Need welding advice

[cascadia]

I'm in the process of removing the tiny screws that hold on the windshield surround pieces.  Got most of them but some have stripped heads.  I was able to carefully drill out some of them with cobalt bits but I have 2 that for some reason refuse to drill out.  I also am not looking forward to removing similar screws that hold down the interior sill plates.  I've tried EZ-outs, reverse fluted drill bits, etc.   I've started toying with the idea of building up a weld on the heads, eventually welding a nut onto them and trying to back them out that way.  Problem is, I don't have experience with welding.  Is there such thing as a micro welder for working on tiny objects like these?

[jeffc280sl]

I think a Tig welder is what you need.  It can do very fine welding like this.

[stickandrudderman]

The trick is to place a small washer over the remains of the screw and then weld to the washer. Repeat if necessary with a larger washer and then a nut.
Usually the heat has freed the seized screw and it will happily unscrew with the use of a spanner on the nut.

[jeffc280sl]

Great suggestion!

[ja17]

Hello Jeff,

The problem with drilling is that these sheet metal  screws can be  too hard to drill and the drilll bit simply moves off to the side of the screw and drifts into  the softer body steel or simply ruins the drill bit.

The welding trick almost always work. However if it is a very small screw and you do not have a tig welder or do not weld you are stuck.

Some other techniques I use are;

First use a dental pick to clean the rust and dirst out the phillips head of the screw. Your first effort is the most important since the head of the screw will damage after a failed attempt

Next try Impacting the screw  with a blunt end punch or drift.  The impact jars the rusty threads loose.  Use a good quality phillips screw driver and also tap it into the screw head with a hammer ( again to jar the threads loose and seat the driver). Impacting the screw first is very important.

You can get a very nice smaill impact screw driver. I got one at Harbor Freight which holds standard interchangeable hex screwdriver bits. Some of these bits I have specially modified to engage damaged screw heads.  The interchageable bits are inexpensive and I discard them when they show any signs of damage or wear.

If you fail to remove the screw at this point, get a dremmel tool. You can get very small cut off wheels for these. (they are about the diameter of a dime and are very thin),  you can then cut a slot in the damaged head of the screw.  It now becomes a "slotted screw" and you can hopefully remove it with a slotted screwdriver!

If this fails, carefully finish grinding off the head of the screws with the dremmel and remove the part it holds. Try removing what is left.  If you still fail, grind the screw off flush, drill it out or "pop it through the metal with an automatic center punch.

I will try to post some pictures later of these tools and techniques.

[lurtch]

 - -  I have a couple  small additions  to Joe's post: TIP #1   - - before you engage the screwdriver tip into the screw head, dip it into a can of coarse lapping compound. This will help cancel out the tendency of the S/D tip to ramp out of  the screw head.  TIP # 2  - -  get a bit holder adapter and attach it to an air hammer. Then use large vise-grips to apply torque while the air hammer taps away at it. This worked for me on the door sill trim strips.

Larry in CA

[Dash808]

Ok I'll throw in something crude and rudimentary. 

JB Weld an old screwdriver to the screw head after making a clean slot for it to sit in. 

[Allenh]

OK, here is my 2 cents.  I did a complete restoration myself and was faced with the same problems with these small screws.  Please, follow the instructions given by JA17.  He is correct in method.  I was able to extract ALL of my screws, from the entire car, not with ease, but successfully.  Use a good penetrating oil. new # phillips bits, prefferably with serations on the blades and use care and patience.  striking the bit with a hammer will help break the hold of the rust.  If you clean the heads well enough and use enough care, most of thos screws could be reused.  With those small screws, I don;t know about an air hammer, but I like the idea of the valve lapping compound!  Great tip.

Welding- Absloutley last resort, lots of patience and work slowly and methodically.  I even got all if the small screws out of the bows of my top frame.

Allen 

[Peter van Es]

Great tips: added to the Technical Manual here: http://www.sl113.org/wiki/Maintenance/Start#workshop

[Benz Dr.]

I sometimes use my plasma cutter to heat the screw before I emove it. If it wont come out I use the cutter to make a small slot in the screw. This doesn't always work but the heat will help in most cases.

[cascadia]

Thanks for all of the advice, made some good progress on the hardtop today and those of you that have taken them apart know there are a zillion small screws.  Over the weekend I picked up an adapter for my impact driver, one that will accept 1/4 hex bits.  Most of the small screws need a #0 phillips bit and most impact drivers come with big 3/8 hex bits.  The adapter gives you the power of an impact driver while still using a tiny bit.  The new system worked pretty well and I was able to get most of them out.  For the stubborn remainders I took Joe A.'s advice and cut a notch with my dremel and took a slotted screwdriver to them.  This technique worked beautifully, really well, and a big relief when those suckers finally start turning. 

[dseretakis]

If you do decide to go the welding route then you might just want to buy a cheap $2 screwdriver and weld the screwdriver to the screw.  You can use a mig welder carefully.  I have done this successfully