Needs Pictures: 0
Picture(s) thanks: 0
Results 46 to 60 of 73
Thread: Bugga. Broke a tap
-
13th November 2014, 09:22 PM #46SENIOR MEMBER
- Join Date
- Aug 2012
- Location
- Australia
- Posts
- 521
I had a similar problem with a broken small (m3 or 4) HSS tap. The way I got it out was wrecking a few fine Dormer carbide slot drills. It ended up coming out with a pick after hours of slot drilling. A ton stuffing about. I figured the pros used EDM but by the sounds of it maybe not. I have been meaning to get some small 3mm carbide drills for when this inevitably rears its head again. Blowing through expensive Dormer gear in a bind is not my favourite pastime.
-
13th November 2014 09:22 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
13th November 2014, 09:34 PM #47Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
I tried with and without the nozzle/ tube but with a tap that small the flutes are mainly full of thread.
As for your second thought, I tried to plant a piece of filler wire on the end of the tap when I was mucking around with the TIG but the filler at 1.6mm just about fills the minor diameter by itself. I know what you mean though and if I could get something attached on there it would probably come out easily enough. I did think about using the spot welder but as it works on resistance there would be greater resistance tap to CI, so I'm just as likely to weld the tap in.
Tomorrow is another day (and attempt...)
Michael
-
13th November 2014, 11:05 PM #48SENIOR MEMBER
- Join Date
- Oct 2007
- Location
- Sydney
- Posts
- 2,340
Keeping in mind the full disclosure mentioned earlier regarding having never tried it, nor can I recall it ever being mentioned as a legitimate way to remove a tap, but what I'd do is switch from TIG to Stick on the welder and put it in the rod clamp. Then just jam the (insulated) fastener down the hole and on to the end of the tap. While I think I can honestly say I'm a pretty handy AC/DC TIG welder, I'm truly crap at stick. Abysmal in fact and I truly hate stick welding. One of the reasons is having to unstick rods, and at times I've had those suckers really well planted into my "weld" (to use the expression generously). I figured if I can do that without trying with a welding rod, it should be possible to do the same thing when I AM trying with a fastener!!! What the weld current would do to the threads in the hole I don't know, maybe they'd weld up ... or be disintegrated a little by the current? I genuinely don't know, but if it came down to having to grind/edm/etc the tap out, this is what I would try first and if it buggers it up more, well that's just the price of trying I guess.
-
13th November 2014, 11:17 PM #49Senior Member
- Join Date
- May 2010
- Location
- rural s.a.
- Posts
- 120
Hi Michael, Great thread, If you continue with the hole saw, I would turn up a plug of cast iron to a press fit in the hole, drill & tap 3.0 mm & screw in a SHCS so that the underside of the head was tight up against the plug face & drive it in with a hammer, remove SHCS, cut, file & polish level with table, remove screw & the job is done.
Ian.
P.S. I have made several hole saws over the years, fine for a one off.
-
14th November 2014, 01:42 AM #50
-
14th November 2014, 07:00 AM #51Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
Understood, and worth trying as a potential solution
The arc comes off the point so unless the point is closer to the tap than the sides it will arc there. The tap end is currently around 1mm below the surface, so to establish an arc on the tap the electrode will need to be less than 1.25mm from the tap. Not much room. Having thought about it more I also wonder whether I'm making things worse - I was tapping dry so the hole will be clean as was the tap. Have I zapped the tap to the table?
Michael
-
14th November 2014, 07:21 AM #52
How deep is the hole?
-
14th November 2014, 08:38 AM #53GOLD MEMBER
- Join Date
- Jul 2006
- Location
- Adelaide
- Posts
- 2,680
-
14th November 2014, 10:29 AM #54Member
- Join Date
- Jun 2012
- Location
- melbourne
- Posts
- 59
Not sure if this is a really stupid idea but could you try a dremmel and a carbide cutter to cut away the cast iron round the tap to lower the level of the CI wide enough to get a narrow pair of pliers onto the tap. Maybe if cutting the CI near the tap, you could swap to just a grinding stone so the carbide doesn't snap on the tap. I like the hole saw idea and this is jsut cowboy version of the same really but I think it could be realtively fast and easy if it was me, because i'm not sure i could make a hole saw. It would need to be drilled and plugged afterwards of course, with a bigger plug than making a nice neat hole saw, so not as good really.
-
14th November 2014, 10:30 AM #55Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
Roughly 10mm
Thanks, but I'd need to borrow an operator too - I last lit up an oxy in around 1986.
Anyway, the prize today goes to Andre - His comment about a carbide drill twigged my memory. I was going to go for the holesaw thing but realised a guide would be needed to hold it one place, so before doing that I had another idea. I got a 4mm masonry bit, sharpened it up and managed to drill/ pick the tap out that way. If I'd had a third hand to apply coolant it would have been useful as at the end of it the bit was not in great shape.
P1020652 (Medium).JPG
I then got a real drill and took the holes out to 5.5mm in the hope of neatening them up. I found a piece of scrap CI, turned up a plug the right size*, applied a liberal amount of bearing glue, pounded it home with a big hammer and dressed with a file. (The marks around the hole are from the TIG torch experiment)
P1020655 (Medium).JPG P1020658 (Medium).JPG P1020660 (Medium).JPG
Anyway, I then refitted the cover strip, spotted through and have now retapped the holes**. That was a little nerve racking too.
*I bought a set of pin gauges around a year ago. It seemed like a good idea at the time and this is another use for them. In this case the pin was just fitting a hole at 0.216", so the plug was made a smidge larger.
**You know when you break a tap you think that you could grind it off and use it as a bottoming tap? Not always the best idea...
Michael
-
14th November 2014, 11:05 AM #56
Nicely done. Looks pretty neat and tidy.
Now that it's done, someone should unravel this thread and weave it into a set of ideas for broken tap removal, for future reference.
Ray
-
14th November 2014, 11:08 AM #57
Talk about snatching victory from the jaws of defeat. Congratulations - I bet you feel better now.
-
14th November 2014, 11:29 AM #58future machinist
- Join Date
- Mar 2008
- Location
- nowra
- Posts
- 1,361
Am Glad I could offer some inspiration Michael and really happy you got r done. I think a lot of people are overthinking the problem. Good job.
BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE
Andre
-
14th November 2014, 12:04 PM #59Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
-
14th November 2014, 12:44 PM #60future machinist
- Join Date
- Mar 2008
- Location
- nowra
- Posts
- 1,361
I hadn't heard about using the Tig till this thread. Considering the tap was below flush with the surface I would be to scared of welding the tap in the hole did you use a 1 mm tungsten?
But I will remember that for rusted bolts. One thing I have learnt working in a machine shop is that simple solutions are better.BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE
Andre
Similar Threads
-
Bugga@#$%%
By PsychoPig7 in forum CNC MachinesReplies: 15Last Post: 8th March 2011, 05:06 PM -
Bugga!
By artme in forum WOODTURNING - PEN TURNINGReplies: 10Last Post: 5th April 2009, 01:32 PM -
Bugga
By Daddles in forum BOAT BUILDING / REPAIRINGReplies: 4Last Post: 11th July 2008, 04:03 AM -
bugga
By Tonyz in forum NOTHING AT ALL TO DO WITH WOODWORKReplies: 7Last Post: 5th October 2006, 09:39 PM -
Bugga, Bugga, and Sod it.
By chrisb691 in forum MARQUETRY and INTARSIAReplies: 8Last Post: 8th May 2006, 07:32 PM