Starret 6" Dial Calipers. wont hold zero can they be fixed?

[Joe0121]

Any idea how to get the face off?

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[astjp2]

You need a watch hand remover to do it right, I just sent my brown and sharp in for the same thing and for $35, it was not worth buying the tools to do it right.

http://griffinincorporated.com/

Good prices and easy to deal with. Ask for Steve when you call.

 

[12bolts]

Joe,
After seeing the video, they look to me like the pinion is skipping on the rack or, more unlikely, the pointer is slipping on its shaft. Have you removed the rack and cleaned it. Give it a go with a fine wire brush, (brass preferably). check the teeth with a good light and magnifying glass. You might have a bit of crud stuck in the teeth that occasionally makes it skip. Try moving it slowly open and closed a couple of times and see if the fault still occurs. Maybe the rapid travel is compounding the fault.
You can make a pointer puller simply from a largish nut or piece of pipe. drill and tap from the side. Grind the opposite side thin and flat. Cut a partial opening to slide the puller around the shaft. Turn or grind a point on a suitable screw as accurately centred as you can to suit your needle.
and
A bought one, annnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnd a home made job from a piece of pipe.

Cheers Phil

 

[Mike Nash]

Just last weekend I worked on 4 cheapy calipers. They all have two pinion gears though. However, 1 skipped tooth is .025" on mine. I got one of them out by about the same 8 thou you are seeing. That turned out to be the rack position. It was screwed in but also glued. Without the glue it will shift up to 8 thou depending on which order I tighten the screws in the rack. We had another set at work years ago and it had a loose needle that would move if closed too fast.

 

[Joe0121]

You need a watch hand remover to do it right, I just sent my brown and sharp in for the same thing and for $35, it was not worth buying the tools to do it right.

http://griffinincorporated.com/

Good prices and easy to deal with. Ask for Steve when you call.

I'll get a hole of them if a second cleaning using a small wire brush (I was going to use a bronse cleaning brush for a .30 cal rifle)

Joe,
After seeing the video, they look to me like the pinion is skipping on the rack or, more unlikely, the pointer is slipping on its shaft. Have you removed the rack and cleaned it. Give it a go with a fine wire brush, (brass preferably). check the teeth with a good light and magnifying glass. You might have a bit of crud stuck in the teeth that occasionally makes it skip. Try moving it slowly open and closed a couple of times and see if the fault still occurs. Maybe the rapid travel is compounding the fault.
You can make a pointer puller simply from a largish nut or piece of pipe. drill and tap from the side. Grind the opposite side thin and flat. Cut a partial opening to slide the puller around the shaft. Turn or grind a point on a suitable screw as accurately centred as you can to suit your needle.
View attachment 65985 and View attachment 65986
A bought one, annnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnd a home made job from a piece of pipe.

Cheers Phil

That tool is used to remove the needle from the shaft? Could I just take take the face cover off and bend the end of the needle up slightly if it is in fact touching he face?

Just last weekend I worked on 4 cheapy calipers. They all have two pinion gears though. However, 1 skipped tooth is .025" on mine. I got one of them out by about the same 8 thou you are seeing. That turned out to be the rack position. It was screwed in but also glued. Without the glue it will shift up to 8 thou depending on which order I tighten the screws in the rack. We had another set at work years ago and it had a loose needle that would move if closed too fast.

What odd is occasionally I will move it and it will return to zero within .0005. Maybe santa will get me these for Christmas:http://www.starrett.com/metrology/p...ls/Slide-Calipers/Dial-Calipers/R120A-6 W~SLC I think the red face makes them more accurate

 

[gheumann]

When this happened to me it was the indicator needle slipping on the pin. If you went slow it was fine. If you "slammed" it closed the inertia would run the pin past the mark.

Maybe you just like fixing stuff. I do. Otherwise, for $10 you can get a digital caliper from Harbor Freight. I've bought a few and checked them agains my Mitutoyo. Good enough for work within .002". For a little more (and only a little more) you get one that's accurate to .0005" like the Mitutoyo itself (but still Chinese).

 

[Mid Day Machining]

My starret Caliper wont maintain zero. The action seems overall smooth and it seems to hold zero when measuring longer parts but when I return the caliper to "zero" that is fully closed it will often read .005/.010 usually low but not always. Also the needle is pointed at the 7 oclock position as opposed to 12. The faster I return to zero the worse it seems to be. These Caliper have more sentimental value to me than their intrinsic value and I would mostly use them for reloading.

I had a Starrett dial caliper about 30 years ago. It was a very accurate caliper, but if it got a small chip in the gear rack it would skip .025. I put up with that for about 10 years, then one day I was working on some parts that has a close tolerance and it shipped. I was in a particularly pissy mood that day so I made an adjustment on my Starrett dial caliper that fixed the problem forever. I carefully set them on a large steel plate and I hit them with a 3 pound ball peen hammer. I never had another problem with them skipping again.

 

[kd4gij]

Here you go some good reading
http://longislandindicator.com/p44.html

 

[Radarguy]

Take it apart and clean the gear and rack. It takes only a small particle to start do that. Mine was doing it and the clean up worked great. The gear is spring loaded and if you are very careful you can lift the gear and and move the carriage along the rack to re align it. If you are squeamish about that take to a clock repair shop or send it back to Starrett.

 

[astjp2]

Here you go some good reading
http://longislandindicator.com/p44.html

Long Island is to expensive for me. I went with Griffin Incorporated for 35 for the 6" and 50 for the 8". Tim