6-32 Helicoil: Is it really 8-32 or special

It's also the weakest of the bunch. How about tapping up to 8-32, is there enough meat?

Jim

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Doug Goncz wrote: (clip)Will an 8-32 tap properly prepare the worn threads for a Helicoil? (clip) ^^^^^^^^^^^^^^ Helicoil taps do not match standard threads. By a huge coincidence, it is conceivable that the 8-32 might be close enough, but I wouldn't bet on it. Installing a Helicoil involves a special insertion tool which pulls the coil from the bottom, causing it to collapse slightly, so that it is slightly loose as it goes in. After insertion, it springs open, so it becomes secure. If the tap diameter is not perfect, the insertion will either be too loose, or else the finished thread diameter will be too small.

In order to install Helicoils, you would have to buy a kit, good for several threads, for about $25. This will include the insertion tool and the tap. I would opt for that before I would pay someone $25 to do just one.

There are other thread repair inserts, which look like set-screws, which can be installed using standard taps.

It is also possible to repair a stripped thread using an epoxy type material, available from Loc-tite (I think). You spray a screw with a release agent, smear on the plastic, and push it into the hole. After it is hardened, just unscrew the screw, and you have threads. It's not recommended for critical applications like connecting rods, but ought to be OK for what you're doing.

Or . . . fill the hole with JB Weld, re-tap after JB sets up - at least 12 hours.

You spray a screw with a

Special insertion tool: take one bolt of correct thread, file a notch in the end to pick up the tang on the helicoil. Wind the insert onto the tool thus formed, and use it to wind the insert into place.

For one-off stuff, it makes sense to simply buy the tap and a couple of inserts.

Jim

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Perhaps replacing the outlet box would be the easiest fix.

I ended up filing tap teeth grooves into the end of a #8 sheet metal screw and "tapping" the hole with this. This gives threads that fit best with plastic.

I did mention the box is plastic, didn't I?

Replacing the box is difficult. It gets sawed and milled to fit in the space available. I haven't optimized that process yet to make spares.

I can now remove and refit my "digital dashboard" any number of times. One is a voltmeter and ammeter, and a dimmer in the middle. The other, smaller, is my Pocket PC in its dock. Various configurations are possible.

To read about my senior project at ODU, Go to Google Groups and enter dgoncz along with any or some of these words: ultracapacitor electric bicycle motor generator fluorescent energy display