How to remove this stuck tapered pin?

Get a drift punch same size as drill bit.

If you are touching bit from other side then try this.

Grind new tip to broken bit but as flat as possible to get as much material removed from where tip of broken bit is.

Or use dremmel tool.

Get a GOOD drift punch and biggest hammer you have and use drift punch against broken bit from small end.

If real lucky it pops drill bit through.

If more lucky it pops pin out.

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Friendly non murdering Sword said:
Alright folks, worst case scenario. I managed to properly f*ck this one up.

There are two tapered pins that hold the shaft in place so before tackeling the above mentioned one I decided to get the other one out. It looked to be in way better condition however I couldn't tap that one out either. So I decided to practice drilling this one out first and everything went good. I drilled it all the way through and that was enough to drive that one out easily:

View attachment 390240View attachment 390241

After that I tried the above mentioned and from the start I noticed this material was a lot harder than the one before. Either the welding caused hardening in this area or the pin isn't made out of soft material. I smoked the first drill and had just gotten a tiny bit in. With the second it started to get easier and I got in maybe half way through... when the drill bit broke on me. :cower:

Somewhere in there is the drill bit burried:

View attachment 390242View attachment 390243

A little panic attack later I decided to drill from the other end with a slightly larger drill bit and I got to maybe half way through the bore when I noticed I hit the stuck drill bit. I tried to knock the tapered pin out in hope there may be enough material removed but I wasn't lucky.

View attachment 390244

So my last idea is ordering some carbide dremel tools and grinding the drill bit away? Or are there any other suggestions? Anyways I had enough for now and I'm out.
Click to expand...
I had the same problem of broken bit in cast iron. I hit a really hard spot of cast iron. Broke the bit.
I tried a bunch of solutions .. carbide drill bit. It snapped.
What I wound up doing was taking a masonry bit , and drilling it out.
It's not going to fracture the same way. It's soft then a hard tip. the hard tip is meant for concrete / abrasive so it's not a brittle carbide.
it worked. I did this in my Hilti (hammer drill).

I'll also recommend investigating different drill bits:
or https://www.msdiscounttool.com/catalog/index.php?cPath=165
Hopefully others will have input.
 
If I was using a milling machine, I would use a carbide end mill and plunge. On a drill press, it will work but the machine tends to be a little less accurate and less stiff. Definitely not a job to try free hand.
Pierre
 
2022 is starting off in my favor... :angel:

With the combination of two advices from the forum I pulled that sucker out.

The broken drill bit was 3mm and the tapered pin was 4mm nominal so there was still some material that could be removed and I started with these two carbide dremel tools to carv out material on the perimeter around the drill bit on both sides.
IMG_20220101_103658.jpg

And after about 90mins of careful grinding I tried a drift punch and indeed I could see a separation between the remaining pin and the bore, meaning that the pin and stuck drill bit had actually moved a bit:

IMG_20220101_102859.jpg

After some more grinding and hammering I got a little surprise... that round dinged up thingy protruding on one edge of the smaller side of the pin what appeared to be a tag weld... turned out to actually be a second, smaller pin. :distrust: (I thought it was a tag weld anyways because it had angle grinder marks on it.) In red is the remaining drill bit and in blue the second pin:

IMG_20220101_105302.jpgIMG_20220101_140404.jpg

The bore was so messed up that the guy before me decided to fill that hole with a second pin I guess?

IMG_20220101_142508.jpg

It took me approx. 3h to get everything out and I'm thankful for every tip you guys gave me.

I haven't yet taken the shaft out; it's all still soaked in WD40 to help loosen those connections but I will keep you posted on the progress. When the time has come I will also probably need some opinions on what would be best practice to rescue these bores or make new ones 90° offset... maybe drilling and reaming the existing ones out for a larger size tapered pin? But we'll see in some time...
 
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Yes, nice work getting through this and sharing the process.
 
I would abandon the existing hole and start fresh at 90 degrees. Too many possible bad outcomes!
Pierre
 
pdentrem said:
I would abandon the existing hole and start fresh at 90 degrees. Too many possible bad outcomes!
Pierre
Click to expand...
I agree, I also think they didn't jig drill these, I think they were individually drilled.
Fill the hole with JB weld. give it time to cure before redrilling 90. Why? well it may offer some support to that metal around it. And it will be nicer than have a hole in the middle when redrilling.. Although braze would be better on the redrill.
And that's just my opinion.
 
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