Tapped Hole Location Gages

[[Da...]]

I have read many times that using a tapped hole location gage is better than trying to scan the thread with the probe. Management approved us to get one or two per month and want me to determine which sizes are the highest need. But before I do all that, I am curious:

Do you use them at your facility?

Do you find them helpful?

How many of each do you need? I see there are sets with 2 of each but what if a part has more than 2 of that size? Do I need a gage for each hole or can I do a programmable stop and prompt to move the gage the next hole? (seems risky in case the part gets moved but buying a bunch of each size gage would be very expensive)

 

[[Ri...]]

Unless you are using flex-plugs, just know that you measuring a projection of the thread to the surface that you are mounted on. 

We typically do not use thread plugs unless there are specific requirements. One thing that would drive us to use thread plugs would be if there is the need to measure the thread severely projected above the surface, and the measured cylinder isn't long to begin with. 

[[DW...]]

Please sign in to view this quote.

Please sign in to view this username.

 Unless your facility only makes/checks a certain size threaded hole, having multiples of location plugs for most common sizes would be insanely expensive. 

[[Da...]]

Please sign in to view this quote.

We make MANY sized threads, so that is why I am curious how other people do it because it would end up being ALOT if we needed one for each hole on each part. 

[[Ma...]]

I would say - if you are working with tight tolerances and/or you are having troubles with evaluation of TP/axis then it's good to use flex-plugs as

Please sign in to view this username.

 mentioned.

Otherwise find a method which suits your needs.

You can also buy one set just to test how your strategy is matching plug strategy.

[[Ri...]]

I have found through testing that typical thread Plugs (Levasa and or Tru-Pos) can affect repeatability when installing and removing/installing and removing, etc.

I also found depending on the thread pitch diameter (If it is above nominal) and the thread purposely not perpendicular (Minimally out of perpendicular), you can get an invalid projection to the surface that would be in tolerance. This normally happens because a user will "tighten" (The three finger monkey grip) the gage to mate to the surface when the gage should be basically, finger snug.

Flex gages were more superior in repeating and location but still can be affected by perpendicularity (See above for tightening). These types of gages can also cause minor damage to flank angles which could lead to rejections. You should examine the gage at leading and trailing edges where the splits are for buildup, especially with aluminum, magnesium and titanium, any soft material products.

I personally do not use any of these types of gages anymore. It is my belief that scanning is superior for size and or location.

Edited 3 hours ago

[[Ch...]]

We use somme from them tu drill the part on it an use it foe clambuíng. We mesure with Helix path wit enough points and filter.

 

We had one customer who prescribed that for us. Automotiv😎

[[Ke...]]

I use them often. M8 through M20 for machined parts & M4 - M6 for stamped parts. I have not had any repeatability issues using solid or flex plugs (of course, I am the only person running parts on the CMM, so that's one less variable). I use programmable stops without issue (as you noted, make sure that your fixture is solid & use care when inserting them, so that the part does not move). Our prints are ASME, so the position applies to the thread pitch (not the minor diameter, unless it is stated on the print). I'll also note that I do not use the on anything that is high volume (mostly prototype work), so I do not send them out for calibration, and treat them as disposable items (wear could be as much of a factor as buildup, depending on the application)

[[Cl...]]

I've passed type-2 Gauge R&R's (<10%) for position of threads without the use of flex plugs. I use 4-5 (slow) linear scans.

High point density and a large stylus. Evaluating with Maximum Inscribed Element for ID's and Maximum Circumscribed Element for OD's