Adjustment/locking Screw

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jin
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Adjustment/locking Screw

Post by jin »

Hi all,

Need advise the exact screw size and name of the screw used on the Olympus illuminator as shown.

the thread outer diameter measured ~2,85mm but i found using M3 screw (measured ~2.83mm i have) can also go through the threaded hole but i need the one with a 'round' tip as show below.

Kindly advise.

BRImageImageImage

JKT
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Post by JKT »

I'd guess that is special and you'll have to make one yourself.

JohnyM
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Post by JohnyM »

No head, M3, partial front-thread screw... will be hard to find.
Example:
http://www.mecavit-screws.com/special-p ... rettyPhoto

Something like in first row, 3rd from left.

On the other hand, if you to have the tools, would be very simple to make. But i guess you wouldnt be asking then :)


Also, keep in mind, that if it's just for locking the head, and you can live with that gross, ugly, unmatching screw , any longish m3 will do the job. :lol:

JKT
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Post by JKT »

The required tools for this could be reduced to electric drill/screwdriver and Dremel. Might need a few extra DIN 914/915/916 set screws for practice. :)

The length of that part might pose problems. Those set screws are not that long in M3.

bralex
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Post by bralex »

Would it be reasonable to file it down from an existing screw? I personally would run an over-long screw through a nut, hold the nut in a vise (so as to not damage the threads), file the end, then cut off to the desired length. A slotted head can be cut with a hacksaw or a dremel.

genera
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Post by genera »

bralex wrote:Would it be reasonable to file it down from an existing screw? I personally would run an over-long screw through a nut, hold the nut in a vise (so as to not damage the threads), file the end, then cut off to the desired length. A slotted head can be cut with a hacksaw or a dremel.
Yes, but I wouldn't do it in a vice. It's important that the screw is round and straight. The OP could try mounting one in a Dremel tool collet chuck and filing as the setscrew rotates in the Dremel. I see a lot of M3 x 20mm setscrews on eBay but many don't show the pitch. It seems like that should be long enough. Is a sample available? This is something that a machinist could make in a few minutes, once setup.
-Gene

bralex
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Post by bralex »

Unusual to see critical roundness in a setscrew - clearly I misunderstood what this is?

jin
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Post by jin »

I’m not a mechanical guy but don’t think the exact size/shape does matter but I think with a ‘rounded tip’ it will not damage ie., causing any dent or cut the dovetail’s surface, I assumed.

Thanks all for the suggestions and certainly I’ll try the option using a vice and hand file and get the job done ?

BR

ChrisR
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Post by ChrisR »

MUCH easier with a cordless drill, really. If you do it all by hand and it's not circular in any section, it'll dig into the dovetail on the high-point, as you tighten it.

You can also spin it in the drill while holding it against abrasive paper, too. Aluminium oxide or silicon carbide though, "sand"paper is too soft.
Chris R

rjlittlefield
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Post by rjlittlefield »

ChrisR wrote: it'll dig into the dovetail on the high-point, as you tighten it.
Hhmm...

As I read jin's picture, the screw that he's replacing is one of the two fixed points that just establish centering. It's the screw at lower right, with the thumbwheel not shown, that gets turned to tighten the thing. So, no real problem for this one as long as the tip is not unusually sharp or rough.

--Rik

ChrisR
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Post by ChrisR »

:roll: Yes of course, it does stay put once centered. I'd use a drill anyway..
Chris R

jin
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Post by jin »

thank you all and i have since hand made a few pieces using a power drill, sand paper, hacksaw and 8" hand file, not nice but it works for me :D


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