can anyone advise the correct RPM when using a flap wheel for finishing s/steel,the max speed is on the wheel,yet i'm sensing these speeds are too fast on stainless.thanks.
cue tig Paul...i don't use them often but usually just take light passes at full rpm until in happy, which doesn't give the best finish ever but i am the only person that will see it so i don't worry too much
What flavour of flap wheel/type of abrasive? SCM (non woven stuff like scotchbrite) typically want to be run slower than bonded stuff (aloxide/zirconia) or you end up smearing them over the work as they melt
What diameter? Makes a big difference to rpm as surface speeds are usually done in m/s.
If we were talking about the various different flavours of pad and flap disc for a 4 1/2" angle grinder then optium speed is usually in the 3 - 8000rpm range depending on abrasive type
If you download some abrasive manufacturers catalogues they often have this stuff in them, here's one from SIA... http://www.sia-abrasives.com/files/Industrieprsp_MET_EN_low.pdf speed data is towards the end including a graph for the rpm versus dia for different flavours of spindle mounted flap wheels. If using 'em in a drill you'll be well under optimum speed (which is better than t'other round) even for SCM abrasives
hotrod-i'm using 115 flap discs & then flap wheels 25/50/100mm grit type & then grit/fibre. using a 7000rpm die grinder & a pistol drill for the larger wheel. graham-planning on those for the final polish,heard about the wd treatment ,on here in another thread thanks.
Flap discs on the angle grinder are maybe running faster than optimum but vast majority of us do that (no choice with normal grinder), especially when using them to just knock the weld back. Some of the 'posh' stainless finishing flap discs that are supposed to let you skip a finishing step are fussier about being used at high rpm and i gather are pretty much a waste of time on a regular angle grinder? They're 'kin expensive anyway. You're not really running the flap wheels too fast but obviously there's a bit more control/everything happens slower at lower rpm, i typically use 'em in a 3000rpm mains drill (only thing it's used for now) as my cordless that gets used for everything else drilling wise is too slow and for reasons of lazyness and cheapness i haven't got a low/adjustable rpm die grinder