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Member Since 01 Apr 2002
Offline Last Active Apr 15 2014 08:54 AM

Posts I've Made

In Topic: Inon strobe knobs

15 April 2014 - 08:49 AM


I suspect those were custom made.  I have the XIT ones and they are great, but I saw a guy on the Spectre who had metal ones and he told me he made them himself. Any competent machine shop could make some for you.

In Topic: Molykote 3451 vs. Tribolube 71

11 April 2014 - 02:22 PM

Well I wandered into the lab and made some measurements (usually they only let me in to get water for my coffee machine) and I was quite surprised by what I found.  I used two aluminum (aluminium to those of you in the real world) blocks to measure the sliding coefficient of friction and a force gauge to measure the stiction between the two plates when the bottom plate is clamped down and I pull on the top plate. 


To start I used Al/Al and measured f for this system at between 0.47 and 0.48 for 20 runs. Then I used a commercial MoS based grease and the f went down to about 0.06 or 0.07 (20 measurements with no control of the thickness of the grease). Then I used commercial silicone grease (triton tub) and found that the f value was about 0.33 to 0.34. This suggests that in this test at least, sliding friction was only reduced by about 30% (I was expecting a lot more). With the tribolube 77 and 66 the f values were about 0.09 to 0.10 and with the Molykote the f value was statistically the same.  No differences in running friction at all. 


For stiction, I pushed on a force gauge attached to the top block and calculated the force that it took to start the block moving. Again surprisingly the Trident actually increased the stiction a bit. Naked, clean Al vs. Al, required about 370 g to start sliding, the Trident grease took 450 to 460 g to start sliding. The Tribolube and Molykote samples took between 240 and 250 g.


Conclusion is that there is minimal difference between the two polyfluoro lubes, and both (from a slipperiness standpoint are better than Trident (thick grease).



In Topic: Adobe Lightroom for iPad released (more platforms to follow)

08 April 2014 - 08:10 AM

Is it part of the photographers package? I pay (I think) $10/month for LR and PS. I will see if I can download it to my iPad.


In Topic: keyword lists - anyone use JP Dodel?

08 April 2014 - 08:08 AM

it seems like the Dodel version has only fishes and no invertebrates, but I have no direct experience with it.


In Topic: Safe and convenient storage of photos.

07 April 2014 - 05:25 PM

If you have a reasonable internet connection you can use Transporter as well with Chronology, or if you need really lots of storage any NAS or Drobo type box.