Dial gauge preload

[hoodeng]

The Mitutoyo bore gauge most commonly used [if Mitutoyo is used] in engine reco is the 511 series gauges,[imperial in my case] these usually have a 2923F or 2923F-10 dial gauge mounted on the head, these gauges give a reading preload of 1.5N or less according to the Mitutoyo master catalog.This preload on measuring pins is a standard, there is a variance in preloads between some gauges but the most common by far is the one stated.

If you want to cut the dial rotation down to a minimum turn up some spacers specific to the bore you are doing, the pins come in either .100" or .200" increasing lengths so if you cut a spacer .075" thick and add it to a say a 4.000" gauge and pin set you get 4.075" be aware that if you set for 4.000" the gauge will rotate for just over one rotation. I have made a number of different washers for my pins to keep rotation down to a couple of thousandths,and also to keep the pointer central at the top, but the load of the pin does not rise appreciably with more rotations, this will help alleviate drag marks on soft surfaces, but be aware that the arc the device is rotated through also helps centralize the instrument.Racear's method is also very practical.

This preload standard is similar on micrometers but is in the 5 to 10N range,, my cringe is watching someone wind a micrometer into a job with the thimble and not use the ratchet, then back the mike off the job with the ratchet, its almost like they are trying to make the instrument read what they need to see,,,but that's just me.

Cheers.

[Wolf_Tm250]

ahhh, now there is something that has not been considered in the past threads. Ball (point) size.
second thought...maybe not.
For the same pressure there is only one solitary point on a ball regardless of diameter that contacts the bearing shell.
A smaller ball than say the Sunnen under higher pressure should push in deeper.
Yes, no, maybe. Get my drift?

Yes, sure, you're right as soon as both material are pretty solid...but I'd say a larger ball would sink less in a softer material...



Hoodeng

The Mitutoyo bore gauge most commonly used [if Mitutoyo is used] in engine reco is the 511 series gauges,[imperial in my case] these usually have a 2923F or 2923F-10 dial gauge mounted on the head, these gauges give a reading preload of 1.5N or less according to the Mitutoyo master catalog.This preload on measuring pins is a standard, there is a variance in preloads between some gauges but the most common by far is the one stated.

If you want to cut the dial rotation down to a minimum turn up some spacers specific to the bore you are doing, the pins come in either .100" or .200" increasing lengths so if you cut a spacer .075" thick and add it to a say a 4.000" gauge and pin set you get 4.075" be aware that if you set for 4.000" the gauge will rotate for just over one rotation. I have made a number of different washers for my pins to keep rotation down to a couple of thousandths,and also to keep the pointer central at the top, but the load of the pin does not rise appreciably with more rotations, this will help alleviate drag marks on soft surfaces, but be aware that the arc the device is rotated through also helps centralize the instrument.Racear's method is also very practical.

This preload standard is similar on micrometers but is in the 5 to 10N range,, my cringe is watching someone wind a micrometer into a job with the thimble and not use the ratchet, then back the mike off the job with the ratchet, its almost like they are trying to make the instrument read what they need to see,,,but that's just me.

Mine are the 511 series with digital gauge (410 iirc).
And yes, when I talked about "preload" I was actually talking about putting a next size smaller pin spacer (that is to say minus 0.5 mm ), as I found that it is going to drag less and leave no marks on bearing, even if reading few thousandths less...
so it seems that "cut dial rotation" (while mine is digital) helps reducing the load that the internal spring would push against the bearing, as it seems to me the load is not coming from the dial gauge but from the bore gauge itself.

Anyway I tested many times the accuracy and repeatability of my setup, and for any hundredth less on my digital micrometer I read the same difference on the dial gauge

[Dan Timberlake]

0.005 mm / .0002" error in bearing clearances ?

I think I'd spend my time torque cycling any new fasteners or using ARP Ultra-lube per Mondello.
http://www.mondello.com/page24.html

[hoodeng]

Hi Wolf, the preload on your digital is 2.0N or less, there is also no extra return mechanism in the extension bar, it sort of goes, base measuring pin receptacle, heel block, internal push pin then the gauge.
And yes cutting the sweep down cuts the marking down,,, but,, i have never seen a gauge mark compromise a bearing yet, we would rather just not see it.

I have an old Mercer 226 that i just pulled from the case [hasn't been opened for years] to admire the quality,, i don't use this one as it is in half thousandths, the Mitutoyo's are good to half ten thousandths and repeatable. When setting up roller pinion bearings this is invaluable as the minimum clearance is two ten thousandths.

The trouble with measurement is it is application specific, some things need to be within a thousandth to be effective and reliable, some things in half thousandths others in ten thousandths, i have seen a guy worry a piston to death looking for some mystical bulge measurement point [the manufacturer had already given the gauge point] when the thing was going in with a +-.0005" and give perfectly good service, he made it look like a real dark science, wanker.


Cheers.

[jed]

Dan I would also like to use the ARP ultra lube but don't know how to adjust the torque ratings on the fasteners.
ARP used to have instructions in there fastener packaging that specified when using 30W oil torque to X.
When using ARP lube torque to X which was always less.
How do you arrive at the torque setting on your fasteners using ARP lube.

[Wolf_Tm250]

Hi Wolf, the preload on your digital is 2.0N or less, there is also no extra return mechanism in the extension bar, it sort of goes, base measuring pin receptacle, heel block, internal push pin then the gauge.
And yes cutting the sweep down cuts the marking down,,, but,, i have never seen a gauge mark compromise a bearing yet, we would rather just not see it.

I have an old Mercer 226 that i just pulled from the case [hasn't been opened for years] to admire the quality,, i don't use this one as it is in half thousandths, the Mitutoyo's are good to half ten thousandths and repeatable. When setting up roller pinion bearings this is invaluable as the minimum clearance is two ten thousandths.

The trouble with measurement is it is application specific, some things need to be within a thousandth to be effective and reliable, some things in half thousandths others in ten thousandths, i have seen a guy worry a piston to death looking for some mystical bulge measurement point [the manufacturer had already given the gauge point] when the thing was going in with a +-.0005" and give perfectly good service, he made it look like a real dark science, wanker.


Cheers.

Hi,
yes, the gauge preload is very low, but in my experience there is much more load in the extension bar.
Anyway, I'm not afraid of the marks on the bearings, but of the measurement precision and accuracy, as there are 0.005 mm difference with the two "settings" and maybe the "more loaded" one reads 0.005 mm more because that's the amount the pin can sink in the softer material