In 6061-T6 btw. Is there a regular tool for this?
Thanks,
-Neil.
Printable View
In 6061-T6 btw. Is there a regular tool for this?
Thanks,
-Neil.
Drill out the core of the tap with a carbide drill....not a twist drill but a heavy duty spade type drill point. Personally, I reserve old worn carbide endmills and burrs for this kind of 'last legs' service :D It is a practical necessity to have a diamond grinding wheel to frequently reshape or touch up the edges.
it all depends on how much time you've put into it, and how much the material is worth, before i even consider taking it out. sometimes it's just cheaper to scrap the part.
I like to practice on things that aren't important so I have a half a clue what to do when I get a job that really needs the tap taken out ;)
That's fine and good if you are between production runs, but man we're here to make $$$$$$$$$$ LOL
I know I get caught up in that stuff too!!!!! Just wait until those guitars take off Hu, THen I can tinker all day!!!!!!
Only half? I thought you aspired to better than than. :DQuote:
Originally Posted by HuFlungDung
I have successfuly, and quickly, removed broken taps from aluminum by welding a nub on the end with a stick welder and stainles steel electrode. Just enough to grip with ViseGrips. The heat tends to loosen the tap which helps start it turning.
This also works on brass and to a lesser extent cast iron but on steel you have a better than 50% chance that you will finish up welding the tap to the job.
Just burn the center core of the tap out with a copper tube in the handy dandy EDM.
In this case, it's not that important, and I really didn't need that tapped hole (since I overkilled the number of holes), so I ground down the stub of the tap with a dremel and ignored it. I want to know for the next time I mess this up. :-) This was 8-32 btw.
I'm very new to all this machining stuff so I expect there will be other times and scrapping or salvaging will depend on how much time/money I have invested in a given part. I am really mostly using endmills of 3/8" and 1/2" dia, so I'll have to get some others and experiment with some drill bits.
Thanks,
-Neil.
EDM? Fat chance for me, cause my machine shop is a 5' x 5' corner of a single car garage. :-)
Sounds like my shop!Quote:
Originally Posted by cnczoner
If I break a tap, and need to remove it, I take a 4 flute carbide end mill just a tad bigger than the tap's web. Then I hold the end mill short and rigid, and lock the quill. Then i raise up the knee slowly to remove a portion at a time. while cleaning out the hard chips with air, as they will crumble the carbide if not removed.
When through the tap, I carefully pick out the remaining tap pieces and use a needle type air nozzle to get to the bottom of the hole.
It is time consuming, and it may take a few end mills, but sometimes a part can have a lot of time in them and that makes them valuable!
By the way, an 8-32 tap is proportionally one of the weakest taps and very easy to break, especially in soft aluminum!
Hope this helps,
Widgit
If you don't have fancy EDMs, or stick welders and stainless electrodes, or carbide spade drills, but are working with a CNC machine all is not always lost.
Interpolate around the broken tap, close but not too close, maybe 0.01" away from the tap OD. Go down deep enough that you can break off the little cylinder of metal that the broken tap is in and extract it from the hole. The reason you don't want to be too close is you don't want it breaking off prematurely and smunching the cutter.
Then open the hole up to a standard tapping size, tap an oversize thread and screw in a plug. I have done this a few times when making tooling for use in-house; but don't ever do it for a customer's job
Really. Interesting info. So from 4-40 to 10-32, which is considered the strongest? My most popular size is 6-32.Quote:
Originally Posted by widgitmaster
Hmmm... hadn't thought of salvaging the hole this way, but I like it! ;)Quote:
Originally Posted by Geof
Cheers,
-Neil.
Just dissovle it!
http://www.metal-club.org/Remove.html
Aaron
Wow, if this really works as easily as it sounds, it would be awesome. I'll give this a try, but what is the brand/regular name of "alum"? Googling tells me that "alum" is the household name, but I have never seen or heard of this before.
If the chemical method doesn't work, here is a very simple edm system that can be built from electronics junk box variety parts. He used his cnc mill to feed the electrode but you may be able to do it by hand.
http://pico-systems.com/edm.html
Hi all, one things for sure, the man who never broke a tap hasn't been born yet.
So with this in mind it is a definite fact that you're gonna break one.
Which means it's like crossing the road with your eyes closed, your gonna get hit sometime.
When you work on saleable items for customers who expect quality, be prepared, and this means EDM, which will burn out a tap without damaging the job.
Last firm but one I worked at had a small edm type tap burner that was mounted in a drill press like stand and just burnt the tap out by pecking it with the electrode made of copper.
Never failed and never scrapped a job.
Ian.
Then this makes me like a thousand years old. :DQuote:
Originally Posted by handlewanker
This is commonly known as a 'Tap Disintegrator' , not quite EDM but a similar principle, it uses very low voltage, high current AC to spark erode the offending tap /screw etc. EDM is generally DC, so it is a much more expensive machine.Quote:
Originally Posted by handlewanker
It is very easy to make, if you peck at it manually, but commercial ones use auto peck/retract, similar to auto EDM.
Al.
Sandvik makes hardcut drills for the job.Clamp the part rigidly in the mill and hold the drill in a collet. for a 5/32" drill I run about 1500 rpm and clear chips (and cool the drill) with an air nozzle. These drills cut amazingly well, even when dull. Make sure to clear out flutes of the tap.
Hi Steve at rel, That's awesome, a drill cutting a tap! Strewth.
I still have to think that as the tap has 3 or 4 lobes that are not continuous metal, all it takes is a small deviation and the threaded hole is ruined.
On the other hand if the drill is kept short and rigid and the spindle is firm, like in a mill, then the tap will be cut out, like boring a hole, and there won't be any deviation from centre. Cool.
I have a mate that does rework for a firm and one of the tasks is tapping 5/8" BSW holes in some tough steel.
Occasionally a tap gets to go to valhalla, and this method from SandviK with the drill thingy will probably be the answer to a maidens prayer.
Thanks for the tip.
Ian.