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Laser Engraving Spheres and Balls

How to Laser Engrave a Sphere

Laser engravers handle flat surfaces very well. With an appropriate rotary accessory they can be made to engrave on a cylinder by making the cylindrical surface logistically flat. To engrave a sphere there are two obstacles you have to overcome. One caveat is that I only have experience with the Epilog Legend 24TT so all my designs, comments and results are targeted to that environment.

The Problem

A client wanted to engrave company logos on a set of nested wood spheres. These spheres, similar in concept to the Nested Russian Dolls, ranged from 1.25" in diameter up to 4" in diameter. There were five nested spheres and each one would have something engraved on opposite 'faces' of each sphere along the joint where the top and bottom of the sphere split. For reference sake the smallest sphere was solid. All the others were hollow and were apparently made from a Russian wood called Linden wood. This very blond, lightly grained wood is very soft, sands easily to a smooth finish and wicks sealer and finish rapidly to start.

Limit the Area to Engrave

If you limit the area to that needs to be engraved to a narrow ring around the sphere you can effectively manage it as if it were a cylinder. The width of the ring is determined by the radius of the sphere and the focal characteristics of the laser engraver. The larger the radius the wider the ring. Depending on your laser's focal characteristics you will most likely want to focus the beam on the highest point on the sphere. You could focus on a spot to one side of the maximum diameter, but you have to be careful that the laser head does not impact your workpiece.

Holding the Sphere in a Laser Engraver - Plan A

Assuming you've defined a ring around the sphere in which to engrave the next hurdle is to hold the sphere so that the rotary accessory can reliably rotate the sphere. Since most spheres will not have any sort of journal or tenon on the ends you will need to attach something so that it does. A few solutions were suggested in the Saw Mill Creek forums on laser engraving (see this Saw Mill Creek forum thread ) including a cardboard tube such as a mailing tube. This closely approached my idea which was to use PVC pipe adapters. They are relatively inexpensive, can be found at most hardware stores, are made to fit / nest, come in a variety of sizes and can be machined if needed. This seemed to be the ultimate solution for handling spheres of varying sizes.

Thinking that this might not be the only time I need to engrave a sphere I thought a reliable, reuseable jig would be worthwhile. So, I used a jig made of two halves that would become journals or tenons on the sphere. Each half started with a 2" PVC coupler. It is the right size to hold a 4" diameter sphere and the outside diameter came reasonably close to matching the diameter of the drive wheels of the rotary accessory (more later on why that wasn't so important). Pictured here are all the parts for the entire jig. One half is 'assembled' (not glued, just put together). The black ribbon is a strip of rubber from an old bicycle inner tube. The yellow ribbon is a packing strap material saved years ago for just this purpose (doesn't everyone?). The clamp is a hose clamp often sold for assembling 2.5" diameter dust collection hoses. All the PVC parts were chucked on the lathe, and slightly smoothed, especially the raised letters on some of the ends. The 2" PVC coupling has a 1/4" hole drilled all the way through and a 1/2" hold drilled all the way through at a right angle to the 1/4" hole. The 1/4" hole was made to hold a 1/4" brass rod that is used as a pivot point for the straps. The 1/2" holes were used to pull the straps tight so they could be clamped on the outside of the coupling using the hose clamp. Refer to the two assembed version pictures above to see what the whole jig looks like in operation.

The strap (one or the other, not both) is used to hold the two ends of the jig against the sphere.

Results and Critique

As you can see from this picture, I was able to engrave on the spheres. However, the jig proved to be not at all useful on the smaller spheres and I opted to just engrave them while they sat still in the engraver the same as you would a flat surface. The larger two I was able to use the sphere holding jig and you can see that the engraving goes about 40% of the way around the circumference of the sphere.

The good news is that this approach works. The major limitation is that you must limit the engraving to a ring around the sphere as mentioned above. The second limitation is that the strap going around the sphere means you cannot engrave all the way around the circumference of the sphere. This could be solved if you created an external clamping mechanism that somehow pushed the two ends from the outside rather than trying to pull them together from the inside.

The bad news is that this is difficult to get set up. I aligned the two ends of the jig on a lathe. I chucked one in a chuck on the headstock and the other in a chuck on the tailstock (using a Oneway live center and appropriate adapter for the chuck). This holds the two ends in perfect alignment while you adjust the sphere and everything else. It allows you to tighten the straps and clamp them in place. Then with everything aligned you dismount it from the lathe and take it straight to the laser engraver.

Notice in the earlier pictures that there are small black and / or white pieces of material around the sphere where it touches the PVC jig. The black pieces are more of the rubber inner tube. The white pieces are double sided tape. It turns out that double sided tape is not very effective on PVC. It helped, but not nearly as much as I thought it would.

The bottom line is that I got the job done. If I do more of these I'll consider a plan B jig that pushes the two halves to clamp them onto the sphere rather than trying to pull the two halves together.

Build a Hand Plane

This class was inspired by a David Marks Woodworks show on making a European Hand Plane. David made it look so easy that I thought I could do it. Turns out it is easy and I highly recommend that you try it yourself if you have an interest or need for a good wood hand plane. There are similar designs available through other sources so please do a little research on hand plane design and use so you can make the best use of your new wooden hand plane.

This class can be downloaded as a PDF document here - Build aWooden Hand Plane

Build a Wooden Hand Plane

Materials needed

Plane Iron - Hock Straight Edge 1 3/4" with chip breaker as an example
Dowel - 3/8" x 2.5" (hardwood or metal such as brass or steel)
Wood for the plane body - approximate rough size 11" L x 2 5/8" W x 1 3/4" T

Estimated time to complete this project: 1 hour to 2 hours

Steps to Build Your Own Wooden Hand Plane

1)    Select a plane iron and chip breaker (optional) and flatten and sharpen the iron
2)    Select and cut the plane blank to approximate dimensions (11" x 2 5/8" x 1 3/4")
3)    Flatten and square the bottom, top and sides of the plane black
4)    Rip the sides of the plane blank to leave a center block about 1/16" wider than your selected plane iron
5)    Mark, cut and sand the bed angle and relief angle on the center block
6)    Glue the two center blocks between the sides you created in step 4
7)    Flatten the bottom and square the sides of the plane blank
8)    Mark and drill the hole for the dowel
9)    Cut, sand, and fit a wedge to hold the plane iron in place
10)    Relieve the edges, customize the shape and try it out

Laser engraving setup fees

Setup fees depend on the work involved. We will charge a setup fee if there is a lot of work needed to develop or manipulate artwork for your project. But, often our setup fee is minimal or zero in favor of encouraging a long term relationship and follow-on projects with our clients.

When we do charge a setup fee it is based on a rate of $55.00 per hour.

Does the type of finish on my wood pen or pencil matter?

To date we have not had a problem laser engraving through normal finishes. In most cases we don't even know what finish is on the pen or pencil. There is always a first time, but we have yet to find it.

Can special requests be handled?

Often we can handle special requests. Here are some examples.

Left or Right Handed

A right-handed person will generally hold the wood pen or pencil such that the engraving needs to be left of the clip. A left-handed person will generally hold the wood pen or pencil such that the engraving needs to be right of the clip. Most people don't think of this when giving pens as gifts, but to give the perfect laser engraved turned pen or pencil gift you should know whether the intended recipient is right-handed or left-handed.

Text That Wraps Around

In extreme cases text can be written length-wise on the pen in multiple lines. We can also actually engrave something around the barrel of the pen or pencil, but there are several caveats with doing this. We cannot at all be reasonably expected to 'make ends meet' going around the barrel of the pen or pencil. Barrel finished diameters can vary widely and since we are working with such small dimensions and tolerances it is nearly impractical to get this to work from one pen to another. Also, there just isn't that much surface to engrave on most wooden pens and pencils. Engraving the barrel where it will be handled constantly can result in obvious issues such as breakage of fine pieces in the engraving, and in not so obvious issues such as filling the engraved areas with "stuff' that comes from the owner's hands". Think about it.