By Jim Burleyque
When the need arises to drill out any hardened bolt (grade #5 or grade #8) or standard (grade #2, which may be surface-hardened due to rust and / or corrosion), it is best to use a cobalt drill bit. Cobalt bits are harder, than your regular high speed steel bits and last a little longer when drilling difficult materials, (not to be confused with a carbide masonry bit). If you have the choice, choose a "screw machine length" bit. They are shorter and, therefore, stiffer -- so keeping it on center is less of a chore. Also they cost less than regular "jobbers length" bits, the most common drill length, or the slightly longer "taper length" bits. All good tool supply catalogs or shops will have these short "screw machine length" drills. One good source is Travers Tool Company.
Use low to medium speed and it will make a very precise and accurate hole for a screw extractor, etc.
One of the oldest tricks in my bag (after twisting wrenches on Stovebolts for over 50 years), is as follows:
For screws, place the largest screwdriver that will fit in the slot or Phillips recess (all the way to the bottom). Twist it gently to the right (tighten) and smack it a couple of times with a medium hammer. Then, reverse the procedure, (loosen) and smack it a couple more times. Then try to remove it. This will usually do the trick.
For bolts, use a flat-ended punch and smack it several times on the head of the bolt. Then use the wrench.
Have patience and try again if it doesn't work the first couple of times. All of you purists out there will be able to salvage a lot of your original fasteners.
Initially submitted: January 2005
By The Crew
Ca-CHING! An Excuse to buy a wire-feed welder!!
How do I get those pesky clutch
head screws out when they are rusted without damaging the pieces they fasten?
Answer from Gary W Stevens:
These screws can be impossible
to remove when rusted. I have found two resolves:
- Use a speed-handle with a socket that will fit a clutch-head driver bit,
like the ones used in most cordless drills, and with an enormous amount of pushing
pressure they will usually turn out. Work the handle back and forth a bit to
get them started.
- Drill the heads off, but you must use a carbide-tipped bit, like those used
to drill masonry, 1/4" seems to work the best. With the head removed, the
part can be removed and the piece of screw left can be dealt with without destroying
the removed part. Caution must be used because the masonry bit chews the head
off rather quickly, again like the speed handle a lot of pressure and slow speed
works best with the drilling operation.
And here's some additional info from David
In the past, I have used a Dremel tool with the cutting disc to
cut a slot across the long portion of the clutch -- this allows one to use a large
flat head screwdriver to turn them.
And from John Fenn :
Get yourself a cup of cold water, a welder and a pair of vice grips.
Take your wire welder and weld a blob of weld onto the screw or bolt about the
size of a pea. Pour the water over the blob of weld then clamp on the vice grips.
The bolt or screw will undo very easily. The weld gives you something to hang
onto and the cup of water shrinks the bolt inside its thread.