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Drilling a VERY hard PTO or some such shaft


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Good Morning all,

 

I have some kind of axle that I want to use as part of a power hammer. I would like to drill a hole in the shaft for pins at each end. I have tried consumer grade Titanium bits, the axle scofted. I was able to make a good size pock mark with a solid M35 cobalt steel bit and cutting oil. I am starting to think I need to use the low speed carbide bits that lock smiths use on a safe. Please let me know if anyone has any other ideas.

 

thanks

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I'd think that if it was an axle of any size it wouldn't be through hardened but with a quite hard outer zone and a "chewy" interior.

 

In such cases if the design allows you could grind through the outer zone and drill the interior; or even use the high dollar bit on the outer layer and switch to a cheaper/tougher bit for the interior and then when it starts to complain switch back to the carbide one.

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Rather than spend a fortune on drill bits and end up with an unknown piece of metal that may be too hard for the application, why not spend a much smaller fortune and get a known piece of metal that is suited for the job?
Because I am too pig headed? The shaft fits like a glove so that is why I liked it.


Thanks for the info, the shaft had what looked like a universal joint coupling on it but I think you are right I need to anneal it before I try anything else.

Have a good weekend.
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I once bought a chunk of shafting that was for a down well application in an oil well. lovely looking material I thought was stainless. After wrecking a bandsaw blade and re sharpening my bits it Turned out to be Monel. Which is THE single biggest Pain to work I have ever seen. I also managed a pock mark is all. It sits on a shelf near my anvil to taunt me now. I have not made a 47th attempt at it yet, but I will. I am told the issue is the speed and feed rates. And that if you attack it slowly you can win but the speed will set up an impenetrable hard spot if you start it wrong. What speed is right I know not and I can't find anyone that knows and will say.
Monel is only 3% iron if I recall right. So It is very lightly magnetic. Is yours? I hung a neodymium magnet on a string to find a tiny deflection. Good luck and welcome to the club I think...

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I once bought a chunk of shafting that was for a down well application in an oil well. lovely looking material I thought was stainless. After wrecking a bandsaw blade and re sharpening my bits it Turned out to be Monel. Which is THE single biggest Pain to work I have ever seen. I also managed a pock mark is all. It sits on a shelf near my anvil to taunt me now. I have not made a 47th attempt at it yet, but I will. I am told the issue is the speed and feed rates. And that if you attack it slowly you can win but the speed will set up an impenetrable hard spot if you start it wrong. What speed is right I know not and I can't find anyone that knows and will say.
Monel is only 3% iron if I recall right. So It is very lightly magnetic. Is yours? I hung a neodymium magnet on a string to find a tiny deflection. Good luck and welcome to the club I think...

I don't think this shaft is anything so exotic and it is magnetic. I also have things that I keep around to remind me I am not 1/2 as smart as I think I am from time to time. 

 

Ernest

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I once bought a chunk of shafting that was for a down well application in an oil well. lovely looking material I thought was stainless. After wrecking a bandsaw blade and re sharpening my bits it Turned out to be Monel. Which is THE single biggest Pain to work I have ever seen. I also managed a pock mark is all. It sits on a shelf near my anvil to taunt me now. I have not made a 47th attempt at it yet, but I will. I am told the issue is the speed and feed rates. And that if you attack it slowly you can win but the speed will set up an impenetrable hard spot if you start it wrong. What speed is right I know not and I can't find anyone that knows and will say.
Monel is only 3% iron if I recall right. So It is very lightly magnetic. Is yours? I hung a neodymium magnet on a string to find a tiny deflection. Good luck and welcome to the club I think...

I was just reading the wiki on Monel and not for nothing but it is used with contact with hydrofluoric acid is needed. This stuff looks like it would scoff at your bits and blades for sure. 

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Monel is also used as the shaft in fire hydrants from the top valve nut to the valve down in the pipe.  I had the same experience trying to cut or machine it.  I had to use a grinder to cut the shaft.  I did manage to machine it with carbide bits, but I too finally gave up on it.

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I was just reading the wiki on Monel and not for nothing but it is used with contact with hydrofluoric acid is needed. This stuff looks like it would scoff at your bits and blades for sure. 

It is amazing material, I never would have believed the strength until I ran headlong into it, anyone that works it, especially by hand has my respect. If you ever get up to PA you should check out the Bryn Athyn cathedral http://brynathynchurch.org/cathedral/
Well worth my trip from Alaska to see the wonderful Monel forgings they have.
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Michael Bondi has forged a lot of Monel. I remember chatting to him about it and seeing some images. As far as I remember he preferred it to working with stainless steel. We didn't touch on machining or drilling it though...
 
Alan

Thanks, I doubt a business man like that would have time for me though.
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Thanks, I doubt a business man like that would have time for me though.

 

Why not? What is so special about you? :) 

 

The Michael Bondi I met was an artist and blacksmith and a fellow enthusiast for the material and process. Nothing ventured nothing gained, an email to him is not going to break the bank! 

 

If you want an introduction, mention my name he might even remember me…He generously let me have free rein of his forge in Oakland to prepare tools for the demonstration I gave at the ABANA conference he organised in Saint Louis Obispo many years ago. 1992-ish?

 

If you do ask him about drilling Monel, give him my regards!

 

Alan

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