Thread: thread repair
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04-02-2014 08:01 AM #1
thread repair
This is a follow up to something I had posted about a while back: welding in a hole and re drilling and threading it.
I had decided that next time I would over drill the hole before I welded it back in. Well, the hole had already been oversized from an M4 to M5 and the threads were wallowed out, and I wanted to get back to the original fastener.
The hole was already oversize, the part was 5 mil thick mild steel. I used a copper flat bar between the part and the bench, and migged the hole shut. This time, I did NOT quench it! While it was still toasty, I ground the weld flat, and let it air cool from there. A badly abused transfer punch gave me center with the cap plate set in place. The tap index was missing the drills, so I eyeballed a drill laying about, and drilled it nice and slow using the end mill as a drill press; the vice on the drill press is junk. No problem drilling through the weld. The tap was a little tougher, and more than once I questioned the wisdom of not having miked the drill. But it was a nice spiral. The tap, and I went slow, no problems. The cap plate I left with oversized holes, it's not critical, and a couple washers under the fasteners will make it all good.
To sum up, the oversized holes seemed to make it go easier..
Education is expensive. Keep that in mind, and you'll never be terribly upset when a project goes awry.
EG
Thanks for the inputs guys !
Exhsust system