mark poulson Posted November 21, 2015 Report Share Posted November 21, 2015 I'd like to grind off some aluminum in a couple of my molds. I tried the metal cutting bits, but they are very slow. What bits would you guys recommend I use? Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted November 21, 2015 Report Share Posted November 21, 2015 I'd use a carbide endmill with a decent light cutting oil like Tap Magic for Aluminum or Tap Magic for All Metals., but they tend to grab and go when used in a hand tool. Depending on how large the cutter is slow may be the correct speed. The smaller it is the faster you want to spin it, and the slower you want to feed it. The rule of thumb is crank up the feed rate until you break some cutters, and then slow down. At 10-15 for cheap 1/8 shank endmills and 15-30 for good ones you want to learn the right speed pretty quick. Also, not the approach I would want to take with my hands near that cutter. 1 Quote Link to comment Share on other sites More sharing options...
djs Posted November 21, 2015 Report Share Posted November 21, 2015 I have modified molds with end mills in a drill press. Raise the table to the cutting depth and be careful. Wear gloves, safety glasses. 1 Quote Link to comment Share on other sites More sharing options...
Apdriver Posted November 21, 2015 Report Share Posted November 21, 2015 I've had good results with ball end mill and flat end mills, also. Use a drill press and take the handles off your mold and square up your mold in a drill press vise. Go slow and the drill press vise's weight will help keep the mold from walking. Easier to manipulate this way. 1 Quote Link to comment Share on other sites More sharing options...
mark poulson Posted November 21, 2015 Author Report Share Posted November 21, 2015 (edited) Thanks. I was thinking more along the lines of the abrasive cut off wheels, but I am nervous about something that wide, thin, and brittle spinning that fast. If I wind up doing it that way, I can see leather gloves and a face shield in my process. Edited November 21, 2015 by mark poulson Quote Link to comment Share on other sites More sharing options...
Travis Posted November 22, 2015 Report Share Posted November 22, 2015 Thanks. I was thinking more along the lines of the abrasive cut off wheels, but I am nervous about something that wide, thin, and brittle spinning that fast. If I wind up doing it that way, I can see leather gloves and a face shield in my process. The face shield or safety glasses a must for sure. Several years ago I shattered one of those discs and put a shard in my cheek. I was wearing safety glasses as they always during use pelt you with fines as the wheel wears. 1 Quote Link to comment Share on other sites More sharing options...
Apdriver Posted November 22, 2015 Report Share Posted November 22, 2015 I'm sorry guys, I see this is posted in soft plastics. My post referred to modifying lead molds in taking handles off. Usually I modify a lead mold to take a different hook, maybe add a swivel or something. Modifying a plastic mold is a whole different animal. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted November 22, 2015 Report Share Posted November 22, 2015 I'm sorry guys, I see this is posted in soft plastics. My post referred to modifying lead molds in taking handles off. Usually I modify a lead mold to take a different hook, maybe add a swivel or something. Modifying a plastic mold is a whole different animal. Yes and no. Quote Link to comment Share on other sites More sharing options...
Apdriver Posted November 22, 2015 Report Share Posted November 22, 2015 Yes, I'm thinking you have to remove a whole lot more material. That in itself is more difficult. Not something that can't be done, just kicks the difficulty up a notch. 1 Quote Link to comment Share on other sites More sharing options...
fishon-son Posted November 22, 2015 Report Share Posted November 22, 2015 mark use wd-40 and spray it on the mold it wont let any aluminum stick to it/ or spary the cutting tool ...a carbide burr and dermel will work to by hand but your finish will be jumpy I'd like to grind off some aluminum in a couple of my molds. I tried the metal cutting bits, but they are very slow. What bits would you guys recommend I use? 1 Quote Link to comment Share on other sites More sharing options...