Was replacing/upgrading valve covers and broke off the drivers side top bolt of the valve cover. Nope problem (i thought), drilled it out and began retapping the hole. Well, the tap broke off this time . Attempted to redrill for retapping, no go. Seems the tap will break easily, but you can't drill through it. Any suggestions?????
if the tap isn't to far deep you can place a flat washer over it, weld the tap to the washer (remember to ground the washer) with 6013 3/32 electrode rod. Use this filler rod because it releases a lot of crust and helps not to weld the tap to the sidewall. don't forget to chip hammer the crust every time you strike and weld. Once you welded the tap to the flat washer, weld a bolt to that. Let it cool. Try removing it slowly moving it back and forth while adding a small stream of water. the water will help clean any loose debris.
Machine shops use a high grade cobalt bit to drill out broken bolts and studs in blocks. I am taking my engine block down on Monday to have a water pump bolt extracted. Same problem, I drilled out the bolt and broke off the easy out(garbage foreign steel from you know where). They are charging $25 to extract it. Weigh your options, try it yourself or get someone who already has the tools and know how.
Depends on the shop, sometimes it is easier to EDM them out Instead of spending $25 bucks and having them do it spend $14 bucks and get yourself a tap extractor. Unless you really buggered it up good they are fairly easy to remove and only take a few min to do. http://metalworking.mscdirect.com/CGI/MWSRCH?ns=1&scrNtt=tap+extractor&Ntk=Keyword+Search
Do they work well? I have never used them. I remember the old easyouts, the old square edge worked better than the round ones, the round ones seemed to stretch the bolt making them tighter.
Yeah we use them all the time at the shop here. What it has is some fitted prongs that slide in the flutes around the tap be it a 2,3, or 4 flute tap. They fills in all of the open area of the flutes and they are actually what turns the tap out. Here is waltons instructions http://www.newmantools.com/walton/extrtap.htm Oh and the taps we use for blind holes in most materials are these http://metalworking.mscdirect.com/CGI/NNSRIT?PMPXNO=1997990 You dont break the chip the same way you do a "normal" tap. These create one chip per flute and evacuates the chips out the back so they dont bind in the holes. So basically you screw it in down to the bottom of the hole rock it back and forth a couple of times to break the chips and back it out of the hole. These were originally designed for NC machines but they have become popular in the last couple of shops I have worked in due to the ease of them.
We use a similar looking tap at work called a Turbo-Flute. The chip comes out the top as a spiraled string something like a drill bit would do. Cut beautiful threads and are nearly unbreakable.
Tap extractor rock, or if you can get your hands on some, there is a product called tap-away. It will dissolve the tap, but not the head. Expensive and tough to come by, but it works.
