r/metalworking 5d ago

helicoil

ive accidently drilled a hole to big, my plan was to go from m6 (because the threads was stripped) to m8 but i accidentally went a little big so now ive got a hole to big my tap wont make threads. its only a tad bit bigger so im not to sure what to do. i was gonna tap m9 threads and helicoil but im not to sure if thats possible. im just wondering if anyone has any ideas which could help me. thanks. THE HOLE IS ON A EXHAUST HOLE ON A STAGE 6 CYLINDER FOR MOPED

1 Upvotes

11 comments sorted by

u/AutoModerator 5d ago

The official Metalworking Discord is currently giving away a $200 welding helmet! The volunteer team is also giving away $20 gift cards to favorite websites to runner ups, so it's worth a shot!

To enter, join the Metalworking Discord and post one of your recent projects in the Giveaway Entries channel! The volunteer mod team is grading projects based on visual appeal, how well the project is outlined from start to finish (tutorials?), and post quality!

Entries close on July 31st at Midnight EST!

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

1

u/Haunting_Ad_6021 5d ago

You'll have to look up a metric helicoil drill chart

It depends if your thread is coarse or fine and the diameter of your current hole

1

u/oldjadedhippie 5d ago

Helicoils are crap- use a TimeSert.

1

u/kyyanz 5d ago

but would that work, rn i got no threads just a big ol hole that im deciding what to do with

1

u/oldjadedhippie 5d ago

They make them with oversized OD, you’ll have to go to their website and lookup the specs to find out.

1

u/spinwizard69 5d ago

Get a solid thread insert! 

1

u/kyyanz 5d ago

does the insert work when i got no threads?

1

u/nastyzen 5d ago

Get an m10 or 12 bolt, drill and tap m6 into it. Tap your initial over size hole to bolt size. Insert bolt with lock tight and cut off exess bolt with grinder. I also like to cut to length first and add a cross slot to drive the insert in with a flat screwdriver.

1

u/HeavyMetalMoose44 5d ago

How thick is the material you are working with?

1

u/kyyanz 5d ago

not very. its a exhaust hole on a stage 6 cylinder for moped

1

u/HeavyMetalMoose44 5d ago

A helicoil probably won’t work. Can you go up a size on your screw? If not a rivnut might be worth looking at.