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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

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.