O Ring sizer

[Martin3528]

I ordered some O-rings from the O Ring Store and saw they had this grid paper that you can use to determine the size of O rings. For $10, I thought I'd give it a shot.
I will insert some pictures and hope they make sense. It works pretty well. What you do is lay your O-ring on the grid, open the app and take a screen shot. It computes all the data and gives you a dimension of the O-ring.

Here is the grid

Set your O-ring in the middle and screen shot in the app. It processes the picture and:

Then it gives you a screen of the dimensions and a possible part number. The first O-ring I shot was a 8mm x 1.5mm.
pretty close dimensions. 0.02mm difference.

This is one of a 20.5 x 2mm. ID is a little farther off, but probably my picture taking.
FWIW, it may be useful to someone. I would use it to order the best size that makes sense. For instance, on this one, I would look for a 20.5 x 2 mm

 

[bigHUN]

I trust my digital caliper more, but I may be an old fashioned mechanical engineer
The other thing is, I always download the (airgun) Manuals from websites, re type the entire o-ring BOM (bill of material) into my spreadsheet.
When I need to order anything for my own stock - I buy in little bags of 25 or 50 = that volume is for lifetime.
If I can recall correctly I have about 78-80 sizes - from the books - in my o-rings safe.
I like oringsandmore, the online selection is well organized and ordering I find very friendly.

 

[marflow 777]

Oring are hard to measure sort of, if it is an added tool fine but a 6 inch stainless ruler will do very well also and some calipers
i have in the past mostly used the Oring store until their shipping got way out of line so getting a 10 dollar sheet of paper might have o wait

 

[Grey-Kiwi]

I use this chart...print it out at full size (it's a PDF so will be accurate).
Then just place your O ring on the chart to work out size and thickness.
It's a handy wee chart. Has Metric and Imperial sizes.
https://www.imperialsupplies.com/pdf/B_O-Ring-Charts.pdf

 

[kahu]

Have you scanned the same o-ring multiple times to see how consistent the app's analysis is??

 

[Matt247365]

Pretty cool! Thanks for sharing.

 

[OTmachine]

I use this chart...print it out at full size (it's a PDF so will be accurate).
Then just place your O ring on the chart to work out size and thickness.
It's a handy wee chart. Has Metric and Imperial sizes.
https://www.imperialsupplies.com/pdf/B_O-Ring-Charts.pdf

That, is very useful! Thanks!

 

[Bigragu]

Does it compensate for a used o rings stretch and swell?

 

[Martin3528]

Does it compensate for a used o rings stretch and swell?

It is supposed to, at least minimally.

 

[OTmachine]

Does it compensate for a used o rings stretch and swell?

Best to just measure the groove and sealing surfaces; no guessing.

 

[BGarney]

I could see it being a useful tool if it works as they claim.