I searched to board and found referances to using a router to cut br*** but not much discussion on aluminum. I'm doing a fan shroud and need a couple 14" holes and would like a machined appearance. Any advice is apprciated, thanks oj The aluminum is .090 thick and i'd mount it to plywood.
I have used a router to round off 1/2" aluminum. It worked great, was a little easier than doing it to oak.
I've used on to round off br*** and it work like a charm I would not see any problem in using one on aluminum. I would set up a jig to make sure the holes were perfectly round then drill a hole, plunge the bit and cut.
If your cutting out the 14 in. circle by hand the router will follow any irregularities. Water jet cut the holes if there is a facility in your area and they will be perfect.
Use wd40 to lub and cool, alum sticks to cuting tools real bad.Take it slow and eazy You should make out good Cal
First heard of this years ago in a Rodders Digest artical JustSteve wrote about BigOlds, he used a router to make the finned aircleaner. I found it routs like hardwood. Just take your time and relax.
router work great with good bits. i call mine my mobile milling machine these where ruff cut on a band saw then finished shaped to a sheet metal pattern made from 3/8 an end mill will also work in a router for cutting slots.
for what OJ wants to do it sounds like the RotoZip tool would be ideal..i don't have one and have never tried one. are they any good?
Fasten aluminum sheet to a piece of s**** plywood with some sheet metal screws - #8's are about right. Scribble a rough pattern with blue or red felt tip marker. I like red on aluminum the best, but any color works. A felt tip marker or Sharpie works better then ****Em in my opinion. Tap a dimple in the center with a ***** punch. Scribe a circular line with a pair of dividers or pencil comp*** if that's all you have. If using a pencil you don't have to use a layout fluid. Cut close to the line - plywood and all - with a fine blade Sabre Saw. Finish to size with a drum sander on a 3/8 variable speed drill motor. Fine to medium grit works ok here. The finished product will have a somewhat machined look and the hole will be as accurate as your pattern. The shoe on your Sabre Saw will probably scratch the aluminum. Covering the aluminum with one thickness of masking tape will prevent that. The tape goes on parallel to the last bit of tape and don't overlap them. With tape you can lay out the pattern with pencil - and erase if necessary. As is obvious you'll have to put the sheet metal screws in the s**** aluminum area and make sure there's room to operate the Sabre Saw without hitting a metal screw. Sample shown is 1/4" aluminum, but it works just as well on sheet aluminum if you're patient. As you can see, wide masking tape helps here.
I've routed aluminum a lot. Use a carbide tipped bit. I use a pattern following bit [bearing on the bottom same od. as the bit] I would rough out the hole with a jig saw about 1/16" away from your finished line. Use a backer board that you previously made your 14" hole in using a router and trammel. Secure them together and route away. Route clockwise inside a hole and counter clockwise outside of a hole [you won't be doing this] Wear a face shield and safety gl***es. I don't know your end plans but after doing this I would separate the 2 pieces and then round over the wood pattern using a 1/8" radius bit with a bearing on the bottom, and then reattatch the 2 pieces. Now you have a hammer form for rounding the inside edge of your 14" holes. Hope this helps you. Peter
I have one and don't think it would do well for what OJ wants. Handy tool, but more for woodworking. Woodworking is fun, but the damn stuff is hard to weld....
I build industrial control panels for a living. In doing so I cut a lot of holes in sheet metal doors of the enclosures. When I lay out the hole patterns on the sheet metal I lay out a sheet of light colored contact paper on the sheet metal, mark my lines with a ink pen. I recheck all of my layout marks and if I made an mistake I scribble out my mistakes, remark the lines. Before cutting with a saber saw I surround the cut out areas with a couple of layers of masking tape and make my cut. After I have the holes cut, and the edges filed smooth, I pull of the contact paper and the metal is clean. This saves me a lot of time in cleaning.
Those using routers, are you using generic woodcutting bits? What about aluminum shavings damaging the router? Any concern for that? Do you travel faster or slower than wood? TIA
You can get various bits for the router. A top pattern bit has the bearing on top to follow a pattern. You could also get a set of bushings for the base plate. Both of these would allow you to cut your circle out of plywood and finish it smooth (it needs to be smaller than your hole - the amount determined by the diameter of your bit. A circle cutting attachment is easy enough too. Ever use the pencil and string method to draw a circle? Same idea, except you can use a piece of 3/8" plywood as the "string". Drill a hole in the center of your sheetmetal and use it as the pivot point. These methods prevent having irregularities to follow. Yeah, a router works well on aluminum! Definitely wear eye protection! I'd even go the extra step of wearing a face shield over safety gl***es. Those hot bits of aluminum can hurt like hell! Tim D.
I used to fab a lot of shrouds, and had the same problem cutting holes. I had a nibbler that I adapted for the job. Mounted it in a box with a sliding center to set hole size. I pop a 1/2" hole at the outside of circle, and a 5/16" hole for the spindle. Here's a couple pics.
I use a trim router at work, daily, to flush up aluminum panels to frames. Your typical bits work just fine with aluminum. As do high tooth count blades for radial arm saws and miter saws
Carbide edged power wood working bits of most any design including circular saw blades - table or portable SkilSaw type - work great in aluminum. Noisy with circular saw blades . . . wear hearing protection along with the eye protection.
I worked in a foundry pattern shop where we cut 1" thick aluminum plate on a table saw, and even used a router a couple of times to clean up a parting line on an iron corebox. (I about S%!T first time I saw a guy do either one!) If we could cut iron with a router, aluminum would be like cuttin' ****er!
I've used it on sheet aluminum, it runs through the aluminum really nice, too nice, I overshot my lines using it freehand to make a rustic looking sign, but it was for a tiki bar so it was OK.
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