Help Broken dial foot

[DeanT]

Hi,

I’m looking for some advice on how to fix a broken foot on a chapter ring from a 1720’s lantern clock. Unfortunately there’s isn’t much meat to play with as the foot was broken off with about 3mm on one side and 2mm on the other. It would appear the original hole was too close to the chapter and would have placed a lot of force on the foot. Therefore moving the hole a mm further out would lessen the tense to acceptable levels. The foot is right in the middle of a lovely fleur de lys on the other side so drilling it out would mean engraving the dial again!

I’m a bit stumped on what to do?

Thanks for your help
Dean

 

[SuffolkM]

This looks like a job for silver solder. You don't want to vary the height of the finished repair (as it won't align to the plates) so try to keep the surfaces as they are, clean with alcohol, then bind the post in place using a jig to make the job as secure as possible before you start. Compress the parts together gently.

The amount of heat needed here is quite a bit, and of course the chapter ring will radiate the heat away. You'll need one of those small butane torches or a pretty large iron to get this to flow, and flux could help if you don't want to leave filing marks. That amount of heat may well cause some cosmetic problems on the front, but the repairs to put that right are not difficult.

A repair with epoxy would work but the materials would be out of place - and you can't polish the join up! Other ideas, maybe a collar with an inner thread and use a die to cut a thread onto the remaining post. That would let you vary its height.

 

[wow]

In order to avoid using heat, you may be able to carefully drill a hole in the post and insert a tight pin. Then makes post extension, drill a hole in it so it will fit the pin, and use JB Weld to connect it. Once it dries, it can be cleaned up and will be very secure.

 

[Jerry Kieffer]

Hi,

I’m looking for some advice on how to fix a broken foot on a chapter ring from a 1720’s lantern clock. Unfortunately there’s isn’t much meat to play with as the foot was broken off with about 3mm on one side and 2mm on the other. It would appear the original hole was too close to the chapter and would have placed a lot of force on the foot. Therefore moving the hole a mm further out would lessen the tense to acceptable levels. The foot is right in the middle of a lovely fleur de lys on the other side so drilling it out would mean engraving the dial again!

I’m a bit stumped on what to do?

Thanks for your help
Dean

View attachment 621989 View attachment 621990 View attachment 621991

Dean

While no one wants or should have an issue like this, I have been looking for a real life example for sometime.

When doing classes, I like to challenge students and this is one example that I use. As part of their repair solution, they are not allowed to use heat or chemicals in the repair and the face of the dial can not be disturbed.

In this case ,performing a secure invisible repair without dial restoration can be an issue. What one is willing to except is of course a personal preference thing. I take it from your description, you would prefer a sound repair that would not disturb the face of the dial.

When being faced with this dilemma a couple of times over the years, I have repaired as follows where it was excepted by the owner.

(1) The following explanation and dimensions are based on a metal dial that is .094' or about 2.4mm thick.

(2) First, the dial is clamped to a small milling machine bed face down with the spindle centered on the broken post. Hand wheel is then "Zeroed" and the spindle center is moved .750" or about 10mm in any direction from the "+" to the red arrow first photo.

(3) Then a .375" or 10mm center cutting endmill is used to machine a hole .060"/ 1.5mm deep per red arrow first photo.

(4) Next I changed over to a .375/ 10mm 60 degree dove tail cutter and lowered it to the bottom of the hole second photo. I then machined a slot by returning to the original center of the post where I started "+" sign first/third photo.

(5) At this point a 60 degree bottom post was machined ( Left side first photo) to a friction fit and driven into position per fourth photo.

In cases where this method was used, the post and exposed slot were aged to appear to be a very old repair.

Jerry Kieffer

 

[novicetimekeeper]

That's very creative Jerry, and it is very desirable not to use heat.

What is the issue with removing the broken foot and riveting in another? You have the clear advantage that the visible side is silvered so even a different colour brass would not be an problem.

 

[Jerry Kieffer]

That's very creative Jerry, and it is very desirable not to use heat.

What is the issue with removing the broken foot and riveting in another? You have the clear advantage that the visible side is silvered so even a different colour brass would not be an problem.

Novicetimekeeper

Thanks for the kind comment.

If we are refinishing a dial, reinstalling a post in the same manner it was originally installed is the only way to go.

In this case where the OP has indicated that where the post would be installed, the face is engraved. Without seeing the dial face and its details or knowing the value of the clock , its difficult to determine restoration issues. In addition, it appears that the OP did not want to disturb the face of the dial.
I should have mentioned that this procedure was offered as an option to produce a sound repair, without disturbing the engraved face of the dial that appears to be the OP`s concern.

Another words as they say, "the lesser of two evils".

I should mention that I have also used this method on watch dials where heat was an issue. In those cases I have used .060" or 1.5 mm dental burs per attached photo.

Jerry Kieffer

 

[novicetimekeeper]

Novicetimekeeper

Thanks for the kind comment.

If we are refinishing a dial, reinstalling a post in the same manner it was originally installed is the only way to go.

In this case where the OP has indicated that where the post would be installed, the face is engraved. Without seeing the dial face and its details or knowing the value of the clock , its difficult to determine restoration issues. In addition, it appears that the OP did not want to disturb the face of the dial.
I should have mentioned that this procedure was offered as an option to produce a sound repair, without disturbing the engraved face of the dial that appears to be the OP`s concern.

Another words as they say, "the lesser of two evils".

I should mention that I have also used this method on watch dials where heat was an issue. In those cases I have used .060" or 1.5 mm dental burs per attached photo.

Jerry Kieffer




View attachment 622227

Ah yes, seeing it was a chapter ring I wasn't sure where the engraving bit came from but I assume it is a half hour marker. The good news is there are others to copy and it probably doesn't cover the hole of the engraving, I think (depending on the value of the clock) I would go for riveting a new foot.

It may be that if your method was used the old rivet may loosen anyway, as the foot needs to be in the same place as the original.

 

[Jaap]

Dean

While no one wants or should have an issue like this, I have been looking for a real life example for sometime.

When doing classes, I like to challenge students and this is one example that I use. As part of their repair solution, they are not allowed to use heat or chemicals in the repair and the face of the dial can not be disturbed.

In this case ,performing a secure invisible repair without dial restoration can be an issue. What one is willing to except is of course a personal preference thing. I take it from your description, you would prefer a sound repair that would not disturb the face of the dial.

When being faced with this dilemma a couple of times over the years, I have repaired as follows where it was excepted by the owner.

(1) The following explanation and dimensions are based on a metal dial that is .094' or about 2.4mm thick.

(2) First, the dial is clamped to a small milling machine bed face down with the spindle centered on the broken post. Hand wheel is then "Zeroed" and the spindle center is moved .750" or about 10mm in any direction from the "+" to the red arrow first photo.

(3) Then a .375" or 10mm center cutting endmill is used to machine a hole .060"/ 1.5mm deep per red arrow first photo.

(4) Next I changed over to a .375/ 10mm 60 degree dove tail cutter and lowered it to the bottom of the hole second photo. I then machined a slot by returning to the original center of the post where I started "+" sign first/third photo.

(5) At this point a 60 degree bottom post was machined ( Left side first photo) to a friction fit and driven into position per fourth photo.

In cases where this method was used, the post and exposed slot were aged to appear to be a very old repair.

Jerry Kieffer



View attachment 622164 View attachment 622165 View attachment 622166 View attachment 622167

It is a great example of out of the box thinking. Love it.

 

[Jerry Kieffer]

Ah yes, seeing it was a chapter ring I wasn't sure where the engraving bit came from but I assume it is a half hour marker. The good news is there are others to copy and it probably doesn't cover the hole of the engraving, I think (depending on the value of the clock) I would go for riveting a new foot.

It may be that if your method was used the old rivet may loosen anyway, as the foot needs to be in the same place as the original.

I have never had an issue with old riveted mountings coming loose using this procedure. However, if quality surface restoration of the dial can be done with less effort, then original type post replacement is the way to go.

Jerry kieffer

 

[DeanT]

Thanks very much for your replies, I had been thinking about doing something similar to what Jerry Kieffer was suggesting. The original pin hole is now a slot and I was thinking about converting it into a slot described. The previous hole was far to close to the chapter ring and I think the pressure was enough to snap it off so it needs to be moved further away from the base anyway.

The post is right in the middle of the Fleur de Lys on the chapter ring so I was hoping not to disturb the engraving.

I was also toying with the idea of a pin as suggested by wow or making a new post with a screw on the end and tapping the remaining post.

 

[novicetimekeeper]

or making a new post with a screw on the end and tapping the remaining post.

If you have enough left to do that it is a method Graham Morse uses to repair broken movement pillars where the top has broken away from the pin hole.

 

[shutterbug]

I think it would be pretty tough to put threads in such a shallow hole. You'd almost have to go through the dial to do it.

 

[Jerry Kieffer]

Dean

What is the thickness of your dial and the diameter of the post.

Jerry Kieffer

 

[DeanT]

Dean

What is the thickness of your dial and the diameter of the post.

Jerry Kieffer

The chapter ring is only 1mm thick and the post is 7mm across. There is 2mm or at best 2.5mm of the post remaining behind the chapter ring.

Thanks
Dean

 

[Jerry Kieffer]

The chapter ring is only 1mm thick and the post is 7mm across. There is 2mm or at best 2.5mm of the post remaining behind the chapter ring.

Thanks
Dean

Dean
While the dial is only 1mm thick, less than I expected, my post #4 would still apply but require far more precise machining.

With your criteria in mind
(1) do not want to disturb the face
(2) need to move the post location slightly.

There is possibly another option to consider as follows.

(1) As long as the post will not need to be moved more than .5mm, I would mount the dial in the Mill also as first suggested.

(2) I would again locate the spindle center to the post and then any desired location not more than .5mm from the original center spot.

(3) At the new desired spot, I would then machine the post to .250" or 1/4" diameter. This would be done using a small boring head with a micro boring bar installed 180 degrees from normal per attached photo red arrow. With the mill rotating in reverse or a left hand boring bar, diameters can be machined similar to the use of a core drill. Size should be preset by testing on test stock before use.

(4) Once the post has been machined in its new location, I would then thread the post with a 1/4" x 80 TPI die. The very fine thread will allow 6 full threads at only .2mm depth per your post. Threading is not practical or even possible with standard course threads. This requires an adjustable die for a tight thread per the fine threads. In addition, the "exit" side of the die may need to be ground down so it can be used to produce a full thread all the way to the bottom of the post. Start large and work your way down to a tight thread fit.

(5) Next, thread a steel 8mm OD 1/4" ID sleeve to 1/4 x 80 TPI to thread over the existing post per second attached photo.
The only down side is that the mounting hole will need to be enlarged from 7mm to 8mm.

Special fine thread taps and dies can be purchased from several sources such as the following example link.

Special Pitch Taps - Sizes to 1/2 Inch | HSS Taps

Find special pitch taps in sizes up to 1/2 inch at Victor Machinery. We carry a variety of HSS taps and can also create custom-made leads, helixes, and more.

www.victornet.com

The third photo shows the thread difference between a 10/32 and a 10/72 that were handy.


Jerry Kieffer

 

[DeanT]

Thanks Jerry Kieffer that seems like a good idea. I think I can do that. I was referring to moving the cross hole for the pin which was too close to the chapter ring originally causing it to break. The stud itself is in the correct location.

Your help is very much appreciated and easy to understand. You've obviously spent a lot of time teaching others given your ability to convey concepts.

Cheers
Dean

 

[Jerry Kieffer]

Thanks Jerry Kieffer that seems like a good idea. I think I can do that. I was referring to moving the cross hole for the pin which was too close to the chapter ring originally causing it to break. The stud itself is in the correct location.

Your help is very much appreciated and easy to understand. You've obviously spent a lot of time teaching others given your ability to convey concepts.

Cheers
Dean

Dean
Thanks for the comments.

I hope it or another method works for you.

I teach micro machining classes 3-4 times per year for the NAWCC and Industry. It is my practice to never suggest anything I have not successfully completed myself and or demonstrated. Its only been about 20 years.

Jerry Kieffer