[pure-silver] Re: WTB Dry Mount Press

Thanks for all the valuable advise. Yes, my model is a 210M, bought new
about ten years ago in the US. I can email you a picture of the bolt/nut
detail directly if you like? I don't think I need the imperial nut anyway. A
local metal shop will make a solid solution for me. Just shouldn't be
required for the Mercedes of dry-mount presses, I think.





Regards



Ralph W. Lambrecht

http://www.darkroomagic.com







On 2005-08-17 17:45, "Edward C. Zimmermann" <edz@xxxxxxx> wrote:

> Quoting DarkroomMagic <info@xxxxxxxxxxxxxxxx>:
> 
>> All a lot easier said than done. These imperial nuts are tough to get even
>> in the US (little to no chance here in Germany). These nuts are very thin
> 
> In Munich a good source of imperial nuts and bolts is Schrauben Central
> Preisinger near Viktualienmarkt. There are, I'm sure, other similar shops
> in most German urban areas--- I recall a few, as well, when I lived in Berlin
> and have seen similar shops in Frankfurt.
> 
>> (just 3 mm). There is no nylon replacement nut available and there is no
>> space or clearance to add any washers or add counter-nuts. Also, since the
>> housing is aluminum and the bolts are steel, I'm not sure if grease could
> 
> Are we talking about the same model I have: 210-M ?
> 
>> make things worse and cause corrosion? I remember side strip on automotive
>> doors falling off, because the door was aluminum and the fasteners were out
>> of steel.
> 
> This is what one does all the time. In bicycles the typical crank interface
> is an aluminum arm press-fited onto a steel axle. Forces climbing a mountain
> or in a sprint are quite large. Elite cyclists can generate beyond 1500 watts
> of power for short periods of time acting on a crank arm of between 165mm
> (track) to as long as 180mm.
> 
> Its important that the parts are correctly fastened.
> 
> The general formula for calculating torque is:
> Torque = 0.2 x nominal diameter of screw x load where load is 80% of yield
> strength. Torque for bolts with nuts may be slightly higher. The load depends
> upon the friction cooeficient of the screw (and the material into which the
> fastener is attached) and the depth of the thread. Lubrication and/or platings
> can effect torque values by as much as 25%. Some platings increase torque and
> some actually decrease it.
> 
> The use of lubricants is especially valuable where steel bolts go into
> aluminium
> components. The lubricant helps to prevent galling of the threads on assembly,
> helps to prevent galvanic corrosion in service and helps with removal.
> 
> 
> A good reference is:
> 
> http://www.bsn.com/Cycling/other/tm584c.html
> (my local copy of the "CORROSION CONTROL AND TREATMENT MANUAL" from the
> John F. Kennedy Space Center (KSC) )
> 
> 
> 
> 
> 
>> 
>> Anyway, none of these action should be required for a press, retailing
>> around $2,000. It functions well as a dry-mount press, and I don't know of a
> 
> Its a specialized "machine" with, I'd expect, some margins..
> 
>> better one, but the mechanical design leaves something to be desired as far
>> as quality is concerned.
> 


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