Wood Hold Down - #2 Making the Form, Lamination Glue Up & Shaping

With the laminations cut and pre-bent next is to cut the form apart using the bandsaw.  This is done freehand getting close to but touching the line.  It may not look like it in the photo but the wings on either side of the sharp center curve are not straight but have a slight curve to them.  I did this because I think they will be stronger but don’t have the engineering to prove it.  Think of an arch supporting a bridge versus a flat surface.  

The outside curves of the form are brought down to the line and smoothed out using the large disk sander.

The inside curves of the other half of the form are brought down to the line and smoothed out using the oscillating drum sander fitted with a coarse sleeve.  The surface really does not need to be smoothed out like it would be for finishing.  That’s because all the surfaces will get a layer of packing tape applied to them giving a smooth non-stick surface to keep from gluing the hold down to the form when it is used.

Gluing the laminations together is next.  No photos of the process because it’s a race against time to get the glue on, the pieces assembled in the form and clamped within the glue’s working time which with the glue I am using is about 5 minutes.  The process is not that complicated but can get messy.  First, a sheet of 6 mil plastic sheeting goes down on the workbench where I will be making the mess.  After that a base piece of wood a little narrower than the form gets wrapped in the same plastic sheeting and set on the guides in the bench vice.  The form gets set on top and it’s ready for the glue-up.

• The first lamination gets set in the form up against the front part.  
• Glue is applied to the inside of the next piece and it is set in place next to the first piece.  
• Repeat spreading glue and setting the laminations in place until all seven layers are in the form.  
• Align any of the laminations that may be out of line.    
• Apply a little pressure with the bench vice.  
• Using a rubber mallet level the layers as needed. 
• Tighten the bench vice down more making sure the reference lines on the form are lined up adjusting as necessary. 
• Continue to tighten the bench vice down until really tight keeping an eye on form alignment.
• Clean up the squeezed-out glue.

It takes a couple of days for the glue to mostly cure within the laminations and on the bottom.  That’s due to the plastic at the bottom preventing air from getting to the glue and the form with its packing tape slowing the cure down.   After the initial overnight set the part is removed from the form and clamped as shown in the photo to hold its shape until the glue fully cures. 

Flattening the edges is next so all the lamination layers are flush.  That starts by drilling two holes in the form for screws that will hold the blank securely in the form while its edges get roughly flattened with a hand plane and finished with the thickness sander.  The two photos below show the setup in the drill press with the clamps needed to hold everything together and square.

Once the holes are drilled the laminated blank and the form are put back together in the vice and the screws, circled in red, get run in clamping the blank square and plumb in the form. 

Now that the blank is securely held in place both faces can be roughly hand planed smooth.  That’s followed by loosening the screws then moving one face flush with the bottom of the form and retightening the screws.  The assembly is then run through the thickness sander until the top edge is smooth.  Next the blank is repositioned so the sanded edge is flush with the form and the other face sanded flat. 

After the edges are flattened, in looking at the blank I thought that because there is a hole for the clamping bolt right at the peak of the curve that could be a potential weak point.  The drawing at the top shows the hole.   Adding a little reinforcement around the hole seemed to be a good idea so a short piece of oak about 1 ½ laminations thick is cut, bent and glued to the underside of the laminated blank shown in the bottom two photos.

After the glue dries both sides of the brace are cut down using a hand plane until it’s almost flush with rest of the blank.  The form and blank are then run through the thickness sander to flush the brace with the blank and make both edges parallel.

Next the end of the brace gets a small fillet sanded in it using a small drum in the oscillating drum sander.  This makes for a smooth transition between the brace and the body of the blank.  In the bottom photo the red arrow points to the finished fillet while the left edge of the brace is before sanding it.

Adding a small block at each of the blank’s ends is next.  They are the contact points for the hold down and top drawing shows what the end result will look like.  The middle photo shows the blocks cut to size and set in place while the bottom photo shows the blocks glued and clamped in place along with the pattern that will be used to layout the end shape.  The blocks are just a smidge taller than the blank and will be brought down flush after the glue dries.

After the glue dries the blocks are brought flush with a hand plane then the curved ends are marked out using the hold down template.  Below are the laid out ends ready to be cut.

The ends get roughed out using the bandsaw.  Final shaping is done with the large disk sander and the oscillating drum sander then hand sanded with 220 grit sandpaper.  The top photo shows the original aluminum hold down while the two bottom photos show a front and back view of the hold downs to this point.  A slot still needs to be cut at the top center of them but that will come later.

Next Up – Making the Knobs & Finishing

Wood Hold Down - #1 The Beginning & Bending Wood

To help keep parts in place while I work on them a number of different things are used including my bench vices, clamps and an aluminum hold down like the one shown in the photo.  A good one runs $15 to $20.  This hold down is designed to be used with an aluminum “T” track recessed into a work surface.  The photo shows how that works on my drill press to hold a stop block in place.  If the knob and bolt are switched out to a different type it can also be used with a ¼”-20 treaded insert mounted in a worksurface.

I would like to have a couple more but they are a little expensive for the frequency that they get used.  You can find plans for them online made from wood but my concern with those has to do with the grain direction.  The typical plan calls for them to be sawn out of a wood block which makes the grain run like in the drawing below.  The problem with that has to do with wood’s strength in relation to the grain direction.  A piece of wood is strongest when the grain runs parallel to the piece’s long dimension as in the flat piece in the top drawing.   The more it varies from this the easier it is to break when a load is applied.  Due to the shape of the hold down you can’t have grain running the long direction the entire length of the piece if it’s cut from a solid piece a wood.  I suppose if you could find a chunk of wood that had a natural curve or branch growing off the trunk then used that area where the grain curves to make the hold down the grain would follow the piece’s shape.  It’s not unheard of since old wooden sailing ships used parts just like that as shown in the bottom photo but it's not too practical.  

Another option would be to take a piece of straight grained wood and steam bend it around a form so the grain follows the curve.  However, since I don’t have the equipment needed to steam bend my solution to get the grain to flow is to laminate thin strips of wood together to form the blank needed.  Below the top drawing shows the hold down and the bottom drawing is of the form needed for clamping the strips together while the glue cures.

This is a technique I have used before for the arms of a Civil War Folding Chair (left photo, pre-blog) and for rockers on a Maloof Rocking Chair (right photo).  It works out well although the glue-up can get a little hectic and messy.

Making the form is the next step.  That starts with printing out a full-scale pattern and gluing it to a flattened scrap of 2x6 that’s thinned down to 1 3/8” thick.  As the pattern won’t fit on a single piece of paper it’s printed on two sheets and taped together.  This is taped to the prepared 2x 6 just at the top of the pattern.  Flanking sheets of paper are taped to either side of the pattern to mask off the 2x6 to prevent overspray of the adhesive.  That’s all been done in the top photo.  The bottom photo shows the pattern folded back so the bare wood and the back of the pattern can be sprayed with adhesive. 

Once sprayed the paper pattern is folded onto the bare wood, the flanking masking sheets of paper removed and the form is clamped in the bench vice.  Since the bench vice isn’t deep enough to clamp the whole form a scrap piece of plywood along with some clamps are added until the adhesive cures.

There will be seven or eight layers making up the hold down blank so selecting material is next.  Going through my thin scraps several candidates are selected.  They are mostly red oak but also include a couple of walnut and cherry pieces.  Not all this material will be used but it gives me a good selection to work from.

In the end I decided to use seven layers.  Six layers are oak with the center one being a contrasting wood, either walnut or cherry.  To get these pieces the blanks were first cut to rough width then milled to thickness using the thickness sander and finally cut to a consistent length.  It’s not the final hold down’s size as the laminated blank is made wide and long.

Taking one of the scrap laminations I tried to just bend it to shape and that didn’t work too well as the piece cracked.  To make the strips a little more pliable I tried a two-step process.  First a wet cloth is wrapped around the area where the bend is the tightest and let set for a while.  Once wetted a heat gun is used to heat/steam the bend area to soften the lignin in the wood allowing it to bend without breaking.  Once bent it’s set between a couple of clamps until it cools.  Going a little deeper into the “why” this works lignin is an organic polymer found in wood.  When heated, lignin in wood relaxes, becoming soft, flexible and just stretchy enough to compresses to a point where the wood fibers can be manipulated.  When the wood cools it retains its new shape.  The photos below show the bending process being done and the finished piece in front of the form.

Doing the bending of the actual pieces starts with marking a line centered at the apex of the bend.  Once marked a wet towel folded to a couple of inches wide is set flat on a waterproof surface, the pencil line is centered on the towel and a second wet towel set on top of the wood pieces.

This is the setup for the production bending process.  The heat gun set on low is held in the bench vice to heat the piece for bending.  The form with the pattern is in front of me so the bend can be checked.  Heating up the inside is first followed by outside.  That’s because the outside of the curve is the side most prone to cracking or splitting so it’s the limiting factor when bending.  At the lower left is the jig set up to hold the pieces shape until they cool.

Here you can see the finished set of laminations needed for one blank ready to get glued up.

Next Up – Making the Form, Lamination Glue Up & Shaping

Jointer - #3 The Handle, Finishing & Assembly

Laying out the handle is done with a half-pattern.  It’s used to draw the left half then flipped over to draw the right half.  This gives me a perfectly symmetrical layout.  While the original piece had a lot of cracks and some knots the early planning I did worked around them.

Cutting the handle out is done on the bandsaw.  Because I have a ½” wide blade on the bandsaw I need to make some relief cuts as the inside curves are too tight for that wide a blade to make.  Those cuts are shown in the top photo.  I could have changed the blade from the ½” to ¼” which would have let me make the cuts in one pass.  However, it takes a while to change the blade and reset the guides so for three handles it’s not worth it.  The bottom photo shows how the handle’s larger outside curves can be cut in one pass.

Once the handle is cut out the outside face gets smoothed using the large disk sander.  The inset is a closer view that shows the sanding marks.  Because the sandpaper is pretty coarse some additional sanding with the ¼ sheet sander will be needed to get rid of those marks. 

Sanding the inside curve of the handle is done using the oscillating drum sander.  Fortunately, the drum has different grit sleeves available so I can start with a coarse grit for shaping then switch to a finer grit which gives a pretty good finish.

Making the base plate out of ¾” thick oak plywood is next.  All went well until the final rip on the last base.  That cut edge had a void in one of the plies as shown in the top photo.  If I had another piece of the plywood I would have just tossed this one but the only pieces available are good sized and I didn’t want to take a small piece out of them.  The fix is to glue in a patch.  That starts by using the table saw to cut a slot as wide and deep as the void the full length of the piece.  The setup to do that is shown in the bottom photo using the cutoff scrap from the bases.

The slot gets filled with a spacer made from the cutoff when the handle blank got ripped on the bandsaw.  It was just a tiny bit too thick but was milled to just the right thickness using the thickness sander.  After being rough cut to width and length it gets glued in the slot.  Here the top photo shows what it looks like ready to be trimmed on the table saw and the bottom photo shows the setup for ripping.  The ends are cut using the chop saw.

With the ends and the edge trimmed you can’t even tell there was a patch used.  The bottom two photos is a closer view with the patch identified by the red arrow.

Clipping the corners of the base is next using an adjustable jig set at 45 degrees.  The top photo is with the jig and saw set up and ready to go.  The bottom photo is after one corner has been cut. Flipping the board end for end then top to bottom gets all four corners clipped with one setup.

Next the handle gets centered on the top and its feet get traced onto the base.  The positions of the screws that will be used to attach the two get laid out followed by drilling pilot holes for the screws.  That’s been done in the top left photo.  The right photo shows the base flipped over and a stepped drill bit being used to countersink the hole.  This will allow the screws to be run in anchoring the handle in place while being below the surface of the base.  I like using Kreg® screws (bottom left) because the head has a square drive rather than a Phillips or slot.  The screw is also case hardened and has a self-tapping tip so it’s less likely to spit the wood when driven in.

Here is a side and bottom view of the push block with the handle screwed in place.  After this test fit the piece is disassembled so work can continue.

Rounding the edges of the handle is next.  That’s done with the router and a round over bit.  Here the top face has been done along with the outer edge of the face that’s down.  The bottom inside edge still has to be done.

After the handle’s edges are routed it gets finish sanded along with the base.  The base also gets its top edges softened.  Last before finishing is to mask the areas where the handle and base come together.  The tape will keep those areas clear of finish when sprayed.  I want bare wood where the handle and base come together so there will be a good glue joint.

Spraying the parts with lacquer is next.  The photo below shows most of the items used; lacquer thinner, lacquer and various mixing bottles.  There is also protective gear consisting of a mask with N100 filter cartridges that filter out both organic and acid vapors and gloves. 

This photo shows the spraying setup where a base is on yellow painter’s triangles set on a lazy susan so the part can be easily turned to get to all sides.  The handle gets sprayed while I hold on to it using the screw.  Wrapped around the screw is wire used to hang the handle from a support.  After the second coat of lacquer is applied the surface gets sanded with 600 grit paper to remove any dust nibs followed by the final finish coat.

After letting the finish cure for a few days, the pieces are wet sanded with an 8,000-grit pad and the masking tape is removed.  Below is a before the tape is removed and an after.  It’s easy to tell where the wood is still unfinished.  The letter "C" on the right is used to match the handle to the proper base.

Assembly consists of gluing the handle to the base and running in four screws.  Last, is to glue a slightly oversize piece of 120-grit sandpaper to the base using spray adhesive.  The sandpaper provides some grip between the push block and the piece to be jointed.  Once applied the push block is put in a vice to put pressure on the glue joint overnight.  In the photo you can see masking tape around the base’s bottom.  This keeps the adhesive overspray off that edge.

After curing the tape gets removed and the sandpaper is cut flush with the base’s edges.  Below are the three completed push blocks.  The top left one is different than the other two in that it has a small lip on the left end which provides a positive stop to the trailing end of the piece being jointed.  The two on the right are the same except the bottom one is a little narrower.

Last is to make and mount a small shelf on the jointer to hold the push blocks.  It’s made out of ¼” plywood with a ½ square rim of oak.   Here is what that looks like.

This competes the work on and related to the jointer.  My only problem is I still have not found a good home for it in the shop.  So, for now it gets moved around depending on what equipment is being used.

Next Up – Wood Hold Down - #1 The Beginning 

Below is a drawing of the Hold Down.

Jointer - #2 Finishing Dust Collector Adapter & Starting Push Blocks

Making the hardware to attach the adapter to the jointer is next.  At the top I used a couple of steel splicing plates left over from a previous project that only needed to be flattened, one mounting hole added and painted.  The bottom gets attached to the jointer’s steel frame base using some long machine screws that go into some threaded holes on the jointer base I added.  The top photo below shows the front of the finished adapter along with the mounting hardware.  The bottom photo shows the back of the adapter.  The black is a piece of foam that will seal the adapter against the rail’s stand and the shallow recess at the top is for the chute’s cover.

Here is the adapter mounted on the jointer with the vacuum hose connected.Along with the jointer came a pair of push blocks that are used to keep one’s hands away from the cutterhead which spins at 4,800 RPM’s with the knives making 14,400 cuts per minute.  To me the push blocks are an essential piece of safety gear.  This is from family experience as when my dad was young, he slipped and lost a part of one of his fingers on a jointer.  These blocks are OK but I wanted ones that are a little longer, wider and have larger handles for more protection.

I decided to make three blocks not because I have three hands but to make two who’s bases are flat plus one with a stop at the back to grab the end of the piece to be jointed.  No drawings for these as they are going to be designed on the fly depending on what materials I have available.  Two of the bases will be made out of ¾” oak plywood 4” wide and 11” long while the other one also from out of ¾” oak plywood will be bit narrower.  The handles will be made from scraps of 2x6 construction lumber salvaged from the Master Bath Remodel.  I am using these since they were put in place in the mid 1990’s and have been drying for well over 25 years so they should be thoroughly dry and stable.  They are however cupped and twisted.  The photo below shows the cup, twist and cracking pretty well.  Since I had a paper cutout of the final handle, I moved it around on the blanks so they are free of knots, cracks and splits.

Here the bandsaw has been used to cut off the worst part of the blank which also helps to reduce the cup although it really does not help the twist much.

This is what the jointer and shop-vac look like set up and ready to go.  They are plugged into two different electrical circuits because the jointer needs a 20 amp breaker and the shop-vac draws 11 amps.

In the top photo looking down on the jointer the handle blank is set with the to be jointed face up.  Since I am not in a rush to flatten the board, the jointer is set up to take off only 1/32” per pass.  That amount does not bog the machine down so it’s easier on the equipment, there is less chance of a catch particularly as there are a couple of knots plus I end up taking no more off than absolutely needed.  The bottom photo shows the face flat and true.  This gives me one reference surface that will be used to bring the other faces square and parallel to it.  In use the jointer worked great, smooth effortless cuts and the dust collection captured all the chips.

The top photo shows the completed reference face to be use used to joint an adjoining edge square to it.  This is one reason I took the time to make sure the fence is square with the bed.  Squaring the edge is done by holding the reference face against the fence and running across the jointer until the surface has been cut along its full length and width.  When that’s done, I have one face and one edge flat and square with each other.  The top bottom photo shows the two squared edges.

Next is to bring the second wide face parallel and flat with the one previously jointed.  That can’t be done on the jointer because while it will make the second face flat it wouldn’t necessarily be parallel with the first face.  Either a planer or the thickness sander will work since they are designed to make opposite faces parallel.  Since this is a small piece and there is not a lot of material to remove, I will use the sander since it’s easier for me to set up and use than the planer.  Shown is the second wide flattened face. 

With both wide faces straight and parallel plus one edge straight and square with the faces last is to make the remaining edge straight and square with the others.  That’s done with the tablesaw.  Here it’s set to make a cut closer to the final width needed for the handle.

Ripping the blank to rough thickness on the bandsaw is next.  A marking gauge is used to give me a line to cut to.  A pivot point attached to a magnetic fence is set up to guide the thickness.  Here is the handle blank and the cutoff.

The bandsaw leaves a fair cut but to smooth it out it’s back to the thickness sander.  Here in the top photo, you can see where I have pencil marked the surface.  That along with the bandsawn marks will allow me to gauge how the flattening is going and when to stop.  The bottom photo is of the finished piece.  All in all, it’s a little bit of work to take a piece in as bad a shape as this was and make a flat and square piece of wood.  However, in practice the individual steps move right along.

Next Up – The Handle, Finishing & Assembly