MadModder
The Shop => Metal Stuff => Topic started by: raynerd on November 04, 2012, 10:25:50 AM
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I`m getting ready to start my next project after a long 6 month break doing constant house work - building a porch, knocking a fireplace through and redecorating 2 bedrooms!
My next project is another clock.
The wheels are all to be cut from half hard CZ120 engravers brass. This brass is one of the most expensive types and it seems standard to cut these disks from sheet rather than part disks from a bar. You can buy sheets of it or even wheel blanks, ready cut round to the approx size desired. With sheet you get a lot of waste which in all honesty, is in such a funny shape (after cutting a circle) that it isn`t really useful anyway.
First question and the most important one is what sort of brass is most bar end material. All my stock seems to cut freely and cleanly so I`m presuming it can`t be too far off leaded engravers cz120 brass?
Second question is probably a little more subjective but for bigger wheels, would parting brass bar be more economical than cutting brass disks from sheet and having the wastage anyway?
Thoughts appreciated.
Chris
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Ignore question two... I`ve answered it myself.
Consider a 16g 1.5mm (quite thick) 2.5" wheel.
------BUYING DISKS ------
1 pre cut round disk (2.6" to allow cutting true) = £2.30
------BAR STOCK-----------------------------
1 length of 2.5" dia bar 100mm long = £35 inc postage
My parting tip is 2mm (+ 1.5mm disk blanks)
100 / 3.5 = 28.5
So that is 28 disks from the bar working out at £1.25
So it works out more than half price to part them from bar! I`m interested to know now how much the others work out at. Considering I already have in stock large bar sizes, I can still consider it more worthwhile to cut from bar rather than order the sheet!
I suppose that highlights further my first question - will it be the same brass or equally good as the CZ120 know sheets?
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Chris,
The bar is likely to be CZ121. I'm not sure if it will be quite as strong as CZ120 in half hard form.
You might waste slightly less material sawing and facing it but you'd need a good saw which will cut parallel and a way of holding the blank in the lathe to machine it parallel - possibly not worth the effort.
CZ121 does machine very nicely. I've made a few parts out of CZ108 sheet which machines awfully.
Cheers.
Phil.
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You are probably right...I should stop being a tight arse and just buy the brass sheet :lol: :lol:
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Hi Chris.
I have used blanks, sheet and bar stock. All three have produced good results. Using bar stock you can vary the thickness to what ever is required in the gear train. I use the metal cutting band saw, which cuts nicely parallel disks and loss of only 1mm cut width.
Is it the Wilding Regulator you are planning to build?
Regards David
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Thanks for your reply. David, just out of interest, what bandsaw do you own?
I`m planning to build John Parslows Skeleton clock.
Chris
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Hi Chris
My band saw is an Alpine 6"x4.5" vertical & horizontal ,supplied by Graham Engineering years ago. The machine however is still available re badged with the Clarke label, from Machine Mart where I get my blades. This has been one of the most useful workshop additions I have acquired, it has saved me weeks of work. I have made many improvements mostly posted in forums.
I like the Parslow clock, I am sure you will find it a fascinating build.
David
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Thank you David. I currently have two Kennedy Power Hacksaws and very shortly one of these will be sold to generate funds for a bandsaw. I`ve found the Clarke model you refer to and will be seriously considering it.
Thanks again
Chris