Truing Caliper

[rleegabe]

I just bought a used truing caliper, I was watching a video of a guy showing the proper use of this caliper. He is saying to put the pivots into the holes and that when you adjust the wheel to tighten the caliper until the caliper is up to where it meets the conical part of the pivot and then move the arms of the wheel up or down as needed, the reason to tighten up to the conical is so as not to snap the pivots during adjustment. I put the wheel in the caliper I just bought but the pivot only goes about a third of the way in. The end of the caliper will not go up to the conical part of the pivot. Is there something wrong with this caliper

 

[SpringDriven]

The style of caliper I have used that looks similar to this has two sides with large pivot holes on one end, and smaller pivot holes on the other.

The pivot holes could have debris in them as well.

 

[rleegabe]

The style of caliper I have used that looks similar to this has two sides with large pivot holes on one end, and smaller pivot holes on the other.

The pivot holes could have debris in them as well.

I checked for that, both sides seem to have the same size holes. I tried digging around inside the holes and found nothing.

 

[DoughBoyWatches]

most watchmakers have more than one truing caliper for this reason.

 

[Jerry Treiman]

Many calipers have two different types of points. One set, for truing, has deep holes for the pivots and a cross-hole so the bottom can be cleaned out if dirt gets in it. The other set of points have shallower holes or conical holes that are only for poising; they do not have cross-holes. I do not see cross-holes in the points you show so I suspect these are for poising and you will snap your pivots off if you try to use them for truing.

 

[karlmansson]

I’ve also talked to watchmakers that advocate checking the wheel for truth in the calipers and then doing the actual bending with the wheel between two hollow stakes in the staking tool. Two stakes that will accept the entire diameter of the staff, including hub and roller (if you have the roller installed. This way there is no risk of bending a pivot during truing. But it does involve a lot of swapping between tools which in itself poses a risk to the balance.

Regards
Karl

 

[rleegabe]

Many calipers have two different types of points. One set, for truing, has deep holes for the pivots and a cross-hole so the bottom can be cleaned out if dirt gets in it. The other set of points have shallower holes or conical holes that are only for poising; they do not have cross-holes. I do not see cross-holes in the points you show so I suspect these are for poising and you will snap your pivots off if you try to use them for truing.

Yes they do have the cross holes, just not showing up in the pictures.

 

[karlmansson]

Yes they do have the cross holes, just not showing up in the pictures.

How big is the balance you are trying to true? Pivots range from over 0,12mm for pocket watches down to 0,08mm for small ladies movements. Maybe you just got the wrong size calipers?

 

[DoughBoyWatches]

I’ve also talked to watchmakers that advocate checking the wheel for truth in the calipers and then doing the actual bending with the wheel between two hollow stakes in the staking tool. Two stakes that will accept the entire diameter of the staff, including hub and roller (if you have the roller installed. This way there is no risk of bending a pivot during truing. But it does involve a lot of swapping between tools which in itself poses a risk to the balance.

Regards
Karl

I get the idea and sounds good in theory but we rely on the arm of the caliper to gauge how flat and round the wheel is. If done as you said you would be relying on your eye being perfectly level with the balance and/or having constantly remove the balance from the stakes and back into the caliper. I would also think you run the risk of creating unwanted bends in the arms when they are sandwiched between two stakes. Sometimes trying to reinvent the wheel or build a better mousetrap isnt the answer, when the original way and equipment is the best solution.

 

[karlmansson]

I get the idea and sounds good in theory but we rely on the arm of the caliper to gauge how flat and round the wheel is. If done as you said you would be relying on your eye being perfectly level with the balance and/or having constantly remove the balance from the stakes and back into the caliper. I would also think you run the risk of creating unwanted bends in the arms when they are sandwiched between two stakes. Sometimes trying to reinvent the wheel or build a better mousetrap isnt the answer, when the original way and equipment is the best solution.

The idea is that you switch tool after each correction, as I implied in my last sentence.
I think the whole point of pinching on the arms is to avoid compound bends in them or altering their relation to the staff. On top of protecting the pivots. This is not a new way of doing this, the man who taught me this technique used to teach at a WOSTEP certified watchmaking school.

Regards
Karl

 

[DoughBoyWatches]

The idea is that you switch tool after each correction, as I implied in my last sentence.
I think the whole point of pinching on the arms is to avoid compound bends in them or altering their relation to the staff. On top of protecting the pivots. This is not a new way of doing this, the man who taught me this technique used to teach at a WOSTEP certified watchmaking school.

Regards
Karl

In my opinion you have much higher chance messing up the pivots going back and forth. But to each his own i guess, if it works it works. I would also have to say this may be better suited for a modern balance wheel rather than a split wheel.

 

[praezis]

Good hint, Karl! I will try that method next time (if not forgotten till then).

For bending I use a pliers with brass tips similar to this one:


Bending in the caliper is questionable in my eyes, as it is stress for the rivet.

Finally, none of my calipers are used any more: now I test in the depthing tool only, much more comfortable!

Frank

 

[DeweyC]

I’ve also talked to watchmakers that advocate checking the wheel for truth in the calipers and then doing the actual bending with the wheel between two hollow stakes in the staking tool. Two stakes that will accept the entire diameter of the staff, including hub and roller (if you have the roller installed. This way there is no risk of bending a pivot during truing. But it does involve a lot of swapping between tools which in itself poses a risk to the balance.

Regards
Karl

Good hint, Karl! I will try that method next time (if not forgotten till then).

For bending I use a pliers with brass tips similar to this one:
View attachment 650522

Bending in the caliper is questionable in my eyes, as it is stress for the rivet.

Finally, none of my calipers are used any more: now I test in the depthing tool only, much more comfortable!

Frank

Indeed Karl and Frank. We use(d) the Horia tool as the clamp. You mark the low spot with a pen and move it to the Horia tool. You are correct about the pivots and the rivet being damaged if the attempts are made in the truing caliper.

We also did/do this with major corrections to balances. There is no way you are going to correct a glucydor balance in the calipers.

 

[DoughBoyWatches]

I have been using truing calipers for years never had an issue. You obviously need to know how to do it right, and how to use your finger to support the opposite side of the balance wheel. JD RIchard has an amazing video on this. does anyone have a video or some sort of demonstration on these other ways because Iam curious to see how you find where the high and lows spots are.

 

[karlmansson]

You still use the calipers to find high/ low spots with the staking/jewelling tool method. You just mark the spots as Dewey says and have to go back into the calipers to check your work.

Glad to hear you haven’t had issues with your method! By supporting the balance with fingers on the other side you take most of the load off of the pivots but instead you make the rivet the fulcrum of your lever as you lift up. On a large balance, that is quite the lever.

 

[DoughBoyWatches]

You still use the calipers to find high/ low spots with the staking/jewelling tool method. You just mark the spots as Dewey says and have to go back into the calipers to check your work.

then how do you mark the high low spots when transferring out of the caliper. are using your eye or physically marking the balance.

 

[karlmansson]

then how do you mark the high low spots when transferring out of the caliper. are using your eye or physically marking the balance.

Permanent marker I would wager. That’s how I’ve done it.

 

[DoughBoyWatches]

Permanent marker I would wager. That’s how I’ve done it.

Cool! glad its works for you, and good to know other methods but personally I would stick to the good old fashioned way as illustrated in the "Bulova School of Watchmaking" handbook.

 

[karlmansson]

I have been using truing calipers for years never had an issue. You obviously need to know how to do it right, and how to use your finger to support the opposite side of the balance wheel. JD RIchard has an amazing video on this. does anyone have a video or some sort of demonstration on these other ways because Iam curious to see how you find where the high and lows spots are.

Interesting to see that JD also uses the wrong size or wrong end of his calipers in the video. The staff is supported by the pivots and not the cones. You can't see the pivot end in the cross holes and the entire cone is visible on either end of the staff, which means that it is not supporting the staff at all.

EDIT. Looking at it again I may have been mistaken. But that is a weird looking balance staff... One of the pivots is broken, I listened again and he did actually mention this. And the other pivot is insanely long. Even stranger that it's not visible in the through hole for that reason though. One size up on the truing caliper would have been fitting there I think still.

As I mentioned before, the way of holding the balance in an auxillary tool for manipulating is not my, nor a new idea. Loads of practices in those older manuals have been updated or revised in schools today, as I understand it. Never went myself.

Regards
Karl

 

[DoughBoyWatches]

FYI to avoid putting stress on a riveted staff i make my adjustments away from the rivet. I do all the low spots first then flip the balance making the high spots into low spots and again adjusting opposite the rivet.

Interesting to see that JD also uses the wrong size or wrong end of his calipers in the video. The staff is supported by the pivots and not the cones. You can't see the pivot end in the cross holes and the entire cone is visible on either end of the staff, which means that it is not supporting the staff at all.

EDIT. Looking at it again I may have been mistaken. But that is a weird looking balance staff... One of the pivots is broken, I listened again and he did actually mention this. And the other pivot is insanely long. Even stranger that it's not visible in the through hole for that reason though. One size up on the truing caliper would have been fitting there I think still.

As I mentioned before, the way of holding the balance in an auxillary tool for manipulating is not my, nor a new idea. Loads of practices in those older manuals have been updated or revised in schools today, as I understand it. Never went myself.

Regards
Karl

Its a large pocket watch balance. the pivots on these staffs are short and the conical area of the shaft is also short and very wide, if you look close you can see just the tip of pivots. Its far down enough to where it will not break the pivots. This not a standard wrist watch balance if it was an elgin 8/0 then i would say he has a problem. But the information in the video on how he bends the wheel and finds the high/lows is what Iam referencing. And keep in mind split wheels are much easier to true in these calipers, which is why I suggested that using auxillary tools would be better suited for a modern balance. Personally since I work on movements that are mostly 70+ years old, I use the same tools and methods that where used during the time period. Just like when I service an A-11 movement I use the guidelines laid out in TM-1575 with some minor but obvious substitutes. Call me old fashioned, But if it worked 100yrs ago it will work today.