A few days ago, I cut in a hole to accept a Gretz pitot mast. First, I used a Unibit to remove most of the material from the hole. That was followed by more material removal using a small cutoff disk fitted to a Dremel-like pneumatic pencil grinder and finally edge finished using a small rotary file fitted to the same tool. I pretty much use the same technique for cutting in all odd-shaped holes.prkaye said:What are some methods for cutting rectungular holes, or other odd-shaped holes, into a skin, or other piece of sheet metal? ....
the Dremel cut-off wheels are very fragile when it comes to side loading - I've busted bunches of them.
The pencil grinder can do everything a Dremel can do. Having both varieties, I prefer the pencil grinder. About the physical size of a Corona cigar, it uses air for power. It is much slimmer than a Dremel in which you are actually holding its motor. As such, a pneumatic pencil grinder is easier to manipulate, particularily useful in accessing very narrrow recesses. Having said that, a while back I purchased this really great deal at Sams.prkaye said:In general, what can a Dremel do that a pneumatic die-grinder can't do? I have a small die-grinder that I got for about 20 bucks. A dremel costs about $80CAD. Is it worth getting one? Can't I just use dremel bits in my die-grinder with exactly the same effect (being careful of the RPM of course).
prkaye said:In general, what can a Dremel do that a pneumatic die-grinder can't do? I have a small die-grinder that I got for about 20 bucks. A dremel costs about $80CAD. Is it worth getting one? Can't I just use dremel bits in my die-grinder with exactly the same effect (being careful of the RPM of course).
Mark,Mark Burns said:........and then use a nibbler. The nibbler reminds me of the old Pac Man game. If you don't have one, get one. Usually they are less than $20. Mark
Rick6a said:Mark,
Thanks for the excellent tip. Personally, having never considered nor used a hand nibbler...sometimes you just know instinctively a real tool winner when you see one. I'll be picking up my copy real soon. Thanks again.
Hey, that is some nice, clean work, Mark!The nibbler made this defroster cutout easy:
Mark
Mark Burns said:I have a regular variable speed "corded" dremel. I've used it very little on the RV project. Not real sure why. I think it's because it's noisy and it usually throws all the dust right in your face. More times than not for me I just can't hold it in a position that will allow me to see what I'm doing and not get sandblasted in the face. Maybe I need some schooling.
I prefer to drill the corners with a unibit and then use a nibbler.
The nibbler reminds me of the old Pac Man game. If you don't have one, get one. Usually they are less than $20.
Mark
There are at least two types of cutoff wheels available for the Dremel. The thinnest ones are indeed very fragile and grenade with little provocation. There is another fiber-reinforced disk that is much more durable and the kerf is only a little larger. But these disks can tolerate more abuse and are much more practical to use. Both are used with the same mandrel.
And has been stated---Wear Eye Protection!