Stop Screw falling out of Thru Hole in machined Clamp

[Zibraz]

I'm struggling here. I have a clamp which will be tightened over a rod. The clamp and rod will be enclosed in a box and the thru hole you can see in the model will not be easily accessible. I'm trying to think of ways to fit a captive screw in this thru hole so it can be tightened from outside the box. I'm trying to look up information on typical captive screws, but all the information I find only references sheet metal. Can captive screws be fitted to machined blocks?

Failing that, what other methods can I use to have a screw in this through hole without it falling out? I want it idiot proof so someone won't fully loosen it. One idea is a seperate sheet metal plate fixing onto this area with it's own captive panel screw, but that seems inelegant.

Thanks

 

[MintJulep]

Almost certainly something here will work better.

https://www.destaco.com/products/manual-clamping

 

[MacGyverS2000]

If you mill off the threads along the top 1/3rd of the screws, sliding an e-clip over the screw between the two compression faces would prevent the user from removing the screw completely...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[rb1957]

I would be worried about stripping the thread ... tighten with a torque wrench ?

could you reverse the whole thing ? have a stud on the body, and tighten a nut ?

another day in paradise, or is paradise one day closer ?

 

[Zibraz]

I think this is what I might go with. I have been looking up all sorts of unique and interesting methods to retain it. Dropping a plate down with a shoulder screw to retain it, putting a thread at the end of one hole as a sort of stop and captive washers.

I think the easiest solution is to just drop a nut down and using a shoulder screw.

 

[Zibraz]

I could reverse it, but my only worry is the stud coming loose (Unless I put tons of lock tight on it.

 

[rb1957]

I wouldn't tap the bore ... use a threaded insert, and step the bore (so it's easy to install the insert) or have a flanged insert.

another day in paradise, or is paradise one day closer ?

 

[MacGyverS2000]

My e-clip idea is essentially what you've shown, Z, but mine has the benefit of not requiring any further machining to the block (the clip goes into the pre-existing gap). I think you're thinking too hard on this one...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Zibraz]

Actually yeah, an e-clip is the easiest and simplest solution. Quick to install and requires less work.

I will go with that, thanks!

 

[BrianE22]

There are screws available for adding an eclip:

https://www.mcmaster.com/retaining-screws/socket-head-captive-panel-screws/

 

[btrueblood]

We have a cheap gasketed box we have made by a local shop, they use an o-ring instead of an e-clip to retain the fastener. Reason is that you can squeeze the o-ring back through the hole by grabbing the screw by the head with a pair of pliers and giving it a yank. A bit easier than trying to extract an e-clip buried in the slot.

 

[hendersdc]

These guys make a few OTS options that might work for you: [URL unfurl="true"]https://matdanfasteners.com/captive-fasteners/[/url]

I am specifically thinking of their snap in option that makes instalation easy: [URL unfurl="true"]https://matdanfasteners.com/captive-fasteners/mts-series/[/url]