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Camera Lockdown Screws, or just how fast CAN rust form?


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#1 PeterAbraham

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Posted 22 July 2014 - 06:38 PM

I'm a big fan of making my own camera lockdown screws. Early on, pre-Steadicam, I was aware of how gored up ( for lack of a better term ) the slot in a regular lockdown screw was after repeated use. Most lockdown screws have a slot wider than many screwdrivers. ( Yes, I know, Filmtools and others make a splendid thick-bladed "T" handled Vüunder-tool. I wish I owned one. )

 

My solution 28-odd years ago was to go to McMaster-Carr. Buy a box of 3/8-16 socket head bolts. Grind down the head ( so there is clearance for the underside of the plate-to-top of stage area ) and grind down the shaft. The shaft length was a dicey thing. Even a few threads too many could insure damage to some older film camera bodies. ( We are talking 1986-era ) Some bodies had important boards mounted in the area of the Helicoil or otherwise moulded into place 3/8-16 insert. I always ground down the shaft to match the regular slotted lockdown screws.

 

While this may seem an awful lot of work, consider one of the real pains in the butt for single-hole lockdown cameras. When is the last time you ran just one screw into a body without running a strip of 1" camera tape down the underside of the body on each side of the hole? This, in a valiant effort to reduce or eliminate rotation of the camera once it's mounted onto the sled. While a tripod situation will do just fine with a slotted camera lockdown screw, trying a whip pan and finding the camera body rotating freely on its screw is always somewhat disheartening.

 

The socket head offers me an immense amount of torque because an "L" Allen key or "T" Allen wrench grabs in a way that ( I would assert ) no flathead screwdriver can.

 

And so, every few years, the ritual of grinding down a handful more of the machine screws. Put on some music, blast away and make a ton of sparks. Kind of soothing in a way.

 

Until today. There is nothing remarkable about today's weather. High in the low 90's (f) and medium humidity. I ground away, tossing each sizzling hot screw into a bin of water to cool it down post-grind. After an hour or so, I had about 10 workable machine screws ( and two I'd utterly bollixed up by grinding them too far because my mind wandered. :D )

 

Finished up. Dumped out the water and set the little plastic bin containing the new lockdown screws into the car. Drove in to Manhattan to pick up my Dearly Beloved™ when she wrapped her shoot.

 

In the 80-odd minutes that I was in the car, the machine screws went from black and damp to dry and rusty. Not covered of course, but with deep rust marks and streaks all over all of them. Remarkable. Never seen anything like this. Now, I get it. The intense heat drove the oils out of the surface layers of the metal, the dousing drenched the oils away and the metal was painfully dry. But- rust in an hour more or less? Weird as hell.

 

Having labored over them, I couldn't very well throw them out. I decided to heat them slowly and oil them up again, hoping that the oil would soak in enough to prevent any rust from forming.

 

In a moment of culinary/cinematic inspiration, I doused the machine screws with Extra Virgin Olive oil from Greek Kalamata olives. See attached photo. :D

 

I then set the small square cast iron pan onto the stove and ran a flame for a few moments. Repeating this effort, and turning the bolts now and again. As I went to heat up dinner in the oven, in they went to get hot to about 325º (f again. ) They're still sitting in the oven, cooling. I do plan to warm them one more time to thin the oil enough to rub off all extraneous lubrication. Then let them cool.

 

Either I've come up with a tasty new way to cure and protect hardened steel machine screws, or in a few weeks these screws are going to REEK as the oil goes rancid.  I'm kinda curious to see which way it goes.

 

An amusing way to pass a quiet day in the home office.

 

The temptation was IMMENSE to "infuse" the machine screws with a scent by drizzling peppermint oil onto them as they cooked....  ;)

 

Peter Abraham, S.O.C.

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#2 Jarrett P. Morgan

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Posted 22 July 2014 - 07:09 PM

I have a question about the whole process: what is the purpose of grinding down bolts rather than just buy shorter ones from McMaster. They make all sorts of different sizes in 3/8-16 hex socket bolts...? Perhaps they don't make the right length?

 

Just curious.


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#3 PeterAbraham

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Posted 22 July 2014 - 07:23 PM

The heads are too high. And yes, they do make lots of different lengths on the threaded end. I could look for slightly shorter threading, but the cap heads must be ground down or they do not clear the plate/stage. The remarkable amount of tightening force I can apply with ease opposed to using a flathead screwdriver makes this work for me.


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#4 Jarrett P. Morgan

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Posted 22 July 2014 - 08:02 PM

Ah, fair enough. 

I have actually used hex keys for tie-downs quite a bit. They work great!


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#5 PeterAbraham

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Posted 22 July 2014 - 08:09 PM

Yeah, but do they smell like a Greek salad?  ;)


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#6 Victor Lazaro

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Posted 22 July 2014 - 11:08 PM

What about dipping them in some AFC-50 which is an anti-corrosion formula? http://www.learchem....cts/acf-50.html


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#7 PeterAbraham

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Posted 23 July 2014 - 08:16 AM

Absolutely the best solution. ( Pun intended ) Since I don't have any on hand, I used what I used.

 

Had I had a spray bottle of it, I'd have doused each screw in it.


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#8 nick franco

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Posted 23 July 2014 - 10:33 AM

This is also a good product for finishing off small areas of small raw steel.

http://www.brownells...--prod1072.aspx


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#9 PeterAbraham

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Posted 25 July 2014 - 12:26 PM

Oh sweet!! I like this. May go with this over ACF50.
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#10 Brant S. Fagan SOC

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Posted 25 July 2014 - 03:27 PM

Peter, you may not know this but there are Low Head Socket Cap Screws available in 3/8-16 thread in either 1/4" or 1/2" thread length from several suppliers.  Yes, I know the 1/2" is too long for most film camera bodies and some digital applications as well, BUT you can take them down to 3/8" thread length on a lathe and then just dress the threads with die and coat them with a 'special sauce.'  I do 'em in batches, too!


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#11 PeterAbraham

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Posted 25 July 2014 - 04:47 PM

You learn something new everyday.
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