Nylon set screw in Al

Hello all,

I am getting close to drilling the radial set screw holes we discussed. The goal is to grab a $25k instrument for an experimental setup. To start, I have a unit that fell off the assembly line. Damaging it would be bad for future fit testing, but otherwise is not a problem. For the real thing, I am leaning toward nylon set screws.

One thing that concerns me about nylon is that the hex socket could strip. Is there a good way to remove a set screw in that situation? Shoving a jeweler's screwdriver into it might work, but there must be a better way???

Is there such a thing as a rubber-tipped set screw? I would rather buy something like that, but an old inner tube, a punch and epoxy comes to mind also. We need this thing to work about ten times. After that, it is off toward commercialization or muttering about the one that got away.

Bill

Reply to
Bill Schwab
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How about nylon tipped?

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I've also dropped a round lead fishing sinker down the hole before inserting the setscrew when I didn't want to mar a part.

Reply to
BillM

CA glue will hold the tips temporarily for assembly for certain species of rubber (not all).

Enco sells sheet rubber, and nylon cap screws that work as thumbscrews. Setscrews and true thumbscrews in nylon from MSC or McMaster.

Do you really need a nylon screw? Can't just use steel with a rubber cushion?

A bit of polyethylene (from any old bottle) also works as a cushion. So do the gaskets in soda bottle caps.

Reply to
Richard J Kinch

Every time I've used a nylon tipped setscrew, they have slipped. Maybe on a D-shaped shaft they'd be OK but on round, forget it.

Lead shot is also good for this, if you know a reloader.

Reply to
Dave Hinz

Do a Google search for "nylon tip set screw"

Reply to
Usual suspect.

McMaster-Carr has Nylon, brass, and silver tipped setscrews. I think MSC does (nylon and brass, at least) as well, but their stupid search function means it's page through the book to look for it, as the search thing offers a selection for "point" but then only offers cup point as an option. Duhhh.

Reply to
Ecnerwal

Bill,

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If nothing else, it would reduce the stripping concern, as the hex socket is metal. I am thinking of rubber because it should be even more compliant than nylon (right???), and it would hopefully offer a higher coefficient of friction than nylon.

If the test fits make me at all nervous about damage to the instrument, I will add a "cage" to pull it vs. dragging it by the sides.

The analogous trick here would be to have rubber BBs or something. Space is tight in one of the two rings, but that could still work. Now the question is where I saw what I am thinking about - that's gonna drive me nuts ;) The damn things were greenish yellow, and maybe in a black carton??? No way I still have them, but a stop at a toy store is probably in order.

As a digression, and at the risk of sounding prematurely curmudgeonly, I am immediately forced to wonder whether our wussified culture would still dare sell something that no doubt was along the lines of a nerf BB

- violence and all that. I know every generation thinks the one behind them will put an end to our culture, but one has to wonder...

Thanks!

Bill

Reply to
Bill Schwab

Airsoft BBs.

You might also consider cannibalizing some pencil erases.

Reply to
Richard J Kinch

"Ecnerwal" wrote in message news: snipped-for-privacy@news.verizon.net...

What's the application that would require a silver tipped setscrew? It's soft in an annealed state and conductive. Much the same qualities as copper. The price seems to run over a buck each---pretty steep for a single setscrew. So why silver?

Just curious,

Bill

Reply to
BillM

yes

Reply to
Ignoramus13880

Werewolves.

Reply to
Richard J Kinch

Heat the screwdriver with a heat gun nice and hot until it sinks into the nylon on its own. Let cool and then remove set screw.

Wayne D.

Reply to
Wayne

What material is the $25K instrument made of, at the location where the setscrew will press?

One classic solution, especially if the material is iron or steel, is a brass ball dropped into the hole followed by an ordinary hex socket cap screw (~bolt). The brass balls can be bought for small dollars from MSC.

If the material is aluminum, I'd be tempted to make a plug from dead soft aluminum to take the place of the brass ball.

Joe Gwinn

Reply to
Joseph Gwinn

OK---sounds like the voice of experience. Just exactly how does one apply a silver tipped setscrew to the typical werewolf, and what is the desired effect?

Looks like they come in sizes from 2-56 to 3/8-16----What determines the proper size for any particular werewolf?

Bill

Reply to
BillM

Bill Schwab wrote in news:13l35pqps689v65 @corp.supernews.com:

Use the readily available brass, swivel tipped set screws.

Reply to
Anthony

Wayne,

Brilliant - thanks!!

Bill

Reply to
Bill Schwab

Joe,

Sadly, the material is plastic. We do not need to grab it very firmly, so I suspect that some "sticky" set screws will suffice. If there is any problem, I can add a "cage" to transfer thrust rather than relying on friction. We will know more soon.

Bill

Reply to
Bill Schwab

Plastic? I'd be tempted to use a clamp ring instead of a setscrew.

Joe Gwinn

Reply to
Joseph Gwinn

Joe,

No argument. Size and weight are important considerations, and the ring and setscrew approach allows the ring to do double duty. After a first try, the worthless shell of a device appears no worse for wear, and that was with metal set screws.

Bill

Reply to
Bill Schwab

I don't use them, just reporting what was available - according to McMaster's info, "conductive and softer than brass" seemed to be the relevant criteria - and I'd agree that you should be able to get those from annealed copper.

Reply to
Ecnerwal

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