Removal of tiny roll pin

That is such a sick construcktion that I doubt it really is that way.

Bright? How about a (hardened) screw for sheet metal and pulling it out? I'd expect failure but have no better idea.

At least penetrating it with some de-ruster is never wrong.

Nick

Thanks for the thought - I've tried it! The problem is that the screw tends to expand the pin as you screw it in making it an even tighter fit! And it is a very small pin, so the screw has to be tiny and does allow much pull as the pin is in pretty tight anyway. Why didn't they just put a bloody screw in it in the first place! (Cost I suppose) MIke

can you hydraulic it out? make tight fitting pin same dia as the id of the pin. fill blind hole with oil, insert pin and belt with appropriate sized hammer. pressure increase will force out the pin (if you are lucky). of course depending on where the hole is and its angle might not work...

Dave

screw

I suppose there is no chance of drilling through from the other side and pushing the pin out?

AWEM

could you use a hollow drill of 1mm ID, bore out around it, then fit a bigger pin to reassemble?

Is it in a situation where you can use a fine tip oxy torch to heat up and either weld on an extension to pull out or soften and crush then pull out ?

In article , MikeH_QB writes

Since this is a roll pin, and therefore presumably hollow, could you hook it out with some kind of puller with a step on the bottom, pushed down the hole?

The other method no-one has mentioned is spark erosion, but unless you happen to know anyone with a spark eroder that would be a major project to make. Might be tricky to get to it in view of the location though.

If none of the other ideas work, try dissolving it out with some dilute sulphuric acid. It should not affect the alloy (assuming it's an aluminium alloy) but test it first. Again, access might be a problem.

Battery strength acid should be about right. If you have to use concentrated sulphuric acid, add about 10% to water (NOT the other way round) slowly, stirring continuously, and wear eye protection.

David

might use most/all the set but if the repair is worth more than the six quid or so , maybe worth a try? Probably best in a pillar/pedastal drill for rigidity and feel....

In article , MikeH_QB writes

BTW Mike, further to my previous post, FYI 1mm carbide drills are quite readily available - try an electronics component supplier, they are used for drilling circuit boards (which are very abrasive and wear out steel drills rather quickly).

They do tend to be quite brittle though..... (don't ask how I know that).

David

How tiny is it? I managed to remove a few in blind holes, by inserting a small screwdriver, and twisting in whatever direction winds up the pin like a spring. Pulling at the same time moved them a little at a time. Once they were out a bit, the job was finished with pliers. Another was annealed, by connecting one terminal of an old battery charger transformer to the shaft, and a piece of heavy gauge copper wire to the other. The wire was touched to the centre of the roll/spirol pin, an it was soon red hot. Removal was easy at that point!

Steve R.

I wouldn't even try. It will crack after 1/2 a turn. There is a slot in the roll pin!

Nick

Yes. But now that you have formed a thread, how about retracting the screw a bit so it doesn't expand the pin and then try pulling?

Nick

Thanks for all the ideas folks! I'll try using some of them over this bank-holiday weekend - its abviously going to be much more fun (spending the time bent double in an arkward space trying to extract the unextractable) than going out and enjoying myself! I'll just ensure there are no children or easily-offended adults within ear-shot when I try! I'll let you know of success or not! regards Mike

I think a lot of people have not realised the hole down the centre of this is going to be in the region of 0.5mm dia.

Freeze the item

-- Mr Cran

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If you've got a Dremel type tool, beg an old diamond burr from the local dentist, some are less than 1mm diam, and carefully grind it away. Its worked for me.

make a slide hammer ...and turn the end down to the bore of the pin ... plonk a bit of super glue on it ...and bang away till its out ..

all the best.mark