When a cylinder is used as a datum to clock (Example: Rack and pinion housing yoke bore)do you just use the center point of a circle or slice of the cylinder or use a line constructed from two separate circles of the cylinder?
Thanks Dgallop,
I had one further question. When you add both together or zero then you have doubled the rad so there is no need to multiply by two like when you calculate true position correct?
Thanks Again,
Gary
John, David, Even,
Thanks for all the help. Picture a large step cylinder. The datum is half way up the longest bore. The gage chucks up on that datum. Then the indicator drops down through a bushing and checks the TIR of a smaller bore. 1) First we chuck up on the master cylinder. 2) Then we...
Right now the instructions are find the smallest reading, zero the indicator and sweep then record the highest reading. That's TIR right? but the print says True position. Can I get TP using this TIR Gage? The part is sitting on the datums and there is a master.
Appreciate the response, It is a cleanliness specification. Normally we get cleanliness specifications with max weight, but this one is max size, We have to prove we are capable Ppk 1.67.
While certifying MMC pins I noticed some differences to what I've always used as a formula to calculate the size of an MMC pin. I learned take the minimum hole size allowed then just subtract the positional tolerance.
Like this: Diameter 4.5 +/-.25 TP 1.50m [-A-][-B-][-C-] would have a pin...
Thanks Dave,
Appreciate the function gage info. I do have MMC. For capability studies of machined hole positions I plan to set it up on the CMM RFS for the variable readings. Maybe if the [-B-] slot locater had 2 spheres with a spring in between forcing them apart, but I just don't think I'll...
Every hole or slot is toleranced to [-A-],[-B-]. [-B-] is a slot. [-A-] is a plane perp to the slot. How do I align the part for layout purposes? The part is 8 times longer then the [-B-] slot.
OK if 7X INDIVIDUALLY will cover it, that's what I'll do. I have a Lowell W Foster GEO-METRICS III that references ANSI/ASME y14.5M-1994. How much catching up do I need to do?
That looks more like a composite tolerance for all 7 bosses to be in a pattern to me.
It got me thinking though why not name all bosses datum
[-J-]. Has anyone ever seen this used [-J1-], [-J2-],
[-J3-]... [-J7-]. I don't think the bosses could be mistaken for target datums. So then Boss 1...
Let me explain again. I have a print change which added seven bosses. We will take metal out of the die and cast the bosses in. Then we machine one hole in each boss. Those holes need to be in the center of the bosses or the screw might break through as it self taps. The position to A/B/C is...
I thought so too. But I thought there would be a better way then naming every boss a datum that would be seven new datums. I think we're to H now so I have enough letters to make them all datums. If I have to I will.
Appreciate all the help.
The feature control frame for concentric to should be ?
Self tap hole diameter +/- tol
Small circle in big circle (for concentric)1.0 to its boss?
Thanks
I think I see what you're saying. The word INDIVIDUALLY means to make each boss an unnamed datum and check it like the one that is described.
Am I understanding ?
Thanks Again
Joe
I have a product that is getting seven new holes added. It's more important that the holes be drilled in the center of their bosses (so the self tappers wont bust out the side) then the holes be positioned to [-A-], [-B-], [-C-].
Should I call each boss a datum tolerenced to A/B/C and then...
