Centerline Gage accessory for dial calipers. Measure hole to hole spacing precisely.

[LCHIEN]

These are handy to measure the distance between two holes, something that's normally hard to do accurately.
I bought a set some time long ago. I think you can get these for around $20 at Amazon.

https://www.amazon.com/HHIP-4100-0040-Center-Line-Calipers

$10.95 with free shipping on eBay

https://www.ebay.com/itm/30069167212...3Avlp_homepage

Zero your calipers first. You clamp them to the jaws of your calipers (dial or digital) and use the set screws and supplied Allen key to lock them in place. They are 3/8" diameter and the groove depth is machined to be at the centerline of the gage. So closing the jaws so the gages butt each other results in 0.375" (on mine I got .377-.378)
Now you can measure the distance between holes accurately as long as they are more than 3/8" apart. They have a conical tip so they will self center in most any holes up to 3/8" dia. I'd judge the accuracy to be +/-.003". The points of the gage tips should be right directly below and centered on the measuring face of each jaw.

I just used them to measure the spacing between mounting holes on my router base.

They go on and off fairly quickly... you just have to remember to set the zero before installing.

A useful accessory for the well-equipped shop.

[leehljp]

I just used them to measure the spacing between mounting holes on my router base

THAT is what I need to measure the holes center to center!

Thanks for the tip and link!

[LCHIEN]

I wonder if linking them caused the price to jump. They tracking copied links figuring it was being referenced or recommended.
When I looked as I was writing the post it was $19.99 or so.

I just clicked the link and is now 3 hours later $23.50.

I suggest you wait and see if the price comes down.

I shortened the link to rid it of all tracking info. Still works AFAICT

[LCHIEN]

Price just given to camelcamelcamel.com was 22.71 just now.
I have Camel tracking the price

They are jacking with the price!

[leehljp]

Ebay has them for a varied amount of prices. Some much cheaper with high shipping rates and some more expensive and free shipping. The average looking price is around $20.00 but some less and some much higher.

https://www.ebay.com/sch/i.html?_nkw...023.m570.l1313

[d_meister]

Thanks for making me aware of these! I jumped on the $10.95 ones on eBay. I wonder if I can calibrate my old dial caliper to them so I can leave them on

[LCHIEN]

Thanks for making me aware of these! I jumped on the $10.95 ones on eBay. I wonder if I can calibrate my old dial caliper to them so I can leave them on

The hard thing is that the gages affixed you can't get to zero and set it to zero.
You have to set zero and then put the gages on. Then you drive the points close as possible and it reads .375" (which is the sum of two half diameters of the gage)
You cannot rezero without removing them.
My calipers hold zero even when off which is convenient for that purpose.
However, AFAICT the on off of the calipers only turns off the display which is why it holds zero. But also why the battery life is the same (and not that long) whether you turn it on or off. LCD Displays don't really take power./

[leehljp]

I also ordered a set from eBay.

[Slik Geek]

I order a set from eBay as well. Hats off to Lchien for bringing this to our attention.