Wore out a Dial Caliper

-
nm9stheham

nm9stheham

Well-Known Member
Joined
Dec 20, 2013
Messages
12,087
Reaction score
4,281
Location
Waynesboro, VA
I tend to check my German made dial caliper regularly against micrometers and never saw it off more than +/-.001. But was measuring a 1.125" OD on a needle bearing assembly and kept getting .003" small. Compared with a vernier caliper, and 2 micrometers, and darned if the dial caliper was not off by around .0025". But, if it was used for measuring items that were 1.065" or .984" piston pins, the dial caliper was spot on.

Observing the dial movement going very slowly, I spotted some small movement of the needle center as it moved past one point on the dial; happened each revolution at that particular spot, and that was the area in which the above measurement was off. I am guessing that the gear on the back of the needle is damaged or worn a bit right at one or 2 particular teeth or the internal bearing is shot.

So, keep a good check on anything like a dial caliper for engine work. This one will be fine at the reloading bench but won't get used much for engine work anymore.
 
nm9stheham said:
I tend to check my German made dial caliper regularly against micrometers and never saw it off more than +/-.001. But was measuring a 1.125" OD on a needle bearing assembly and kept getting .003" small. Compared with a vernier caliper, and 2 micrometers, and darned if the dial caliper was not off by around .0025". But, if it was used for measuring items that were 1.065" or .984" piston pins, the dial caliper was spot on.

Observing the dial movement going very slowly, I spotted some small movement of the needle center as it moved past one point on the dial; happened each revolution at that particular spot, and that was the area in which the above measurement was off. I am guessing that the gear on the back of the needle is damaged or worn a bit right at one or 2 particular teeth or the internal bearing is shot.

So, keep a good check on anything like a dial caliper for engine work. This one will be fine at the reloading bench but won't get used much for engine work anymore.
Click to expand...

That's why you need a gauge block to check them periodically to make sure that they are still accurate...
 
They make new ones. If it's inaccurate you may be able to send it to get rebuilt. May be not. It might cost more than a new one.
 
If it's German made there might be a few "Millimeters" (Millipede with different legs) inside the gauge chewing away on the large gear inside the dial.:rofl:

I use a good insecticide on my calipers to keep them in tip top shape!!:soapbox:
 
These folks have been around a long time.
The website now includes ads but the content is same unvarnished as it was before.
Dial Calipers 011: Dial Calipers & Digital Calipers
"While dials may be an advantage, it causes all sorts of problems. For one, all those gears and parts will eventually malfunction. Count on it."

General Index: Long Island Indicator Service
 
Last edited:
Dial calipers are nice,because they are quick and easy.
Accuracy-micrometers.
 
krazykuda said:
That's why you need a gauge block to check them periodically to make sure that they are still accurate...
Click to expand...
Unfortunately, a gauge block or standard would have not caught this odd error unless I knew exactly at what dimension to check with a large gauge block set.... it only showed up at certain rotation angles of the needle. At other needle angles, the caliper is still quite accurate. I only caught this as I suspected the reading to be in error, and compared it to other devices that are not subject to the gear wear that dial calipers are. It was surprising that the error went from under .001" to .0025" in a few 10's of thousandths of, but if a gear tooth gets worn or damaged, then the expected result would be 'localized' errors.

toolmanmike said:
They make new ones. If it's inaccurate you may be able to send it to get rebuilt. May be not. It might cost more than a new one.
Click to expand...
Already have a new Mitutoyo here....(The 6" Starretts look to be made in China.) This one is probably 40-50 years old so it will just get consigned to work needing low accuracy.
 
Last edited:
nm9stheham said:
Already have a new Mitutoyo here....(The 6" Starretts look to be made in China.) This one is probably 40-50 years old so it will just get consigned to work needing low accuracy.
Click to expand...
See if LI indicator service has parts for it. They don't fix 'em anymore but do have some 'how to' info and parts for some brands.
 
Tnx... they did list the brand (Helios) but have no info on parts.

I liked this intro on their 101 section: "Before we start, let's state outright that the best, most reliable, and most useful caliper you can own is a vernier caliper. It isn't electronic and it doesn't have a dial. Only seasoned pros are likely to own and use the vernier calipers." A verier caliper is one of the tools I used to check this dial caliper. It's getting hard for me to read the gradations on one but I still have this old one 'Made in Germany, Western Zone'. Not sure I meet the 'seasoned pro' thing but, for now, I'll pretend I do LOL
 
You must log in or register to reply here.
-

Back
Top