Dial caliper fail

-
pishta

pishta

I know I'm right....
Joined
Oct 13, 2004
Messages
23,821
Reaction score
13,677
Location
Tustin, CA
My cheap *** HF dial caliper that I've had for 15 years finally started to give me fits. Would not return to zero repeatable. So...take it a part! A few pics. Key is to pry the bezel ring off and you'll be on your way. Remove the needle with 2 screwdrivers prying up in it at the shaft. It's a female so don't think the pins gonna come out. Take the gace odd and remove the 3 large screws. This will release the dial part. Under that you'll see 2 pinions for the rack and if you look closely under them you'll see one of them has a spring pawled to the brass gear and one has it but does not seem to be attached. Maybe this is my issue as the needle has about 6 thou of play on a locked up dial. If you lock the gears there is no play. I think the spring that looks to be floating should have some tension on it as the other one does? I cleaned it and put it all together , tightening some screws that I found a little loose enough to provide me a smooth travel and I still have the play. There is a brass shim in there that is bowed to provide some tension on the slide, you have to make sure that piece is installed correctly (bowed out) and the pin is in the hole or it won't go back together properly. It will if its not pinned but it will slide out once you start using it. It's the small screw closest to internal jaws and it has a nub on the end that fits in the hole of the shim to anchor it. So its all back together and it's still sloppy unless I snap the jaws to the piece and that swings the needle to its stop but that's not how we do this. There are 3 Phillips screws that hold the pinion retainer down but I stripped one trying to get it out so I didn't get any deeper than, just a visual but I need a new dual SAE/Metric digital caliper anyway so HF gift cards up! It worked for 15 years, not bad for a tool drawer dial caliper who's crystal broke 10 years ago! I kept it in its case after that.
20220202_123913.jpg
20220202_123902.jpg
20220202_123702.jpg
20220202_123404.jpg
20220202_122647.jpg
20220202_121843.jpg
20220202_111906.jpg
20220202_111855.jpg
20220202_111552.jpg
20220202_111505.jpg
 
You're WAY more patient than I am.
 
OH CRAP, I FIXED IT!

plugging around the internet, I found a starrett site that described the movement and mentioned spring preload. Soooo, I delved back into the HF clone (I think they are all the same style movement) and removed the face again to expose the 3 mounting screws. Remove them and **** the movement up on the right side so the pinion is free of the rack but the left pinion is still engaged. now rotate the hand CW (I think) a few turns until you feel some tension. You should see the left gear turning indipendently of its bottom gear through the little holes. This is the preload tension that keeps the indicator needle biased toward one side for repeatability! The pinion gears mesh on a common dial gear but the left pinion (closest to the jaws) is on a clockspring to the gear so you can wind up the pinion independent of the gear. Once you get the dial preload wound up, push the indicator CAREFULLY back flush into the rack so both gears are now engaged on the rack. DONT MOVE THE INDICATOR until you set at least one of the 3 mounting screws back in or the indicators gears (now under tension) will slip on the rack and unload. Put all 3 screws back in and put the dial hand back on and move the jaws off and onto zero to see if the needle returns to the same spot. you can also feel if the needle feels loose on the shaft, Its never loose, you are feeling the clock spring tension OR LACK OF IT! Put it all back together...blamo! It zeroes 100% of the time now with no needle play! I think Ill still get me a metric dial indicator......
 
Pishta , How the hell are you seeing this ****. I can't see wear on a ring and pinion at my age without my No.#3 glasses .
The one day I had to put 2 pairs on at once to see a big splinter in my finger. You must have very good eyes.
 
the gear you can see is the one that will wind up when you catch one pinion on the rack. I had to start all over as I forgot the bezel under the brass part but got it back working 100%
20220202_110743-jpg.jpg


20220202_132139.jpg


20220202_132128.jpg
 
Last edited:
Oldmanmopar said:
Pishta , How the hell are you seeing this ****. I can't see wear on a ring and pinion at my age without my No.#3 glasses .
The one day I had to put 2 pairs on at once to see a big splinter in my finger. You must have very good eyes.
Click to expand...
Heck no, I'm almost blind in my left eye! I cant even read the yellow "A-Bodies" on this page from 18 inches away and I got a 17" monitor! I am wearing my glasses under some magnifiers...
glasses.png
 
Oldmanmopar said:
Pishta , How the hell are you seeing this ****. I can't see wear on a ring and pinion at my age without my No.#3 glasses .
The one day I had to put 2 pairs on at once to see a big splinter in my finger. You must have very good eyes.
Click to expand...
Ain't that the truth!!
 
pishta said:
OH CRAP, I FIXED IT!

plugging around the internet, I found a starrett site that described the movement and mentioned spring preload. Soooo, I delved back into the HF clone (I think they are all the same style movement) and removed the face again to expose the 3 mounting screws. Remove them and **** the movement up on the right side so the pinion is free of the rack but the left pinion is still engaged. now rotate the hand CW (I think) a few turns until you feel some tension. You should see the left gear turning indipendently of its bottom gear through the little holes. This is the preload tension that keeps the indicator needle biased toward one side for repeatability! The pinion gears mesh on a common dial gear but the left pinion (closest to the jaws) is on a clockspring to the gear so you can wind up the pinion independent of the gear. Once you get the dial preload wound up, push the indicator CAREFULLY back flush into the rack so both gears are now engaged on the rack. DONT MOVE THE INDICATOR until you set at least one of the 3 mounting screws back in or the indicators gears (now under tension) will slip on the rack and unload. Put all 3 screws back in and put the dial hand back on and move the jaws off and onto zero to see if the needle returns to the same spot. you can also feel if the needle feels loose on the shaft, Its never loose, you are feeling the clock spring tension OR LACK OF IT! Put it all back together...blamo! It zeroes 100% of the time now with no needle play! I think Ill still get me a metric dial indicator......
Click to expand...
We used to calibrate and repair a lot of dial calipers at our place. The cheap calipers that needed repair we tended to just replace as it wasn't worth it usually.

Anyway... I saw that you probably didn't preload the gears against each other and that was your most likely the problem... You figured it out, so you're all set.

The cheap calipers are great for what they are... I've taken junk ones and fixed them for use in my garage toolbox. They can take a beating and worse case, you toss them and buy a new one.
 
my favorite disposeable tool store HF of course! I always get gift cards so Im always buying random ****. These work great, 2x and 5x switcheable. These are old, the new ones have 4 interchangeble lenses, invaluable in servicing electronics, especially 0402 and 0603 SMDs
A%2F%2Fresources.ultralibrarian.com%2Fwp-content%2Fuploads%2F2020%2F11%2Fshutterstock_1345628249.jpg
 
Pishta, you should probably get yourself a stereo-zoom microscope. I used one at work for 35 years and now I wished I would have taken one of the surplus scopes that they put up for salvage sale a few years back.
I have a pair of the 5x like you have but for some of the stuff a microscope would save my neck some strain.
 
Last edited:
Oh wow! I know what to do with my old stereo microscope I got second hand now. Thanks!
 
And I was proud of putting a new cord in my $20 flea market find Rockwell drill... I know that one day I'll regret repairing it, though. It's a single speed reversible 1/2 inch drive monster with a 3/4 X 8 inch pipe handle opposite of the trigger grip. It's not going to end well when It hangs up in something and I can't get away from it!
 
Last edited:
pishta said:
My cheap *** HF dial caliper that I've had for 15 years finally started to give me fits.
Click to expand...

Feel lucky my friend. In the 70's I bought a then expensive Craftsman, that I used maybe ?? 30 times. It sat in the case for years. Sometime in the early 80's I needed it and ----same thing---full of "something" in there.

I've now got some junk various China electronic ones. A couple are fairly accurate "for a caliper" but the damn battery life is terrible. You must remove the batteries as they don't ever truly turn off.

BUT I DID BUY here within the last few years about three old Craftsman VERNIER calipers. I have to use a magnifier, but I can read them to near a thousands, and if careful, a bit better. These are all the old school ones and I bought them off Egag. I RECOMMEND THEM HIGHLY as there is nearly nothing to go wrong!!!

They are all slightly different.........one is decimal and 1/128", other two are metric and decimal, and the charts on the back vary. One is fraction to decimal, the other has tap sizes

An example off Egag. The vintage Craftsman ones were made by 2 or 3 different manufacturers

s1-l1600.jpg


s-l1600.jpg
 
67Dart273 said:
Feel lucky my friend. In the 70's I bought a then expensive Craftsman, that I used maybe ?? 30 times. It sat in the case for years. Sometime in the early 80's I needed it and ----same thing---full of "something" in there.

I've now got some junk various China electronic ones. A couple are fairly accurate "for a caliper" but the damn battery life is terrible. You must remove the batteries as they don't ever truly turn off.

BUT I DID BUY here within the last few years about three old Craftsman VERNIER calipers. I have to use a magnifier, but I can read them to near a thousands, and if careful, a bit better. These are all the old school ones and I bought them off Egag. I RECOMMEND THEM HIGHLY as there is nearly nothing to go wrong!!!

They are all slightly different.........one is decimal and 1/128", other two are metric and decimal, and the charts on the back vary. One is fraction to decimal, the other has tap sizes

An example off Egag. The vintage Craftsman ones were made by 2 or 3 different manufacturers

View attachment 1715863541

View attachment 1715863542
Click to expand...
Yep, accurate once, accurate forever. As long as You can see them..
 
Well done. I would have sprayed it out and blew it dry with compressed air and tossed it if it didn't work. Shavings and grit in the rack and missing teeth in the pinions are usually the culprit.
 
67Dart273 said:
Feel lucky my friend. In the 70's I bought a then expensive Craftsman, that I used maybe ?? 30 times. It sat in the case for years. Sometime in the early 80's I needed it and ----same thing---full of "something" in there.

I've now got some junk various China electronic ones. A couple are fairly accurate "for a caliper" but the damn battery life is terrible. You must remove the batteries as they don't ever truly turn off.

BUT I DID BUY here within the last few years about three old Craftsman VERNIER calipers. I have to use a magnifier, but I can read them to near a thousands, and if careful, a bit better. These are all the old school ones and I bought them off Egag. I RECOMMEND THEM HIGHLY as there is nearly nothing to go wrong!!!

They are all slightly different.........one is decimal and 1/128", other two are metric and decimal, and the charts on the back vary. One is fraction to decimal, the other has tap sizes

An example off Egag. The vintage Craftsman ones were made by 2 or 3 different manufacturers

View attachment 1715863541

View attachment 1715863542
Click to expand...

I bought an el cheapo vernier caliper from JC Whitney when I was a teenager. Still have it, still use it. I agree completely that there is nothing that can go wrong with a vernier with even a little bit of care.
 
I had (have somewhere) a composite (?) vernier caliper. Supposed to be more accurate due to no temperature variations. I think its just cheaper to make! I got it at college book store for the dimensioning class I took. It was a blue green (and I had a yellow brown one pass through my toolbox). The jaws were the weak point as you could get a bur on one and it would have to be filed off. I dont think either had a depth probe but its been a while since Ive even seen it. I bet its in my drafting box! I found one online...plastic. I got a dial because this one was 1/128 inch and metric, not thou. I guess it did have a metal depth rod..like $12 online. HF is $24 now. I got it for $16 and 30% off coupon so like $13 long time ago. The HF has a surprisingly good fit and finish. Says stainless and I bet it is as its heavier than an AL frame would be.
vernier-caliper-500x500.jpg
 
^^Interesting you should mention 1/128, Pishta. My first "very bad" experience was with 1/128, which I never learned to deal with. WAY back in the early 70's I bought a "General Tool" brand 6" caliper which was in 1/128's. (They were for sale in just about every hardware store) Hell I did not realize there was anything else, at the time. I struggled trying to learn to read it, and it wasn't until ?? sometime in the 80's that I discovered that reading a metric or decimal vernier is about 100000000000000000000000000000000000 X easier LOLOL
They were stamped steel, not machined, and a "little rough"
722_verniercaliper_1200px_300ppi.jpg


One of the HANDIEST tools I carried through my years in auto parts was a little bitty pocket caliper, and another slightly larger one, also by General. I had about 3 of those over the years

133ME.jpg



In my years in auto parts I had .03037 imblazoned in my mind, and carried a tiny pocket calculator, after they became popular in the early 80's. We had a nice Mitutoyo caliper at work, and we dealt with a LOT of bearings. You had to be careful, because some metric bearings are converted into inch ID bore for such as saw mandrels, and a couple of sizes are quite "close."
 
You must log in or register to reply here.
-

Back
Top