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Author: Subject: 8mm broken tap sheared off !!!
steve m

posted on 17/5/20 at 04:54 PM Reply With Quote
8mm broken tap sheared off !!!

I had to tap a new 8mm thread, as the old 6mm had stripped completely
so I got the hole to about 6.2mm and started to tap the thread, it was a bit tight, and the tap broke, no warning or creaking,

So, what could I do, as the part is not really replaceable under the current guidelines,

it was sheared in the hole, so nothing to grip, small tweezer type plyers just bent,

I was getting really annoyed,

In the end, I got three nails, just normal wood nails, and forced them into the three cut outs in the tap, and after a couple of goes with plyers, managed to unscrew and free the tap, and out it came along with the nails that all looked like a spring, but they did the job!!

How would anyone else tackle a broken sunken tap ??

Steve





Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at




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Shooter63

posted on 17/5/20 at 05:49 PM Reply With Quote
Personally I would have drilled the hole the right size, the only time I have ever broken a tap was using it in the tailstock of my lathe and feeding it too fast, 6.2mm is miles to small, you were basically asking the tap to gouge out at least .5mm of material+ cutting the thread, how did I get it out I unscrewed it with a pair of long nosed pliers.

Shooter

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blue2cv

posted on 17/5/20 at 05:56 PM Reply With Quote
6.8mm is m8 tap size
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Theshed

posted on 17/5/20 at 10:15 PM Reply With Quote
You invented your own tap remover! Also available commercially - these work quite well

https://www.ebay.co.uk/i/173541711340?chn=ps&var=472227225204&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=472227 225204_173541711340&targetid=878706529565&device=c&mktype=pla&googleloc=9044936&campaignid=9794911188&mkgroupid=101625062844&a mp;rlsatarget=pla-878706529565&abcId=1139126&merchantid=114916188&gclid=EAIaIQobChMI7N3b2vW76QIV1vhRCh2iYgSYEAQYAiABEgKstvD_BwE

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steve m

posted on 17/5/20 at 11:01 PM Reply With Quote
I know that my 6.2 mm was too small. but the nearest I had was 7mm and that also would not of work of worked
any way, its sorted now

steve





Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at




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nick205

posted on 18/5/20 at 07:55 AM Reply With Quote
Broken taps are a bugger for sure, but you seem to have it sorted.

Broken bolts still take some persuasion and I usually find a left hand drill bit followed by some concentration a punch and a small hammer help me (not always though).

Anyway glad you have it out and are able to move on - I hope you can rescue what remains of the hole/thread!

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David Jenkins

posted on 18/5/20 at 09:17 AM Reply With Quote
I was making a cylinder for a 5" gauge steam locomotive, and one of the last jobs was to tap the many small holes in the cast iron (probably a 1/8" tap). And, you guessed it, I broke the tap on one of the very last holes. This was a casting that I'd spent upwards of 50 hours machining.

I ended up taking it to a local machine shop and they got it out with a spark eroder, under a "do it when you've got a spare moment" arrangement. Got a call back the next day: the tap was out and the hole was still in good shape. Cost me £5 in the beer fund, IIRC.

So, the moral of the story is - if you can take the part to a machine shop you'll save a lot of grief and may not cost as much as you think.






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jollygreengiant

posted on 18/5/20 at 10:36 AM Reply With Quote
quote:
Originally posted by nick205


Broken bolts still take some persuasion and I usually find a left hand drill bit followed by some concentration a punch and a small hammer help me (not always though).




Correct, NOT always.

I was changing the exhaust manifold gaskets on on XJ6, undid the nuts, removed washers, pulled manifolds back, removed the old gaskets, fitted new gaskets, put manifold back, put washers on, spun ALL nuts on by hand, picked up spanner to tighten nuts, put the ring spanner over the first one and got ready to turn. The nut, washer and half the stud dropped out of the ring spanner to the floor.

So, I took all the other nuts and washers off and puller the manifolds back. there wash the clean broken face of the 9mm stud staring back at me flush with the Alloy head. GROAN.

Picked up a screw driver and idly started to touch the stud, thinking OH SHITE. As I touched it I noticed it turn (anti clockwise), so I pressed my finger against it gently and continued the rotation. 20 seconds later I had the errant stud lying in my hand. Go Figure.





Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.

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coyoteboy

posted on 18/5/20 at 10:38 AM Reply With Quote
Wish I knew of a local machine shop that would do stuff for beer tokens and was actually competent. All the ones I know of only take on jobs £100+ when they're totally slack - most of the time it's "not worth their time". Hence I now have most of the tools I need to be self sufficient.

That includes a full set of metric tap drills and taps - these things always go wrong!

Usually you can get the broken tap out with a centre punch and a hammer.

[Edited on 18/5/20 by coyoteboy]






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nick205

posted on 18/5/20 at 02:47 PM Reply With Quote
quote:
Originally posted by coyoteboy
Wish I knew of a local machine shop that would do stuff for beer tokens and was actually competent. All the ones I know of only take on jobs £100+ when they're totally slack - most of the time it's "not worth their time". Hence I now have most of the tools I need to be self sufficient.

That includes a full set of metric tap drills and taps - these things always go wrong!

Usually you can get the broken tap out with a centre punch and a hammer.

[Edited on 18/5/20 by coyoteboy]



Your local machine shop comment is too true. Few of them left and the ones that are are often don't make themselves very approachable. I found and befriended one whilst building my MK Indy. They helped me with a few bits of material and jobs I couldn't do myself. Sadly they've now been swallowed by a larger company and no longer speak to the man at the front door

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coyoteboy

posted on 18/5/20 at 08:52 PM Reply With Quote
I get that it's not really worth their while, and I know they need to make cash, not friends, but it does work both ways.

Worth their weight in gold if you find one.






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02GF74

posted on 19/5/20 at 01:23 PM Reply With Quote
quote:
Originally posted by David Jenkins
I was making a cylinder for a 5" gauge steam locomotive, and one of the last jobs was to tap the many small holes in the cast iron (probably a 1/8" tap). And, you guessed it, I broke the tap on one of the very last holes. This was a casting that I'd spent upwards of 50 hours machining.

I ended up taking it to a local machine shop and they got it out with a spark eroder, under a "do it when you've got a spare moment" arrangement. Got a call back the next day: the tap was out and the hole was still in good shape. Cost me £5 in the beer fund, IIRC.

So, the moral of the story is - if you can take the part to a machine shop you'll save a lot of grief and may not cost as much as you think.


Not quite. The moral of the story, and I have fallen foul of it too, is to think the order of work through and do those that risk breaking the part near the beginning.






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