Sp r108

[boat sju]

The retainer band screw heads on my R108 are stripped. Before I drill them out, are they a standard screw that I can get at a hardware store or will I need to get them on-line?

 

[herman]

The heads stripped or the threads? Are they hex head cap screws or straight slot, I have seen both. The screws themselves are stainless but otherwise nothing special.

 

[boat sju]

herman,

Just the heads are stripped. Actually, they look like they were phillips. My octo's screws are in decent shape and they're phillips. Probably not originals.

thanks

 

[redacted]

It is a standard thread but there are a few styles of head (allen, phillips, and slotted) and at least two thread sizes. It is not something you can expect to find in just any HW store. Found some old notes: The thread size on most is 4-40. They are not hard to find in a place like Home Depot, usually in brass rather than SS, but the slotted heads are too large. Nothing a Dremel tool can't fix. For a while, annual service kits had spare socket head screws but the thread size was finer than 4-40. You might be able to find some of those and re-tap the threads in the threaded clamp. If you can't find any, send me a PM and I'll see what I can find. I know I have some brass 4-40s around somewhere.

 

[Luis H]

Some of the later ones used hex key (Allen wrench) cap screws, but the earlier ones used Fillister head screw. Fillister heads machine screws are available with slotted heads or for Phillips screw drivers.

I personally prefer the slotted head for a standard screw driver.

The early screws were 4-40, but as mentioned, they later used finer threads. The 4-48 screws are standard US screws, but I have the impression that they might have used a metric thread in some of them, but I don't know (some of these regulators were built in Italy).

The 4-40 and 4-48 Fillister head screws are easily found at McMaster-Carr. They are available in Stainless Steel or brass (I buy the Stainless Steel).

McMaster-Carr

McMaster-Carr

You may need to buy a box of screws, but they are less that $5 for 100 of the 4-40 and about $9 for 40 of the 4-48 size. A life time supply, for about the same that will cost you at a local hardware store (if you include gas and maybe your time).

Good luck


Note:
The ANSI basic major diameter of a #4 screw is 0.112 inches. The thread pitch is 40 threads per inch for the coarse thread (#4-40) and 48 threads per inch for the fine thread (#4-48).

 

[boat sju]

Thanks for all the good information guys. Turns out I was able to get the screws out without a drill so that will make it a lot easier. They were fillister/phillips. We have a specialty hardware in town and it's amazing what you can find in there. Between them and HD I should be good.

 

[Couv]

Some of the later ones used hex key (Allen wrench) cap screws, but the earlier ones used Fillister head screw. Fillister heads machine screws are available with slotted heads or for Phillips screw drivers.

I personally prefer the slotted head for a standard screw driver.

The early screws were 4-40, but as mentioned, they later used finer threads. The 4-48 screws are standard US screws, but I have the impression that they might have used a metric thread in some of them, but I don't know (some of these regulators were built in Italy).

The 4-40 and 4-48 Fillister head screws are easily found at McMaster-Carr. They are available in Stainless Steel or brass (I buy the Stainless Steel).

McMaster-Carr

McMaster-Carr

You may need to buy a box of screws, but they are less that $5 for 100 of the 4-40 and about $9 for 40 of the 4-48 size. A life time supply, for about the same that will cost you at a local hardware store (if you include gas and maybe your time).

Good luck


Note:
The ANSI basic major diameter of a #4 screw is 0.112 inches. The thread pitch is 40 threads per inch for the coarse thread (#4-40) and 48 threads per inch for the fine thread (#4-48).

I bought a box of 4-40 ss allen head from a fastener store, but I didn't have a reg with me. The head turned out to be a little too large and the length a bit too long....so what length is best?

Thanks,

Couv

 

[knowone]

0.43-0.45 with some screw ends concave and others round, not just deburred

But depending on where the screws were made and batch

And depending on the condition of the dude that cleaned up
and polished the clamps

and considering that most folks didn't have the correct size phillips screwdriver
that fits in the head without countersinking the clamp
and then rounds head and no can screw face to face.

The original originals with supple rubber as you have, have the clamps screwed down face to face with No thread protusion and a rounded end.

Others have thread protrusion

Others have thread protrusion also with the screw end poking past the extremity of the clamp.

Then good thing is I found a long lost Conshelf IV I didn't know I had
in bits in my SP dept. The box bottom has been sitting on a bookshelf
for infinity.

Good for what, I'll figure out.

 

[boat sju]

couv,

What length did you try, 1/2" ? I was able to find (pretty easily) stainless 4-40's with a flat phillips head. I'm trying to use awap's suggested dremmel tool approach to get the screw heads recessed into the retainer bands. Unfortunately, due to my general lack of patience and OCD that's not working out real well. I'm going to Home Depot today to look for some fillister heads to see if they work better. I'll let you know what I find.

 

[boat sju]

clamps screwed down face to face with No thread protusion and a rounded end.

This is another issue - my clamps won't screw down face to face. I wonder if my original clamps got switched out during servicing somewhere over the years. I bought my primary new in 1982. The octo was a used rental from the LDS, so older than 1982. Primary has 4-40's and the octo 4-48's.