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Screw Tap Broke While Tapping Rear Window & Roll Bar

avatty

Well Known Member
Here's one I hope for which I hope someone has a method ...

In the process of drilling and tapping the rear window and roll bar (p. 38-04) I managed to break the tap with only a small shard exposed above the window - too short and jagged to "unscrew" with pliers. So the problem is how to remove the rear window without cracking around the tap die. If that can be done, there should be plenty of tap protruding from the roll bar for removal.

A few, probably desperate, ideas have occurred to me: would heating the window locally with a heat gun, after removing all of the other screws, make it possible to pry the window off around the tap without cracking?; is there a solvent that could be applied to the flutes on the tap that might make removing the window easier?; or, is there a Lilliputian hole saw available that would barely fit around the tap, since the threads in the window get drilled out anyhow?

So I'm posting in hopes of finding someone who's been there before ....

- Tom
 
P.S. In looking further online, there are things called "hollow screw extractors," if I could find one in the right size. Maybe one could be improvised from a piece of thin tube?
 
Get a tap extractor. I got mine at Mcmaster Carr. Get a decent tap there too. I bought the hardware store tap and mine broke off too. Extraction was a piece of cake with the right tool. I'll try to find my receipts and part numbers later. I was afraid to use lubrication because I wasn't sure about using chemicals with the plexiglass. After breaking my first tap I used a good quality tap and boelube and it wasn't a problem.
 
HSS taps are best for 6-32 and 8-32.

Get a HSS tap, it is harder, sharper, stronger and will tap with less force. Also, use mineral spirits for tapping lube, it won't harm plexiglas.

Good luck with the extraction.
 
Thanks, guys. Jeff, I found the extractor on the McMaster-Carr website, thanks for providing the solution!
 
Been there. Very frustrating.
Another suggestion: Use your soldering iron to heat the stud just enough to get it loose. Then pop the window up off the stud. You can then get good purchase on the stud to remove it.
 
Heat the tap with a soldering iron and you will be able to lift the plexi off without cracking. I cracked mine after doing the same and not waiting for the vans answer (heat up the tap with an iron, lift window, and remove the tap with a pair of Knipex pliers wrench). Ordered a replacement window. I then glued via sika flex and am very happy with the results.
 
Just happened to me two days ago. Was not fortunate to get it free without crack. Now I am trying to “fix” the crack. Does anyone have info on where I can get cyanoacrylate with an acrylic crack sealant needle applicator?
 
Thanks again for the responses. The tap was pretty stuck, all I accomplished with the extractor was to twist the fingers into a tight wrap.

So that left the soldering iron for removing the window, which actually . . . worked really well! It took several minutes of heating but I was able to hold the iron against a flute to keep it steady. The triangular hole that remains is not much larger than the nominal final size (no. 27), drilling out a bit more should not be a problem.

I was only able to remove the tap from the roll bar by drilling out the flutes, which left a triangular crater almost 1/4 inch on the longest leg. According to the chart in the Spruce catalog, this should be fixable with a 8-32 nutsert, although possibly a 6-32 would do. So I'm hoping the worst-case scenario of all this is using a no. 8 screw instead of a no. 6 (can you get "oops screws"?) in this position.

A couple of photos are attached, definitely not the happiest part of my build, but I wanted to show that a broken tap is not necessarily the end of a $600 window (after all, there are a few more steps to go . . . ).

Onward!
 

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Looking into this more, I found that a no. 6 countersunk rivnut covered the damaged area nicely, and now the repair should not be visible.

I made a drill guide from some bar stock to keep the new hole centered while drilling out the damaged area of the roll bar. I only had to enlarge the hole in the window to no. 23, so a no. 6 screw still works. :)
 

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Keep in mind that a #6 screw has the lowest root to OD ratio and is small enough to fail while removing after it has had a chance to corrode a little.

Take care if you're removing several screws. Get comfortable removing #8s and you're setting yourself up for a broken screw.

FWIW
 
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