82mm letus allen key broken, can't get mount off. at DVinfo.net

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Old December 5th, 2009, 08:52 PM   #1
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82mm letus allen key broken, can't get mount off.

I was on a shoot today and my Allen key bolt that takes the 82mm mount off the adapter won't come off since you can't loosen the third Allen key because the bolt broke off. I tried to twist it and it won't come off, what do I do"?
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Old December 5th, 2009, 10:50 PM   #2
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Any help? I'm freaking out, I have a shoot this coming up Saturday that I need the LEX for.
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Old December 5th, 2009, 11:38 PM   #3
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Hi Joseph..............

Reading between the lines I take it the Allen head from one of the bolts has sheared off, not allowing you to get a purchase on said bolt to remove it?


So, no Allen key broken, just a bolt head?


If the head has detached from the bolt, there is, as far as I know, only one way to remove the offending bolt, and that is to drill it out.

(At this juncture any updates on technology are gratefully received).

If that is the case, seeing as you are not in a position/ of a mindset to do it, I can't see any choice but to go to a specialist engineering firm and get them to remove it at whatever expense/ damage they may cause in the process.

Guess you're stuffed, chum, till you find said firm.

Of course, if I have translated your post incorrectly, please advise.

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Old December 6th, 2009, 01:48 AM   #4
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You are correct, I been shooting since 3:30 AM till around 9:30 PM so I was bit tired when I posted this thread. I sent a email to Letusdirect so hopefully they'll be able to help me out.

Honestly I only shot with the HVX today & I don't usually shoot with the HVX, maybe once a month or so I will shoot with the HVX. Hence the reason why I have the 82mm ring on the letus right now.

I currently own the XH-A1 and that requires me to use the 72mm ring which the 19th I am shooting another scene of a feature and I need the 82mm ring off the camera unless it makes it next to impossible to shoot my scene....

Ugh so hopefully Letus will allow me to next day them my adapter & they'll be able to send it back to me the next day so I have it for the 19th.

I honestly want to disagree with you about drilling the screw thats in there out. If you drill into the screw it has to push out, if it pushes out it'll apply to much pressure resulting in cracking the glass... If it comes down to it I'll tell Letus to destroy the 82mm ring, the ring is what 85$ vs a 1,200 adapter.... I'd rather not salvage a ring over the adapter.
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Old December 6th, 2009, 08:17 PM   #5
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I regret there will be no quick fix for this one unless you have some engineering skills and some tooling.

But perhaps tell me why the setscrew was bedded down so tight as to break the head off.

Is the 82mm ring now turning on the shoulder now that the other two screws are loose?

If so, my method for dealing with this would be :-

1. Unscrew the achromat lens out through the opening in the 82mm ring so it is not damaged from drilling vibrations. It should unscrew and drop out as there is about a 0.5mm clearance.

Expected complications :-

The achromat lens might turn on edge as it drops out and need a bit of teasing.

You will need a Rolyn wrench (lens engineer's spanner) to unscrew the achromat.

Due to excessive tightening of the three setscrews there may have been crush damage. The internal threaded hole in the rear body for the achromat may have deformed and may bind the achromat threads tight, in which case the lens may be best left where it is and the appliance sent back to Letus for fixing.

If lens can be removed and the ring can be rotated, the least destructive fix will be to cut a clearance slot in the raised rim of the shoulder on back of the Letus body for the screw-end to slip rearwards through as the ring is puilled rearwards. My personal preference would be for a hole through the ring on a radial centre carried on into the raised rim. This enables the squarest end cut with a standard drill bit and least wastage of the shoulder metal.

A hole could be drilled on an axial centre from the rear but there is too much room for error and deviation of the bit due the clearance between the ring and the shoulder.

Make and place a neat fitting cardboard cover over the rear surface of the compound prism window isude the space left by the removed achromat lens. You do not want to scratch this surface or get it grubby.

Measure back 7.5mm from front face of ring.

Drill an accurate pilot hole through the ring to the raised rim of the Letus Body and 1.5mm into the raised rim itself. This will be slightly deeper than the square groove in the shoulder of the Letus body.

Widen the pilot hole with a 6mm bit, again to a depth of 1.5mm. This should result in a channel in the raised rim sufficient to clear the end of the broken screw.

Rotate the ring until the broken screw end comes to the hole you have just drilled. With a bit of teasing, the ring should slip off with the screw end passing rearwards through the hole you have cut in the raised rim.

If it hangs, you might need to drill the hole another 0.5mm deeper but no more. If you have and end mill, use a 6mm mill to square off the bottom of the drillhole and that should end any clearance problem.

Once the ring is off, chances are the broken screw can be extracted inwards as the screws are a generous fit in their holes and it may become loose enough to be screwed inwards with fingertips or ratnose pliers.

If the ring cannot be turned on the shoulder, you may have to drill the screw out. This will need a very accurate pilot hole down the center of the broken screw and then a larger drill to remove the screw material.

You can assume the threaded hole in the ring will be ruined, need to be drilled to a larger size, rethreaded and a helicoil inserted to restore the original thread diameter.

As you can observe, a camera repair shop or Letus themselves are the best bet for this repair. I have just been on the bad end of repairing a P+S Mini35C with the same sort of problem and have had to remove and send the damaged part to P+S for them to fix as they know best.

Last edited by Bob Hart; December 6th, 2009 at 08:26 PM. Reason: error
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