A Pantograph Engraver is a very handy piece of equipment, for the hobbyist. This machine was developed by me for engraving name plates, it could also be used for various other purposes... Like Cutting miniature parts on wood and acrylic with a template.
It uses a sewing machine motor coupled to bearing driven shaft... other types of engraving motors too could be mounted.. provided they are mounted in the right place or plane.. this engraver was constructed around 6 months ago..and is in its assembled form, therefore photographs from various angles will be presented to understand the construction..
Step 1: WHAT IS a PANTOGRAPH
A pantograph is basically a square with pivoted comers, if holes are drilled in it's arms it could be used for enlarging or reducing drawings or artworks. Fig 1. shows a basic panto graph.. Note the pivot points.. Note the point at the top left corner is secured.. drawings could be enlarged or reduced in accordance with points A, B & C....
Point B is usually the place where drawing or engraving takes place, it usually reduces the image of an artwork which is made using point A or C, if a large artwork is traced using a point at A, an accurate and reduced image could be made at Point B... This is the basic mechanism of a pantograph. With this understanding it is easy to develop the machine you need... one special NOTE: The pointer for tracing ( A or C) and the Engraving Motor ( B) should be placed right in the center of their respective arms.
Step 2: DESIGNING AND BUILDING THE ARM ARRANGEMENT
The most important point part of this type of engraver is, the construction of the square Parallelogram.. If a motor is going to be used it needs to be a strong and balanced design. at this point I will present the design that is displayed in the Photograph, The arms according to the drawing are 7/12" long from the center points of the two bushes, the 1/2 " stainless steel pipe is inserted into the hole of the bush, after the hole is drilled, when fitting I used some two part epoxy resin glue, which I applied inside the hole, it is best to assemble all four arms together, using two 6 mm shafts, which could be passed on both sides of all four shafts. through the bushes.
After assembly with the shafts placed one on top of the other, insert two long 6 mm pins on both sides, make sure the bushes are inserted first, they too can be fixed with resin glue so that it will not move around. leave the whole assembly to dry, before removing to construct the pantograph arm.
The pins were made with 6mm steel shafting, cut to size and threads were cut on both ends using a 6mm tap. When assembling do not forget to use washes were they are necessary.
NOTE: WHEN MAKING THE FOUR ARMS REMEMBER TO USE A LONGER WOODEN BUSH FOR THE RIGHT ARM AT THE FRONT END, SO THAT AN EXTENSION COULD BE ADDED TO CONSTRUCT THE TRACER ARM...
Step 3: DESIGNING AND BUILDING THE MOTOR ARM
The motor arm was constructed with two identically shaped pieces of wood, both parts were glued and bolted together in the middle with another block of wood, which was later used to attach the motor assembly.
NOTE: THE PIVOT POINTS ARE LOCATED IN FRONT OF THE MOTOR ASSEMBLY ARM. This is because the center of the engraving tool or the engraving shaft, should be in the same plane with the pivot points in the front. Follow the pictures provided.
Most engraving motors that are sold at E bay or Ali Express AND OTHER SITES, come with mounting brackets and come with power ratings of 100 watts to 1.5 Kilowatts. The framework of this machine will withhold motor power from around 100 watts to 300 watts. it is good enough for fine engraving work on Aluminium, Brass, Copper, Acrylics and Wood. The Diameter of the motor body plays an important role, and, the arm must be designed so that the shaft is centered in the exact plane with both pivot joints, that hold the motor arm in front.
Most engraving motors in the 100 - 200 watt range have a body diameter from around 48 mm to 55 mm...Thus it is important to decide on which motor you are going to use before constructing your MOTOR ARM.
Step 4: THE BASE FRAME
The Base frame is made of 1/2" square aluminium tubing, it has two rails on both sides, and, a center rail for reinforcement, which is screwed on to two planks, as seen in the photo. the machine is mounted on two sliding planks, which are bolted together on both sides with four nuts and bolts.
Step 5: FITTING THE PANTOGRAPH
The pantograph is fitted on a thread shaft, which is supported on two bearings, the pivot joint is fitted onto a wooden bracket with a 6 mm pin, the bracket is then fitted to the support bearing frame, which is bolted to the main frame, this feature permits it to be moved forward and backwards, by rotating the hand nut on the right of the thread shafting it could be move horizontally. An extra attachment is the tracing arm which is fitted with a doweling pin to the right of the pantograph mechanism, it is built with a tracing needle which can be adjusted for both height and distance.
Step 6: THE MOTOR CONSTRUCTION & HOW IT IS MOUNTED
The motor I used is a sewing machine motor, which drives a spindle on a bearing shaft with a chuck fitted, it can take different sizes of engraving tools, further, the motor can be controlled with the speed controller provided with the sewing machine motor, it helps in the engraving process because it is foot operated. The illustrations show how the motor arrangement is built and fitted. It is mounted with four 5 mm nuts & bolts. as shown in the motor mounting bracket, further an adjusting knob & sliding attachment is fitted to manually adjust the height and distance of the motor, and, tool fitted, and, the workpiece.
As I have stated in step 3, Motors are freely available at various online sales sites, they are robust and very reasonably priced, it is best to start with the specifications of the motor.
Step 7: THE ENGRAVING AREAS AND ENGRAVING
This is the final step since all areas of construction have been discussed. Note two 1/2" plywood boards have been mounted on the frame via the sliding aluminium rails, one for placing the artwork, and the other for mounting a small acrylic sheet for engraving on, note the following...
1. Where the artwork is pinned
2. How the material to engraved is mounted ( red acrylic sheet)
3. Adjust the counter weight behind with the fixing screw shown.
4. These engravings were done without any aligned adjustments, and, the engraved depth is about 1 mm usually too deep for an engraving, it is best to have an engraving depth of around 0.25 mm, adjust the point of the tracing arm by loosening the tightening screw that holds it in place.
For best results use two 1" wooden planks instead of plywood, make sure it is a hardwood, and both surfaces must be perfectly flat and well aligned. This may need another fitting that is not included in this instruction. I leave it to INNOVATIVE YOU...WOULD LOVE TO HEAR FROM YOU IF YOU HAVE ANY IMPROVEMENTS.....
Step 8: SOME ADVICE ON ENGRAVING BITS
The picture of some engraving bits is attached here. Note the two bits in the center were used to do this engraving, the fine bit which did the Robot has a 0.5 mm tip a with an angle of 10 degrees, the other is a 2 mm 4 flute engraving bit which was used to do the letter "A" . note the errors... The Robot should have been engraved with a 0.1 mm engraving bit for more detail, the jagged edges on the letter "A" is due to the movement of the tracing arm on the artwork, it takes some practice to do good engravings, usually letters are done with special templates, the templates have engraved lines in it, so it helps to move the tracing arm perfectly,
Note: THERE ARE MANY TYPES OF ENGRAVING BITS WHICH ARE AVAILABLE, I HOPE YOU FOUND THIS INTERESTING AND WOULD LOOK FORWARD TO YOUR COMMENTS ON IMPROVEMENT... Because I will be doing an INSTRUCTABLE on engraving.... in my next project....