Vox AC30-CC2X Dress Nuts Not unthreading

[nevetslab]

The latest delima in my shop is getting the control panel out of a Vox AC30-CC2X, so I can remove the very gritty Master Volume pot and a couple other controls that are very scratchy. These have to be my favorite fasteners! No tooling steps allowing open end wrenches to grip the base of these cone-shaped dress nuts, as is typically found on Alco Dress nuts. I've always resorted to gripping the base of the nut with 8" Gas Pliers, as seen below. Grip it tightly, and rotate while pulling up on the nut is the method.



Only this time, all I"m succeeding in doing is radiusing the base of the nut as well as the panel finish. I've seeped in WD-40 oil, Machine oil, alcohol, tapped on the nuts all around and from the top with a drive pin punch and hammer (not beating on it, mind you), and thus far, it's behaving as though the amp was sent out to another shop for repair, and some clever fool placed Loctite on the threads. Though, I don't see any evidence of that.

I don't have any freeze mist on hand to try. I haven't yet tried a heat gun.

Any suggestions?

[Enzo]

Sometimes I get a stuck phillips screw and the cross hole strips out. I get out my Dremel with a thin cutoff wheel on it, and saw a slot across the head and use a flat blade driver.

In this case, I would lay down a layer or two of tape on the panel to protect the finish, and use my Dremel to grind flat spots on two opposite sides of the nut. That ought to improve the grip. What is there to lose, the nut already looks chewed up from the pliers.

Get some acetone from the wife, worth a try. (Nail polish solvent)

[Bloomfield]

Another thing that I do sometimes is to take a very small cold chisel- well sharpened so it won't slip- and hold it tightly against the nut near a corner, and gently tap it around counterclockwise with a small hammer. Something thin like a pot nut will often stretch doing this which makes it come off more easily.

Might be good to try some stronger penetrating oil like PB blaster or Releaseall, just a little dab with a q-tip.

Good luck,

Andy

[nosaj]

Another thing that I do sometimes is to take a very small cold chisel- well sharpened so it won't slip- and hold it tightly against the nut near a corner, and gently tap it around counterclockwise with a small hammer. Something thin like a pot nut will often stretch doing this which makes it come off more easily.

Might be good to try some stronger penetrating oil like PB blaster or Releaseall, just a little dab with a q-tip.

Good luck,

Andy

In a bunch of tools I bought I ended up with a pair of pliers where the ends wire coated in a urethane. Later found out they are for glasswork, but they work good in cases like this.

Nosaj

[J M Fahey]

Serious heat might work, either by softening possible Loctite or whatever or by expanding the nut slightly more than threaded shaft ... or both.
Bring the old Weller 150W into the party.
Nut might end up damaged or stained but if you can get new ones, no problem.

[Mick Bailey]

+1 on the soldering iron. I have a monster that I use for chassis soldering. It takes 1/2 hour to heat up but when it does it's got huge thermal mass. The problem with gripping something like that nut is when you apply enough pressure to get a grip it's also squeezing it, so Enzo's suggestion of grinding flats on the nut overcomes this. With some jobs I just regard the part as sacrificial if it means getting the thing dismantled without damage to anything else.

[Enzo]

There is always the final effort: snap the whole darn top off the switch and install a new one.

Here is a way to use the old Weller guns that really can apply some heat. Anyone who has a Weller gun knows the wire tips wear out and break apart at the tip. And to finish what you were doing, you bend the tip halves together to complete the circuit and make heat to solder the last couple joints. (Rather than stop and replace the broken tip RIGHT NOW) But you then discover that just touching the two tip ends to the work conducts the current THROUGH the joint so it self heats.

You could do the same thing here: Take the tip out of the gun and touch the two empty ends of the gun to either side of the nut. That would make the nut the new end of the tip and the nut would self heat.

REminds me of another Weller trick. If you need to tin a large number of wire ends, a solder pot can be faster than your iron. The Weller tip is a heavy wire form with a narrow space between the legs. You take a spent 22 shell and wedge it up this space near the tip as possible, and fill it with solder. Now you have a little solder pot to dip wire ends into.

[Pedro Vecino]

With a small amount of lubricating oil, a waiting time for it to take effect and a conventional pliers that hold the nut horizontally with its circular grooved part should not be a problem. You may need to hold the switch at the same time on its other side. In the image you try vertically. It is less effective.

[nosaj]

With a small amount of lubricating oil, a waiting time for it to take effect and a conventional pliers that hold the nut horizontally with its circular grooved part should not be a problem. You may need to hold the switch at the same time on its other side. In the image you try vertically. It is less effective.

Automatic Transmission fluid works great for breaking things loose. I keep a bottle with a syringe tip in the shed.

Jason

[nevetslab]

Serious heat might work, either by softening possible Loctite or whatever or by expanding the nut slightly more than threaded shaft ... or both.

Heat was the solution! I did add more WD-40 before I went home last night. Overnight, I thought about my large Starrett Tap Wrench, but in trying it, the taper of the dress nut just laughed at that tap wrench's jaws....no way to tighten it. I then added more WD-40, and got out the heat gun, which had a small nozzle with a right angle exhaust port. After applying that to the first one for maybe 30 sec, I set it aside and grabbed the vintage gas pliers, and it untrh3eaded just fine. Nearly burned my fingers upon first touch of the dress nut to see if it was coming loose.

So, mission accomplished! Thank you all for your input!

[nevetslab]

As luck would have it, the initial attempts with the gas pliers to un-thread the dress nuts from the threaded switch bushing loosened the bushing within the body of the switches. The first two hex nuts came right off, while the next pair just rotated the bushing instead of un-threading. That took a pair of needle nose pliers and an open end 8mm ignition wrench to get the nuts off.

The switches themselves work fine still. The hardware on these switches are 6mm fine pitch, and don't thread onto American 1/4" threaded bushings like C & K 7201's. I can thread an Alco dress nut onto the Vox switches, but only as far as the end stop of the dress nut allows. The 6mm hardware doesn't thread onto the C & K or similar switches.

I could replace the four switches with C & K PCB mount SPDT toggles, as all the mounting attributes are common, and the lead spacing is close enough to fit. I'd have to machine out the end stop of the Alco dress nuts if I wanted that feature on the re-build. Wat a PITA. For now, I think I'll just mix up some JB Weld and app;ly a bead around the base of the threaded bushing/switch body and let it cure over the holiday, and see how it looks afterwards.

[J M Fahey]

I would replace them all and sleep like a baby.

[Mick Bailey]

Automatic Transmission fluid works great for breaking things loose. I keep a bottle with a syringe tip in the shed.

Jason

Mixed with 50/50 with acetone it's the best penetrating fluid going. They separate out so need shaking together and applied quickly. Like Newman's Own salad dressing.