Spinning Brass

So for Christmas I made a Candlestick out of steel and brass. Mainly to prove to SWMBO that my hobby could actually produce recognisable things.

This quite confused her as it was reasonably good and recognisable, but soon enough she found the flaw. It drips wax. It's a fire risk. It needs a wax catcher. And it was duly put to one side.

Never one to be daunted, I've eventually got round to making my wax catcher.

the idea was a round plate of brass flat to the base of the tulip thing that has the candle in and then curving up.

In metalwork in the Dark Ages we were told about spinning (and may have seen a demo, though that's beyond my memory).

I've put a threaded hole in an MT3 blank, made a drawbar for it and added a 50mm extension (which is the size of the tulip things outside diameter).

I mounted the brass place more or less snipped to shape onto a piece of ply and bolted it to the MT3 thing (is that an arbour of sorts?).

That worked really rather well (always a bad sign).

Next took the wood back off, bolted the plate back on, turn the speed up to high and tried to reshape it.

Somehow, it's managed to have almost no effect except to buckle the plate very slightly out of flat (1mm or so).

I can get a curve out of the brass with my pusher as it spins (first a spanner end and then a hammer shaft to get a bit of leverage), but it always springs back (apart from the buckle I've somehow put in). The curve looks to be around 10 - 15 mm at the edge so it's a fair amount.

The plate is about 3mm thick and 100mm diameter the inner diameter (the tulip ) is about 50mm.

Don't ask me what sort of brass it is. It's the sort sold at the Alexandra Palace show.

Any assistance would be welcome (including the less than ideal, 'You can't do that with brass you daft brick'.

Thanks

Iain

Edited By Iain Downs on 22/07/2017 18:40:35

I'll probably be excoriated by forum members for replying when I haven't actually done any serious metal spinning. But I have been reading up about it, as I plan to spin the chimney caps for my traction engines rather than use the castings I bought (refund I hope). Two thoughts:

1. Has the brass been annealed?

2> I think you'll need a lot of leverage to spin 3mm brass. If you look at pictures of spinners at work they use tools with long handles. The handle goes under the armpit and they're using their whole body to apply plenty of welly (technical term).

Andrew

Hi Iain,

Try annealing the brass before spinning,carefully heat all over to nearly red and

allow to cool.I use a wheel type of tool ,the one in the photo is about 4 inch in diameter.For inside edges

or sharp forms a mounted ballrace can be used as seen on right hand side.

Hi Iain ,
Here is a better view of the spinning tool making something similar to
what you are doing ,material is stainless steel.
John

Blimey - 3mm thick. What sort of lathe have you got - one with plenty of grunt I hope.
BobH

Have you read this thread ?
**LINK**
BobH

Thanks all.

I was afraid it was annealing. I don't have a blowtorch or similar. Why is it that you always need just one more thing.

Does anyone have a recommendation for something I could get from B&Q or homebase that would be decent starter for this sort of thing and soldering?

The

lathe is a 500W motor 7x14 Real Bull. I reckon it might just do the job if I soften the brass.

Iain

Well it does depend on who you bought it from at Ally Pally but I would say it's 95% likely you have a hard brass like CZ120 which will be difficult to spin even if annelaed, half hadd CZ108 would be a bit better as that is whats used when you need to bend it such as loco and traction engine tenders. Best for the job would be actual spinning brass CZ106 which is even softer.

3mm thick is also going to need a hell of a lot of force to spin, try something 0.5mm to 1.0mm thick.

I have spun steel using a rounded hardened tool held in the toolpost, this cap on the end of the cylinder was done that way and for a one off easier than making a load of spinning tools and rests.

J

Off to eBay for me then.

Iain

Iain- Kitchen stove for heat source ? Look in the cheap shops- often have small torches at good price.

Most small plumbers blow lamps should give you enough heat to anneal copper or brass sheet. Have a look at Emma Ritson's YouTube channel. She made a spinning bar for her small Lorch lathe to spin the copper end plates for her boiler build. You might get some inspiration there.

If you want to make things easy, then use guilders metal instead of brass. It will spin far more easily than brass and SWAMBO won't be able to tell the difference in colour!

Andrew.

OK. Kind of success....

So I ordered some CZ106, but then realised that the disc was actually only 1mm thick, so I decided to carry on with that. I borrowed a blowtorch from a chum and found some firebricks I'd bought earlier. So two mistakes there. I suspect sticking with the original brass has made things more challenging and the firebricks are for a hearth so designed to absorb not reflect heat. I had the devils own job getting it red when it was touching the brocks.

The first time round I was freestyling. This time I made a former and used the topslide with a bolt in to apply pressure.

The main challenge with that was that at 10 degrees the cross and topslide were too close together so I had to take the handles off and turn with an allen key.

I had to anneal 4 times to get close to what I wanted. In the end I gave up with getting a cone and settled for a sort of saucer.

You can see the profile above

So it's worked and I've learned loads of stuff. and the candlestick now has a catcher.

Unfortunately, the catcher hasn't really added to the aesthetics of the stick and the form and finish are a way off perfect.

So success, but it could have been better. I can add spinning to the list of things I can do at a mediocre level in the shop.

Many thanks for all the advice.

Iain