Rockler caster threads -- 50 years obsolete!

--Hey Alan how ya doin? When're you going to get SCHEMES active? :-)

Somebody probably still has some 50 year old Brit machinery running in China.

Jeff

Probably cranking em out on BSA screw machines

Gunner

"In my humble opinion, the petty carping levied against Bush by the Democrats proves again, it is better to have your eye plucked out by an eagle than to be nibbled to death by ducks." - Norman Liebmann

Boy, you sure know how to embarass a guy! :-) It's on the list of things I *really* should get around to.

Ever since you bailed out of SoCal, I really miss the meetings at your place.

Right now the #1 project is a kitchen remodel for my wife. My metalworking experience actually gained me some big points on this project. Instead of simply buying a stainless steel backsplash from the stove vendor, I took my wife to Industrial Metals and showed her the embossed SS sheets. She spotted one pattern that went perfectly with the floor tiles. She thinks I'm wonderful for knowing where to go, and the best part is saving several hundred dollars!

Now we're just waiting for Viking to formally announce the

30" wide separate refrigerator & freezer she wants. Until then, we can't start construction.

We're going to do the demolition ourselves so that she can have the joy of taking a Sawzall to the cabinets and counters she hates so much. I found the perfect company to rent the big dumpster from: a company in Sun Valley called Looney Bins.

I wish the old oven were not so small, or I would move it into the shop for powder coating. I'll just have to keep my eyes open for other neighborhood remodeling projects and see if I can score an oven that way.

Alan

1/2-12 60 degree pitch is a UNS thread. It is listed before 1/2-13 in the preferred screw thread tables in Machinery's Handbook, so the Chinaman who picked the thread for your casters must have thought it was the preferred US thread for half inch screws (he must have missed the footnote on page 1547). Lots of China made equipment uses this thread.

Gary

Why do you say BSW is obsolete? If it were obsolete it wouldn't be used on most of my machine tools!

Mark Rand RTFM

1/2"-12 threads are quite common on Chinese machinery today, and in some Japanese as well (what isn't metric). Some may be Whitworth, but others are 60 degree, just an odd (for today) pitch. It's likely some 'legacy' thing from old British machinery in China years ago.

I found so many examples of it, I bought a tap.

Dan Mitchell ============

OK, perhaps I should have said that it is "officially" considered obsolete for new applications. What year were your tools built?

I don't know exactly when Whitworth stopped being used for (most) new applications, but I suspect it just kind of decreased over time. I remember from working on British motorcycles in the early 1960s that it was considered obsolete by most mechanics. My 1962 Triumph TR4 may have a Whitworth thread somewhere, but I haven't found it yet. Everything seems to be SAE.

Alan

Sorry, but you won't find any SAE fasteners on your TR4. They will be either UNC or UNF.. The nuts & bolts will be appropriately marked.

Tom

I thought that SAE implied UNC/UNF, but I guess I'm wrong. What is the difference?

Alan

SAE threads had a flat at the root and the crest, whereas UNF & UNC the root and the crest of the bolt are rounded as is the root of the nut, the crest being flat..

Tom

Thanks for the clarification. I'm going to print this out and post it in my shop until I've got it memorized. :-)

Alan

Many years ago, I used to work for a well known manufacturer of commercial woodworking machines. We had a horrendously expensive malleable iron casting... a chip breaker. It had a 1/2-12 tapped hole for adjustment and we had the only 1/2-12 bolts in the world ( I guess).

It was "common knowledge" in the plant that this was done to sell more chip breakers... since a 1/2-13 would start, but would ruin the existing thread.

Years ago, The National Cash Register Company (NCR) was notorious for using proprietary threaded fasteners in their products. They made nearly all of their own threaded fasteners, and it virtually guaranteed that any replacements would have to be supplied by their own repair people.

John

When I was going to school in tool & die shop our instructor told us that all Brown & Sharp machine tools used 1/2-12 threads and his opinion was that it was their scheme to sell more machine parts. Engineman1

;-) must have been cut on a metric machine trying to do Imperial ! A 1/2-12!

Martin