Odd Magnet configuration

[Steve17]

After about two years of trying to scrape together information on my own, I just found this site. I'm really excited.

Anyway, I am building a set of pickups for the guitarist in a local band. Its a Strat (3 SC's) and he wants something that will emphasize the lower/mid frequencies but still provide a lot of clarity.

I decided to go with an Alnico4 bar magnet as sort of an experiment because I have never used it before. I had kind of a weird idea for the placement though, and I was wondering what you all thought it would do.

Standard single coils that have a bar magnet put it on one or both sides. What I want to do is drill 6 holes in the magnet the put the pole pieces through them.

Would this work? How would it affect the polarity? How would it affect output/overall tone?

Thanks

[black_labb]

how do you plan on drilling the alnico? its hard and brittle, not easy to machine.

[Possum]

...

If the screws don't go past the bottom of the magnet, assuming the poles are on top and bottom it would probably work, there are old Dearmond pickups with rubber magnets like that. It wouldn't work at all if the magnet poles are like a humbucker magnet placed flat, the middle of the magnet is a dead zone....

[David King]

If I understand what you are proposing to do I don't think it will work (beyond the complexity and expense of drilling and tapping into an extremely hard material). As Possum says, if you are drilling into the center of an A-4 bar magnet that's magnetized across the width, you'll be tapping into a neutral zone of the magnetic field. It would have to be magnetized through the thickness and alnico magnets don't like to hold a charge across the shortest dimension.

I'd experiment with poles touching the surface first and if that works -then get a solid carbide drill (about $10 surplus) and a ground carbide tap (about $100) and have at it. My instinct tells me you can get the same or better results with a different configuration.

I'd just grind the ends of the magnet round and wrap some tape and then your wire directly onto it with the magnet in the vertical position like a lipstick pickup.

[Steve17]

That makes sense, I guess I forgot some of my magnetics stuff from physics. BTW I had planned to use some equipment at my university to drill through it, but I see what you guys are saying and I will probably just put it to one side like I do P-90s. Thanks for the info.

[Joe Gwinn]

how do you plan on drilling the alnico? its hard and brittle, not easy to machine.

It's not hard to drill alnico if one uses the correct equipment, but as other posters have mentioned there in little point to doing so.

For small quantities, the easiest way is to solder a brass tube to a steel rod, cut at least one slit in the tube lengthwise, and using a drill press and some Permatex valve grinding paste, grind your way through the alnico (or ferrite or glass or ceramic tile). The brass tube traps the grit from the paste and carries it round and round, cutting the alnico. It's slow, but quite reliable.

[Mike Sulzer]

Another way to understand why you cannot do what you want to do with a normal humbucker magnet: The field points horizontal in the magnet. You need to magnetize the pole piece with a vertical field. In the normal configuration, the field bends around into the pole piece. That cannot happen if you put it in the middle, since the symmetry implies no net vertical flux.

[spud1950]

how do you plan on drilling the alnico? its hard and brittle, not easy to machine.

Diamond coated bits are avaiable and are not that expensive.Seems to me a diamond coated core bit would make fast work of it.Here's one source as an example.

http://www.diamond-drill-bit-and-too...-Drill-Bit.htm

[Possum]

....

You can use diamond drills made for lapidary use but alnico is so hard you will probably burn a few of them out just drilling through one magnet. I used to drill quartz which is alot less hard than alnico and the drill bits have a real short life, you also have to drill under water....

[Joe Gwinn]

Diamond coated bits are available and are not that expensive. Seems to me a diamond coated core bit would make fast work of it. Here's one source as an example.

http://www.diamond-drill-bit-and-too...-Drill-Bit.htm

Actually, it's the other way around. The alnico will make fast work of the diamond coated bit, unless one turns very slowly and operates under water. Note that the vendor does not list any ferrous metal as suitable for drilling.

The problem is that iron dissolves carbon, so if the drill rate is at all reasonable, the heat of drilling causes the diamond to dissolve in the metal.

[jonson]

stellite

I grind all my alnico magnets and that takes some doing but have drilled some as well. Look at Stellite drills, they are expensive and work on materials above
51c rockwell. The drill gets red and then white hot under a constant pressure and changes the material being drilled. I have had no problems rechargeing afterwards so I stick to that method. I find diamonds under water better for sliceing and slotting ceramics.

[David Schwab]

The problem is that iron dissolves carbon...

For some twisted reason this made me think of "rock, paper, scissor".

[Steve17]

For some twisted reason this made me think of "rock, paper, scissor".

haha, Carbon, Paper, Iron

Carbon scribbles on paper, and paper covers iron, iron dissolves carbon?

[David Schwab]

haha, Carbon, Paper, Iron

Carbon scribbles on paper, and paper covers iron, iron dissolves carbon?

Ha! I'm getting over a really bad cold so I didn't have the mental energy to come up with something, but that's good!

That reminds me of the XTC song "Paper and Iron (Notes and Coins)"