I made that mistake and got the set in the red case. They were REALLY shitty! I ended up with the shars set off fleabay in the plastic case. Gotta say, they seem much smoother than the scamazon junk.
Great video. New to this an didnt know about rocking the bore gauge out of the bore. Also i was about to order a Chinese set tonight but will not now seeing you got a sterrett kit for that low of a price so il be patient an shop around
That's a good question and one that's pretty hard to answer. You need to have it tight enough to hold the pistons in place but still allow them to move. You don't want to use too much force because you can break that tiny little screw. If you practice with a known accurate bore, like a bearing race, you'll develop the feel you need pretty quickly.
Hi Mike. The radius on the ends of the pistons is tighter than the smallest measurement for that range of telescoping gage. The smaller sizes also have smaller diameter pistons. This ensures that only one point on each piston is contacting the bore.
Am I to understand that when the gage is locked, the pistons can still be squeezed together? My chinese version when locked is locked. Thanks for posting.
This is new to me, but why in Heaven's name wouldn't you lay the micrometer frame flat on a wood block so the thimble can be turned, then only touch thimble intermittently as you close down. You could even lay gauge on two parallel little wood wedges that miss the head center, and rock to get exact height. This would reduce the variables and let you focus on the feel, while also avoiding hand-heat micrometer distortion.
No, because how would you know the gauge was at it's smallest size (ie. perpendicular to the bore), when you tightened the screw? The idea is to tighten the screw just enough to prevent the gauge from springing open again, but loose enough to allow it to close in, when manoeuvred against the walls of the bore.
Great video and I'll second his comment to avoid the sets that are made ....... over there by ........ ummmm... the nice intentioned people in the Far East. ABSOLUTE JUNK !!!
One of the most important things for a telescoping gage is the fit of the pistons in the head and I think that is where the import sets fall short. The pistons are so loose that they flex out of the way when you sweep the gage out even when that locking screw is super tight. That opens you up to a lot of wonderful possibilities for errors.
And the cylinder finish too. I can actually feel the course scraping of piston against cylinder. Yup ... ordered a set through Ebay and wrote them off as complete junk. Fortunately a set of mitutoyo's now inhabit a place in my tool box with a couple bonus bell gauges for the really tiny stuff.
The most frustrating thing for me is the ranges. On my Starrett set, if it says it goes up to 3/4" it probably goes up to at least .800". On the import ones the 3/4" one barely touches the bore at .750" which is a disconcerting feeling.
We will just concur that having a set of far east telescoping gauges is worse than having none at all. One can always use an inside caliper at lesser cost and better accuracy.
I got a set from Amazon, for under £15, and they're decent, nicely knurled and chromed.
They work fine.
I love videos like these, cuz they’re useful even years after their initial release
Thanks, Danger Dan! Stay safe!
Terrific video thanks, with good practical advice.
Damn probably should have watched this before I ordered my Chinesium telescoping bore gages off of Amazon. :) thanks very instructive
I made that mistake and got the set in the red case. They were REALLY shitty! I ended up with the shars set off fleabay in the plastic case. Gotta say, they seem much smoother than the scamazon junk.
Good practical video for beginners
Great video. New to this an didnt know about rocking the bore gauge out of the bore. Also i was about to order a Chinese set tonight but will not now seeing you got a sterrett kit for that low of a price so il be patient an shop around
Great instruction.
One thing I missed is - how tight should we wind the pinching screw on the handle bar?
That's a good question and one that's pretty hard to answer. You need to have it tight enough to hold the pistons in place but still allow them to move. You don't want to use too much force because you can break that tiny little screw. If you practice with a known accurate bore, like a bearing race, you'll develop the feel you need pretty quickly.
great explanation, thank you.
You're welcome. Thanks for watching!
Best video sir
excellent!!
larry
Stuart: Why wouldn't the diameter of the gage influence the measurement of very small diameters?
Hi Mike. The radius on the ends of the pistons is tighter than the smallest measurement for that range of telescoping gage. The smaller sizes also have smaller diameter pistons. This ensures that only one point on each piston is contacting the bore.
Very nice, but I wish you use a vice or holder for the mic. Two hands for steady
Thanks
Nice
Never saw a telescoping gage yanked out of bore like that
Am I to understand that when the gage is locked, the pistons can still be squeezed together? My chinese version when locked is locked. Thanks for posting.
The pistons are supposed to be squeezed in, yes.
you are locking them too tight or they are junk
This is new to me, but why in Heaven's name wouldn't you lay the micrometer frame flat on a wood block so the thimble can be turned, then only touch thimble intermittently as you close down. You could even lay gauge on two parallel little wood wedges that miss the head center, and rock to get exact height. This would reduce the variables and let you focus on the feel, while also avoiding hand-heat micrometer distortion.
This is how I was taught to do it years ago. Makes it much easier
or use digital calipers
you are really supposed to use a mic stand, so all your holding is the telescoping gauge
@@jeremykemp3782 when you are striving for accuracy who would use the guessometers
I thought the purpose of tightening the screw is to stop the movement after the measurement.
No, because how would you know the gauge was at it's smallest size (ie. perpendicular to the bore), when you tightened the screw?
The idea is to tighten the screw just enough to prevent the gauge from springing open again, but loose enough to allow it to close in, when manoeuvred against the walls of the bore.
Great explanation. I figured that's how these were supposed to work, but I'm no machinist!@@BedsitBob
Or use digital calipers to measure the telescoping gauge
calipers aren't as accurate as micrometers. Usually calipers are good to 0.01", while micrometers can go 100x finer accuracy.
Great video and I'll second his comment to avoid the sets that are made ....... over there by ........ ummmm... the nice intentioned people in the Far East. ABSOLUTE JUNK !!!
One of the most important things for a telescoping gage is the fit of the pistons in the head and I think that is where the import sets fall short. The pistons are so loose that they flex out of the way when you sweep the gage out even when that locking screw is super tight. That opens you up to a lot of wonderful possibilities for errors.
And the cylinder finish too. I can actually feel the course scraping of piston against cylinder. Yup ... ordered a set through Ebay and wrote them off as complete junk. Fortunately a set of mitutoyo's now inhabit a place in my tool box with a couple bonus bell gauges for the really tiny stuff.
The most frustrating thing for me is the ranges. On my Starrett set, if it says it goes up to 3/4" it probably goes up to at least .800". On the import ones the 3/4" one barely touches the bore at .750" which is a disconcerting feeling.
We will just concur that having a set of far east telescoping gauges is worse than having none at all. One can always use an inside caliper at lesser cost and better accuracy.
That’s shit was crooked asf
POINT SIX SIX NINE THREE? How dare you. IT is said as follows: six hundred and sixty nine thousandths and three tenths.