Cast brass for lathe parts?

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Water-mark
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Joined: Tue Jan 03, 2017 2:09 pm
Location: England UK

Cast brass for lathe parts?

Post by Water-mark »

A few year ago i picked up an old RandA type A long bed, It's a whopping 20" between centres and a 6" swing.
It was in pretty poor shape and missing several parts but gradually I've go it into running order and starting to turn parts.

Amongst the missing parts are any steadies, a compound slide and I could use a couple of extra back plates.
I've already made up some half nuts and a post to raise the QCTP in absence of the compound out of brass that I cast in my small foundry.

This got me to thinking if I could cast steady frames and chuck backplates from brass ( I'm a plumber so have no shortage of brass scrap )
I have the scrap, the foundry and a milling machine to make them (maybe even a small compound slide if I get adventurous).

The only thing I'm a little unsure of as I can't find any examples is, is it a suitable material for these parts?

Any help, opinions or educated guess work greatly appreciated.
SteveM
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Re: Cast brass for lathe parts?

Post by SteveM »

I'm no expert, but cast iron has dampening properties that brass (and even steel) doesn't have.

I've been told you can use Fortal aluminum as a backplate (I think it's 7075).

Using brass for a backplate may work, but there may be unwanted vibrations that will show up on the workpiece.

If it's all you've got, it may be better than nothing.

Steve
Water-mark
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Re: Cast brass for lathe parts?

Post by Water-mark »

Thanks for the reply.

I could buy cast iron back plate blanks as they are readily available and fairly cheap and I could weld up a steel steady and paint it as it's unlikely to be available ever.

But it just doesn't have quite the same ring to it as "I made them myself from scrap"

That said, I would like them to be functional.
spro
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Re: Cast brass for lathe parts?

Post by spro »

Alternately, you can use a brass plumbing part as a sleeve to the spindle. I did this to my Dalton in order to fit 1 1/2" X 8 tpi chucks and plates. It is really an engaging process, holding and cutting the internal thread to fit the spindle. You learn a lot doing that. Once it fits super well, the outer diameter is turned and threaded to a shoulder. Don't think you're the only one who stopped the motor and continued the thread to shoulder by turning a pulley etc. The reason here is to use the available type plates now. This is all reversible for as soon as you modify, the right parts show up.
As said before, plumbing parts are a good source and of making a steady rest. The large flange of some iron and steel pipe is ready to be cut into heavy semi-circle. Look here and the web, it has been done. You don't need a full circle, so the opening/top part, has a tongue and the base a slot for pivot. TMI but the adjustable fingers and welding is definitely "made it myself from scrap" .
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mcostello
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Re: Cast brass for lathe parts?

Post by mcostello »

We are not talking about a big honking beast like a Lodge and Shipley or Monarch.Probably could make one out of suitable hardwood and not tax the strength of the materials with that lathe.
spro
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Re: Cast brass for lathe parts?

Post by spro »

I don't agree with that. If OP was asking about the suitability of brass, he has certainly discounted wood.
spro
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Re: Cast brass for lathe parts?

Post by spro »

http://www.lathes.co.uk/randa/index.html
An interesting gap bed, metal lathe. Perhaps the largest of that maker. Cantilever style with foot. Worthy restoration and find or build the compound. Cool.
Water-mark
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Location: England UK

Re: Cast brass for lathe parts?

Post by Water-mark »

Thanks for the replies.

I'm fairly new to turning so I doubt i'm up to turning an acurate spindle nose adapter quite yet.
Not to mention anything of myford dimensions seems to carry a premium in the UK.

The biggest chuck i have is a 4" 4 jaw and i doubt the lathe would take anything larger than that.

I mainly work in softer metals though i do tend to do quite a bit of intermittent cutting due to most parts being rough cast.

I might do a back plate purely as a technical exercise, unless it's likely to break something or blind someone.
SteveM
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Re: Cast brass for lathe parts?

Post by SteveM »

When you say 6" swing, do you mean radius or diameter?

We use diameter here in the US, but sometimes they use radius in the UK.

For a 12" diameter lathe, a 5" or 6" chuck is typical.

It is possible to use something larger, like an 8", but you risk the jaws hitting the bed if the jaws are extended beyond the chuck body.

Steve
Water-mark
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Re: Cast brass for lathe parts?

Post by Water-mark »

6" diameter, the two 3 jaw chucks i have are 80mm diameter.
Water-mark
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Re: Cast brass for lathe parts?

Post by Water-mark »

Having said its unlikely to find a suitable steady second hand i took delivery of one today, what are the chances of that!

Its not a perfect fit but the centre height is spot on and i can adapt the bed fit to suit.

Should be good for £23.

Now i might try and make a lottery win
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mcostello
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Re: Cast brass for lathe parts?

Post by mcostello »

Winner!
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