Introduction: 'His and Her' Laser Cut Keyring

I love to design and make things - It's my passion! 

This is my entry for the Full Spectrum Laser Contest. If you guys like my work and enjoy what I do, please show your support and vote for me :). I have many more design ideas that could easily be realised with the addition of a laser cutter or SLA machine. 

I wanted to design and make something that used the laser cutting process but was also highly functional - if you built this you could definitely use it day in, day out! This 'His and Her' Keyring is designed to be mounted on the wall whilst holding the owners housekeys. As you leave the house, you take either the male or female figure with you. When returning, the keyring is placed back into the holder - remember this and you will never forget where you put your keys!!

Thanks for looking and I hope you find this useful and interesting. For other designs, please check out my other Instructables (knife, pizza oven and cider) and my website - www.philreillydesigns.com

All the best,

Phil

Step 1: Sketching the Concept

This stage is one of the most important stages in the design process. Here you where you will decide how the product will operate and how it will assemble. It is much easier and quicker figuring this out before entering the CAD stage.

I decided that I would make the whole thing from 5mm acrylic to minimize on material cost. The back plate will be glued to the front plate to create a solid body with some cut-outs on the front, for the figures. Screws will be used to hold the back plate onto the wall in conjunction with rawl plugs. The countersunk holes ensure that the screw heads lie flat and then get completely covered when the figure is placed in the front. The heart will be a red piece of acrylic that will be glued into the front plate. 

Step 2: Designing the Product Using CAD

Do not worry if you don't have access to CAD, I have attached the dxf. files I used in the next step :)

I have attached some step by step images of the CAD model taking shape. One of the most important things is to make sure that all your sketches within the CAD model are fully defined (have dimensions and constraints). This will provide you with a more robust CAD model.

First of all I created the front plate. This is because it is the most complicated and most of the geometry for the other parts can be copied from this one. 

The back plate is constructed from the outline of the front plate. It then has two 5mm clearance holes in the middle of both heads to accommodate the screws.

The heart is also copied from the heart profile in the front profile.

Both the male and female figure are copied from the cut-out in the front profile. 

All the dimensions for the parts create a "face on face" assembly, i.e there is no tolerance for assembly. This is because the diameter of the laser is 0.25mm and that is enough on both parts to provide a snug but not tight fit. Perfect for being able to remove the people but also snug enough to hold it in place when on the wall.  

Step 3: Creating the Dxf. Files

Once you are happy with the CAD model, you will want to export each part as a dxf. file. This is one of the most common file formats for laser cutting but just to be sure, check with the laser cutter as to what file type they would prefer.

If you do not have access to CAD then don't worry, I have attached the dxf. files that I used into this step! :)

Step 4: CAD Renders (Optional)

This step is most definitely optional and not necessary, but something I wished to complete to visually see how the project might look upon completion. I imported the CAD Model into a rendering program and generated a few images.

Step 5: What You Will Need

Below are the parts required for this project:

• 4 x Countersunk zink plater threaded screws, 3.5 x 25mm
• 2 x Rawl Plugs
• Fine permanent marker pen
• Vernier Calipers
• Brass Picture Hooks
• Countersink / oversized drill bit (8mm approx.)
• Super Glue
• Black 5mm Acrylic Sheet).
• Red 5mm Acrylic Sheet
• Vertical Pillar Drill
• Engineers Vice

The place I used for laser cutting actually supplied the material as well. It is worth sending off for various quotes and finding the cheapest. I had a quote of £150, £45 and £23 (this was for enough parts to make two sets). I went with the guy that quoted me £23 and that included laser cutting and the material - he did an excellent job. 

Step 6: Drilling the Male and Female Figures

Once receiving the parts back from laser cutting, the first job is to drill the bottom of the male and female figures to enable the brass hooks to be attached. 

Using a pair of calipers, measure the diameter of the brass hook including the thread. The aim is to drill a hole that is fractionally bigger than the pitch of the thread on the hook, enabling the hook to slide into the hole with minimal wobble. 

Take a permanent fine marker pen and a ruler and mark on the centre of the base. I used a vertical pillar drill with the pice clamped in a vice. This was to make sure that the drill piece went in vertically and accurately. 

The hooks I used had a diameter of 2.5mm. The drill bit I used had a diameter of 2.6mm. This .1mm Clearance was enough to enable the hook to slide in with little movement.

Step 7: Attaching the Brass Hooks

Carefully put some super-glue down the hole that you previously drilled. You do not want to overfill the hole as when you push the brass hook in, all the excess glue will come leaking out!

When positioning the brass hook, make sure that you orientate it the same way as what is in the picture below. You want the hole in the brass loop to be vertical (as shown) rather than horizontal. This is so that when you put the keyring in, it doesn't rest against the wall. 

I positioned the bottom of these figures hanging over the edge of a table whilst drying to ensure that the hook didn't accidently rotate and dry in the wrong orientation. 

Step 8: Countersinking the Back Plate

The holes in the back plate need countersinking so that when the screws are used to hold it to the wall, the screw heads are flush with the acrylic. This will make sure that the red male and female figures will then also sit flush.

Take a countersink or an oversized drill bit and drill the top of the hole. You want to countersink it just enough so that the screw head sits flush. It is best to drill a little bit, try the screw, drill a bit more, try the screw.. This way you won't drill it too deep.

Step 9: Gluing the Front Plate and Back Plate Together

Make sure that the glue is applied to the back of the front plate as shown in the picture. If you were to apply the glue to the back plate there might be a chance that some of the glue might end up in the place where the male and female figures will locate. Applying it to the back of the front plate you can be sure that the glue is in the correct plate.

Be careful not to apply too much glue as when you sandwich it together the glue will squirt out and spoil the clean visual faces of the keyring holder. When you stick the two pieces together, you can check by looking at the exterior faces to whether the two pieces are perfectly lined up in the correct position.

Wait until the glue is fully dried before completing the following steps.

Step 10: Gluing the Heart in Position

Apply a small amount of glue to the back of the heat and a small amount in the cavity where the heart will sit. Make sure that you are careful not to get any glue on the visual plastic faces as it will discolour it.

Drop the heart into position and hold horizontal until the glue has fully dried, preventing the glue from running out.  

Step 11: Attaching to the Wall

This product is designed to be screwed to the wall inside your home. I would suggest positioning it somewhere accessible, possibly out of view near your front door.

To attach this to the wall, position the main body where you would like to have it and use a pencil to draw the location of the holes onto the wall. Select a drill bit the same size as your rawl plugs and drill two holes where the pencil has marked the wall. Make sure that the hole is deep enough to accommodate the full length of the rawl plug. Push the rawl plug into the hole and make sure that the end is flush with the wall (just not protruding). 

Position the main body on the wall and screw through the countersunk holes in the back plate into the rawl plugs. The screws should hold the plate flush against the wall and have the screw heads flush against the back plate due to the countersinking. 

Step 12: 'His and Her' Keyring Complete!

Congratulations your 'His and Her' Keyring is complete!!

I hope you enjoyed this instructable and I hope I have helped you along the way! Feel free to post pictures of keyrings you have made – I would love to have a look!

Thanks for reading,

Phil

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