Brake discs a suitable source of case iron

[Neil WyattModerator @neilwyatt]

I should have made Southam's axle boxes with a single lip like that. Much easier to machine accurately than a groove each side.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Lee

Point proven nicely

MichaelG.

[Martin 100Participant @martin100]

The discs are used on a wide range of GM vehicles in the 80's and 90's usually the lower powered ones

Drawing here but as shown in the photo above you'll lose some flat area to the radiused inner edge.

http://www.brakebook.com/bb/pagid/en_GB/52404_82/datasheet.xhtml

The pad friction area enables an estimation of the usable disc material

http://www.brakebook.com/bb/pagid/en_GB/T0841_402/datasheet.xhtml

[BazyleParticipant @bazyle]

edit – hadn't checked the datasheet link.

How about ideas for good uses for the centre section.

Edited By Bazyle on 15/01/2017 12:02:37

[Lee GriffithsParticipant @leegriffiths86022]

Brake shoes ? if you are lucky with the diameter that is

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bazyle on 15/01/2017 12:00:44:

How about ideas for good uses for the centre section.

.

There should be the makings of a cone-clutch in there somewhere.

… For small lathes, etc.

MichaelG.

Edited By Michael Gilligan on 15/01/2017 13:21:50

[JasonBModerator @jasonb]

Does anyone know the iron spec of the brake disc cast iron?

Seems to me that a nice high graphite content one which is what you want for bearings would be the last thing you need on a brake disk where any self lubrication properties would be counter productive.

J

[Michael GilliganParticipant @michaelgilligan61133]

Good question, Jason

… There's a fighting chance that these guys do: **LINK**

http://www.iaeng.org/publication/WCE2010/WCE2010_pp2322-2326.pdf

MichaelG.

.

[quote]

Traditional material for automotive brake rotor is the cast iron. The specific gravity or density of cast iron is higher which consumes much fuel due to high inertia. Following section will describe the potential candidate materials those can be used for brake rotor application. Cast Iron: Metallic iron containing more than 2% dissolved carbon within its matrix (as opposed to steel which contains less than 2%) but less than 4.5% is referred to as gray cast iron because of its characteristic color. Considering its cost, relative ease of manufacture and thermal stability, this cast iron (particularly, gray cast iron), is actually a more specialized material for brake applications particularly the material of choice for almost all automotive brake discs. To work correctly, the parts must be produced at the foundry with tightly monitored chemistry and cooling cycles to control the shape, distribution and form of the precipitation of the excess carbon. This is done to minimize distortion in machining, provide good wear characteristics, dampen vibration and resist cracking in subsequent use [12].

Edited By Michael Gilligan on 15/01/2017 13:46:35

[Lee GriffithsParticipant @leegriffiths86022]

"provide good wear characteristics"

The significant bit ?

Lee

[Gordon WParticipant @gordonw]

I've long since forgotten the spec for brake disk cast iron, but I do know it is/was a standard spec. and not graphite reduced.

[julian atkinsParticipant @julianatkins58923]

I might suggest, despite all Lee's hard work, if a job's worth doing…

1. Meehanite cast iron is supplied in various sizes by M-Machine Metals Darlington. It is very good for miniature loco axleboxes

2. The extra work in making split axleboxes on an inside cylinder crank axle loco such as your 5"g GWR 14XX will be repaid later on. Felt pads underneath the axlebox keep are also a very worthy improvement which split axleboxes also allow.

Cheers,

Julian

[Michael GilliganParticipant @michaelgilligan61133]

Just an observation: Meehanite is a trade name, and covers various grades of iron:

Quote from the Wikipedia page: **LINK**

The Meehanite specifications can be classified into three broad types: High duty Flake or gray irons; High duty “nodular” or ductile iron (SG); and A group consisting of special Types for applications requiring resistance to heat, wear and corrosion.

https://en.m.wikipedia.org/wiki/Meehanite

I haven't checked what specification[s] 'M-Machine' supplies.

MichaelG.

.

Edit: This may be of interest: http://meehanitemetal.com/technical-lit/

Edited By Michael Gilligan on 15/01/2017 23:34:59

[not done it yetParticipant @notdoneityet]

provide good wear characteristics"

Yep, discs generally outlast the friction pads (which are the more regular service replacements).

Friction pads are formulated for differing characteristics while discs are most commonly just cast iron.

[Brian WoodParticipant @brianwood45127]

Hello Ed,

​Sash weights are not made of the best quality cast iron, there is a lot of slag and rubbish in them. Nor do they need to be when you look at what they are made for, like a paper weight, they do what it says on the can.

​Having said that, I have used the material selectively, the worst of the rubbish will be at the top end where they hang from. I'd recommend using the bottom 2/3rds and throw the top end away.

What is salvaged will only be useful for small diameter work of course

Regards
Brian

[roy entwistleParticipant @royentwistle24699]

I have about 15 sash weights, some when suspended will ring when struck, others give a dull thud. I suspect that the ones that ring are of better quality but I've not got round to trying them yet

[Neil WyattModerator @neilwyatt]

Posted by roy entwistle on 16/01/2017 11:18:52:

I have about 15 sash weights, some when suspended will ring when struck, others give a dull thud. I suspect that the ones that ring are of better quality but I've not got round to trying them yet

I bet a virtual pint it's the other way round

The ringing ones may be chilled and hard.

Good cast iron is known for its vibration dampening properties.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Roy,

At the risk of stating the obvious …

It might be worth checking whether the "dull thud" versions are Lead

MichaelG.

[vintagengineerParticipant @vintagengineer]

I cannot imagine sash window weights being made from good quality iron, garden furniture is made of similar crap iron. It is so bad some it cannot even be welded!

[Neil WyattModerator @neilwyatt]

Should be obvious from the much greater density of lead, plus lead sash weights have a hole through the middle.

[julian atkinsParticipant @julianatkins58923]

My apologies,

But I cannot see how some of the above recent posts contribute to good axlebox design and material for miniature locomotives.

We have here a 5"g GWR 14XX class loco with inside cylinders and crankaxle.

Cheers,

Julian

[roy entwistleParticipant @royentwistle24699]

Michael The dull thud is probably more of a clunk, however a magnet is attracted so I'm going for cast iron

Neil There is a hole across one end for the sashcord. I've never come across one with a hole up the middle

Roy

[Michael GilliganParticipant @michaelgilligan61133]

Posted by roy entwistle on 17/01/2017 21:39:12:

Michael The dull thud is probably more of a clunk, however a magnet is attracted so I'm going for cast iron

.

Sounds like a good deduction.

One man's dull thud is another man's clunk, I guess.

MichaelG.

[Sam Longley 1Participant @samlongley1]

Posted by roy entwistle on 17/01/2017 21:39:12:

Michael The dull thud is probably more of a clunk, however a magnet is attracted so I'm going for cast iron

Neil There is a hole across one end for the sashcord. I've never come across one with a hole up the middle

Roy

I am going to come in here because I think i have seen quite few sash weights in my time. When i moved my factory shortly before selling my joinery business I took the left over sash weights to the scrap yard & there were 9 tonnes.

Some sash weights had a hole through the centre top inch down to a cross hole so one could put the knot. Good in that it allowed the weight to go right to the pulley but not so good that the edge could dig into the box. Others had a tapered end with a cross hole. Better in that they did not grate on the box so much but if the carpenter did not tie the knot tight they took up more room. Make weights, designed for increasing weight where one needed to due to the initial weight being undersized were usually about 1/2 to 1lb & had a hole right through so the cord could pass through & tie to the main weight. We used to see how many different forge names we could count cast on the weights of the old ones.

We had lead weights that more often had a hook cast in, square steel weights with hooks welded on & some with holes drilled. The largest weights would be about 34 – 36 lbs & the average 12 lbs although I had hundreds in the 6 & 7 lbs size . Shape would vary from round to square. size from 1 inch to 2 inch across

As for quality – some times we might cut one down & some were like honeycomb & would break somewhere else whilst being cut & some were really close grained. You takes yer pick

I just wish i had kept a few, but i mentioned in the pub last week i wanted some & 2 have turned up unannounced on my drive, so who knows in another 25 years I might have some more

I made quite a few sash windows in 25 years & sometimes had orders for up to a 800 at a time.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for sharing your recollections, Sam

… It's good to have something more than hear-say and speculation.

MichaelG.

[Martin KyteParticipant @martinkyte99762]

As a small boy I built a "nuclear reactor" from an old metal tank with sash weights as control rods operated by string. If you lit a fire in the tank the whole thing warmed so was more realistic when sitting on the top 'controlling the thing" Somehow never go round to making a real one though. Happy days.

Martin

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