Anyone know what size screws fit these threaded holes? M6 and 1/4 inch (both thread pitch) don’t seem to work.

 

Dang, I can't remember, but I know they are metric, and they are a coarse thread. Perhaps M6.
I got mine at Ace Hardware...

 

I went to Ace Hardware too. I’m in my mid 50’s, and I now strangely prefer Ace to Lowe’s and Home Depot. Anyway, the M6 didn’t work. Then I ordered M6 with .75 pitch fine thread from Amazon, and it didn’t fit either. It’s very perplexing.

 

I remember they look almost like a lag bolt with a sharp point on the end...

 

Those are not machine threads they are closer to screw threads. Same fasteners that hold the flange at the bottom of the steeringcolumn at the firewall. They have a 10mm head but no idea what the thread pitch or design is called.

 

Ok - that makes sense. Thank you!

 

Here is the correct one:
From Amazon.

 

Ace should have those...

 

not sure if you guys have a Runnings store near you. i recently found one local to me and they have a really good hardware selection.

 

The head looks different than the original GM bolt.