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I live in a house that is easily more than 100 years old. Living here has taught me that the term ‘this ole house’ is the basis of conversation with the repairman I called last week, rather than a syndicated production. By the generosity of God, I grew up on a farm learning to do all that you can to save paying others to do what you might accomplish. Life has taught me that you are a much better person if you mow your own yard rather than get a job, that pays enough money, that after taxes, you can still afford to hire someone else, to mow it for you, and pay for their weekly service, while you also pay a monthly fee to go to the gym or health club, in order to have a place to exercise.

Think about it……..Bob

Wednesday, March 8, 2017

A FANTASTIC LAPTOP COMPUTER CREDENZA, TABLE, DESK, OR WHATEVER ………..

I enjoy having my laptop computer turned on and beside my chair when I am watching TV. 


If I get bored I can play card games, check email, and many other time occupying chores.  I had it on top of a  large waste basket, but I had to move it to throw paper in the basket.  So I designed a very light weight but sturdy small table for the laptop to be in a perfect place and quickly available, but out of the way.  I use a wireless keyboard and mouse which means I can recline and work with my computer.


The design of this table is based on the triangle, the strongest and most stable geometric shape.  Each of the two vertical legs is joined by mortise and tenon into the horizontal foot and this is reinforced with an Oak dowel to form a triangle.


The work surface is adjustable for level, 15 o , 30 o , 45 o , or 60 o , and the support under the surface also forms a triangle.


 Looking at the back side you will see two pieces form an “X” between the legs which is just two triangles that overlap. 


The front edge of the work surface has two short uprights instead of a full piece, like a book stand.  This allows you to access the SD card slot or any other feature on your computer that is located on the front.  The tops of the legs do not extend above the work surface so USB ports, AC adapter, and DVD access is not a problem.  The weight distribution is focused on the center of gravity for the unit and because of only two legs, this unit sits firmly on the floor by making contact with all 4 foot pads.

This design offers very light weight but an impressively stable unit. 

After I chose the wood I had to plane and edge the wood for the cutting of the stock pieces.


To get started on the structure, I cut the 2 legs, 2 feet, and 4 foot pads, sizes and dimensions are shown in the table at the end of this presentation.  The leg and the foot are joined with a mortise and tenon. 


Once I pair the two I make marks to show front, back, left or right.  Here you see a dot inside the mortise and on the side of the tenon which mates the two and reminds me of the orientation when putting them together.  I dry fit the leg’s tenon with the foot’s mortise.  When this is correct, I place two pieces of tape on the side of the joined pieces.  One from the joint up the leg and the other from the joint along the short part of the foot, lay a piece of 1/4 inch Oak dowel about 7 inches long on the two joined pieces and mark the outline of the dowel on the tape. 














This gives me the target to set the alignment for my Shopsmith to the horizontal bore and clamp a board as a fence at the correct angle for the approximate 45 degree angle to drill. 


A small piece of tape placed on the wood fence after the first piece is drilled will give me the mark for placing the other leg for drilling the ¼ inch hole.  The angle will change for drilling the feet but the process is the same.

Now is the time to round the top of each leg and drill the correct side of the top with a 5/16 inch hole, but not all the way through.  Stop the drill about 3/16 inch short so there is a stop for the dowel to butt against.  This is also when I chamfer and sand the pieces before assembly.

One final dry fit test for each assembly before glue up will prevent many problems. 


I found it easier to put the dowel into the hole in the leg first and then line it up for the hole in the foot so that it slides in as you guide the tenon into the mortise.  For the glue up on each assembly, I use a small 3/16 dowel sanded flat on one end to coat where I need glue in the dowel holes, the mortise, and the tenon.  Once they are together with the glue, I insure the two are perpendicular.


I use a piece of hard board that is the same width as the wood stock is thick with a 3/16 hole in it as a template. 


















This will be placed on the underside of the foot and the top of the foot pad to guide me for the drilling of the 3/16 hole. 

Just be careful to remember to flip the hard board over after drilling the underside of the foot before drilling the top of the pad. 


When I glue the two together I put a short piece of 3/16 dowel in the hole to add strength and alignment, and then clamp.


After about 2 or 3 hours I can lightly sand any marks and glue squeeze out.  This is the best time for fine sanding touch up and to coat both assemblies with polyurethane.

For the table surface I used a ½ inch pre-primed cabinet grade plywood about 12 by 16 inches.  Because the edges expose the layers of wood, I add a trim around the piece with a 3/8 inch wide and 5/8 thick strip that has been put on the table saw to cut a rabbet 1/8 inch by ½ inch.  Now this trim will align perfectly with the top, have a 1/4 inch wide trim, and


a small 1/8 x 1/8 lip that will extend under the top and insure the best alignment.  On this and all pieces I will chamfer and sand the long stock before final cut to length so I have a little extra to choose the best area for the finish part. 


To avoid nails I simply apply glue and used my TABLE TOP (PORTABLE) WORKBENCH for a strong clamp to attach the trim.  I cut the corners to a 45 degree before attaching.

After cutting the trim for the top, I also dimension the pieces for the horizontal, the "X", the two uprights for the front edge of the top, and the supports for the top. 


I let the trim around the top dry for a couple of hours and then back to the table saw to cut rabbets in the front edge so I can glue the uprights in position. 



Using a long piece of stock about ¾ thick and 1 ¼ wide, I set the miter gage to 45 degrees and cut four (4) trapezoids with a 1 inch long top and almost a 3 ½ inch base.  On two (2) of these I drilled a 5/16 inch hole with the center about 9/16 inch from the top 1 inch edge and centered from side to side.  I stop the drill at a depth of 9/16 inch to leave a thin wall to butt the dowel against when assembled.  This is the ‘pivot block’.


The other two (2) blocks of the same dimensions are used for the support to the table top.  The ‘support block’ has a ¼ inch hole ½ inch from the top, centered side to side, and drilled all the way through.  On the table saw I set the height of the blade to 1 inch and the fence should be 3/16 from the blade.



By placing the block upside down with the 1 inch top on the table saw and sliding it very carefully, I am able to cut a grove in both blocks.  I move the fence away from the blade about 1/8 inch and do the same again.  This will repeat until I have a grove that is slightly over 5/16 wide.


These 4 blocks will be glued to the underside of the top.  First I must insure the center of the holes will be positioned accurately from the front edge.  For this I insert a short piece of 5/16 dowel in the pivot  blocks and a 1/4 dowel in the support blocks.  Now I mark on the underside of the block the end I am going to use as the front of the block.


With a sanding block I am able to sand the longer block's front edge to align properly with the other mating block for both pair.


Now I am able to drill a 3/16 hole in each of the blocks by aligning the template with the front edge of the block. 


I place the table top with the bottom side up so I can use the front edge of the top as my reference to measure to each pair of block's front edge.

Once the four blocks are in position, I place tape at the 3 edges to isolate the area for the blocks to be attached.  With the template positioned, I drill a 3/16 hole about 3/8 inch deep. 


Remember with the support blocks you put the thin wall to the outside and the hole in the pivot blocks face the outside.  I have learned the hard way…….  Again I must be very careful to be sure to flip the template in order for the mating holes to be positioned perfectly for the blocks to be glued. 


These holes will allow me to glue the blocks in position with a 3/16 dowel to join the pieces just like I did for the pads on the bottom of the feet. 

After this has set over night, I very closely inspect the trim and especially the mitered corners.  Lightly sanded will adjust the trim to a perfect transition from one to the other at each corner. 


I will apply the first coat of polyurethane now, and then I move on to getting the remaining pieces.

Each leg is custom fitted to allow about 1/16 gap between the leg and the edge of the table. 


This is accomplished by slightly rounding one end of the dowel and then carefully shaving the length of the dowel and dry fitting it until the ends are butted against the stops that were left in the block and the leg. 


When this is accomplished I am able to add glue to the hole in the pivot block and inserting the dowel to dry and be fixed in that position.

I gave the dowel about an hour for the glue to set.  Then with the top upside down and the legs positioned,



I slip the hole in the leg top onto the corresponding dowel from the pivot block on both sides.  By holding the two pieces together with one hand I slightly move the foot of the leg so as to have it parallel with the side of the top. 

I round one end of the horizontal piece, then place it in position,


and mark the other end for the length and a small dot to show where to drill the hole for the screw to be inserted.  This hole is the same diameter as the shaft of the screw.   When this is ready I place it in position again and with a small pick it can press through the predrilled hole in the horizontal piece into the leg to mark for the next holes.  These holes are 2 sizes smaller than the shaft of the screw and only as deep as the screw will extend past the thickness of the horizontal piece.

The "X" is done in the same manner.  These two pieces are cut to length, chamfered, drilled, and ready to attach.  Before they are attached I position them and place a tooth pick through the holes in the ends and into the holes in the legs so that I have them ready to mark for a rabbet to cut where they cross.  This will add extra stability to the structure.  I mark the top surface of bottom piece and the bottom of the top piece.  Then on my table saw I carefully adjust the miter guide for the correct angle and remove about one-fourth of the thickness.



I add a mark inside the rabbet so I will be sure to place the two back correctly for the assembly.  A small amount of glue is added in the rabbet before assembly and once the two are screwed into their position, I clamp the two for the glue to dry. 


At this point I also drill a 1/4 hole in one end of the two support piece.  This hole must be positioned with the center of the hole about 3/8 inch from the end and centered on the piece.  This is because when it is assembled within the rabbet of the support block it will not bind against the bottom of the grove as I rotate it 180 degrees.  Cut this piece to 12 inches, and round both ends.  Before I drill the other ends I place the two support pieces together and insert a single piece of 1/4 dowel through both pieces.  This will insure the holes in the other end are equal distance.  Now I drill through both pieces at the same time at the opposite end.  This hole is the same diameter as the shaft of the screws that will go through that piece and into the legs.  I place the end of the support piece with the 1/4 hole into the rabbet of the support block, inset a 1/4 dowel that I have cut to the same length as the thickness of the block.  Just before it is fully inserted I add a small amount of glue around the dowel end, push it in until flush with the block, and wipe away any squeeze out glue.

I remove the horizontal, the "X", and one leg.  This will let me position the remaining leg on its side.  I place a long piece of tape on the inside of that leg, measure up from the foot 5 inches, and mark. 


That mark will allow me to transfer the tape to the other leg after I have marked for the holes in the first leg.  A line is also drawn on the tape from end to end to show the center of the leg.  Now by joining the table top with the leg and placing a block under the front trim of the top,


I am able to use a protractor to position the top perpendicular to the leg.  Carefully I align the other end of the support piece so that the hole in the end is over the center line on the tape.  I use a small pick and press the point into the leg to mark where to drill. 

Using the protractor I reposition the top to have a 15 degree tilt down and mark the leg for another hole.  This is continued for 30, 45, and 60 degrees tilt.  I remove the tape from the first leg and put it on the inside of the other leg so as to align it with the mark at 5 inches from the foot.  The small holes in the tape are my guide to press the pick into the second leg.  I now drill 5 holes in each leg that are 2 sizes smaller than the screw that will be used.

At this point I join the legs with the top, attach the horizontal and the "X", and stand the unit in the upright position.  I move the top to whatever tilt I feel is best and set it there by putting the screws through the ends of the support pieces and into the holes in the inside of the legs.  The screw used to join the support piece with the legs is not screwed tightly, but rather leave a 1/16 or less space for movement.


This unit is so light that it is easily moved, and sturdy enough hold anything from a plate of food to a laptop computer.  I am including a table of lengths and dimensions, but you may want to alter the numbers to your own preference.  


This unit is for sale on eBay, my username is "stirlingbay".

Thanks for looking and tell your friends.....

Thursday, June 18, 2015

Make Your Own Engraver ... ALSO known as a Pantograph...3D no less

I watched a fellow wood worker on You Tube.  His name is Matthias Wandel  and he approaches his work with a great deal of mathematical analysis.  He made a jig for cutting "finger joints" that is very impressive.  Then I found his video on making a pantograph.  It looked like something that I might find a use for and enjoy, so I started my search for making my own.

First I did Google "pantograph" and found plenty of references.  Some of those I downloaded and printed for me to study.

















I found that the first basic requirement is a parallelogram as the foundation of the unit.  Then you anchor one of the extended ends to the table, the other end holds the "tracer", and the tool is mounted on one side of the parallelogram.  Next, and after a lot of trial and error, I realized that the three points (anchor, tracer, and tool) must be fixed so that they are always in a straight line.  This keeps the finished work from leaning to one side or the other, or being skew.  Finally I began to understand that the measurements for the sides of the parallelogram and the distance from the parallelogram to the anchor and the tracer are the controls for the scale of the finished work compared to the original.

So I decided to play with the measures to get an understanding and to be sure that after I make one, I do not have a list of things I did wrong.  I started with some small pieces of wood and drilled holes at different location.


























I even made a pencil holder and mounted it on one side.  This assembly is held together by one inch bolts and nuts.  

I used my logo and traced it to see what my efforts might uncover as problems.




Finally I stopped and went back to precise measures.  I settled on the following diagram:


These measures will give me a 2:1 ratio for engraving.  The master that the tracer will follow must be twice the size of the finished engraving that I want.

So I started cutting my pieces.  I added one inch to the length of each piece so that I had extra space.  Then when I drill holes for the pins that are at the pivot points, the extra inch will give me an extra 1/2 inch between the holes and the end of each piece.  The pieces that I first cut are:

4 - 13" long, 3/4" thick and 1" wide
2 - 7" long, 3/4" thick and 1" wide
1- 10" long, 3/4" thick and 1 5/8" wide
1 - 10" long, 3/4" thick and 2" wide
1 - 4" long, 3/4" thick and 1 1/4" wide


Then I rounded the corners at each end, just to make it look better.

On six pieces ( 4 - 13" long and 2 - 7" long), I drew the center line from end to end, marked the location on each center line for a 3/16" holes, and began to drill.  Each side has a top and a bottom piece.  To insure that the holes are in alignment, I clamped the top and bottom together and drilled the first hole.  Next I put a 3/16" dowel in that hole and then drill the other hole, or holes, as my diagram indicates.


The difficult side to work on has two 10 inch pieces because this is the side that holds the tool.  The center lines have to be moved off center to allow the positioning of the tool. 

The tool is my DREMEL Multi Pro, 2 speed, Model 285 Type 5.  I removed the cap on the base of the tool and measured the diameter of the threaded area, which is 3/4".


Then I drilled a test hole to be sure it would fit.


I marked with my awl an off center line end to end on a thin piece of metal 3" x 1 1/4" and another perpendicular at the center, then drilled a 3/4" hole, which the tool will fit through, and 4 - 1/8" holes for screws.


Next I had to position a 1 1/4" hole on the bottom 10" piece that is 1 5/8" wide.  This will generate an over size border that will allow me to slightly adjust the positioning of the metal piece that is screwed to that bottom and allow room for the cap to be screwed back on the threaded area.

Once the tool is inserted and the cap screwed back on, it will guarantee that the tool will not slip and possibly change the depth of the cut.  The lines drawn from end to end and the lines perpendicular to that are the guides for the placement of the metal piece that also has lines indicating the center of the hole.


These lines will give you references for alignment.

I turned the bottom over and realized that I will need to remove some wood so my fingers can gain access to the collet when changing bits, as well as being able to screw the cap on or off with my fingers.


I used a rasping type bit in my drill press and carefully removed enough that gave me space.

Next I designed the top of this part.  I marked a line end to end and then a perpendicular for the center of my 3 holes.   I placed the 4" piece beside the larger one as it will be when finished so I could position the larger tool hole.



  I used a 2" hole saw to remove the area needed to secure the DREMEL.


Then I trimmed the circle so that it is a "U" and glued some strips of cork to line the inside.


I marked the 4" piece,


cut that arc away, and added cork there also.

After making sure that the tool fits into this holding area, I clamped the two pieces together and drilled holes for two 1/8" bolts that will have "wing" nuts on them and hold the two pieces together.



Now I start to make the "spacers" that will be between the top and bottom of each side.   To insure balance I marked the center of the edges on the spacers and when joining these together,



 I aligned this mark with each line on bottom and top that goes end to end.

I started with the tool assembly side first by attaching the top and bottom piece to the tool.  This gave me the chance to position the top piece to the best possible place for grasping the tool and not interfere with the "off/on speed switch".  It turned out to be about  2 1/2" for the measure needed between the top and bottom.  I cut two pieces that wide from a 1 x 4 and cut the length to fit within the area allowed.  Next I glued the spacers and clamped them to the bottom, then when the glue was set, I added two screws in each into predrilled holes .


I put a 3/16" wooden dowel through the holes in both ends of the bottom and added the top so that the dowels keep the top and bottom in alignment.  Repeated the process of glue, drill, and screw to add the top to this assembly.



I realized that the parallelogram will be in constant motion while in use, so I used 3/16" dowels and assembled the entire unit without any spacers other than those on the tool side.  Next  I moved the unit to each extreme position that it would have to accommodate and with my pencil I marked the areas on each of the bottoms that must be free of obstruction for the unit to operate correctly.


Then I cut some card stock in those shapes and punched holes for locating the screws.















I cut the spacers  2 1/2" wide and 4" wide and placed the card stock on top of one end.  This showed me how each of the spacers had to be shaped before I put the pieces together.

Once each spacer was cut and shaped, I glued and clamped each to the bottom.  After about an hour I removed the clamp and used the card stock to mark the location for predrilled holes for two screws into each spacer through the bottom.  Then I put a dowel through the holes at the ends of the bottom and added the top.  Repeated the process of glue, drill, and screw to add the top to each of the remaining sides.
 
Next I cut the 5 pivot pins from a long piece of 3/16" metal rod.  On one end I heated and flattened for a top and slightly tapered the bottom to help guide when inserting.




















Finally the pantograph is assembled.



I moved it to all extremes and checked that the spacers are not prohibiting movement.





Since this is a 3D pantograph, I need to attach it to a 1 x 4 board using a hinge.  This is another pivot point.  From a 1 x 4, I cut a 4" piece and a 1 1/2" piece.  For this unit the  1 1/2" piece is 4" long so it will fit between the top and bottom of the anchor end.  I cut a rabbet  3/4" wide and about  1/4" deep down the middle of the 4" piece.  Then I rounded one edge of the 1 1/2" piece, drilled a 3/16" hole, and glued and screwed it into the rabbet.



I left a 3/4" space at the bottom because this will allow the pantograph to slide a top and bottom over this piece and a pin to go through.

To attach the mounting piece to the base board I used a section of piano hinge that I cut from a long one.



When I first tried to use the unit, I realized that it must be elevated because of the thickness of the wood that I will be engraving.  I cut two pieces to that thickness and placed them under the base board.



I cut another piece of 1" wide about 8" long, drilled a hole in the center, and added it to the end where the tracer is located.



I hold the ends of this piece in each of my hands and this is like a steering board.  It helps me to make a smooth and continuous movement while engraving. 


I added some pieces to keep the steering board from slipping up the tracer.


For my test run I clamped the unit to my TABLE TOP (PORTABLE) WORKBENCH (one of my other blogs in this set), placed the dogs in position and opened the bench vice.  By adding strips of wood I was able to place a strip horizontally against the dogs, then the work piece, then another horizontal strip of wood, then two strips perpendicular to that strip and butted to the bench vice so there is a space between the two for the master that I will copy.  Then I tighten the bench vice and secure this assembly so it will not move.


Now I found a new and difficult problem.  I must move the pantograph so that the bit in the DREMEL scans the area where I want to engrave.  At the same time I must watch the tracer so that I am able to position the master design that the tracer will be following.


At first I used trial and error, but finally I realized that I need to cut a rectangle out of paper that is twice the length and width of the area that is to be engraved.


Then I put the bit in the top right corner of the engraving area, and I slide the rectangle so that the tracer is in the top right corner of the rectangle.  Next I do the same for the bottom left corners.  Now the master is placed inside the rectangle and positioned for proper spacing.


Tape it down and engrave.

The bit I finally found to be the best is a diamond coated one with a very, very small tip.  I got this bit off eBay with a set of about 12 or so.


This one works best for what I want to do with the pantograph.



I also wanted to test the 3D application of this unit, so I used a three dimensional piece and a block of soft red wood ... and after some effort....


I found that sometimes I do want to adjust the depth of the bit, so I made a small piece of 1 x 4 that allows me to raise the unit and rest it while I make adjustments.


Finally the unit will rest and be out of the way when not needed because of the hinge on the back.


I hope this will help you to be encouraged to make one for your own use.  Remember that you can control the size ratio by adjusting the measures and placement of the pins that are the pivot points for where the sides come together.  You might want your engraver to be larger or smaller.  Do a lot of searches and test before you settle on your design so your efforts will produce an engraver that is just what you want.

Thanks for looking and good luck.