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Don't understand this caliper

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Forum topic by Avi posted 11-12-2018 08:01 PM 584 views 0 times favorited 6 replies Add to Favorites Watch
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Avi

22 posts in 447 days


11-12-2018 08:01 PM

I got this inside-outside caliper, and it seems to me that when the outside is closed the inside should be at zero too. But here the “inside” side is not at zero. This is “vintage” but it’s not bent or anything.
Am I missing something on how this is used? I though it’s suposed to be the same distance on each side.
Cheers


6 replies so far

View Bill White's profile

Bill White

5135 posts in 4166 days


#1 posted 11-12-2018 08:17 PM

Have you tried measuring something with it? Probably made to give you the readings you wish.

-- bill@magraphics.us

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Wildwood

2483 posts in 2340 days


#2 posted 11-12-2018 08:39 PM

You would think both ends should measure the same outside dimensions but they hardly ever do. Accuracy is not that tools forte can be off few or lot of CM or MM, here talking about fractions of an inch to an inch.

One side measures wall thickness or sides of a glass, cup, bowl, or outside dimensions of items? The other end is for measuring the inside dimensions of items or outside wall to wall.

-- Bill

View MrUnix's profile

MrUnix

7053 posts in 2405 days


#3 posted 11-12-2018 09:11 PM

I though it’s suposed to be the same distance on each side.

Nope – the one shown is not for taking measurements – they are just used to set a reference measurement (distance) that you can then compare to. For example, if you need a 1.75” tennon for your scroll chuck, you would set the ‘outer’ set 1.75” apart, and then turn your tennon until the calipers fit. Or you need a 1” dowel, so you set it to 1” and turn until it just slips over. Same deal with the other side, but for recesses and holes where you would be measuring inside diameter instead.

I believe what you were thinking of is a bowl thickness caliper which shows the same thickness on both sides of the tool like this one:

Both sides will register the same distance apart, so when one side is in a blind spot, the other exposed end can be used to measure the thickness between the two arms.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Bill Berklich's profile

Bill Berklich

482 posts in 594 days


#4 posted 11-12-2018 09:18 PM

You are holding a transfer caliper. Though many people use it to measure the purpose is to transfer an exact dimension from one place to another. It is/was used extensively in pattern making. You would set the caliper directly off of the full scale drawing then transfer it to the pattern. There is no reason for the “inside” to be zero because you 1) can transfer “zero” and 2) the Pattern Maker had other tools to reproduce smaller dimensions. A lot was done by eye and be feel. My Grandpa was a Pattern Maker for Ford many years ago and I still have some of his tools and a bit of his knowledge. Btw my Grandpa laughed at me for trying to set a transfer caliper to specific dimension off one of his scales.

-- Bill - Rochester MI

View Avi's profile

Avi

22 posts in 447 days


#5 posted 11-14-2018 05:01 PM

OK thanks all.
So it’s just really an inside and an outside one in the same tool. I thought the point was to be able to transfer an inside distance to an outside one or vice versa.
Ah well.

View MrRon's profile

MrRon

5203 posts in 3449 days


#6 posted 11-15-2018 05:23 PM

That is a tool that transfers a measurement to a rule or other measurement standard, such as a micrometer or caliper. Both ends are independent of one another.

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