most accurate caliper?

[Eddiesanders250]

What kind of caliper is the most accurate? The dial kind or electronic... they both say they are accurate to a thousandth of an inch... heres a link to some calipers
http://www.amazon.com/gp/product/B0002JFMIO/ref=olp_product_details/105-4238094-0968448?ie=UTF8&seller=

[punker69q]

Dials are just as accurate as electronic calipers. Both should always be checked against some gauge blocks for important measures.

[rebelbanshee]

as long as they are good quality they are both just as accurate. If you are getting them to measure pistons or bores neither will be accurate enough though.

[Eddiesanders250]

Originally posted by rebelbanshee
as long as they are good quality they are both just as accurate. If you are getting them to measure pistons or bores neither will be accurate enough though.
so then what do you need?

[norcalduner]

Get an electronic one as it is easier to read. THAT is the only difference.

[punker69q]

For important measure, get a micrometer and learn to read it's vernier scale. I suggest one with a ratchet stop and both mitutoyo and starrett makes excellent micrometer. This set (http://cgi.ebay.com/MICROMETERS-five-micrometers-0-to-5-with-accessories_W0QQitemZ180063763294QQihZ008QQcategor yZ41937QQrdZ1QQcmdZViewItem) would be a good buy and it even comes with gauges to calibrate them.

[C-LEIGH RACING]

The measuring gauge would be the deal on any kind or brand I think, just keeping it dialed in.
The micrometer is the best, but even with those the threads wear & can got off a little.
Not to worrie though about the thread wear, probably take a 100 years to show up.
Some unexpearanced person droping the measuring tool, now that could make a big difference on the performance.
Neil

[machwon]

Use the micrometer for the pistons, for the bore use a dial bore guage. Otherwise, a set of inside mics are not a bad idea to get either.

[wilkin250r]

It depends on what you are actually trying to measure.

If you just want to know what bore you are on, then an ordinary set of calipers will work just fine. You would easily be able to tell the difference between 66.0mm and 66.5mm with either a dial or digital calipers.

But if you are looking to measure the piston/cylinder clearance, this will often require accuracy beyond thousandths of an inch (0.001), into the realm of ten-thousandths of an inch(0.0001). Most any caliper is only accurate to a thousandths, you'll need a micrometer to get more accurate than that.

[atvmxr]

not to contridict you, but the gauges I see on ebay motors read in increments of .0005", i think.


Are those not acurate enough to determine bore wear?

[punker69q]

when I was talking about gauges, I was talking about small blocks that are certfied to be, for example, at 3.00000 ±0.00001, accurate enough that you can calbrate measuring instruments with them.

If you got a few of them that cover the measuring range of an instrument, you can calculate the offset and the gain error of your instrument. This method is valid for calipers and micrometers and can compensate for tool wear. I will try to explain it more later and make an example with numbers...

[ridemyrice]

Six inch calipers are only accurate to .001" over the entire range, no matter if it's a digital and reads to 4 places or not. Electronic calipers are great if you aren't used to reading dial calipers, or have to switch from english to metric. One isn't more accurate than the other.

If you're only using it every now and then, by all means buy a cheapie set. If you drop it, no huge loss @ $10 or so for a 6 inch cheapie. If you use it a lot or like the best then go for a name like Starett, Brown & Sharpe, Mitutoyo, Fowler...there are a lot of good to very good names. I own both a set of Starett dials and Mitutoyo electronics...both are great.

For quick measurements, can't beat calipers. For exacting tolerances on outside diameters or short lengths, a tenths-reading micrometer is a good way to go. For bores, a dial bore gage is the ticket, or an inside micrometer double checked by an O.D. Micrometer. Hey, and if you have access to a CMM machine...nevermind everything I just said...

Been doing this for a while; hope I helped