What are these pointy things?

[Mick56]

These two things were in a case along with a Starrett dial indicator, and a few other small parts. Any idea what they are for?

 

[Mintgrun]

I wouldn't mind finding a set of those.

Google Search

 

[whateg01]

I keep meaning to make a set but haven't yet.

 

[whateg01]

I wouldn't mind finding a set of those.

Nice timing. You beat me to it!

Btw, found a set for you.

Starrett Center Distance Attachment for Dial & Electronic Calipers, EDP# 64440 - PT26151

Shop Starrett Center Distance Attachment for Dial & Electronic Calipers, EDP# 64440 - PT26151 crafted by Penn Tool Co. to deliver unmatched reliability. Empower your manufacturing with precision toolsget started today!

www.penntoolco.com

You'll notice they are about 200! That's why I plan to someday make some

 

[mike93lx]

Those are snazzy!

 

[Mintgrun]

I guess I don't need them that badly. I'm too frugal to buy them and too lazy to make them.

 

[whateg01]

I guess I don't need them that badly. I'm too frugal to buy them and too lazy to make them.

Every time I measure hole centers on something, I think to myself I need to make a set. And then I get done with the job and I forget about it until the next time

 

[Provincial]

I learned to measure the holes, add the measurement together, then divide by two. This gives you the average diameter of the two holes. Measure from outside to outside of the holes, meaning stick the inside caliper jaws in the holes and get the biggest reading possible. Then subtract the average diameter of the holes and you have the hole spacing.

 

[whateg01]

I learned to measure the holes, add the measurement together, then divide by two. This gives you the average diameter of the two holes. Measure from outside to outside of the holes, meaning stick the inside caliper jaws in the holes and get the biggest reading possible. Then subtract the average diameter of the holes and you have the hole spacing.

That's what I do most of the time. But on poles for say and number six screw the flat on the caliper will screw up your measurements. You can get around that by using dolls or screws sometimes. But, if you are measuring out a lot of holes, that's also a pain to have to do that over and over again. Using a set of centers like that in op makes the job go much faster.

 

[Provincial]

That's what I do most of the time. But on poles for say and number six screw the flat on the caliper will screw up your measurements. You can get around that by using dolls or screws sometimes. But, if you are measuring out a lot of holes, that's also a pain to have to do that over and over again. Using a set of centers like that in op makes the job go much faster.

Having a dedicated caliper with those installed is the answer. As for the rest of us, we adapt.

 

[PCustoms]

How the heck have I never seen these before?

Going to try and order a set later today!

 

[Notgrownup]

Aaaah! The elusive pointy pin thingys.

 

[OccupantRJ]

I do the measurement with the outside tips and also the inside tips to see if the two agree If on something critical as a cross check.

 

[PCustoms]

I do the measurement with the outside tips and also the inside tips to see if the two agree If on something critical as a cross check.

Pretty sure the error in that is going to exceed your tolerance.

Looks like mitutoyo centerline calipers are about $650, cheaper brands well under $200.

 

[pcrov]

cheaper brands well under $200.

I decided to go with about 17¢ in plastic and designed my own. The prints turned out remarkably well. I trust them more than I trust my el cheapo digital calipers.

If any of you lazy folk have a 3d printer and still need a pair of these, I put it up at:

https://makerworld.com/en/models/1586952-parametric-center-to-center-distance-caliper-tip#profileId-1670821

The model is parametric so easy to customize if you need to. Just make a copy of the onshape doc and tweak the variables to your heart's content.

Onshape

Sign in to Onshape, the #1 fastest growing CAD system in the world.

cad.onshape.com

The screws are 6-32. I put gutters on the channel to make sure snug fits still reach the bottom and align with the tips. I'm getting within a few thousandths of an inch which is well within my tolerance.