Drilling out Monel

TiggerToo

TiggerToo

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What drill bits should one use to drill out monel pop rivets? I have managed to snap a few HSS ones which were totally useless.
 
\The biggest problem I find is when the rivet has pulled slightly and thus turns when the drill bites. Care and steady but not too much pressure seem to work for me. Also using a drill slightly larger than the rivet size seems to work well, though take care not to enlarge the hole when doing so.
 
I find that when drilling out pop rivets the greatest likelihood of snapping the drill occurs when it has gone almost all the way through and its tip meets the broken off end of the original setting pin. At this stage you are probably pushing reasonably hard and the drill is cutting well. As soon as it hits the small piece of steel at the bottom of the rivet it can become wedged and it stops dead, whereas the drill keeps turning and fracture is the inevitable consequence. Changing the drill material won't make any difference as they are all pretty much as brittle as each other. It's a matter of going slowly at this stage, press lightly and be prepared to back off when the juddering starts.
 
Well done that man.
When I wer a lad...... This is the method we used to remove thousands of the bloody things on aircraft.
Seriously, I think awol has the answer. Imagine that you are just drilling the head off, and punch it out as soon as it is weak enough to be broken. Unlike aircraft applications though, the ally section is very thin so it must be done with care if you are not to indent the mast.
Breakages may not be the fault of the drill, but the unfair loading as it suddenly breaks through.
 
vyv_cox said:
I find that when drilling out pop rivets the greatest likelihood of snapping the drill occurs when it has gone almost all the way through and its tip meets the broken off end of the original setting pin. At this stage you are probably pushing reasonably hard and the drill is cutting well. As soon as it hits the small piece of steel at the bottom of the rivet it can become wedged and it stops dead, whereas the drill keeps turning and fracture is the inevitable consequence. Changing the drill material won't make any difference as they are all pretty much as brittle as each other. It's a matter of going slowly at this stage, press lightly and be prepared to back off when the juddering starts.
Click to expand...

Actually, VYV Cox, the material of the drill bit DOES matter. He is inquiring about MONEL (hardened alloy steel) rivets, and how to drill them out. If it was just an everyday, averaged rivet, your statement would carry some weight. However, monel rivets and roll (soring) pins, are too hard for even HSS. So, that being said, your comment on THIS particular type of rivet, and how to remove it properly, is of no use to the inquisitor. So, maybe you should retract that, as another might misread/misinterpret and keep wondering why it is not working for them. Just a thought, as the comment was made in order to help another, it is actually misinforming them. But, it is your name out there in helpful forum land, and not mine.
 
INFIDEL82 said:
Actually, VYV Cox, the material of the drill bit DOES matter. He is inquiring about MONEL (hardened alloy steel) rivets, and how to drill them out. If it was just an everyday, averaged rivet, your statement would carry some weight. However, monel rivets and roll (soring) pins, are too hard for even HSS. So, that being said, your comment on THIS particular type of rivet, and how to remove it properly, is of no use to the inquisitor. So, maybe you should retract that, as another might misread/misinterpret and keep wondering why it is not working for them. Just a thought, as the comment was made in order to help another, it is actually misinforming them.
Click to expand...

Monel is not hardened alloy steel.... not even steel ...

Monels... there is a range of them ..........are alloys of copper and nickel!

But, it is your name out there in helpful forum land, and not mine.
Click to expand...

and one of the more highly respected names on these forums!


BTW , "welcome" to the forums
welcome-1.gif
 
Last edited:
,m
INFIDEL82 said:
Actually, VYV Cox, the material of the drill bit DOES matter. He is inquiring about MONEL (hardened alloy steel) rivets, and how to drill them out. If it was just an everyday, averaged rivet, your statement would carry some weight. However, monel rivets and roll (soring) pins, are too hard for even HSS. So, that being said, your comment on THIS particular type of rivet, and how to remove it properly, is of no use to the inquisitor. So, maybe you should retract that, as another might misread/misinterpret and keep wondering why it is not working for them. Just a thought, as the comment was made in order to help another, it is actually misinforming them. But, it is your name out there in helpful forum land, and not mine.
Click to expand...

Ah, you are talking about hardened alloy steel monel when responding to something I wrote in 2009. When I wrote it I was meaning the far more common copper nickel alloy known as Monel. Far from being hardened, the Monel I was talking about is quite ductile and relatively soft, otherwise it would not work as a pop rivet. Maybe when I do my next Metallurgy degree I will learn about the new hardened alloy steel monel but until then I suppose I will have to continue living in the past.
 
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