How to use the hex pole-pieces from A-FX

[rhgwynn]

I'm not asking, I'm telling. Taking out the guesswork for those that haven't tried it yet.

Use a 7/32 drill bit and enlarge out the holes by hand. This is the perfect size bit - it is right on the money. It will not damage the structural integrity of the bobbin. Doing it by hand will prevent screw-ups and actually drilling it out. There is such a thing as too much power here, unless it it a low speed electric screwdriver. Next, use a green dremel cylinder bit with a domed head to smooth the edges of the hole. Again, by hand or on the lowest speed works well.

And that's it, you are done, and your HB bobbin is ready to accept the sexy black (or chrome) hex-top poles.

BTW, A-FX has a new price on these screws, you can get 60 of them for like 16-17 bucks or something like that, I forget the exact price.

-Rob

[R.Madgwick]

Aren't they 3mm? (.118) 7/32(.219) would be quite excessive, standard m3 tap drill is (.098) #40 7/64 (.109) would be OK but. 009 of thread is all that's left (.0045) per side.

[rhgwynn]

Aren't they 3mm? (.118) 7/32(.219) would be quite excessive, standard m3 tap drill is (.098) #40 7/64 (.109) would be OK but. 009 of thread is all that's left (.0045) per side.

You misunderstand. The bobbins, as they come, do not allow for these poles to countersink, because the holes are slightly smaller than the 5.4mm heads of this hardware. So you use a 7/32" (5.4mm) drill bit to tap the holes out for them. You are NOT tapping out the part that the shaft threads into; hence, the do it by hand that that does NOT happen.

-Rob

[David Schwab]

You misunderstand. The bobbins, as they come, do not allow for these poles to countersink

You didn't say anything about countersinking the head. You talked about tapping.

Use a 7/32 drill bit and tap out the holes by hand.

You did not use the work countersink anywhere. Try to read your post before hitting the post button to see if people would understand what you are saying. I sure didn't.

[big_teee]

countersink, enlarge, ream?
Tap usually means to thread.

[rhgwynn]

My bad fellers

-Rob

[R.Madgwick]

I see said the blind man. Sorry I misunderstood I haven't used them yet but just received some, may I recommend an end mill if you are purchasing a tool to do this job, they are flat bottom and will seat true and flat although I would only recommend running it in a press though by hand they will grab and side cut.

[David Schwab]

I see said the blind man. Sorry I misunderstood I haven't used them yet but just received some, may I recommend an end mill if you are purchasing a tool to do this job, they are flat bottom and will seat true and flat although I would only recommend running it in a press though by hand they will grab and side cut.

Good idea. I was thinking some kind of a flat bottom bit is the way to go. The only thing is indexing it to the hole, since they will cut a new hole anywhere. A step drill might be good, or if you were going to make a lot of there, get an end mill with a pilot.

[rhgwynn]

Good idea. I was thinking some kind of a flat bottom bit is the way to go. The only thing is indexing it to the hole, since they will cut a new hole anywhere. A step drill might be good, or if you were going to make a lot of there, get an end mill with a pilot.

I just looked in the holes on two different brand of bobbin and they both had a bevel and not a flat seat in the bottom. So, you may be over thinking it a little bit. Plus, on the mojo bobbin, the top of the pole went 2mm below the surface. I think they are fine as they are, and a regular drill bit with your hand or an electric screwdriver is just fine. No need for any special tooling or a drill press.

-Rob

[David Schwab]

I just looked in the holes on two different brand of bobbin and they both had a bevel and not a flat seat in the bottom. So, you may be over thinking it a little bit. Plus, on the mojo bobbin, the top of the pole went 2mm below the surface. I think they are fine as they are, and a regular drill bit with your hand or an electric screwdriver is just fine. No need for any special tooling or a drill press.

You are probably right, probably doesn't matter much.

[big_teee]

I've also been known to drill the screw bobbin all the way out and use them with slugs.

[rhgwynn]

I've also been known to drill the screw bobbin all the way out and use them with slugs.

Whyyyyy... wouldnt you just buy two slug bobbins....?

-Rob

[David Schwab]

Whyyyyy... wouldnt you just buy two slug bobbins....?

Probably wanted to do double cream and didn't have a cream slug bobbin?

[R.Madgwick]

Easy indexing tip, find a pin that slips into either the hole or the countersink, place the bobbin in a vice/fixture use the pin in the drill chuck, line it up til it falls in freely and raise it up swap in the drill/endmill and you're on center more then enough. Center finders/wigglers also work, machinist tools are pretty extensive for just about anything, enco.com is a good lower cost place.

[David King]

Tis not a countersink in geek parlance but a counterbore. There is an actual bit designed to do exactly that using a drill press at high speed with no risk to operator or part. Counterbores come in common numbered screw sizes #2 on up to #12. A 5-40 threaded hole with no thread clearance could be counterbored for a fillister head using a #4 counterbore. Pilot is .110", OD is .198"
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