[time-nuts] FEI FE-5680A

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Apr 2 00:53:22 EDT 2010


Bruce Griffiths wrote:
> Leigh L. Klotz, Jr WA5ZNU wrote:
>> On 03/24/2010 03:18 PM, Magnus Danielson wrote:
>>> Fellow time-nuts,
>>> ...
>>> Second, anything I should keep in mind as I power one up?
>>>
>>> ...
>>> Cheers,
>>> Magnus
>>
>> There's a bit of discussion in the archives about the need for a heat 
>> sink, and also about the whether it's necessary to anneal the case in 
>> a 400C Hydrogen reducing oven after the SMA modification.  (Although 
>> I do have access to one, it is over the threshold for things I'm 
>> willing to do.)
>>
>> Leigh.
>>
> If one were to use a trepaning tool with loose abrasive and plenty of 
> water coolant and slowly grinds the required hole through the mu metal 
> cover, the thermal stress and mechanical disturbance of the mu-metal 
> shield should be minimised precluding the need for hydrogen annealing. 
> This is easily done using a drill press and a suitable tool.
> The tool can be assembled from brass tubing and rod. Since the forces 
> involved are low even soft soldering should suffice.
>
> Water jet cutting should also work well.
>
> Bruce
>
A heat treatment guide for mu-metal can be found in:
http://www.arcelormittal.com/stainlessandnickelalloys/uploads/media/Mumetal_Permimphy_Supermimphy_Eng.pdf

The following short article indicates how to drill mu-metal if one 
wishes to avoid having to anneal it afterwards:
LABORATORY AND WORKSHOP NOTES: Mumetal magnetic shields
Randall, W. F. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Randall,+W&fullauthor=Randall,%20W.%20F.&charset=UTF-8&db_key=PHY>; 
Sowter, G. A. V. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Sowter,+G&fullauthor=Sowter,%20G.%20A.%20V.&charset=UTF-8&db_key=PHY>
Journal of Scientific Instruments, Volume 15, Issue 10, pp. 342-344 (1938).

Bruce

Bruce





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