Brake discs a suitable source of case iron

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Thanks, Lee ... feedback on suppliers and materials is useful to us all

MichaelG.

I know nothing about these (or any for that matter) brake discs & looking online they seem to have a large boss in the middle & some seem to be the hollow type. So may I ask 2 questions please:-

1) What actual Nova disc did you order & do they come in pairs & did you buy front or rear?

2) what is the usable area of cast that one can reliably get from the disc once the central hub has been removed?

Thanks

Sam

So little that unless the remaining shape saves you a lot of roughing out, it's not worth buying a disc rather than an appropriately shaped blank.

Worked out well and nice to machine. Much cheaper then buying a bar form one of the usual suppliers. £7 inc 24 hour delivery I could probably make at least 10 axle boxes from one disc.

This is the ebay item if interested

http://www.ebay.co.uk/itm/301833633434?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Lee

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

Thanks, Lee

Point proven nicely

MichaelG.

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

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

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

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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

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

Good question, Jason

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

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

MichaelG.

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[quote]

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

"provide good wear characteristics"

The significant bit ?

Lee

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.

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

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.

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

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

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.

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

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