Tappet covers - Disaster!!!

[Beemer634]

After finishing rebuild I decided to check tappet clearances one final time and found to my horror that 2 of the tappet covers wouldn't shift by more than half a turn, they had only been fitted a few days!! After much consternation, frustration and cursing I removed the camshaft cover totally and carefully cut the offending items in such a way that they could be removed.
Unfortunately, the threads within the camshaft cover are partially clogged with broken tappet cover thread which was crumbling and causing it all to jam up, I am not able just to hook out the broken bits as it all seems virtually welded in!
Anyone know if 30mm taps are available to hire? Or any other suggestions to get around this.
If push comes to shove I do have another cover but that will need to go for vapour blasting before use, hoping to find a cheaper / easier option first!
Thanks

[hector2800]

There are things called thread chasers which are used for cleaning up damaged threads. Available from good engineering hardware dealers. You could give them a try, they work on thread pitch rather than dia and can be used rather like a file. Complete sets available for around

[Spitfire]

I'll go with this one, used to call them thread files, just take it very slow.

Cheers

Den

[Beemer634]

My lucky day......Nearly!!!
Spoke to a friend who knew a guy who had a mate etc, who happened to have a 30mm tap, got it all sorted with just minor damage to threads in cam cover, just need to put it all back together now.
Felt so lucky I bought a lottery ticket!  I will let you all know if I hit the jackpot there!!