So my corded dremel style thingy has a variable speed between 8000 and 30000 RPM. I don't think i ever went past 12-15000 but it kind of feels like i'm going too slow for no reason... what speed is appropriate for metal sheets?
slower is a little better i think, it allows you to take your time and not make an error. i also find there is a balance of when higher rmp just eat away your cutting disk without making any benefit in cutting of the material. i don't know the exact speeds, since mine isn't labeled that way, but mine has 5 speeds and i usually use speed 3 for cutting steel with carbon reinforced cutting disks. so based on that i would guess you're using a good speed on yours.
In addition to eating your disks, higher speeds will eat at your Dremel and your sanity. Remember to use ear and eye protection.
why don't you jigsaw the panel with a metal cutting blade and then file back the edges to the marked lines .. ? Or use your dremel to fine tune the trim
Depends on the cutting disks you are using. Have you seen http://www.mnpctech.com/DremelDisc.html ? For Steel..... If it's the ones that look like a "thick-hard-sandpaper-disk" that come with the dremel, then having these run too fast (forgive me, but mine is not a dremel, it's from Aldi and has speeds 1-5 labelled on it). I usually don't run these past 2 or 3, otherwise they glow red and start to erode. They do cut through the metal quicker though... If you use the new click on dremel cutting wheels, I use these at 3 or 4 and they haven't worn down at all yet. Can't recommend them enough... For Ali I use 1 notch down. I thing my dremel-a-like has a top speed of 30k rpm, but I'm not sure tbh, hence the volume settings I've quoted.
Its a double edged sword, usually a higher RPM coupled with teh correct cutting disk will yeild a neater cut. Conversely if you fluff it up. you tend to on a bigger scale. My rotary device (its not a dremel) goes between 12000 - 23000rpm. Hell I used it to cut kitchen tiles recently. High RPM with the right disc and the cuts were extremely clean. As said though the correct discs are very important. I tend to use what looks like a lump of finbreglass, chews through metal and ceramics well enough I would recommend using a jigsaw for longer cuts though, not only is it quicker but also neater. Then tidy it up with the rotary tool or file. Also dont forget you can use small grinding stones on lots of them which I find easier to make nice edges and corners with.
I use the reinforced cutting disks at 30K rpm. I find that as long as my grip is good, I get the neatest, straightest cuts at high rpm. When I'm using carbide disks, I usually go as slow as I can, because when those disks shatter at 30K rpm, the shards usually punch through skin and/or make a mess of your cut.
Do you not find that when using a Jig-saw that this bends the metal with the up and down motion? I've found that the cut is nice and straight, but the profile of the sheet ends up warped.... with steel anyway. Not tried on Ali...
