Prototype bobbins---3D printing!

[David Schwab]

Good point, although they look wide enough for my P bass. Certainly won't do for a 5 string.

Here is an idea tho, why couldn't you cut a piece off another magnet to add to the 2.5" dimension ( I believe you could use a wet tile saw to do this), superglue it on to add to the length as needed, then magnetize the assembly? The flux path doesn't go through the axis of the cut. Anybody tried this? Way cheaper than a special order longer magnet.

Why not just use steel blades charged with a bar magnet? That's how that T-Bird pickup in the other thread was made.

In this case it has three ceramic magnets. (they could have gotten is centered a little better!)

[Tommorichards]

But wouldnt the magnet used to charge the steel blades also not be long enough.....

[David Schwab]

But wouldnt the magnet used to charge the steel blades also not be long enough.....

It doesn't have the be the full length of the blades.

[marku52]

really?? I just shipped a small piece (pickup cover) off to China. Only cost about $10US. it might be less than you think. otherwise, PM me, I think I can help you out with magnets.

[Tommorichards]

If they werent, wouldnt that affect the strength of them?

[David Schwab]

If they werent, wouldnt that affect the strength of them?

That depends on how much shorter, and how strong the magnet is.

Without going into details, I use a much shorter neo magnet in relation to the blades, and it works just fine. The magnet charges the blades all the way across. This is also true of shorter ceramic magnets. I don't use alnico in any of my pickups, so I can't comment.

[marku52]

it is important to remeber that the iron pole piece is thousands of times more "attractive" to the magnetic flux than air is. The magnetic power, if you will, would much rather flow through the iron than through the air. Yes, with a magnet that is shorter than the pole piece, yes, some of the flux will take the short cut and go straight through the air to go from N to S pole. But much more of it will take the less resistive path through the iron and charge up the pole pieces relatively equally along their length. I'm sure David has performed the measurements to confirm this in his design.

[Tommorichards]

Well thats good to know, and could make things a lot simpler.