Tapping aluminum

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So I'm tapping a solid 1/2 rod in 1/4-20. These are pins for a electrical box cover on a boat. Kinda like the old hood pins on hot rods back in the 70's. I checked the tap chart and it says I need 13/64th bit to tap at 1/4. So I picked one up and started the process. It was really hard to turn, I was worried about snapping the tap. I used lots of lube, WD-4tayAny thoughts? Sent from my iPad using Tapatalk
Reply:Use a #7 drill and go at least 1/4" deeper than what you need for threads..I use water and soluble oil when threading aluminum.......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:X2 # 7 drill, worked for the last 50 years for me, Aluma tap or kerosine for a fluid.Don't want to gall or strip the threads.
Reply:Originally Posted by zapsterUse a #7 drill and go at least 1/4" deeper than what you need for threads..I use water and soluble oil when threading aluminum.......zap!
Reply:I wonder if I warped it a little in the drill press vise Sent from my iPad using Tapatalk
Reply:Remember to turn at least 1/4 turn backwards for every 1 turn forwards to break the chips and if this is a blind hole, clean out the chips regularly."You cannot inspect quality into a product, it must be manufactured into the product."Millermatic 210Miller Thunderbolt AC/DC Blue-Point (Smith) O/A
Reply:Ya I was getting about 1/2 or less turn, then backing up breaking chips and spraying lube. I have a glazer friend that does lots of tapping and he uses some kinda wax. Sent from my iPad using Tapatalk
Reply:Originally Posted by Bluehunter40Ya I was getting about 1/2 or less turn, then backing up breaking chips and spraying lube. I have a glazer friend that does lots of tapping and he uses some kinda wax. Sent from my iPad using Tapatalk
Reply:If anything the 13/64th (0.2031) should be easier than the #7 (0.2010). Aluminum likes nice sharp HSS taps. The taps they sell at the hardware store are terrible in aluminum. How deep are you tapping? You might need to back out and clear your chips. Are you using a plug tap or a bottoming tap? Like Zap said... drill deeper and us a plug tap. The cut is more gradual with a plug tap than a bottoming tap. I generally use Rapid Tap with aluminum and it produces a good finish.
Reply:Originally Posted by forhireIf anything the 13/64th (0.2031) should be easier than the #7 (0.2010). Aluminum likes nice sharp HSS taps. The taps they sell at the hardware store are terrible in aluminum. How deep are you tapping? You might need to back out and clear your chips. Are you using a plug tap or a bottoming tap? Like Zap said... drill deeper and us a plug tap. The cut is more gradual with a plug tap than a bottoming tap. I generally use Rapid Tap with aluminum and it produces a good finish.
Reply:Originally Posted by forhireIf anything the 13/64th (0.2031) should be easier than the #7 (0.2010). Aluminum likes nice sharp HSS taps. The taps they sell at the hardware store are terrible in aluminum. How deep are you tapping? You might need to back out and clear your chips. Are you using a plug tap or a bottoming tap? Like Zap said... drill deeper and us a plug tap. The cut is more gradual with a plug tap than a bottoming tap. I generally use Rapid Tap with aluminum and it produces a good finish.
Reply:Originally Posted by Bluehunter40TaperSent from my iPad using Tapatalk
Reply:You could use alcohol (ethanol) on the tap. The problem with some aluminium types is that they will stick to the tap and then it all starts to smear and the tap can get stuck. I don't know why really but with ethanol it just doesn't stick.I personally don't think WD40 works well for cutting threads on gummy aluminium but maybe WD40 in Europe is differently formulated. Closest hosehold item available in the US I would try would be rubbing alcohol (which is another type of alcohol). Just pour some in the hole and on the tap.I would not go out and buy another tap or any specially formulated aluminum tapping fluid just to tap a few holes, at least not if the tap is undamaged and still sharp.PS. You can look on your tap what kind it is by counting how many threads on the tip that are tapered. A bottom tap have something like 2. The taps you buy when it doesn't say what type it is are usually regular taper taps with maybe 6-7 tapered threads. These are made for through holes or as a first tap.Last edited by Pete.S.; 08-26-2014 at 07:42 PM.
Reply:Here's a photo of two plug taps. Both are 1/4-20. The top one is HSS (high speed steel) and likely runs about $9. The bottom one is carbon steel and is the type you'll most often find at the hardware store. They are cheap... like $3. This one came from Napa. Despite being made in the USA it's nothing special. The carbon steel version works ok for chasing threads but requires a lot more pressure to cut because they really don't have or keep an edge worth a darn. They are also more brittle than HSS (IMHO) and will break a lot easier. Not sharp and more brittle are not a good combo. I suspect the higher breakage is likely due to being dull as much as the material. I have found a quality name brand taps (Cleveland, osg, and etc.) will outlast the no-name taps.Kerosene also works well with aluminum as a cutting fluid.Home depot has a HSS tap (import) for $6. Not sure of the brand.http://www.homedepot.com/p/Quiet-Gli...1420/204296509Last edited by forhire; 08-26-2014 at 08:13 PM.
Reply:Okay my taps are all black, idk what brand, I think I got them 15 years ago a discount auto parts. The top broke off and all I have is the fitted plastic bottom. Sent from my iPad using Tapatalk
Reply:Is HSS the same as tool steel? Sent from my iPad using Tapatalk
Reply:I have to check tonight I think mine only have 2 flutesSent from my iPad using Tapatalk
Reply:Being you have the screw length... you could possibly go to a 50% thread using a 7/32 drill and it would be easier to tap.
Reply:OkaySent from my iPad using Tapatalk
Reply:Originally Posted by Bluehunter40Is HSS the same as tool steel?
Reply:I used 7/32 bit or 3/16 the other day at workto tap a 1/4-20 thru hole. Seemed to work fine.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:Originally Posted by Pete.S.No, HSS (High Speed Steel) is just one type of tool steel. There are lot of other tool steels as well.
Reply:So I picked this set of drill bit and tap in HD today, I know they have their faults, but if always been happy with dewalt stuff. Sent from my iPad using Tapatalk
Reply:I tried it and it was night and day, worked very very well. Sent from my iPad using Tapatalk
Reply:we tap aluminum all the time.I use 3/16th drill for a 1/4-20 holewe always use Spiral taps. I've never been able to find them in any hardware store.I just put them in a 18v hand drill and it takes a few seconds. I'll never go back to hand tapping, it is a huge waste of time. I even bought a electrical tapper, basically a special drill that auto reverses to back out tap, I prefer the cheaper battery drills.Also bought a gear box tapper that goes on a standard drill press and it's lost somewhere in my mess. It was OK.Sent from my iPad using Tapatalk
Reply:The tap in on the bottom, I tapped all the way to the top where I cross drilled them. So the chip would clear and if someone tries to cut them they will hit stainless in the middleSent from my iPad using Tapatalk
Reply:In the photo with the two taps. I don't know what happened to the lower one ,but please throw it away before it breaks off in one of your jobs from getting STUCK. Also someone has already said what I could re-itterate that you must use VERY sharp taps for tapping alluminium.
Reply:Originally Posted by scar59In the photo with the two taps. I don't know what happened to the lower one ,but please throw it away before it breaks off in one of your jobs from getting STUCK. Also someone has already said what I could re-itterate that you must use VERY sharp taps for tapping alluminium.