Sonic Screwdriver Mark VI

A while back I was commissioned to make another custom sonic screwdriver out of metal with my usual electronics additions.

A fun note about this sonic is that the front end cycles colors. I am including the arduino sketch for the sound circuit with these instructions. Check out the videos, it is rather fun.

In this instructable I am going to detail as much of the process as I took pictures for to show off some of my machining techniques and tips rather than to tell you how to make this exact sonic.

As always if I am unclear or you would like to know more, please leave a comment or message me and I will do what I can to explain/help.

The standard electronics can be found here: https://www.instructables.com/id/Working-Sonic-Scr...

More information on my other projects can be found at: https://www.facebook.com/dancorriganproperties/

One of the most important steps in creating a prop is getting a solid design down. I have a very graphic oriented mind and will usually work purely in a 3d modeling program but everything from sketches on napkins to cad drawings can be used. The important pieces to knock down at this stage are proportions, how things fit together, the different pieces and to make sure the electronics fit. When I made this model I took measurements of each of the components I would be using and modeled them quickly as boxes or cylinders. I then gave about 20% extra room around my circuit stand ins. If you do not take the time to design out what you want to make you might get 95% of the way to completion only to realize that one dimension needs to be a bit bigger and you have to remake a part. (it has happened to me more times than I would like to admit)

First: Rule #1 of working on the lathe. Turn the chuck at least one revolution before you turn it on to make sure it will not hit anything with large amounts of force.

Rule #2: No baggy clothing, gloves, loose hair or loose sleeves and wear eye protection at all times. Lathes can do nasty things to a person, even mine which I can pick up with one hand, motor and all.

The battery compartment of my sonic is a piece of 1/2" X 4" black pipe (plumbing). While the black pipe is great for holding batteries it is both too narrow and not visually appealing enough for my tastes. To remedy that situation I bought some aluminum tube (amazon or a local hardware store) that was ~.85 inches inside diameter and 1 inch in outer diameter. I quickly cleaned it up on my lathe by taking two 5 thousandths off the exterior and enough from the inner diameter so that my plumbing pipe would fit inside.

I do not currently own a fully functional milling machine (working on one) so I do all of my milling using a milling attachment on my Taig lathe ( http://www.taigtools.com/mlathe.html ).

To start the milling process it helps to have a predrilled hole in the part (mine doubles as a hole for the button). I did this using the following method:

1. Mark the hole location with a center punch
2. place the part in the milling vise with a piece of brass along the top edge
3. line the part up and make sure it is flush with the bottom of the vise
4. tighten the screws down bit by bit as evenly as you can. Tighten the first a 1/2 turn, the last 1/2 turn, middle 1/2 turn and so forth until the part will not move. Do not overtighten
5. With that done put a center drill in the lathe jaws (or a collet if you have one. Those are better)
6. Run the part up to the center drill and align the hole as best you can vertically and horizontally (by eye you should be able to get within a few thousandths of an inch)
7. To lock the carriage on my Taig I push an o-ring between the spinning handle and the shoulder. It also helps to have the cross feed pulled all of the way towards yourself to help with rigidity.
8. To make sure you are tangent to the work put a steel ruler between the center drill and your part. If you are tangent it will be perfectly vertical, otherwise move the part up or down until it is.
9. Pull the work away from the drill, turn the chuck by hand, then turn the lathe on
10. SLOWLY move the part into the center drill until the taper cuts into the part a bit.
11. Move the part away and turn off the lathe

I needed to enlarge the centerdrilled hole to accommodate the top of my button. The setup is the same as the center drill but if you have only moved the part in line with the lathe axis you don't need to set up again.

Usually I would start drilling with a small drill bit and move up in sizes by small increments until I got to the size I need but since the part wall was so thin and the hole was not that big I cut this hole in one step. A side effect of doing this was that the hole was slightly larger than the drill bit but as it was a clearance fit that does not matter.

The actual milling can then be done. I used an 1/8th inch 2 flute end mill starting in the hole I drilled and moving the cross feed from my start position to an ending position. Every time I needed the cut to be deeper I moved back to the hole, advanced the carriage, locked the carriage and then moved the part. Though the wall was less than 1/8th inch thick it took me four passes to make it all of the way through. The taig lathe milling vise is not very good at milling deep passes.

With the slot milled I got to use one of my favorite tools. The yellow handled tool in the picture is a carbide deburring tool. You run it along the edge of what you just cut and it removes the sharp corner. (either file or deburr every corner you make, they are sharp enough to draw blood)

When I started this build I knew I wanted the black pipe to press fit inside its aluminum sleeve. To do this I cut the inside of the aluminum until the blackpipe just got stuck about 2/3rds of the way into the aluminum. I then added the brass nut to the black pipe, slid them together to that magic 2/3rds location and got ready to press fit.

To press fit I put them both in a large vise with the jaws touching the narrow ends. I then closed the vise until the brass nut just touched the aluminum. Opening the vise released the part and there is no easy way to separate them.

If you cut the aluminum too big 2part JB weld epoxy is a great way to hold things together too. If you cannot reach far enough into the aluminum tube to fit the black pipe you can also sand the pipe using a belt sander.

I would advise you to wash your parts before trying this process and dry them very thoroughly. The aluminum will eat away at the steel if there is any moisture between them.

My entire sonic screwdriver is hollow from the marble to the brass nut on the end. To make solid parts hollow I had to drill them through.

1. Face the part in question until you have a smooth surface
2. center drill the part as before but with the part spinning and the center drill in the tailstock
3. Move up in drill bit size until you reach your desired hole size. In the pictures above I am making an interference fit with a piece of brass rod.
4. Something that helps drilling is to peck, Drill 1-2 drill diameters then pull the drill bit out of the hole and do it again. Otherwise chips can build up in the hole, rip at the side walls or jam your machine. Not to mention those chips also hurt the drill bit.

Something that really helps with aluminum: parafin or beeswax. Whether I am turning, drilling, cutting with a bandsaw or hacksaw I almost always add a bit of wax to the cutting surface. Aluminum has a nasty tendency to stick onto tools and that will ruin your surface finish, and maybe your tool. In the last few images you can see the mess my drilling operation made, long ribbons of aluminum. That type of chip means you are working with a sharp cutting tool, are not trying to give it too much or too little to cut and generally have a very happy cutting process.

Also: the type of drill bit seen in the last image really shouldn't be used on a lathe. It is made for cutting wood but with caution they will work on a small machine. I would never risk it on a full sized lathe. They do not like to drill a larger hole from a smaller one.

In my design the floral bead sits inset back a bit into the aluminum of the top. To do this I used my boring tool to enlarge the inside diameter of the part to the correct size.

In the second image I have the cutting tool resting on the face of the part. I then measure with an engineer's ruler between the carriage and the depth stop to get the correct measurement and lock that in place. This method is a quick way of setting depths if super precision is not a priority.

Enlarging the hole did not take very long, but mall depth of cut is very necessary.

To help prevent the cross feed from slipping you can see my o-ring in action again in the second image. It comes in handy quite often.

I designed the final product to me milled from six directions because I knew I would be using hex rod for this part.

The setup is very similar to the last time we milled with a few notable exceptions:

• I am using one of the screws in the vise as a depth stop for the part. I run the part up to that screw before I lock it down.
• Depth of cut on the brass rod was minuscule. 4 passes for the thin wall.
• Each time I finished a cut I spun the aluminum by two faces to give divisions of thirds. When I cut the brass I offset that by 1 face so my new cuts would fall on faces 2,4 and 6 between the previous set.

It helps to have a hand on the vise (safely away from the chuck) to help with vibration and creep. The part will try to push itself out of the vise if you have it set up like in my images and take too deep of a pass.

Wax helps keep the end mill from jamming.

Make sure the brass rod is held tight in the aluminum. Locktite or some other temporary adhesive would not go amiss.

Make sure the vise is clean (I use a brush) before you put the part into it, otherwise the chips could make you inaccurate.

Be sure to clean up after the milling. Burs and sharp edges will try to bite you later if you ignore them now.

After milling the part I removed the brass rod and turned it down to its final shape.

The slanted surface in the first image was made with my right hand cutting tool naturally as the cut progressed, each time I made a new cut the cutting tool would run into this slanted shoulder.

The milled slots will create a bit of chatter when you cut past them. Slower feed (power if you can get it) will help

I made sure to put a depth stop in place to prevent me from hitting the chuck with my cutting tool. Even if I am an inch from the chuck I still like to put the safety there before ever turning on the lathe, for silly mistakes.

I needed to make a part that changed size part way along the external surface.

I use a ruler to measure the length of the 1st section from the end of the part to the front of the cutting tool. I then set the carriage lock at that position. After backing off and making sure I was clear I turned the part down to the proper diameter, a sliding fit with the rest of the handle.

I then made sure to remove the sharp edges that I just made with a file, manually turning the part.

I turned the inside and outside of my part until they matched my designs. Once that was done I slipped a lamp part (the knurled brass nut) over the piece and epoxied it in place.

The last two images show turning a brass tube to length. Often when I need a smooth end to a piece of brass tube I will chuck it up in the lathe and trim it to length with a facing operation

I test assembled the handle top to the handle to locate the button hole, then drilled the hole.

After a bit of filing I epoxied the screw retainer of the button into the handle top, allowing me to hold the handle together using the button as a set screw.

This piece of derlin plastic will sit on top of the black steel pipe inside the handle and hold the positive contact for the batteries.

The positive and negative battery connections were made during this step.

I took a three pin male header and ran the centre pin through the derlin where it was soldered to a battery terminal.
Then I soldered a wire to each of the 2 outer pins so that they would be pressed against the sides of the handle when the cap is in place, provinding a solid connection to the battery's negative terminal.

The negative battery terminal is a modified brass flare nut, modified just like step 10 of: https://www.instructables.com/id/Working-Sonic-Scre...

I etched the handle of this sonic using a saltwater technique for a cool textured effect.

How it works:
Paint on an electrical insulator (I used nail polish here) where you don't want etched

Make some very saturated salt solution

Connect the negative end of a 5-9 volt power source to a q-tip and the positive end to the part to be etched

Dip the q-tip into the salt solution and drag it slowly across the area to be etched. It will hiss and slowly eat away the metal. The higher voltage you use the more agressive your etching will be, but it will also produce chlorine gas which smells terrible and damages any soft tissue it touches (lungs, eyes, etc.)

A better set of instructions can be found here:

https://www.instructables.com/id/Salt-Water-Metal-E...

A better tutorial for the electronics inside one of my sonic screwdrivers can be found in steps 12-25 of

https://www.instructables.com/id/Working-Sonic-Scre...

The main difference I worked on this time was using header pins to connect the different parts of the circuit. This method takes up more space, however, it make troubleshooting and assembly far easier.

Thank you for reading my instructable.
More of my work can be found at:

https://www.facebook.com/dancorriganproperties

http://dancorrigantheatre.wix.com/home

If you would like to talk to me about a prop commission, please use the form found below or private message me.

http://dancorrigantheatre.wix.com/home#!contact/c1...