Partially stripped thread. Need Help!
Thread Starter
Safety Car
Joined: Jul 2002
Posts: 3,754
Likes: 89
From: arvada co
Partially stripped thread. Need Help!
Here’s the problem:
I was replacing the front shock on my C6. When reinstalling the upper A arm, I started the bolt in the hole, it went 1-1/2 turns of semi hard turning and I stopped, I knew it wasn’t right. The inaccessible nut attached to the inside of the box frame is now cross-threaded the first 1-1/2 turns.
I don’t want to re-drill & tap a larger size because the bolt is very special & sized to the a-arm.
I bought the right sized tap, but my fear is that as I start cutting, the tap teeth will grab the first couple of threads and try to recut the entire nut at the incorrect angle. I assume the nut is steel and I don’t like pushing threads around in steel as opposed to aluminum.
Is there a way to recut the thread properly?
Details:
C6 upper front A arm bolt.
Thread size: M10 x 1.5 pitch.
I was replacing the front shock on my C6. When reinstalling the upper A arm, I started the bolt in the hole, it went 1-1/2 turns of semi hard turning and I stopped, I knew it wasn’t right. The inaccessible nut attached to the inside of the box frame is now cross-threaded the first 1-1/2 turns.
I don’t want to re-drill & tap a larger size because the bolt is very special & sized to the a-arm.
I bought the right sized tap, but my fear is that as I start cutting, the tap teeth will grab the first couple of threads and try to recut the entire nut at the incorrect angle. I assume the nut is steel and I don’t like pushing threads around in steel as opposed to aluminum.
Is there a way to recut the thread properly?
Details:
C6 upper front A arm bolt.
Thread size: M10 x 1.5 pitch.
Pro
Joined: Aug 2004
Posts: 566
Likes: 6
From: Pensacola, Florida War Eagle
There are basically 3 different taps for each size thread.
Tapered or starter, plug and bottom.
Use the tapered tap, as it will engage the original
threads and not just the crossed ones.
Hope this helps.
Tony
Tapered or starter, plug and bottom.
Use the tapered tap, as it will engage the original
threads and not just the crossed ones.
Hope this helps.
Tony
Thread Starter
Safety Car
Joined: Jul 2002
Posts: 3,754
Likes: 89
From: arvada co
Thanks much.
Thread Starter
Safety Car
Joined: Jul 2002
Posts: 3,754
Likes: 89
From: arvada co
Looks like Ace sells plug taps. I just ordered a taper tap on ebay.
Hope it works, (will be doing the ocassional backouts as I tap thru).
Jerry,
It is a box frame with no access to the back side of the thread. Would have been a breeze if I had access to the back side.
Thanks for the advice.
Safety Car
Joined: Mar 2009
Posts: 4,191
Likes: 951
From: Corpus Christi, TX
If for any reason you don't have any luck with the starting tap, and the existing threads get really badly damaged, you can use Heli Coils to repair the threads and keep the original bolt size.
Burning Brakes
Joined: May 2011
Posts: 1,138
Likes: 39
From: Florida
How deep is the hole? I've die ground out stripped threads and used a longer bolt.. mind you mine was just a couple threads and neither was a loaded surface or structure. just another option..
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Instructor
Joined: Apr 2011
Posts: 128
Likes: 22
From: Sisters Oregon
Not being familiar with exactly how your frame is constructed in that area could you take a hole saw and drill a hole on the back side of the frame. Save the steel plug. Then take your tap and start it in the good threads on the back side of the threaded nut and then turn in all the way through till all the bad threads are cleaned up. Assemble your shock, if everything goes well have a competent welder weld the saved steel plug back in grind down the weld and re undercoat the area. No on will know of the repair and it will be as strong as new.