INCH CHART BY 128ths

Thanks Winegrower, MrFun & Mr Whoopee for the Starrett Chart! Added it to my collection (of course). I have this 1 from South Bend that I reference often. Of you course you Metric lot won't have a use for it. I work with old American Iron & use whats best for me. I have a great respect for much of the European equipment & designs. If that's what was available here, I'd be daft not to use the system of measure they incorporate in their design. Truth is, I'd measure using tree branches IF that's all I had.......

DRILL TAP SIZES 02.jpg
 
extropic said:
Are you planning another chart of 256ths?
Click to expand...
Working with both Imperial and Metric for years, I am comfortable with both. More so with Imperial because of the (rough) framing work of carpentry. My models are a curious composite from England long ago. 7mm to 1 foot. . . Whatever they were smoking, I want some of it.

A while back I acquired a digital caliper, cheap per the posting here at HM. It is switchable from Metric, Inch thousandths, and Inch fractional. The fractional system is 1/256 of an inch. Fine cabinet work has a target of 1/64 inch. Machine work in the 19th century was often to a 64th, even into the early 20th century. One can, to this day, find lathes with fractional dials. Old, and rare, but they do turn up occasionally. And confusing the operator with 0.125 travel per revolution of feed. 1/64 is about 0.015. Hence 1/128 would be ~0.0075. Still sloppy to a machinist of today. Why in God's name would someone divide an inch by 256? The only answer I can imagine is some engineer with a computer background designing the digital display. 256 counts is common for 8 "bit" numbers. But that gets into binary counting, computer stuff. And machinists don't usually care about counting in binary. Followed through, it is 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, . . . until you're sick of it. Maybe a space alien influencing the engineer. . .

Oh, by the way, thanks for the chart. A convenient cross reference for fractional and letter/number drills.

EDIT:
From this session, interdict
Tyrant fowl of feathered wing
.
Damned machine, the GGGGGGGG is sticked.

.
 
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Bi11Hudson that was well written & enjoyable! But, no, I'll just stick with the 1/2 a 128th rule without a 256ths chart. LOL

Speaking of binary & consequently bits. Way back in the 4th grade I agreed to bags the leaves I had raked for a neighbor for an extra 8 bits. Man the dollar has really devalued since then, cause my pep rally schooling in bits had me convinced that 8 bits was a dollar. I sure was sore over that 15 cents I thought I should've got. But, live n learn. Like: no, the bathroom isn't on the right & Kenny did not sing of 400 children either.

Speaking of drill perspective, I have 1 more chart (though it's hard to read).

DRILL SIZES.jpg
 
Thank you BROCKWOOD for sharing the spreadsheet I really appreciate it.
 
Oh I came to this graphic by chance but it will be of great help to me. Thank you very much for your kindness, it's a great job!
 
extropic said:
@BROCKWOOD

Do you have any machinery with travels (dials) graduated in 128ths of an inch?

What is the practical use of a chart showing the decimal inch equivalent, to seven decimal places (one tenth of one millionth of an inch) of 128ths of an inch?

Are you planning another chart of 256ths?
Click to expand...

Isn't it common for the calipers with fractional vernier to have 128th's so you can measure any fraction from that (i.e. 1/64 = 2/128 , 1/8 = 16/128)

Stu
 
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