How to sort this problem out.

[Michael CallaghanParticipant @michaelcallaghan68621]

Hi. Today’s problem. I have come across a snapped 6ba tap stuck in the crosshead. It’s below the surface so nothing to hold on to. What is the best way to remove the remaining part if the tap? I have tried drilling, but no joy. I was wondering if an acid of some sort my work. Any ideas.

[bernard towersParticipant @bernardtowers37738]

if the crosshead is non ferrous use alum mixture you will get it at an asian spice shop if you keep it warm it will speed the process up.

[michael howarth 1Participant @michaelhowarth1]

A carbide drill, say 2mm, should shift it. A carbide end mill probably better.

mick

[michael howarth 1]

On michael howarth 1 Said:

A carbide drill, say 2mm, should shift it. A carbide end mill probably better.

mick

+1 on the carbide drill.

I had to drill out a 3mm tap yesterday.

 

Luckily I’ve got a good stock of carby drills from work……..

 

Jimb

[noel shelleyParticipant @noelshelley55608]

2.1 mm drill will take some doing if the top of the break is not flat. Spark eroder even a simple one will do the job. You want to save the part ? Noel.

[Mick BaileyParticipant @mickbailey28509]

I’ve used a diamond burr in a Dremel to level up a broken tap for drilling with a solid carbide drill. A ball-type will leave a concave surface that helps the drill to centre better. I have some cheap sets from a tool stall at a market. They don’t last five minutes but are useful for this type of thing if the break isn’t too far below the surface.

 

[martin haysomParticipant @martinhaysom48469]

spark erode. easy to make will be needed again. i just made one to remove a 6 ba tap. broke off flush 1/2 inch of thread to remove

[Nick HughesParticipant @nickhughes97026]

There are Carbide drills made specifically for this task and they do work well, providing the whole drilling setup is rigid. E.g. in a vertical mill, with the workpiece clamped to the machine table.

An example of the drill:-

https://www.drill-service.co.uk/products/drills/spade-and-tap-removing-drill/dctrd-carbide-drill-tap-removing-spade-type/

[Ian HewsonParticipant @ianhewson99641]

Drilled an M5 tap out yesterday, used a carbide drill, fast 2000 revs and steady firmish pressure, don’t force it.

Easy to break the drill though. Bought a few at M E exhibitions stalls for just this occasion.

Ian

[Michael CallaghanParticipant @michaelcallaghan68621]

Thanks for the replies. I think I will try drilling it out. Ordered some solid carbide bits for my dremel. Can not use acid as its in a Steel part and the cost of other methods make them out of the question. Wish me luck.

[Mick BaileyParticipant @mickbailey28509]

Martin, what’s the design you made? Whenever I could get a have done with using spark erosion it always seemed too involved for an easy way out and more involved than mechanical methods. An easy and quick build would be something I’d make and put to one side for when I need it.

 

[Michael CallaghanParticipant @michaelcallaghan68621]

Just a follow up. Last night I had a go trying to drill out the broken tap with one of the two solid carbide end mills I purchased off Amazon. Well the first end mill just destroyed it’s self turning into dust. The second did the job, but only just. Like most things I have purchased one line over the years the quality is hit and miss. O how I long for the good old days when I could visit real tool shops and engineering suppliers, talk to real knowledgeable people face to face and purchase good quality tools that did not break the bank.

 

[mark costello 1Participant @markcostello1]

A hint that may help some with moveable “Z” axis mills, just raise the table instead of lowering the quill. There is a little more control that way. It also may help when drilling holes through sheet metal. Belts and suspenders and all that.

[Michael Callaghan]

On Michael Callaghan Said:

Just a follow up. Last night I had a go trying to drill out the broken tap with one of the two solid carbide end mills I purchased off Amazon. Well the first end mill just destroyed it’s self turning into dust. The second did the job, but only just. Like most things I have purchased one line over the years the quality is hit and miss. O how I long for the good old days when I could visit real tool shops and engineering suppliers, talk to real knowledgeable people face to face and purchase good quality tools that did not break the bank.

 

I really wouldn’t condemn the end mills in this case. Trying to use a solid carbide end mill to drill out a 6BA tap with a (handheld?) Dremel rotary tool is practically guaranteed to result in breakage of the end mill.

 

Everything is against you: the small (and therefore very flexible) end mill, the difficulty of centering it in the hole and stopping it from wandering, lack of rigidity in the set-up, questionable and fluctuating perpendicularity, the jaggedness and hardness of the surface being milled…

[ZanParticipant @zan]

I would have thought it is better to start again than trying to rescue a dead duck

[Howard LewisParticipant @howardlewis46836]

If it is any help, through brutality I broke a 1/8″ centre drill.

Having no carbide drills, I used a 4.7 mm (3/16″?) masonry drill. (The hole was going to be 5 mm anyway).

Applied lots of pressure and all was well.

And the 5 mm drill cleaned it up nicely.

Merry Christmas and a Happy New Year!

Howard

[Mick BaileyParticipant @mickbailey28509]

A friend broke an M8 tap in an alloy motorcycle fork leg. It was a lot of work to remove it from the bike and I suggested grinding a masonry drill to a better angle and drilling it out in-situ. He wondered if it would work and I demonstrated it by drilling through a file. It surprised him how easy it went through and how clean the hole was.

It worked exceptionally well, without wandering or damage. That was quite a few years ago and I’ve used reground masonry drills quite a bit since then. The cheap ones aren’t much good, but I have a stock of drills that were supplied with boxes of Dom brand plugs to the building trade in the early ‘ 70s and these sharpen to a keen edge that lasts.

[noel shelleyParticipant @noelshelley55608]

I have also used Micks trick and it works, I havn’t seen the guys who used to sell these at shows for a while. 2 points, they work best in a pillar drill or mill and coolant helps to stop overheating and weakening the braze holding the carbide tip in. Reforming the tip best needs a green wheel or a diamond. Noel.

[Author]

Posts