Spring Sweeper

This is an over-powered and over-engineered spring sweeping beast, with a touch of style so that it looks nice on your workbench. 8 true N52 power magnets are arranged in a specific Halbach array to maximize effectiveness. A lot of design, testing, trial and error, and energy went into this product.

You can buy these on my shop 44 Delta

• USA version (with magnets included)
• International version (without the magnets)

The scenario: You are gutting (or assembling) a lock. Perhaps it's a cheap lock. Or perhaps it's a very expensive and rare black belt level lock. A lock for which replacement parts are very hard to come by. All of the sudden.... PING! You launch a spring into the sky, totally unsure of where it went. Worse yet, your floor does a fantastic job of hiding tiny parts like these. What. Do. You. Do?

I (eschlenz) have had this exact thing happen to me. My solution was always a super high powered magnet. It worked like a charm. I wouldn't blame you at all for opting to go that route. However....

If you appreciate the testing methodology, the engineering process, and the fact that one of locksport's own (myself) designed and created this, then you may take interest in what I have to offer here.

The specs: 

• 8 true N52 high powered magnets (3/8" cubes, ~80 cents a piece)
• Magnets arranged in a K=1 Halbach array format
• Field strength measured to be as high as 4,388 Gs
• 70mm X 69.95mm X 34.66 mm

How to use:

With the magnets facing the surface (floor, table, etc), slowly sweep this device back and forth hovering somewhere between a half inch to 2 inches above said surface. Let the power of the 8 N52 magnets arranged in a Halbach array do the work for you and find those hard to spot, hard to replace, springs and other ferrous components.

Design Side Note:

For those “in the know”, there are many different types of Halbach arrays. One such arrangement focuses the strength of the magnetic field such that it is stronger on one side than the other. I did not use that specific array in my design for two main reasons: 

1. In actual testing, I found that the arrangement I use (all magnets having the same pole facing outward around the circle) to yield better results in snagging the springs from a distance. I hypothesize that this has to do with the shape of the N and S fields, which in the arrangement I chose are evenly divided around the ring. Obviously, either pole is going to attract ferrous materials. But with this arrangement, the “throw” of the fields is wider and therefore covers more surface area. 
2. It's easier to insert the magnets into the model with the arrangement I chose. All arrangements can be difficult to assemble when the fields are resisting your positioning of the magnets. But this arrangement seemed the least fussy.

This video in particular was very helpful, if you are interested:

Assembly instructions:

Before reading these instructions, just be aware of the goal here. We are trying to create a specific Halbach array arrangement where one pole (N or S) is always pointing in the direction away from the center of the Spring Sweeper, and the opposite pole inwards.

Refer to the “k=1” arrangement here to see a visual example

1. Place the Spring Sweeper model in front of you with the bottom (magnet hole side) facing up.
2. Take 8 of the 3/8" N52 cube magnets and stack them end to end in one straight line.
3. Pick one end of the row of magnets, doesn't matter which, and point it away from your body.
4. Carefully remove the magnet farthest away from you, from the row, being careful to keep the face that was pointed away from you in that same orientation until the next step is complete.
5. Push the magnet into the first hole (of your choosing), always keeping the face of the magnet that was pointing away from you in the same direction. That face should be the side closest to the outer edge of the Spring Sweeper model. 
   1. Side note: This should be a tight friction fit. If it's too loose, or too tight, you may need to calibrate your printer or rescale the model a bit. The magnets should not be able to come out on their own.
6. Repeat steps 2-5 until all magnets are inserted.
7. If you have magnetic viewing film, the fields should look the same as the one shown in the pictures for this Printables entry.

Printing Instructions:

• 15% infill
• Any layer height you wish
• Multi-color to make it look nice (if you want)
• No supports needed