Author Topic: Material for cylinder block  (Read 5485 times)

Offline Firebird

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Material for cylinder block
« on: September 19, 2016, 08:24:57 PM »
Hi

A steam engine I'm thinking of building is in the collecting bits stage.
The cylinder block needs a sizeable lump 2 1/2"  X  2 1/2"  X  2" of brass (not cheap and very difficult obtanium) or bronze
( horrendous expendi impossible obtanium). The design calls for the cylinder block to be bored and a seperate liner pressed in. The liner is machined with a waist so that when pressed in there is a steam jacket around the liner.

My question is, learned friends, could I use alluminium for the block with a brass liner pressed in  :thinking:

I have used alluminium for cylinder blocks with brass pistons before (my beam engine being an example) and have experienced no corrosion problems. The engines still turn freely after being on the shelf for a year.

What do you think

Cheers

Rich

Offline Jasonb

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Re: Material for cylinder block
« Reply #1 on: September 19, 2016, 08:28:51 PM »
If you are going to steam it then you may get problems with the ali expanding more than the brass.

Do you need to solder any of it? if not waht about CI for block and liner, my 2" fowler is done that way.

What is the Engine? another option is to buy hollow core bronze for the cylindrical part of the cylinder and mild steel plate at either end to form the usual flanges, this can be silver soldered together.

Offline Firebird

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Re: Material for cylinder block
« Reply #2 on: September 19, 2016, 08:44:49 PM »
Hi Jason

I did wonder about the different expansion rates. Yes it will be a steamer. No nothing needs to be soldered. Cast iron might be an option, I'll look into the cost

Cheers

Rich

Online Jo

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Re: Material for cylinder block
« Reply #3 on: September 19, 2016, 09:37:20 PM »
The cylinder block needs a sizeable lump 2 1/2"  X  2 1/2"  X  2" of brass (not cheap and very difficult obtanium) or bronze
( horrendous expendi impossible obtanium).

 :headscratch: There are lots of options :stickpoke: These are a few I have picked up over the years  ::)

Our local club had a bring your old gunmetal castings and lets recast them into some more useful lumps. As that Loco cylinder casting sunk on the side of the chamber it was given to me  :shrug: It is possible to buy 75mm diameter bronze/brass off cuts . 1Kg kitchen weights are a little too small. Have you taken a pocket of flash-the-cash down to your local non-ferrous scrap metal dealer and enquired?

The sort of size are you talking about is around a small 5" Loco cylinder casting and I am sure your use is much better than its original purpose :naughty:

Jo

P.S. Or I could ask my supplier for a price for something but the postage would be horrendous  :ShakeHead:
Enjoyment is more important than achievement.

Offline Firebird

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Re: Material for cylinder block
« Reply #4 on: September 19, 2016, 09:46:12 PM »
Hi Jo

Thanks for the info  :ThumbsUp:

I have a few avenues to explore, one being the model engineering exhibition at Warwick in about 4 weeks.

I just wondered if alluminium was an option

Cheers

Rich

Offline John S

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Re: Material for cylinder block
« Reply #5 on: September 19, 2016, 10:30:11 PM »
Know anyone that can melt brass local to you ?

I have a shoe box full of 1/2" round brass parts  2" to 4" long that are no longer needed as they have changed the design. No good as 1/2" brass pieces because of the bits machined out of them but ideal for making into a lump.

Got plenty of steel lumps and alloy lumps in this size but not brass or bronze.

Hang on, in the next week I'm scrapping a big machine, just under 2 tonnes and it's cast iron. They might be a lump that I can saw off before it heads to the scrappy. Won't know until I start unbolting bits.
John Stevenson, Nottingham , England

Offline Firebird

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Re: Material for cylinder block
« Reply #6 on: September 19, 2016, 11:11:06 PM »
Hi John

Don't know anyone that can melt brass yet. Julian and I are looking into melting alluminium but brass is not on the agenda.
.
I have some lumps of alloy big enough which is why I wondered..................

No rush anyway, this project is down the road a bit.

Cheers

Rich

Offline b.lindsey

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Re: Material for cylinder block
« Reply #7 on: September 19, 2016, 11:53:25 PM »
Expansion rate for yellow brass =11.3 micro inch/degree F.
Avg. expansion rate for various aluminums = 13.1 micro inch/degree F.

Difference would me 1.8 micro inch/degree F so for a 200 degree rise the difference would be 200x.0000018 or .00036 inch...not even a thousandth. I would think a .002" shrink fit would be more than enough for a 200 degree rise (say just above ambient to 300 degrees F). I would feel pretty confident with a brass liner in an aluminum block.

Just my 2 pence.

Bill

Offline Firebird

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Re: Material for cylinder block
« Reply #8 on: September 20, 2016, 08:16:58 PM »
Hi Bill

Many thanks for the calculation :ThumbsUp:

Brass or cast iron would obviously be ideal but aluminium might have to do

Cheers

Rich

Online Jo

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Re: Material for cylinder block
« Reply #9 on: September 20, 2016, 09:20:12 PM »
My supplier is looking through his collection of materials  ::).

Based on what  I had to pay  :facepalm: for a bit of HE15 from a normal supplier a bit of his brass is likely to be cheaper. I am waiting for photos ;)

Edit: What size piece of bronze do you need for the liner?

Jo
« Last Edit: September 20, 2016, 09:31:58 PM by Jo »
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Offline Firebird

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Re: Material for cylinder block
« Reply #10 on: September 20, 2016, 11:04:11 PM »
Hi Jo

1 1/2" Dia x 2"

Cheers

Rich

Offline John S

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Re: Material for cylinder block
« Reply #11 on: September 21, 2016, 08:12:19 AM »
That's different to what you originally said at something x something x something.

Got that on stock.

PM me and might have a bit of information that will do you a lot of good.
John Stevenson, Nottingham , England

Online Jo

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Re: Material for cylinder block
« Reply #12 on: September 21, 2016, 08:22:48 AM »
That's the liner.....

Rich: The liner bore around 1"? (it often comes as cored bronze)

Jo
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Offline John S

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Re: Material for cylinder block
« Reply #13 on: September 21, 2016, 09:50:37 AM »
OK, missed that but still got bronze on stock that size.
John Stevenson, Nottingham , England

Online Jo

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Re: Material for cylinder block
« Reply #14 on: September 21, 2016, 11:23:55 AM »
Rich: Sorry he can't find it  ::)

As usual his workshop is upside down trying to shoe horn in yet another machine tool.  :stickpoke:

Jo
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Offline joncarruthers

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Re: Material for cylinder block
« Reply #15 on: September 21, 2016, 03:22:42 PM »
You might also try your local re-enactment society/armourer? they often use brass and bronze for pomels and quilons on repro weapons. We (NFPS vikings) used 2" and 3" bronze and brass bar, but later started casting our own 3 lobed patterns.

Offline Firebird

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Re: Material for cylinder block
« Reply #16 on: September 21, 2016, 09:27:29 PM »
Hi

Thanks Jo, no problem

John, sent you a PM

Jon, thanks for the info

Cheers

Rich

 

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