Drilling out broken studs TIP

[budgie14]

Use a roll pin that fits snugly into the hole left by the broken stud.select the biggest drill bit that will go inside the roll pin,and the fact that the roll pin is hardened,means you can drill the pilot hole dead centre,to the full depth of the hole.Obviously,if you can fit the workpiece into a drillpress,so much the better,but lots of studs are on inboards and sterndrive units,and outboards,making it impossible.If you then enlarge the hole using slightly larger and larger bits,you keep the hole drilled true to the original position.Lot more accurate than centre punch,because usually the broken end your drilling is not flat.Some people may find this tip helpful

 

[chiefalen]

You could use a reverse drill bit also and might get lucky as you start enlarging the hole it might catch and screw out the stud. Works good on starter bolts.

 

[budgie14]

If you had the full range of left hand drill bits,yes that would be better,but Ive only got one[not cheap].Besides,most of the studs that break are small ones [6mm or 1/4"]that are corroded into ali,and never usually come out.If they are in cast steel,chances are theyll move.

 

[j cat]

I have used reverse drill bits to pull brokens stud out . they are well worth the cost .more on land vehicles in my case.

using a sleeve to guide the drilling especially with the soft metals is wise.

 

[wblazer]

Budgie 14,

Sounds like a good idea if the stud broke off a little under the piece surface. I will keep this in mind. I have drilled out screws and studs many times the standard way reverse drill and easy-out method. Thanks for sharing your knowledge.

 

[chiefalen]

I didn't say it was a bad idea good tip, just wanted to add to it.

 

[gl115]

Thanks for the tip Chief.