How do I check this?

[GregS]

I just got a part that is a 2-1/2" dia. tube. Thru the side walls there are 6 equally spaced 1/8 holes. So every 60 degrees on the side wall of this tube there is a 1/8 hole I need to check.

How do you set this up? Any help is appreciated

[Wes Cisco]

How long is this tube? How thick are the walls of the tube? (o.d. minus i.d. divided by 2 ). Most likely I would stand the tube up on table. I "secure" is with clay or maybe laying a V block on it's side and using double sided tape to "hold" the tube to the V block. If the tube is heavy enough to not move, then you don't have to "secure " it. I would try to align one set of holes with the X or the Y axis of the machine. (Placing a gage pin the hole might help with this.) Then I would decide which tip angle I would need or each hole location, calibrate those tip angles , then measure the part. Does that help?

[GregS]

Its a thin wall tube and it only stands 1 inch high.
The setup is what is throwing me for a loop. I was thinking the same thing as far as aligning 2 holes to get my rotation set up. Then I guess I would have to make the moves by hand with the right angle tip for each hole.
I thought using polar coordinates would help me here but I've never used them. Wont using polar coordinates allow me to rotate around the 2-1/2 tube and check to the surface of the tube?

[Wes Cisco]

Yes, polar might well be the easier way to go, but if you don't understand how they work you can do it with cartesian just as well, you only need to understand vectors and be able to calculate the Sin and Cos of 30 or 60 degrees. If it is thin wall and only an inch or so high I would set in on a block and secure with double sided tape or clay. I would take hits on the block for my plane to level to. I would take hits on the od or in the id for my origin point. I would take hits in the hole I had aligned to the axis of the machine and then construct a 2D line from that hole to the center of the od or id for my rotation line. That gives what you need for a quick 3-2-1 alignment. If there is a datum structure on the print, I would set up to it. HTH

[Wes Cisco]

Greg, if you know how to use copy paste w/pattern, you can just measure the 1st hole after you have done the alignment and then copy/paste with pattern. In your pattern set up just enter 60 degrees for the angle and 5 for the number of repeats. You have to have an indexing head on your machine. (PHMQ) and that you will have to put in the tip angle changes between holes after you paste with pattern BEFORE you execute.

[Underspec]

What are you trying to dimension? Are you trying to check the hole locations?

[John Kingston]

Wws

[#2#]

I've got a nifty little 3 jaw chuck that I use for standing up round parts. I use it all the time. It is mounted on a base that can be clamped to the table and when a part is secured in the vise the part points ±Z.

[GregS]

Greg, if you know how to use copy paste w/pattern, you can just measure the 1st hole after you have done the alignment and then copy/paste with pattern. In your pattern set up just enter 60 degrees for the angle and 5 for the number of repeats. You have to have an indexing head on your machine. (PHMQ) and that you will have to put in the tip angle changes between holes after you paste with pattern BEFORE you execute.

Thats what I wasnt thinking of. Paste with pattern gawd so easy. Gonna try this after lunch.

[JamesMannes]

Don't forget you need to be in the correct workplane for paste w/pattern to work properly.

[GregS]

FYI Paste with pattern worked like a champ. I setup 1 hole facing me @ 90~180 rotation. Setup to the center of the 2-1/2 hole and made a line to the hole facing me. Used auto circle to check the first hole with a clearance of 1 inch. Pasted with Pattern 5 times @ 60 deg. each. Made probe tips 90~-120, 90~-60, 90~0, 90~60,90~120 and inserted each one before each hole and it worked like a champ. Thanks a bunch guys.

[kbotta]

Hey Wes...

What do you think would be the correct way to inspect an o-ring groove (ID) that is about half way located on a 4" long tube (1.5" dia)..the groove is about .5 MM in width.
I don't think they make a probe to inspect this, yet there is some detailed geometry on this drawing (position, roundness, and my fav - concentricity!)

Any idea for the correct instrument? Air gage?? How to use with an alignment??

Kev

[Lee Johnson]

Kev
what sort of accuracy are you looking for? They make grove mics that will do the dia . Intertest makes one. this was sold by the Dyer co in Lancaster Pa 800.631.333. , old number not sure if they still exsist. Can you have a special disk probe made up. the real issue becomes an accuracy game. I have made up similar probes to use on a B&S micrehite the old ones with the dial work best for this. Make the disk with a step so that it has some strength.

[#2#]

Measure a replica of the part?

[kbotta]

My concern comes, with the ID of another area of the cylinder as being the primary datum feature, and it is referenced at RFS.
the disk is A possability. The position req is 0.15mm that is what worries me. The owner wants to know if we can make these parts, based on 3 samples i have been given (Rrrrrrriiight!!!) and I am looking to be able tp provide an inkling of an idea as to if they are in "spec" or not...
Kev