I am going to rivet a trans tunnel upper half in place..Is there a drill that can drill a burr free hole in two layers [.058 total thickness] of sheet metal or must I drill some holes, cleco to hold location, drill the rest and dissasemble and deburr? I have tried all the different point styles even created a few with no luck...
Google is your friend............... http://qrpbuilder.com/downloads/sheet%20metal%20drills%20a.pdf http://www.harborfreight.com/3-piece-titanium-nitride-coated-high-speed-steel-step-drills-91616.html
Google and Amazon; I keep forgeting about those...There are wood drills sharpened as in the ones by the fellow doing aluminum [maybe called Brad Piont?] I have some and will dig them up and try..Tried all the step drills I have and they would do a good sized hole but still left too much of a burr on back side; maybe they are dull so I will touch up and re try..Thanks for the Google..
No, there aren't. The forrester-like bits (similar to black and decker 'bullet' tip i think they are called) get close but there'll always be a ridge or chips etcetc that get between the two. You can get close if you can clamp both pieces supertight so that when the drill bit goes thru the 1st piece it penetrates the 2nd piece without pushing the metal away, that rarely happens. I just cleco as i go, knock them apart and deburr/countersink the holes and you might even have to take a hammer to flatten them, then when they go back together they'll fit nice and tight.
.Is there a drill that can drill a burr free hole in two layers [.058 total thickness] of sheet metal? Not that I know of - but if you find one let us know .
I would try a drill with a built in pilot bit and go slow down you feed rate when the drill is almost through. Boeing surplus sells this style of drill bit cheap.
The easist way is to looking in to a chip chaser and a burr away on ebay good luck with your findings
I've been working in the aerospace industry for over 30 years, and that's how we do it. You won't find a bit that doesn't leave a hole needing a deburr. Some bit types perform way better than others, but if you want the panels to fit nice and tight to each other, you've gotta pull everything back apart and deburr it. I would never recommend drilling the holes as you go and installing fasteners. By the time you're done, the part will have moved from it's original position. If you don't have Clecos, get some. No metal man should be without Clecos.
Good advice and the tighter the 2 panels are to each other, it will minimize the burr between the panels. I like the clecos with the wing nut on them, it holds the work nice and tight. Bob
The wing nut Clecos kick ass, especially if you're clamping up something a little heavier and it's absolutely imperative that it must be tight. Spring Clecos are good for lighter gauge sheet metal work in a flat, horizontal, environment. If you're hanging something vertically, a wing nut Cleco (we call them "draw Clecos") is the way to go. They don't droop like a spring-style Cleco can.
What he said..........You can use what's called a "core drill" to get a nice round hole, but you still need to disassemble to de-burr before assembly.....No good way around it! There is a tool called a "Burraway" for de-burring a blind hole, but they're kinda' pricey, and you would dick one up in no time on some steel floor pans! Get you some draw Clecos, pull it down tight as you go, and plan on taking it apart to de-burr! Just curious, but why are you riveting it in? If for the look, are you going to buck solid rivets in there?
""Just curious, but why are you riveting it in?"" Car has the full interior, except for front seats...I entertained the thought of welding but since the car only has 15k miles and it is 41 yrs old I decided to be anal, didn't want to smoke it up or spark things up, or me..lol...I have the tunnel top screwed in place with small self drilling sheet metal screws, plan to drill out every other one with a #2 center drill [makes a pretty clean hole] and cleco then repeat on the rest, remove and deburr and assemble..Draw clecos I would like, I will have to look for them..
.....A #2 drill bit? Thats pretty big!......... If the transmission is in, get yourself a "drill stop" for your drill bit as well. A # 21 drill bit sounds more like it, yes?.........It's 5/32 in diameter.
Proper name I guess is Drill Point Countersink, Plain Style..At work we called them Center Drills because thats what we used to drill the chamfered holes in parts for lathe centers..Really not intended for drilling all the way through but they do work good... http://www.mcmaster.com/#combined-countersinks-and-drills/=lw27kt.... Go to fifth down the page, click on Drill Point Countersink..Plain type #2 has a 3/16 body, the radius type [#2] may do even better but I didn't have any to try...This place will sell to any one...
I found some draw type on ebay..Probably won't be here in time but I'll have them for next time..http://www.mcmaster.com/#cleco-clamps/=lw2ypv... has reg clecos [$1.54] and clamp type, pliers needed
I have used "Brad Point " bits for aluminum but get the ones with carbide tips.I use slow rpms. I haven't tried them yet on thin ga. sheet metal but they should work. I also use the punch and deburr method decribed above. Just an option.
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