SPARKS STRIPPED THREAD! What size Thread Chaser?

[adi1974]

So I got my reverse thread chaser. Did the chasing and now the chaser will wind in and out of the thread no worries. BUT.... my sparks wont go in at all. Still getting stuck after a couple of turns. They're bp7es which is the same size and pitch as the chaser (m14 1.25pitch).

What should I try now? I'm gonna pop out and get some new plugs but I'm not holding out much hope on that. Time to get it tapped?

 

[xjwmx]

I would go around the new threads in a circular motion with a little brass brush a couple of times lightly to try and clean them up. Then I would put grease or oil on the plug threads and try it again. You're doing right by not trying to force it this time... Also, try turning the plug in the out direction and see if you can feel it seat in the threads, then go in the in direction.

 

[XSLeo]

On thr reverse thread chaser there is an adjustment on how deep the chaser cuts new threads. Try snugging the adjustment down a bit while cutting the new threads. Not much just a bit at a time.
Chase the threads, try a plug, repaet till the plug goes in.
Leo

 

[Tim H]

Are these the same plugs that stripped the threads originally?

I'd get a new set. I've had to throw plenty of bolts away that had aluminum stuck in the threads, or damaged crossed threads from stripping out a hole.

 

[adi1974]

SUCCESS!!!! I'm pleased to report I've got two new sparks happily sitting in the block. Thanks for the help and advice. Even after using the chaser and with new sparks and a little oil they were a little stiff and didn't go in as easily as the chaser (by the way Leo, my chaser reaches a point where its limited to 14mm so it can't over cut thread. Even at full stretch it wasn't cutting as much as maybe I'd have liked cos the sparks were tight compared to the puller and my compression tester). I thought I was going to need to give it a few turns with a tap but in the end a little more pressure tightening it down worked. They both seem good and snug but not over tight. They've been in and out a few times. So Thanks guys, could have been a lot worse!

Worth giving these reverse chasers a go I reckon.

 

[lowliferat]

sweet might be hope for me yet, i have been using teflon tape on my plug for a year now , wears out in a few weeks and i get blow-by. by the way how much would a tool like that set me back?

 

[adi1974]

It cost me about £25. Worth ago in my case. Not sure if it would help a loose plug though