create the hole, I need to start with something I know is round.  I can create that with my disc sander by rotating some material (I’ll use 1/2″ plywood) on a pivot.  The pivot, a 1/4″ dowel, will be located in another piece which I can manipulate on the table of my disc sander.  I want the outside diameter (OD) of the pattern to be large enough for the router to ride on easily.  Three inches of material provides plenty of support, so I’ll make the OD about 9″.

I start by drawing a circle with a compass and rough cutting on the bandsaw.  I then drill a 1/4″ hole in the center.  Another piece is drilled to accept a 1/4″ dowel, with the dowel located so that the pattern will be supported well on the disc sander.

Here’s the setup on the disc sander.

The actual size of the outside diameter isn’t important; what matters is that it’s round.  It’s easy to get a flat spot when doing this, so be consistent with your pressure and movement.

Once I have a good outside reference I can start on the inside diameter.  I draw a circle of the desired size and remove most of the material by drilling a few holes on my drill press.  I then use my saber saw to finish the task.

Next, I make a special fence for my router table, shown below.  The outside diameter of the pattern will ride on the two edges of the fence.  A straight bit routs the inside diameter as the pattern is rotated.  By moving the fence back, I increase the diameter of the hole.

Here’s the setup in use.

It’s important to rotate the pattern in a clockwise direction.  The edge being cut should move to the left, against the rotation of the bit.  Moving the other direction would create a climb cut, which could cause you to lose control of the pattern!

Note too that when you move the pattern away from the fence, you move it away from the bit.  This makes it easy to stop and start the cut.

Prior to having a real fence for my router table, I did this process by using two pieces for the fence.  The pieces were about 3″ wide and clamped on the back side of the router table in a position such that the END of each piece was used to guide the pattern.  Quick and easy.

Also note that moving the fence back makes the hole larger by twice the amount of fence movement.  If you move the fence 1/32″, your hole will increase by 1/16″.  It’s easy to overdo it, which I did when I was shooting this demo.  The nice thing about this technique is that it gives you a very fast way to cut a very accurate hole.  I did the second pattern in under ten minutes.

If you have a spindle sander, you could do this operation also, but I don’t think you can get the same accuracy.  But you may not need it, either.

In the next post, I’ll demonstrate how I used the pattern.

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