Author Topic: Aluminium bronze.  (Read 4257 times)

Offline DavidA

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Aluminium bronze.
« on: December 19, 2012, 07:48:41 AM »
I have to make six bearing blocks for my Fowler loco.  My material of choice (because it was free) is aluminium bronze.
I machined this stuff at work with no problems, but that was using industrial strength machines and speeds.
But I find it knocks the stuffing out of my smaller tooling at home.
Any tips on boring and turning this stuff at the modelling scale ?

I've just ordered up an indexible milling cutter and am hoping that the carbide may be an answer.

Dave

Offline Lew_Merrick_PE

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Re: Aluminium bronze.
« Reply #1 on: December 19, 2012, 11:28:35 AM »
Dave,

Aluminum bronzes have the ability to workharden as you machine them.  It is not as great as some of the 200 series stainless steel alloys, but it is there and, like many precipitation hardening materials, you need to take a fairly aggressive cut to avoid this.  There is a good chance that carbide cutters will help, but you also need a rigid set-up which is often beyond the capabilities of lightweight machines.

Good luck!

Offline DavidA

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Re: Aluminium bronze.
« Reply #2 on: December 19, 2012, 01:56:11 PM »
Lew,

Thanks for that.  I did get the impression it was work hardening.

As there are a number of operations to carry out, I may bite the bullet and get some brass instead.

For the amount of work they (the bearings) will get,  I could make them out of Dural. That will work well with the steel axles and the cast iron horns.  Much easier to machine.

Dave.

Offline Lew_Merrick_PE

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Re: Aluminium bronze.
« Reply #3 on: December 20, 2012, 01:09:45 PM »
Dave,

One trick that sometimes works is to freeze the parts before machining.  Liquid nitrogen is the recommended vehicle for such freezing although I have gotten away with dry ice & alcohol in a pinch.  ???

Offline DavidA

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Re: Aluminium bronze.
« Reply #4 on: December 21, 2012, 06:42:30 AM »
Lew,

I must have a Dewar flask somewhere amongst my collection of 'things that may come in usefull'.  'Might have problems sneaking into the old firm and pouring off a couple of litres of Nitrogen though.

I've decided to look around for some brass or gunmetal. If nothing turns up in the next few days I will use Dural;  and paint it black.

Dave.

Offline Lew_Merrick_PE

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Re: Aluminium bronze.
« Reply #5 on: December 21, 2012, 11:12:49 AM »
Dave -- The local trade school or (here in the U.S.) community college will often pony up a litre or so of LN for a small bribe (and assurance that you know how to handle it).

Offline DavidA

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Re: Aluminium bronze.
« Reply #6 on: December 21, 2012, 02:38:23 PM »
Lew,

I'll settle for the change of material option.  Seems much less trouble.

Dave