Broken bolt removal - M4

[Harpo]

I have two broken M4 bolts that I can't remove. I have tried an map gas torch and a LH twist drill bit. My last option seems to be weld a nut to the end of the stud except I'm not a good welder. This is the rear vent window latch screws that are broken.

[john walker's workshop]

Heat, beeswax and mini visegrips if there's enough to grab.

[Harpo]

Thanks John. I just ordered a new pair of small vise grips and some beeswax

[john walker's workshop]

Get the snubnose ones. Too much flex in the pointy ones. Micegrips. Worth a shot.

[salayc]

Vise grips first, if that doesn't work, try using a conical Dremel grinding bit, you can grind flush, then grind a slight depression, then drill out.

[Harpo]

John, what are micegrips? When it google it I get grippy things for my computer mouse

[john walker's workshop]

Mice grips = real small vice grips.

[49willard]

I am a fan of welding a nut to the end. I have generally have had it work the first try with steel in steel. It took several tries with steel in aluminum recently when rebuilding an air cooled aluminum block Onan engine, an under powered 1/3 of a 911 engine (an opposed 2 cylinder).

[Harpo]

One of them came out and the other broke again. Argh

[Mike80911]

I have had a lot of luck on small screws with this
https://www.lowes.com/pd/SpeedOut-8-1-8-in-Double-Ended-Screw-Extractor/1000170531?cm_mmc=shp-_-c-_-prd-_-tol-_-google-_-lia-_-215-_-powertoolaccessories-_-1000170531-_-0&store_code=2664&placeholder=null&gclid=EAIaIQobChMI5Zyy7OSn6QIVw56zCh0-XwGVEAQYASABEgLHP_D_BwE&gclsrc=aw.ds

[gomezoneill]

Grind it flat, center punch then drill it out starting with small bit then increase drill size until
you get near the threads then use the proper size tap. Take your time with it. Be precise.

[Harpo]

While drilling the nut plate behind the sheet metal kept moving around making it tough to stay on center. So I purchased a drill bushing and installed in on the latch base. I wanted the drill bushing to be an tight fit so I heated it up and put the bushing in the freezer and pressed it together. Now my 3/32 drill bit is to big for the hole in the 3/32 bushing . One step forward and two steps back.

base

[walt]

Just get yourself a slightly smaller bit like a 2.3 or 2.35 mm. US #43 is .089.

[Harpo]

Got the smaller drill bit and my "fixture" kept me on center and I was able to drill out the bolt. I was really hoping that when I upped the bit size to my 1/8th LH drill the remainder of the bolt would have come out. Who am I kidding I'm never that lucky. I just ordered an M4 helicoil kit. Wish me luck.

David