Digital Calipers

[gypsyjazzer]

[b]How accurate are digital caliper readings?[/b] When reading a string gauge I can get various readings--somtimes reading in the same place---sometimes along different parts of the string. (I have changed the battery in the caliper.)
How accurate is string making?
Is there a difference in quality of buying a cheap digital caliper to buying a more expensive one?

[lettsguitars]

The calipers will be affected by the ridges in the string winding. They are obviously very accurate or what would be the point? Why do you need to measure your strings anyway? All sounds a bit anal to me
You should zero the caliper before every reading.

[zero9]

Generally you get what you pay for with calipers. I opted for a non-digital one which reads to 0.02mm made by Starrett (good enough for anything I used it for), as there's less to go wrong. I avoided anything made in China (cheap) and also felt that the digital feature is a bit gimmicky.

Does your digital caliper also have graduations down the side? If so, use those to cross-check the digital reading.

[pete.young]

The battery won't make any difference to the accuracy. It'll either light up the display, or not.

Probably technique. Try taking the measurement with the jaws as close to parallel, rather than perpendicular, so you're measuring a length of the string.

[danthevan]

Or chuck the calipers and get a micrometer.
SPI calipers are awful, yet a £12 pair from woolworths (when they were still open!) have lasted in my workshop for about 5 years

[essexbasscat]

Same reading with a micrometer every time for me, also with my cast digital calipers. I always measure at a place where the string isn't played, either past the nut or before the bridge.

[gypsyjazzer]

Thank you for your replies. Most helpful.

[andysleigh]

ebay a micrometer.

older the better!
i have plenty of old tools when i do model engineering. and they are always far superior to anything you buy new

digital calliper is usually accurate to 0.001", providing you have zero'd it properly

Edited January 16, 2013 by andysleigh

[fonzoooroo]

The display on (cheap) digital callipers is VERY accurate. The build quality of the actual vernier - not so much! (You'll notice they don't always read back to zero after being zero-ed, opened and closed again.)

My Dad (a model engineer) thought he was on to a winner (after pretty much giving up with a cheap digital vernier) when he noticed the price of Clarke dial verniers at Machine Mart (as a quick reference tool - he has quality tools for precision work) He's experienced nothing but failure and disappointment from them though - 1's been back under warranty, and 1 seems to have skipped a tooth on the rack!

Afraid the old adage of "buy nice, or buy twice" is relevant here too! (The Moore and Wright and Mitutoyo stuff he's had for 40 years are faultless and still going strong!)

Edit: Oh, and 2nd-hand mics - make sure they're not bent! You'd be amazed how often they get used by idiots as adjustable spanners!

Edited January 16, 2013 by fonzoooroo