Bobbin mount (aka platen) shape

[StarryNight]

Hi Starrynight

I'm using the straight ali with steel screws, but I must admit that it's a lot of faffing about to mount the humbucker bobbins. How good is the grab with the magnet system with tight winding ? Any problems with the bobbins moving ?
Cheers

Andrew

The magnets hold really tight. I'll have to post of a video of what it looks like.

[David King]

Starry Night,
Aluminum is "grabby" which is why some folks find it a nightmare to thread but with the right type of tap and some bacon fat you will have no trouble at all. The taps and dies you buy at the hardware store are typically closer to "thread restorers" as opposed to a precision ground high speed steel tap you buy from a machine shop supply house. The prices are actually better for the good taps and they'll last a lifetime of tapping aluminum provided you ALWAYS use a suitable lube. If you don't have bacon fat available you can use the ubiquitous WD40 or really any type of oil, grease, wax etc.

[StarryNight]

Bacon fat!? In some indirect way I would love to say I use bacon fat to wind my pickups but alas, the wife is a vegetarian. It's all the rave these days you know. Seriously I would love to put down money on some good taps. The cheapo ones I have just add more grey hair to my head. It's good to know there is a difference, thanks David. I've been using motor oil but maybe WD40 is a better choice with Al.

[Stratz]

I'll have to post of a video of what it looks like.

That would be great. I'm still trying to picture the setup in my head.

[StarryNight]

video

alright i'm not a videographer but here's a basic description of the plate. couple of things: the wire that went onto the plate was due to me starting to wind before I put the wire between the guides - nothing to do with the plate itself, I was at a funny angle. Even though I can push the bobbin side to side it takes a fair bit of force and doesn't move when on the winder.

[Joe Gwinn]

I assume you would have to replace or sharpen your bandsaw blade after cutting aluminum as its not much good for wood afterwards.

What kind of blades are you using? Aluminum cuts nicely at wood speed with good blades. One can wax lubricate the blade as well. Nor does it take that long to swap a bandsaw blade.

The trouble I have with aluminum is the tapping for mounting screws. ... But I find tapping 4/40 threads in aluminum and then using steel screws in and out over and over tends to wear the threads out pretty quick. This is probably more to do with my stellar machining skills than anything else. I also find tapping aluminum more difficult than steel as it is soft and tends to grab the tap and break it. Note: it's not me that breaks the tap, it's the aluminum!

You need to avoid hardware-store taps altogether. Buy spiral-point gun taps made by non-asian makers. MSC carries a wide variety. Here is one cutting tap: HSS Spiral Point Taps - Plug Style - Spiral Point Taps | MSCDirect.com.

For aluminum, thread forming taps work well, and don't tend to wander. Use the correct size number drill, which is different from that for a cutting tap. Lubricate with wax or lard. Thread Forming Taps | MSCDirect.com

Denatured alcohol works fairly well as a cutting fluid for aluminum. Lard also works. As does wax.

[StarryNight]

great info! thanks Joe...

[Stratz]

That explains a lot. Nice woodworking and construction on the winder too!
Thanks for posting the video

I'll take one with a 1/2" shaft bore please

Rob.

[SonnyW]

You need to avoid hardware-store taps altogether. Buy spiral-point gun taps made by non-asian makers. MSC carries a wide variety. Here is one cutting tap: HSS Spiral Point Taps - Plug Style - Spiral Point Taps | MSCDirect.com.

By the way, I have had pretty good luck finding quality US made taps on ebay. You have to scroll through a lot of them, but there are a few that come available at pretty decent prices. I like to search for Greenfield, Morse, Hanson, DoAll, Cleveland Tap Drill, etc.

[Joe Gwinn]

By the way, I have had pretty good luck finding quality US made taps on ebay. You have to scroll through a lot of them, but there are a few that come available at pretty decent prices. I like to search for Greenfield, Morse, Hanson, DoAll, Cleveland Tap Drill, etc.

I've had good luck with taps and dies from a local used-tool place as well. Same brands, and one can inspect the goods. The ultimate source of used but good taps is manufacturers, many of which change taps on a schedule because a broken tap causes downtime. Taps bought in bulk are cheaper.

[Bruce Johnson]

A couple of comments on making aluminum faceplates, to add to what David and Joe have suggested:

Yes, to tap small holes in aluminum you need a good quality spiral point tap (aka a Gun Tap). That makes a huge difference in your tapping pleasure! I usually use WD-40 in a small needle-tip squeeze bottle as the lubricant, but many other things will work too.

You didn't mention what species of aluminum you were using? You really want to use 6061 for any aluminum parts that get tapped holes. Most of the aluminum strips and bars that are sold in hardware stores are 3000 series alloy, which is soft and gooey and easy to bend. It has mechanical properties similar to cheese. It's very frustrating to tap small holes in it. Don't waste your time; get some 6061.

To make round aluminum face plates, the simplest thing is to buy a pre-cut slug of round 6061 bar stock. Most metal suppliers sell it in increments of 1/2", in diameter and thickness. For most guitar pickup faceplates that I've machined for customer, I buy a 3" dia x 1" thick slug of 6061. Put that in your metal lathe to face off the front and back, and drill and ream the shaft hole. Then layout, drill and tap any attachment holes on the face. No bandsawing or heavy machining required.

[Joe Gwinn]

Yes, to tap small holes in aluminum you need a good quality spiral point tap (aka a Gun Tap). That makes a huge difference in your tapping pleasure! I usually use WD-40 in a small needle-tip squeeze bottle as the lubricant, but many other things will work too.

Yes, I forgot to mention WD-40 (which is oily kerosene).

You didn't mention what species of aluminum you were using? You really want to use 6061 for any aluminum parts that get tapped holes. Most of the aluminum strips and bars that are sold in hardware stores are 3000 series alloy, which is soft and gooey and easy to bend. It has mechanical properties similar to cheese. It's very frustrating to tap small holes in it. Don't waste your time; get some 6061.

Yes. If one must make threads in hardware-store aluminum, use a thread-forming (not cutting) tap.

To make round aluminum face plates, the simplest thing is to buy a pre-cut slug of round 6061 bar stock. Most metal suppliers sell it in increments of 1/2", in diameter and thickness. For most guitar pickup faceplates that I've machined for customer, I buy a 3" dia x 1" thick slug of 6061. Put that in your metal lathe to face off the front and back, and drill and ream the shaft hole. Then layout, drill and tap any attachment holes on the face. No bandsawing or heavy machining required.

This works too, if one has a large-enough lathe. But my assumption is that cutting the hub in a 1" thick piece of 6061 may exceed the capabilities of many minilathes, as one must remove about one half of the metal in the blank. Thus the two-step process, making hub and plate and shrink-fitting them together. It's also easier to drill and tap the setscrew hole in the hub before assembly to the faceplate, unless one has the necessary pulley drills and taps.

As for making the shaft hole, I usually drill and bore (versus ream) to ensure that the shaft hole is both round and perpendicular to the face of the bobbin face plate. But I've reamed them too - this works if the lathe is heavy enough to ensure that the drill bit makes straight-enough holes, as the reamer will not correct an off-angle hole.

[David King]

As I've posted before several times, there is really no need to use aluminum for a faceplate, it might just as well be plexiglass, cast acrylic or void-free birch plywood. That way you don't need a lathe, just a small drill press or even an electric drill in a vice to true it up. I've trued some of mine up on my table saw with a file and sandpaper. I started with a 5/8" arbor hole in the center, cut the outside to round with a coping saw or bandsaw. The tablesaw spins at about 3000 RPM which worked out just fine.

[StarryNight]

As I've posted before several times, there is really no need to use aluminum for a faceplate, it might just as well be plexiglass, cast acrylic or void-free birch plywood. That way you don't need a lathe, just a small drill press or even an electric drill in a vice to true it up. I've trued some of mine up on my table saw with a file and sandpaper. I started with a 5/8" arbor hole in the center, cut the outside to round with a coping saw or bandsaw. The tablesaw spins at about 3000 RPM which worked out just fine.

If there's a tailstock there's not much issue attaching bobbins to any plate material. Truing the plate is relatively easy with my setup. However I found, particularly with Al, that screw holes were getting looser the more bobbins I wound. Granted my choice in Al was more like, "hey! What's this piece at the bottom of my scrap drawer? I think I'll try that!" so buying a proper piece of 6160 likely would have stopped problems before they started. David K what's your solution to attaching bobbins to softer plate material?

[StarryNight]

As I've posted before several times, there is really no need to use aluminum for a faceplate, it might just as well be plexiglass, cast acrylic or void-free birch plywood. That way you don't need a lathe, just a small drill press or even an electric drill in a vice to true it up. I've trued some of mine up on my table saw with a file and sandpaper. I started with a 5/8" arbor hole in the center, cut the outside to round with a coping saw or bandsaw. The tablesaw spins at about 3000 RPM which worked out just fine.

If there's a tailstock there's not much issue attaching bobbins to any plate material. Truing the plate is relatively easy with my setup. However I found, particularly with Al, that screw holes were getting looser the more bobbins I wound. Granted my choice in Al was more like, "hey! What's this piece at the bottom of my scrap drawer? I think I'll try that!" so buying a proper piece of 6160 likely would have stopped problems before they started. David K what's your solution to attaching bobbins to softer plate material?