DTI vs DI
Re: DTI vs DI
Since I was using mine today I figured I would add this.
To eliminate some confusion when using a DTI that doesn't have constant clockwise rotation in a mill spindle:
Just work with the point on the back side of a pin. And work with the point on the front side of a bore. Doing this will result in the needle indicating in a normal clockwise direction.
To eliminate some confusion when using a DTI that doesn't have constant clockwise rotation in a mill spindle:
Just work with the point on the back side of a pin. And work with the point on the front side of a bore. Doing this will result in the needle indicating in a normal clockwise direction.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
Re: DTI vs DI
Good tip Glenn. You must have some experience with this.
--earlgo
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
Re: DTI vs DI
Thanks Earl!
I was gifted a box of things last week from a friend, and in it is a small DTI with a 1" face made by Lufkin that is graduated in .0001" and has a total travel of .032"
It is .004" per revolution with a revolution counter that counts eight revolutions. I've not seen anything like it before, as most .0001" DTI's have fairly limited travel!
He also gave me a very nice indicator stand that he made that is for use on a surface plate. I'm restoring it now.
I was gifted a box of things last week from a friend, and in it is a small DTI with a 1" face made by Lufkin that is graduated in .0001" and has a total travel of .032"
It is .004" per revolution with a revolution counter that counts eight revolutions. I've not seen anything like it before, as most .0001" DTI's have fairly limited travel!
He also gave me a very nice indicator stand that he made that is for use on a surface plate. I'm restoring it now.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
Re: DTI vs DI
Glenn, not sure I understand the confusion over needle movement, but then I generally am using a BesTest. I guess the needle always swings clockwise (auto reversing?). I have several types of DTI's, many with manual reversing levers and my favorite is a Teclock with a 1" 90° face.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
Re: DTI vs DI
For some it can be a bit counter intuitive at first for the needle sweeping clockwise to be indicating the lowest point. Especially if you are used to using a BesTest DTI.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
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Re: DTI vs DI
A comment. Starrett Last Word DTIs have a switch on the side which changes the direction of needle rotation. I have a Federal .0001" vertical that I inherited and it also has a switch on it. Some modern DTIs will rotate the needle only one way regardless of the direction of the contact arm movement. Others will automatically change direction of needle movement. You pays your money and gets your choice.
Cary
Cary
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Re: DTI vs DI
Steve,
So just thinking about keeping track of .99619469809 convinces me to stay with my DI!
Glenn
So just thinking about keeping track of .99619469809 convinces me to stay with my DI!
Glenn
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
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Re: DTI vs DI
It doesn't change the direction of needle movement with respect to lever movement. In one position clockwise rotation of the lever results in clockwise movement of the needle away from it's position against the stop. In the other position counterclockwise rotation of the lever results in counterclockwise movement of the needle away from it's position against the stop.Cary Stewart wrote: ↑Tue Apr 24, 2018 5:32 pm A comment. Starrett Last Word DTIs have a switch on the side which changes the direction of needle rotation. I have a Federal .0001" vertical that I inherited and it also has a switch on it. Some modern DTIs will rotate the needle only one way regardless of the direction of the contact arm movement. Others will automatically change direction of needle movement. You pays your money and gets your choice.
Cary
Thus clockwise movement of the needle always means clockwise movement of the lever. All that the switch changes is which way the spring drives it as it tries to get back to the stop. Reading ODs or IDs, clockwise rotation means motion away from center.
Re: DTI vs DI
I never bothered to think about correlating needle rotation with the indicator arm movement. Often I'll just touch the indicator to tell which way the high spot is - or it just stops moving and reverses direction at the high/low spot.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...