Bluebird & Other Scale Models

[Renegadenemo]

I remember watching Rich make a beautiful new section of sponson top for the left hand side... then I turned up the smashed original and began cutting lumps out of Rich's work and throwing it away to let in my scrap. He wasn't best fussed, I recall.

[midlife]

I'm really really sorry for bringing up such an obviously traumatic experience for everyone, I'll go & sit on the naughty step for half an hour & I promise to read the above posts to my grandson, as written, to ensure that he understands that it isn't just Richie that wears his underpants on the outside[.]
Cheers
Wayne


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[Renegadenemo]

It's the tolerance factor (on top of the convoluted design) that killed us.

Or, put another way, trying to perfectly mate the underside of a 12 foot fabrication to a 6 foot wedge machined from a solid billet to within 1/100mm... twice!

[conistoncollie]

Or, put another way, trying to perfectly mate the underside of a 12 foot fabrication to a 6 foot wedge machined from a solid billet to within 1/100mm... twice!

1/100mm? Thought we weren't keen on base-ten flummery.
0.0003 inch, or 4 tenths, much more imperial. Pretty tight tolerance on a 1/2 in ground shaft let alone over 6ft. Can imagine temperature variations caused that 6ft lump to expand and contract well beyond that.

Talking of thous, I once had to show a young apprentice lad what a thou was, so I set up the anvils of a mike to 0.001, held it up to the daylight and said "thats one thou, how many of those do you think there are in an inch?" After pondering the question for a while he replied with "there must be millions"

[Renegadenemo]

1/100mm? Thought we weren't keen on base-ten flummery.
0.0003 inch, or 4 tenths, much more imperial. Pretty tight tolerance on a 1/2 in ground shaft let alone over 6ft.

MKW always quoted their planing wedge to be inside 1/100mm end to end so I never bothered to translate it into English as most people can only count to ten.
Our steering shaft was an interesting one. it was centreless-ground from three lengths of cold-drawn seamless hydraulic pipe to 0.9980" The man would only give me two thou clearance on the bearings and two of those were actually 0.998 themselves and had to be lapped before the shafting would slide but the tolerance on those shafts over about 18 ft was very impressive. Green & Preece grinding did it for us.

http://www.green-preece-grinding.co.uk/

[rob565uk]

Speaking of numbers and bases, two amusing stories spring to mind:

A friend of mine, blessed with a sharp mind, and even sharper sense of humour, was asked his opinion of who was right and wrong in a dispute between two people at work.
His reply was "Well , I think its 6 to the base 10 of one and 10 to the base 6 of the other...

Back in the 1970s in the early days of the dreaded decimalisation in the UK, I went to buy an eight foot length of timber, to be told that it was only sold by the metre. So I enquired how much it would cost and was advised " 15 pence a foot Mate"

[conistoncollie]

Had the same once trying to buy some 1/4 ply. Sorry mate, only available in 6mm,
OK, can I have a 2 metre x 1 metre sheet?
Sorry mate it comes in 6 foot sheets.

Once I specified a size on a drawing 1.985 in. Client asked for it to be 2.000, thinking it would be easier to machine.

And finally, had a drawing once where the hole was specified M 1/4. Good luck with finding a tap for that.

[midlife]

We ordered 2 x 1/2" taps & received 1 x 2 1/2" tap, it's been used as a trophy for years


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[conistoncollie]

We ordered 2 x 1/2" taps & received 1 x 2 1/2" tap, it's been used as a trophy for years


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Perhaps try cutting it into five.

Once asked a trainee to cut a 3 inch diameter steel bar in half.
He was gone for hours so I went to check. He had it standing up in the vice, dripping with sweat, cutting it in half .... lengthwise.

[Renegadenemo]

My least favourite metric/imperial gotcha was the top skin for the air intakes. It would come out of a 8x4' sheet but in no way were we going to get it out of a 2x1m sheet. You'll never see it but that skin had to have a 4" strip welded on all the way across the front edge before we could begin wheeling it in.

Here John and me are dressing the weld.

Extending panel.jpg

It wheeled in perfectly after that.

Wheeling intake skin.jpg