Alternative 5-40 x 3/4"Slot Raised Countersink Stainless Steel Screws.

[Irish Jigger]

I'm fed up paying through the nose for Penn screws and decided to look for alternatives in stainless steel. I found these in 1/8" BSW (British Standard Whitworth) which are the same dia and pitch as 5-40 UNC. The only difference being the 90 degree head which is 0.20"dia, almost the same as the old Penn chromed brass screws and 0.015" larger in dia than the new Penn stainless steel screws.

They polish to a mirror finish and look good in my 112H reel.
At 3/4" they fit this reel without alteration to length.

A bonus for you UK (and Irish ) guys and at £0.12 each ($0.16) you can't go wrong.

http://www.a2stainless.co.uk/1-8-BSW-x-3-4-Slot-Raised-Countersunk-Screw-A2_A113EP.aspx

[alantani]

nice!  we need something like this!

[Robert Janssen]

Well, nice find... but unfortunately UNC and BSW are not the same thing, even if the diameter and pitch designation are.

UNC uses a 60* vee thread profile very similar to the meteric M profile; BSW uses a 55* rounded crest vee profile. They do not go together. (a bsw screw might seem to fit a unc hole, but probably not a unc screw in a bsw hole)

So it may fit in the same hole, but it just aint the same. Sort of like a size ten Nike is not the same as a size ten Bally. Wear them together  if you like, but...

.

[Irish Jigger]

I agree Robert, they are not the same thing but in this case the 3/4" long whit screw fits the 112H with no problem whatsoever.
"The proof of the pudding is in the eating"

[Robert Janssen]

...with no problem whatsoever...

Well okay, if it works for you.

I can only reiterate that engineering-wise the two thread forms are well defined and well known to be not compatible*, but i guess you know that.

Do as you like.

Doc.


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*Here, for future reference if someone stumbles across this thread in the future:





"Another area that causes confusion is the fact that some BSW/BSF nuts can be screwed on UNF/UNC bolts and vice-versa. Under NO circumstances should this be practised. Most of the coarse threads share the same threads per inch, which means BSW nuts can be screwed onto UNC bolts and vice-versa (the exception to this being ½ inch, of which the BSW size has 12 threads per inch whereas the UNC size has 13). Whitworth and UNC/UNF thread forms differ greatly, the primary difference being the thread angle. Consequently, if these fasteners are interchanged, considerable loss of holding force, fatigue resistance and strength will result."

From  http://www.timebus.co.uk/rlh/whitworth.htm  
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