Tapping 8020 Extrusions

[greymann]

I have finally decided to go whole hog with 8020 for my shop tables and carts.  Pictures will follow later.  I also decided to tap my own holes in this project.  Can't  decide if I'm just cheap or want to learn a new skill.  To make this work, I've upgraded my tapping tools from the HF set that had been my only bad experience with tapping. 

So, after that as preamble, I have the first of probably many questions.  While my new tapping bits cut like butter especially compared to the HF, I've seen videos showing using a drill to do the tapping.  It looks like it would be much faster.  My problem is that the square end of the tap doesn't tighten well in the drill chuck.

Is there anyone out there who has done this and has found an adapter or fitting that makes this work better?  I've tried all the searches I can think of but haven't found anything yet.

Thanks,

Dick Perry

 

[greg mann]

Chucking a tap in a hand drill is not something I would recommend. It is can be hard on the chuck, and, depending on the chuck design it may just loosen up when you run it in reverse. It is also not that easy to get started straight and true to the hole. If you don't get stared correctly you can bugger the job and slight alignment issues may impact the quality of your assembly. You can bugger it by hand too, but you will at least have more time to realize you aren't straight and can re-start.

 

[Slappy]

unless your using a drill press or a mill to 'power' tap then your cuts/tap are not gonna be plumb & square 100% of the time
I'm doing the same with 80/20 but I try to get the taping done at 80/20 but really when making up items that is not always gonna work when one has to cut a piece at home . with AL being soft I do them by hand , with a restart not being that big of a problem to redo when done slowly
that 80/20 is not cheap
but if you want to power thru then make up a jig  [wink]

 

[Krnbk2]

What part of the extrusion do you plan on tapping?  If you are talking about the predrilled holes at the ends of the extrusion that are already sized for taping you can absolutely chuck up a tap and power through them.  The biggest mistake I see with using a drill to power a tap is selecting the wrong tap.  do NOT use hand taps, instead use a spiral point tap (something like this: http://www.mcmaster.com/#2523a411/=r6er8w).  This tap pushes the chips in front of the tap allowing you to cut continuously.  Dont forget to use some tapping fluid (I use tap magic).  I just built a project that required me to tap both ends of 30 or so pieces of 80/20 10 series extrusion.  I did about 60 taps with 0 breakage, and all of them were straight. 

 

[greg mann]

What part of the extrusion do you plan on tapping?  If you are talking about the predrilled holes at the ends of the extrusion that are already sized for taping you can absolutely chuck up a tap and power through them.  The biggest mistake I see with using a drill to power a tap is selecting the wrong tap.  do NOT use hand taps, instead use a spiral point tap (something like this: http://www.mcmaster.com/#2523a411/=r6er8w).  This tap pushes the chips in front of the tap allowing you to cut continuously.  Dont forget to use some tapping fluid (I use tap magic).  I just built a project that required me to tap both ends of 30 or so pieces of 80/20 10 series extrusion.  I did about 60 taps with 0 breakage, and all of them were straight.  

I would suspect that all of them were straight enough but not necessarily truly straight. Then again, you just may be more adept than the average guy trying to do this. I still think Slappy and I are right to make the OP aware there are possible downsides to freehand tapping. Your recommendation to use a spiral point is correct, BTW. If one wants to do this a spiral tap in the end of 8020 will push the chip out in front of the tap, as you say, and not clog the flutes. Additionally, there will usually be longer thread chamfers which will help in aligning the tap to the hole. In that regard, your advice is easier to accept because you have recommended the proper tap to do what the OP would like to do. Practicing first on some scrap would be useful too.

 

[rst]

I tap with my M12 milwaukee all the time.  What you need is considered a gun tap.  Use slow speed and constant pressure and use WD40 or dedicated aluminum thread cutting fluid (available from machinist suppliers... Fastenal, MSC, etc).  8020 material is amazing stuff.  Their 15 series works perfectly with Festools clamps.

 

[Illogicalstudy]

i reccommend getting one of these these

This tapping handle / magnetic based guide is a god send. i wish i got mine sooner. i use it constantly

i realise your tapping aluminium but on a cast iron table top and a simple set up with some toggle clamps and some stops and you have the next best thing to a power tapper in you shop. no skill or ego requird

i had to garrante the accuray of a bucket loads of taps for a job and it worked flawlessly and quickly.

this one was bought from hare and forbes in aus but i think they are probably harber freight

Order Code: T0119 MTB-150 - Magnetic Tapper
M3-M12 -

just google that

have fun

 

[Krnbk2]

What part of the extrusion do you plan on tapping?  If you are talking about the predrilled holes at the ends of the extrusion that are already sized for taping you can absolutely chuck up a tap and power through them.  The biggest mistake I see with using a drill to power a tap is selecting the wrong tap.  do NOT use hand taps, instead use a spiral point tap (something like this: http://www.mcmaster.com/#2523a411/=r6er8w).  This tap pushes the chips in front of the tap allowing you to cut continuously.  Dont forget to use some tapping fluid (I use tap magic).  I just built a project that required me to tap both ends of 30 or so pieces of 80/20 10 series extrusion.  I did about 60 taps with 0 breakage, and all of them were straight.  

I would suspect that all of them were straight enough but not necessarily truly straight. Then again, you just may be more adept than the average guy trying to do this. I still think Slappy and I are right to make the OP aware there are possible downsides to freehand tapping. Your recommendation to use a spiral point is correct, BTW. If one wants to do this a spiral tap in the end of 8020 will push the chip out in front of the tap, as you say, and not clog the flutes. Additionally, there will usually be longer thread chamfers which will help in aligning the tap to the hole. In that regard, your advice is easier to accept because you have recommended the proper tap to do what the OP would like to do. Practicing first on some scrap would be useful too.

I never said you were wrong, just that its is certainly possible for the average person to power tap with a hand drill [smile].  In the case of the 8020 end, you are generally tapping 1/2"-1" worth of threads in a perfectly formed & straight hole.  Assuming you take a little bit of care to ensure you aren't completely off the tap straightens itself out as it follows the hole.  Not to mention what dictates the perpendicularness (lol) of the joint is the mating surfaces.  Now, if we are talking about through the extrusion t-slots then a hand tapper would certainly be nice to ensure a perpendicular tap.  Here is an inexpensive hand tapper, just double check it has the clearance to fit the taps you want and the extrusion size you are tapping.  http://www.littlemachineshop.com/products/product_view.php?ProductID=2898&category=

 

[greymann]

Thanks for all the input.  The worry about getting a straight tap was certainly on my mind when I started this thread (pun intended).

Yes, I will be doing most if not all of the taps in the end of the 40 series extrusions which since it is so close to the 15 series in size also works well with the Festool clamps and anything else that uses the T-slots.  I will be using M8 taps which are perfect for the existing center hole and don't see them being more than 10-15mm deep.  I chose this size also because I wanted to use leveling casters and the smallest of these uses an M8 stem.

Since the purpose of the taps is mainly to mate two rectangular bars together, how important is it that the threads go perfectly perpendicular to the face of the bar?  Won't the squareness of the side and end of the respective bars be of overriding importance?  ( I went back and reread the replys and saw that Krnbk2 made the same point)

As a start, I ordered these two taps to begin experimenting with.  And yes, I totally agree about practicing on scrap bars.

http://www.grainger.com/product/GREENFIELD-TAP-Hand-Tap-15J414?s_pp=false

http://www.grainger.com/product/WIDIA-GTD-Spiral-Point-Tap-1E818?functionCode=P2IDP2PCP

I also picked up the Tap Magic Pro fluid and the tests I've made so far with just the first tap and a straight tap wrench have been impressive.  I went the full length of the tap threads only backing out once in the process.

For Aluminum the second is probably extreme overkill but I wanted to see if I could tell any difference from the first.  As I was researching they were both listed as hand taps with the difference listed that the first was more useful for starting the tap and the second for once the threads were going well.  Nowhere did they mention that the design of the spiral tap was to keep the it from clogging.  Thanks for explaining that.

Both of the alignment tools suggested seem to have the problem that they assume you are tapping into the side of a nice flat piece of material and not trying to shoot down the pointy end of a 3-4 foot length of bar.  Also on the magnetic tapper I couldn't find a US source.  Does anyone know of something similar that would help line up on the end of the bars?

Again, thanks for the input so far and any further insight will be much appreciated.

Dick Perry

 

[Slappy]

try making a jig that will place the extrusion horizontal & be able to clamp a hand drill that will be square/level with the  extrusion
that way you slide the extrusion in to the tap bit in the drill ?

 

[James Watriss]

I think you guys are a little too worried about straightness... The tap will follow the hole and balance itself as it cuts. The hole will be straight.

I don't think tapping by hand is so bad. Having broken taps before, I'd be more worried about that when using a power drill. Once you break one off, there's not much for it. I know there are technically ways to extract them, but it's enough of a hassle that I'll take the extra minute to do it by hand.

 

[greg mann]

The spiral point Widia is a very nice tap for this application. With a little TapMagic you can go all the way in and out in one go. My recommendation to hand tap was more about concern that not getting started right could result in a broken tap. The spiral point that was ordered is a very strong and free cutting tap. It will work very well and should last for all of the 8020 you will ever care to tap.

 

[freddmc]

I used to cut thread with a tap in tubular aluminum all the time on my lathe.The trick is to get a "machine tap" that pushes the cutting ahead rather than a hand tap that relies on the backward/forward motion to remove the cuttings. And using an aluminum cutting solution is a must.

 

[rmwarren]

Dick,

I have tapped literally 100's of times in 15 and 40 series extrusions, with both M8 & 5/16" taps, using my Dewalt 1/2" cordless drill and it works fine. Never had one go wrong or fail.

I chuck the round portion of the tap shank and have used both normal and spiral taps, either one works. Quick shot of CRC cutting fluid, run the tap in a low speed being careful not to go past the cutting threads to the shank, then back it out. Taking reasonable care to align the tap to the hole it will guide itself with no problem.

Somewhere I have some video I took, will try to find it and upload.

RMW

 

[greymann]

Thanks again for sharing your experiences.  I did have time yesterday to try the spiral tap.  I found that with a tap wrench it was much more particular at getting started.  After that, if the tapered tap cut like butter, the spiral tap cut like very very soft butter.  If I continue to do them by hand, I'm retired and have the time after all, I'll start with the tapered tap until it needs to be backed out the first time and finish with the Widia tap.

I have not had good luck with my cordless drill, it kept slipping.  That could be because it is a 3/8 and like most doesn't have a keyed chuck.  When I have time today I'll pull out a corded drill with a keyed chuck so I can grip the round portion of the shank and really crank down on it to prevent the slippage I've had on my previous tries.

As is usual, these discussions keep raising questions I hadn't considered.  I got the Tap Magic Pro before I saw that there are fluids especially for aluminum.  Would I see any measurable difference if I switched?  If not this 16 oz bottle is probably a lifetime supply.

Dick Perry

 

[rmwarren]

The chuck slipping is definitely a problem. My Dewalt is also keyless, but it grips well.

I don't think the type of tapping fluid is going to make a noticeable difference, just that you have some lubrication.

RMW

 

[rst]

Cheapest tapping fluid is WD40... we buy it by the gallon on use it in cheap spray bottles, We also use it with our chop saws to lub when cutting aluminum.  The fluid is a necessity as aluminum is a gummy metal.

 

[justinh]

For tapping with a drill the easiest way I have found is to take a tap wrench, cut the handles off, and grind a couple of flats on the "shank" for the drill chuck to grab.  If you have multiple sizes of holes to tap you can set up multiple wrenches this way so changing is no different than changing a drill bit.  I saw a guy set up that way years ago and just copied his set up. He had another drill set up with the correct pilot bit or multiples of both if the job required it.  I keep one 1/4-20 set up in my drill box and one in my door box at all times because that is the most common size that I see for the occasional door closer or misc. piece of  hardware.  I do the same with dies for cleaning up screw threads.

It's not hard to tap with a drill. Like anything else it it just takes some practice. 

For a couple of holes or for cleaning threads use a hand wrench.  I haven't had the need to tap aluminum often but when I have I have done it by hand.

Greenlee makes bits that are a combination drill and tap but I have found that they still work best when you drill a pilot hole for the bit to start.  I have a set and they work well for the price.

Bosch used to make a corded tapping drill and I think Fein still does but both where/are expensive and unless you are doing a lot of it there are less expensive ways of setting yourself up.

For lubrication I use Boelube.  Inexpensive and effective without making an oily mess out of doors and frames.

 

[rmwarren]

Here's the video footage.



RMW

 

[Scorpion]

Get yourself a tap socket set.  They're made for holding taps the right way.   You can use a drill, it works fine but tapping the end of an extrusion can sometimes be tricky and you can ruin your day in a hurry.  Also if you use a 4 flute tap and the flutes are thinner than the voids.  My 4 flute falls right in.  This makes for a pita because the tape doesn't track in the threads.  So here's the trick - make a guide.  I made mine out of some scrap and a nut.  It could be made many different ways.

Another tip.  You don't really need cutting oil because the reliefs in the extrusion allow the chips to go somewhere.