I actualy posted this in a another post but thought that it could benefit all that is replacing panels:

As promised I have a some of info on spot weld drilling. The set I started with was one from NAPA part number 770-3841 and has one double ended cutter, size is 3/8. Additional cutter heads come 3 to a pack (That's 6 cutting heads) NAPA parts number 770-3842 Very good. see pics below

http://i7.photobucket.com/albums/y260/keltieanne/DSC00414.jpg

Next I stepped up to a Rotabroach sheet metal cutters from Snap-On part number GA219B but made by a company for Snap-On called:


http://buy1.snapon.com/catalog/item.asp?search=true&item_ID=15684&PartNo=GA219B&group_id=951&supersede=&store=snapon-store&tool=all

Hougen Manufacturing, Inc.
3001 Hougen Drive
Swartz Creek Michigan 48473
810-635-7111

See pics below of this set. It has different sizes from 5/16 to 3/4. I like this set because if in a tight spot you can change out the head and cut smaller.

http://i7.photobucket.com/albums/y260/keltieanne/DSC00409.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00405.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00406.jpg

This is what it looks like cut off. This is the inside right door jam and 1/4 panel of my 67SS.

http://i7.photobucket.com/albums/y260/keltieanne/DSC00353.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00359.jpg

Those first cutters are not even worth the cardboard box they come in, they are flat out junk!

That was my experience as well. Teeth started breaking off within a few uses.

The best one to get is made by snap on called a spot-eze, they are solid hardened steel with a center 1/8 bit. I usually end up breaking the center bit pretty quickly and just use a regular 1/8 to drill pilot holes, sharpen the broken one in the center to a poiint and finish the job. The great thing about them also is that you don't have to drill through both panels to remove the spotweld. I do alot of unibody frame work and they are great. They come in 5/16 and 3/8 and a short or long version. Shawn

The spot weld cutters from Blair are very good. I've had great success during my floor pan repairs.

Next I stepped up to a Rotabroach sheet metal cutters from Snap-On part number GA219B but made by a company for Snap-On called:


http://buy1.snapon.com/catalog/item.asp?search=true&item_ID=15684&PartNo=GA219B&group_id=951&supersede=&store=snapon-store&tool=all

Hougen Manufacturing, Inc.
3001 Hougen Drive
Swartz Creek Michigan 48473
810-635-7111

See pics below of this set. It has different sizes from 5/16 to 3/4. I like this set because if in a tight spot you can change out the head and cut smaller.

http://i7.photobucket.com/albums/y260/keltieanne/DSC00409.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00405.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00406.jpg

This is what it looks like cut off. This is the inside right door jam and 1/4 panel of my 67SS.

http://i7.photobucket.com/albums/y260/keltieanne/DSC00353.jpg
http://i7.photobucket.com/albums/y260/keltieanne/DSC00359.jpg

I own a few of these sets as they are handy for drilling precision machined like holes. I just used the 5/16 cutter to remove a section of old rusted frame rail from a mid 60's falcon. Worked like a charm! I get the Rotobroach brand from a local machine supply company here in town at around $85.00 a set. 1/4 - 5/16 - 3/8 - 7/16 -1/2 -9/16 -5/8 - 3/4 are the sizes in this kit.

One other use I found was using the slugs that were left behind from a piece of 20ga to fill in the many holes left from the molding trim, and vinyl top from my 70.

Just as the cutter busts through, it leaves a very nice (un cut) shoulder on the back side of the slug that is same diameter as the cutter its self. This allows you to place the slug into the trim hole from the back side (interior), while using a magnet on the front side of the panel to hold it in place when welding it up. I did the entire car in just under an hour. Because the slugs are small and just fit the hole with no slop, there was not a bunch of excess metal, or weld to grind away. Also made it look very clean in appearance when viewing the machined inserts from the inside out!