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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Extremely tight back-focus hex bolts - HELP! -

jimhare

jimhare

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I finally got around to adjusting the back focus on my camera, but found I can't loosen the hex bolts using a standard length 4mm Allen key.

Wouldn't even budge. They are so tight I thought the Allen key would break, or I might damage the RED, so I stopped to seek advice.

Has anyone come across this? I've found nothing in the posts I have searched about adjusting back focus so I assume it's not a common problem.

Any advice would be greatly appreciated! :help:

Thanks!

Jim
 
Any comments, especially from those who have successfully adjusted back focus, would be great.

I'd like to know how much force you usually need to use. It felt like I would have to stand on the allen key to make it move. Didn't seem right.
 
Are you using a high quality t-handled wrench, or a shitty little L shaped one? Also, double check yourself that you didn't have a brain fart and go the wrong way. Some thing is wrong if you can't break them with a good wrench. One thing to try if they are really stubborn is to LIGHTLY tap on the wrench on the long axis of the bolt (in out, not side to side).

Nick
 
Hey Nick,

Shitty one... I'll try to get a better one. Brain farts never out of the question. I was attempting counter-clockwise. Even if going the wrong way, with the amount of pressure I was applying, I would have expected it to tighten further, at least showing a hint of give.

I'll try a better wrench and hope for the best.

Thanks for the advice!

Jim
 
the set from red is good. After several screw-unscrew, my wrenches are not used at all.

I have to agree the first backfocus was a bit tight, I thought the same. But it's better to know the camera is not loose on every screw.
 
tight...

tight...

Not specific to your issue, but these might help,

Purchase 10 wrenches, they do not cost much, and you don't want to use one with rounded corners or you can strip the screw.

Heat the mount (or the camera if you can) with a hair drier.

Put a drop or two of WD-40 on the crack around the head, use a tooth pick to move it around, be careful not to spray any inside the camera!

put a good wrench well into the head of the screw, and tap the screw inward via the wrench with a small blow of a small hammer.

Let the camera cool off.

Repeat for several cycles of heat, wd-40, tap before you try to un-screw.

Put some vice grips on the short L of the wrench, and put the good end in the head of the screw, press into the screw hard so the wrench will not pop out, and rotate the vice-grips (maybe have someone help hold and do the rotate while you push). If the wrench turns a little but the screw does not, remove the wrench and use another one, once the wrench gets bent or warn.

If the wrench cork-screws you need to clamp the vice grips down closer to the tip.

If that does not work maybe someone has other ideas, 90% of the time the above has worked for me on stuck screws...
 
once you do get them loose ...

after you adjust the B/F... from what i recall you only tighten to 20-22lbs of torque...
perhaps the Bomb Squad could confirm the approx #'s ?
 
I have three full bolt sets from Red and there wasn't a 4mm in any of them. Do Red provide one for BF?

As you say, all my others are in perfect condition after several uses.

Cheers,

Jim

Bérenger Brillante said:
the set from red is good. After several screw-unscrew, my wrenches are not used at all.

I have to agree the first backfocus was a bit tight, I thought the same. But it's better to know the camera is not loose on every screw.
Click to expand...
 
Thanks for the responses everyone, much appreciated!:biggrin:

I'll keep trying, it just really feels like the allen key will break or the screw will strip. Like I would have to stand on it to get any movement.

I'll try a better wrench and see how I go.

Cheers!

Jim
 
When you get a better wrench that feels like a solid fit with absolutely no play, then you need to crack it first meaning do not put small amounts of pressure and then gradually add more pressure. Give it one quick forceful turn counterclockwise. You will here a crack. They are strong screws. I haven't had a problem with more than a few cameras that I have adjusted.
 
Hey Steve,

That's the specific advice I needed! Thanks for that. :biggrin:

Jim
 
Okay, went out and got the mother of all hex keys and was able to crack them. And I mean crack! Loud sound. Had to do about three rotations before I could start adjusting.

I won't keep them nearly that tight. Just enough so it doesn't move.

Thanks again everyone for the advice!

Cheers,

Jim
 
donatello said:
once you do get them loose ...

after you adjust the B/F... from what i recall you only tighten to 20-22lbs of torque...
perhaps the Bomb Squad could confirm the approx #'s ?
Click to expand...

To specify- the bolts on that ring should be tightened to 22 lbs
 
How do you measure this? Do you need a hex wrench with a gauge on it?
 
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