FILENAMES: studs_from_hell_0.jpg studs_from_hell_1.jpg studs_from_hell_2.jpg studs_from_hell_3.jpg DESCRIPTION: These are pictures of shop made close-quarters specialty drill press and the task it was make to accomplish. Posted by Bob Powell . Bob provided the following description: ================================================================= May 1, 2001 studs_from_hell_0.jpg six broken exhaust manifold studs in Ford 460 head studs_from_hell_1.jpg drill guide and linkage studs_from_hell_2.jpg drill guide and linkage studs_from_hell_3.jpg two studs through-drilled 7/32" These photos are of a sort-of portable drill press made for a specific purpose. It's sort of like a magnetic-base drill press for a hand drill, but without the base, and takes far less space. You may find the idea useful for a similar task or perhaps something completely different. The exhaust manifold gaskets on my truck ('89 F250 with 460ci V8) had been blown out for some time on the front and rear cylinders on the right side, and the rear on the left side. Some classic stupid design problem -- the studs break prematurely. The official Ford replacements are Titanium and cost $10 a piece, and are not supposed to break, that is some consolation. My favorite mechanic for the jobs I'd rather not do said he'd remove both heads and it might cost as much as $1500. Strong incentive to do this one at home. Fortunately the fender liners and the shock towers come out easily and give good access to the side of the heads. I've only done the right side so far. Three of the studs were already broken, and accounted for the leak. Removing the other five, only one came out clean and the other four sheared off. One of the originally broken studs came out clean with a vise grip, leaving six studs thoroughly siezed in the head. Three of the studs protruded enough to fit a nut on. They weren't going anywhere with the vise grip. I welded the nuts on and attempted to remove. Good welds -- each time it just sheared off more of the stud. Drilling out the alloy steel studs by hand was just not going to work -- the drill point pressure is just too high, never mind keeping the drill centered and in line. I took advantage of the two bolts that came out clean and made a drill guide plate for drilling the other six. Using a large vernier caliper I measured the bolt spacing and transferred it to a 19" block of mild steel, in this case 1-1/4" x 1-1/2". I drilled 3/8" through holes for two bolts to attach it to the manifold, and 7/32" pilot holes for the other six. I tried using the guide with a hand drill but the strain was too much to drill these by hand. So, I made a lever linkage to connect the drill motor to the guide plate, that multiplies the force on the drill and also converts it to a "pull" situation which was easier to manage. The net result is in the photos. The drill motor is attached by a split collar clamp -- scrap of 1/2" plate bored to 1.811" for the nose of the Milwaukee, then slitted and cross drilled for a clamp bolt. The guide bar was drilled and tapped for 5/16-18 bolts along both sides, that attaches the linkage to the bar. The rest of the linkage is self explanatory. Note that the orientation of the drill motor and the handle is pretty flexible, with various arrangements it handled all six holes. After drilling 7/32" through the studs, I removed the guide plate and enlared the pilot holes to 19/64 and then remounted it to enlarge the holes. Then hand-drilled to "O" (tap drill size for the 3/8" studs) to get out the thread fragments. At every point along the way I soaked the studs with penetrating solvent, and attempted to remove them with EZ-outs and other tools. I even drilled the holes using left-hand twist drills. At no point did any of those six studs budge -- no other way were they coming out. Bob Powell Vashon Island, WA bobp@dogpatch.com