JMortensen Posted January 12, 2006 Share Posted January 12, 2006 I need to remove my frame rails from the TC rod back to the middle of the floor on my 240. I'm having a hard time so far. My original plan was to use a big drill bit to drill out the spot weld without going through the floor. Doesn't seem to be working so good so far. My plan is to use the new Bad Dog subframe connectors once they're available, but my concern is that if I end up with 50 holes in the floor the Bad Dog connectors won't allow me to weld the new frame in with those same holes (because I think they're meant to fit OVER existing rails). If that wasn't a problem I'd just weld the new rails in right through the 50 holes that I had drilled into the floor... Anyway, I've seen spot weld cutters and things like that, but will they really allow me to remove the spot welds and not punch a hole right through the 24 gauge Datsun floors??? Any help appreciated. Quote Link to comment Share on other sites More sharing options...
78zlt1 Posted January 13, 2006 Share Posted January 13, 2006 If the section you are removing is not going to be reused, What I did was just take an airtool with a 3" cutoff wheel and ground the spot weld down, you can tell when your getting close, the metal changes color (bluish ) when its getting thin , you'll get the hang of it after a few, and it doesnt harm the underlying sheetmetal. pry it up a bit and it should pop right off. hope that makes sense. Quote Link to comment Share on other sites More sharing options...
Wagz Posted January 13, 2006 Share Posted January 13, 2006 I bought a spot-weld cutter/bit from the local autobody supply house. It worked fairly well for me. You need to make sure you get a cutter that is big enough in diameter to cut around the entire spot-weld. The first one I bought was just a tiny bit too small and didn't work well. The second (larger) one worked fine, but I would occasionally cut entirely through both panels if I wan't paying close attention to the drilling depth. Quote Link to comment Share on other sites More sharing options...
Jolane Posted January 13, 2006 Share Posted January 13, 2006 I use the same method 78zlt1 described. It works great, and is fairly quick. After popping off the offending part, use a flap disk on a grinder and knock off the remaining sharp edge that is probably there to cut you. Joshua Quote Link to comment Share on other sites More sharing options...
y-not Posted January 13, 2006 Share Posted January 13, 2006 Marc, 15 years ago I used a spot welder cutter from Eastwood to restore a 74 VW convert, worked great after a bit of the learning curve. Are you going to Knott's this April? I would love to see your car. I'll be there with my Thunder Ranch and maybe the Thunder Rossa. Bill Quote Link to comment Share on other sites More sharing options...
Wagz Posted January 13, 2006 Share Posted January 13, 2006 Marc' date=' 15 years ago I used a spot welder cutter from Eastwood to restore a 74 VW convert, worked great after a bit of the learning curve. Are you going to Knott's this April? I would love to see your car. I'll be there with my Thunder Ranch and maybe the Thunder Rossa. Bill[/quote'] Unless I hit the lottery and pay someone to finish the Velo Rossa, there isn't a snowball's chance I'll make it to the Knott's show. Early this year I partnered with a long-time friend/associate to start an IT/Project Management company. The business has gotten all my time/attention/money this year. The VR has been buried under dust and piles of garage "stuff." My wife and I have also spent whatever time we've had remodeling our rental property and getting it ready to sell. This year will be focused on getting the business "to the next level" and figuring out how to pay for my daughter's freshman year at OSU. Fun, fun, fun... My New Years resolution was to clean-off the piles and actually spend whatever "spare" time I have on the VR. The good news is, I've cleaned off the car, blew off the dust and actually spent the better part of last weekend prepping the interior for paint. It's the first time I've touched the car in over 6 months. Hopefully, I'll find the time to keep the ball rolling. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 13, 2006 Author Share Posted January 13, 2006 Thanks for the input guys, I appreciate it. I'm going to give the cutoff wheel a shot first, since I already have that tool. If that isn't working I'll try the cutter. Quote Link to comment Share on other sites More sharing options...
260DET Posted January 13, 2006 Share Posted January 13, 2006 An angle grinder works most times, as described for the cutoff wheel. A modified proper sized drill bit can also be used. The drill is ground with a flat face ie 90 degree angle to the shank, but with a sharp tit in the center. The tit helps keep the drill centered when starting, the flat face of the drill 'mills' the spot weld metal down. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted January 13, 2006 Share Posted January 13, 2006 I've used Eastwoods "Pro" spot weld cutters with good luck so far. Just be sure to use a variable speed drill and be careful as you can end up with a pinpoint hole in the base metal that you'll have to weld back up (or you could use it when you re-weld the parts back together). I've had good luck using one of their stiff (almost chisel like) putty knives (works good for chipping off tar mat too) the same way their panel knife would work. You'll see the link to their panel knife at the botton of the page. http://www.eastwoodco.com/shopping/product/detailmain.jsp?itemID=1160&itemType=PRODUCT&iProductID=1160 Another idea is just to use a small diameter flap disc, clean the area you'll be welding in while grinding off the majority of the spot weld, then use a putty knife or panel knife to separate the panels. Quote Link to comment Share on other sites More sharing options...
MusPuppis Posted January 18, 2006 Share Posted January 18, 2006 I bought a spot weld drill bit from O'Reilleys that I've had great success with so far. It can be ornery, but its not bad. What I do, is use a strong (chisel like) putty scraper to lightly seperate the panels at the weld, then a center punch in the middle of the spot weld, then the bit. Using the chisel to raise the metal a little helps keep the bit from bouncing or jarring loose and prevents accidentally cutting through the layer you dont want to destroy. I also use cutting lube to preserve bit life. Then just hit th area with a flap disk or grinder disc to cut it down flush and smooth it all out. We pulled about 180 spot welds out of a 67 Mustang upper and lower cowl recently and it did it in about 2 hours with a 50$ variable speed drill from Lowes. Bit was 16$, extra "sleeves" for the bit were 16$. Quote Link to comment Share on other sites More sharing options...
tannji Posted January 18, 2006 Share Posted January 18, 2006 LOL, I can second the recommendation to use cutting lube.... I had the dead-pedal removed from my Z at a shop. The guy went through 3 bits getting the spotwelds out. Granted, I doubt any of his bits were in good shape to begin with, but the lube will ease the cut, and extend the life of the bit. Quote Link to comment Share on other sites More sharing options...
260DET Posted January 18, 2006 Share Posted January 18, 2006 What could be used as cutting lube for the drill? Other than proper cutting lube Quote Link to comment Share on other sites More sharing options...
Lighft01 Posted January 18, 2006 Share Posted January 18, 2006 When you cut out the frame rails is it necessary to brace the engine bay to keep it from twisting or moving? A friend of mine told me to weld pieces of metal inbetween the fender wells to keep them from moving. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 18, 2006 Author Share Posted January 18, 2006 That would be a good idea for sure Lighft01. I'm not cutting the whole rail off on my car though, just the part under the floor. Quote Link to comment Share on other sites More sharing options...
Guest 73TPIZ Posted January 18, 2006 Share Posted January 18, 2006 Black and Decker (and others i believe) make a drill bit similar to the high dollar spot weld removers. I think the B&D is called a bullet bit. It's what 260DET talks about with the factory modification. Here's a link to a pic of one if you need one. Much cheaper than the "specialty" cutters with the replaceable 1/8th" center bit. Also, use a regular 1/8" bit for a pilot hole, and come behind it with the bullet bit. If you are watching close (safety glasses) you can usually see when the bullet bit goes thru the first layer. http://www.bcae1.com/images/jpegs/plexibanddbit.jpg I use the 5/16ths size and it seems to work well. Now since you are not re-using the rail, I'd just cut it off and grind the remaining lip off, as described above. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted January 18, 2006 Share Posted January 18, 2006 What could be used as cutting lube for the drill? Other than proper cutting lube Richard: motor oil (new, used, whatever) tranny fluid anything I was going to say, you are not going to get many spot welds drilled if you don't have some way to keep the bit cool. Same goes for regular drill bit. I did paint and body work for 25 years. Never really took to the spot weld cutter thingies, to easy to burn up and expensive. Stuck to regular drill bits, steel drill bits so I can resharpen them myself when they get dule. Jon: if your not going to reuse the parts... why not just hack them off with the air chisel? Quick! just chisel along where the metal bends downward away from the floor pan leaving just a strip of metal with the spot welds. Once you have only the two stripes of metal, you can practically grab the end with some vise grips and yank the spot welds loose, or work it back and forth until each one breaks, or drill or grind or whatever (a combination of all of the above) The point is, once the majority of the panel is gone, the welds have very little strength. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 18, 2006 Author Share Posted January 18, 2006 Jon: if your not going to reuse the parts... why not just hack them off with the air chisel? Quick! just chisel along where the metal bends downward away from the floor pan leaving just a strip of metal with the spot welds. Once you have only the two stripes of metal, you can practically grab the end with some vise grips and yank the spot welds loose, or work it back and forth until each one breaks, or drill or grind or whatever (a combination of all of the above) The point is, once the majority of the panel is gone, the welds have very little strength. I would do that, but I'm still going to use the floor pans and the front frame rails, so I don't want to damage them during the removal process. I drilled out all the spot welds on the seat bracket and man did I screw up the floor pan trying to get all those welds removed. Granted I'm probably not very good at it, but it was a real mess. So this time I figured I'd try and do it as cleanly as possible. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted January 18, 2006 Share Posted January 18, 2006 What I have been doing to remove spot welds is using a die grinder with a carbide bur (round tip). I start with the bur almost flat on the spot weld then rotate it slowly to about a 45 degree angle as the bur cuts through the spot weld. It is very easy to see and control the depth of your cut in this mannaer and since the carbide bur is a lot harder than the spot weld you can do probably all of them without dulling the bur. The bur that I use is the "SC" on this page http://www.carbidebur.com/shapes/burs.htm. Dragonfly Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 18, 2006 Author Share Posted January 18, 2006 That is an interesting idea. I have that burr as well. Might have to give that a try too and see if the cutoff wheel or the burr is preferred. I've been stuck fixing this stupid computer the last two days. I think tomorrow I might actually get a chance to get out there. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted January 19, 2006 Share Posted January 19, 2006 For speed and ease of use, I use this one from Eastwood: http://www.eastwoodco.com/shopping/product/detailmain.jsp?itemID=14686&itemType=PRODUCT&RS=1&keyword=spot+weld+cutter Use a center punch to locate the cutter in the center of each spot weld. Wedge an old wood chisel or butter knife in between the parts, and as it cuts through the parts will pop apart. It does leave a raised circle at each weld. These can be ground off if needed. (If you are putting the parts back together later they can help locate them.) I tried one like the "professional" one but I got it from toolwarehouse.net. I had trouble keeping it from "walking" across the work and leaving drill tracks... For cutting fluid, Tap Magic used to be the best - but I haven't used it in a few years - it may be reformulated. I actually have been using beef tallow I rendered by boiling some ribs. I keep it in a can in a small fridge in my garage. It works well and the garage smells like ribs when I'm drilling... Sam Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.