Loose escape wheel

[rgmt79]

I have an escape wheel which is a little loose on it's arbor. Any advice on how to fix this please? Under magnification, I can see that the hub of the brass wheel is cut to match the teeth of the pinion, but I cannot work out how it's held in place...some evidence of staking on one side but not on the other side...

Richard

 

[shutterbug]

I would try re-staking the area in your first pic. It appears to be set hard against the pinion, so would only be staked on the one side.

 

[rgmt79]

Thanks for your response shutterbug, but there is no shoulder on the pinion for it to be held hard up against. The first picture is not showing the contrast between the brass and the steel. I hope this picture is better, it appears that the end of the steel pivot is somehow peened over, but I cannot see how that works.

Richard

 

[rgmt79]

I take back what I said in my last post. It is easier to see on the larger wheels from the same movement that there is in fact a small shoulder up against which it should be possible to do as shutterbug suggested and re-stake...I now need to work out how to hold this in a staking block without damaging the 0,6mm pivot.

Richard

 

[shutterbug]

Push come to shove, you could make a collar with a hole slightly smaller than the arbor, and press it on snugly against the wheel. That should hold it in place if the staking fails.

 

[rgmt79]

Thanks for that, it should hold it in place laterally but there is also slight radial movement to deal with....lets hope the re-staking will work...

 

[bangster]

LocTite?

 

[shimmystep]

The chances of you fitting the EW back in situ had having it perfectly concentric are a bit slim I'm afraid Richard. Which will make it impossible to put in beat. The wheel teeth would have had its teeth cut after it had been staked onto the pinion.

I can suggest what I might do? Remove the EW, fit it in a box chuck on the lathe and enlarge the centre hole until it was in the round and concentric with the wheel.
Then fit a collet on the arbour, and then cut that to shape on the lathe. The new concentric hole of wheel can then be fitted to the collet which is concentric to the arbour.

The collet can be made to fit over the top of the end of the pinion in order to keep the EW in the same position to the anchor, or behind the pinion if the anchor is easy to move along its arbour.

 

[Jerry Kieffer]

LocTite?

Hey Bangster
Have you ever read the directions for the use of Loctite??

http://www.loctite.com.au/aue/content_data/354580_7128_Do_It_Right_Guide_v5_Approved.pdf

In the second paragraph Under introduction, it states that it only becomes solid in the absence of air. Unless of course, you are suggesting that this particular part be placed in a vacuum chamber for 24 hours to cure.

By only suggesting Loctite, have you not discriminated against soft solder

Jerry Kieffer

 

[R. Croswell]

.......By only suggesting Loctite, have you not discriminated against soft solder

Jerry Kieffer

Let's not discriminate against JB-Weld.

RC

 

[Fitzclan]

Wi

Hey Bangster
Have you ever read the directions for the use of Loctite??

http://www.loctite.com.au/aue/content_data/354580_7128_Do_It_Right_Guide_v5_Approved.pdf

In the second paragraph Under introduction, it states that it only becomes solid in the absence of air. Unless of course, you are suggesting that this particular part be placed in a vacuum chamber for 24 hours to cure.

By only suggesting Loctite, have you not discriminated against soft solder

Jerry Kieffer

With all due respect, I don’t think the introduction says what you imply. Any part of the product not in direct contact with the air which is in contact with metal will harden.
Have you ever used Loctite? I have, and have never had to vacuum seal the parts involved to get the desired result. It probably wouldn’t sell as well as it does if that were the case.
At any rate, there is always more than one way to skin a cat. The OP certainly has at least several options which will work. Loctite probably the easiest and fastest and easiest to undo if desired, but certainly not the only way to go.
Just my 2 cents.

 

[Willie X]

I usually restake a loose wheel very lightly at first, then a little tighter by small increments. As truth is established and there is no more wiggle, I solder it with tix solder and flux. If properly done this will not be visible and it will probably be stronger than it was when it was new. It usually takes 1 or 2 bits of solder (placed on the joint) each piece being about 1/16" long, flame solder with a small brushey flame.

IMOE? a loose wheel is usually caused by a serious shock. Sometimes the cause is evident, sometimes not.
Willie X

 

[Jerry Kieffer]

Wi


With all due respect, I don’t think the introduction says what you imply. Any part of the product not in direct contact with the air which is in contact with metal will harden.
Have you ever used Loctite? I have, and have never had to vacuum seal the parts involved to get the desired result. It probably wouldn’t sell as well as it does if that were the case.
At any rate, there is always more than one way to skin a cat. The OP certainly has at least several options which will work. Loctite probably the easiest and fastest and easiest to undo if desired, but certainly not the only way to go.
Just my 2 cents.

Fitzclan
My response to Bangster was meant to be humorous as we have commented to each other many times over the years.

However on a serious note, I of course have used loctite as intended and have discussed its use in-depth with factory representatives at major machine tool shows. Its use on the OP`s escape wheel would not be advisable or a sound repair nor was it designed for this type of repair. Personally, I do not use Loctite or any other adhesive not originally used by the manufacturer in Horological movement repair.

Jerry Kieffer

 

[Jerry Kieffer]

I have an escape wheel which is a little loose on it's arbor. Any advice on how to fix this please? Under magnification, I can see that the hub of the brass wheel is cut to match the teeth of the pinion, but I cannot work out how it's held in place...some evidence of staking on one side but not on the other side...

Richard

View attachment 495377 View attachment 495378 View attachment 495379

Richard
This type of Pinion/ wheel mounting system sometimes will have a pinion pocket that was not machined as long as intended at the factory. Thus it may require that the pocket be machined ever so slightly longer to be properly staked. A properly staked escape wheel of this type, will have many times more strength than required for safe operation.

jerry Kieffer

 

[Willie X]

I see what Jerry is talking about. There is a lot of air to air contact! Willie X

 

[Bruce Alexander]

Interesting,

So Richard, if you move the EW Gear away from the leaf pinion, what are you looking at immediately adjacent to the pinion where the EW Gear normally resides? Could you please post a photo if you have the time? Thank you.

Bruce

 

[rgmt79]

Many thanks for all the input guys and I respond as follows:

The chances of you fitting the EW back in situ had having it perfectly concentric are a bit slim I'm afraid

The EW is not so loose that it's flopping around, the movement perpendicular to the arbor is barely detectable and I would say no more than would exist between pivot and bushing, similarly with lateral movement. The most movement is radial by maybe 2 or 3 degrees.

This type of Pinion/ wheel mounting system sometimes will have a pinion pocket that was not machined as long as intended at the factory. Thus it may require that the pocket be machined ever so slightly longer to be properly staked.

I'm sorry Jerry, but I'm not sure what you are saying, can you provide a little sketch please?

if you move the EW Gear away from the leaf pinion, what are you looking at immediately adjacent to the pinion where the EW Gear normally resides?

As I indicated above in my repose to Shimmystep, there is not enough movement to do as you suggest.

Richard

 

[Bruce Alexander]

As I indicated above in my repose to Shimmystep, there is not enough movement to do as you suggest.

Okay Richard. Thank you for your reply. I was hoping to better visualize what Jerry is referring to. Perhaps he'll be able to do as you request and provide visual aids to those of us who do not have his mechanical vision.

Regarding LocTite, a mentor of mine used the red formula (for threads) LocTite on all of his press fit bushings. I started doing that about 10 years ago and then got away from it. I have recently resumed using it routinely on most bushings. If I have the need for an immediate "set", I have the tools to peen a bushing and broach it. I use LocTite 680 retaining compound. I have no doubt that it improves the retention of my bushings to the point that they'll need to be reamed out if or when the need arises (hopefully only due to wear and only after a long service life). I don't think its use is absolutely necessary, and if I ever came across a bushing loose enough to require it, I would not place that bushing. In such a case, either the bushing or my prep would be out of spec. If it's the bushing, that should be a quick and easy issue to address. If it's my prep, I would be forced to turn a custom bushing, seriously consider what I'm doing wrong and stop doing it (sloppy prep, worn reamer...whatever). I like the dispenser the 680 comes in, and personally I like having it on hand. It only has about 1/4th of the compressive shear strength of something like silver bearing solder but it's more easily reversible. It's not intended to be used as a structural material or "glue". I view it as an extra measure, not a substitute. It seems to begin curing very quickly and I feel the need to not dawdle when working with it. I suppose anaerobic conditions are met if I get some on a fingertip and hold something in that finger. In any case it feels 'sticky' to me almost right away. It's not something used in the original manufacture of the movements I work on but strictly speaking, neither are press-fit bushings.

Having said all of that, I don't think I would entertain the thought of using it here as the joint between the gear and the arbor doesn't appear to be a "sleeve" and Richard would have to make matters worse to properly apply it. It sounds to me as though the gear just needs to be carefully staked on the back side.

I'm interested in learning more about this type of metal joint. How about it Mr. Kieffer? Could you please explain/illustrate further? Thank you.

Regards,

Bruce

 

[rgmt79]

Thanks Bruce, I have used Loctite 638 successfully in a very different application (see my post #12 in thread Great Wheel Repair) but I would not contemplate it for this fix.

Richard

 

[Tim Fitzgerald]

Very interesting topic, even for a P/W person

 

[Bruce Alexander]

Thanks Bruce, I have used Loctite 638 successfully in a very different application (see my post #12 in thread Great Wheel Repair) but I would not contemplate it for this fix.

Richard

Hi Richard,
Interesting thread. I understand the restrictions you were working under. I'm not certain I would feel comfortable with LocTite on a Great Wheel but there is plenty of surface area for the "joint" and no doubt you made it a tight fit. Looks good. I take it that the clock is yours? Maybe you can revisit the repair the next time you tear the movement down for maintenance. It would be interesting and helpful to see your follow-up. Henkel (?) may have moved on to other formulas by then but hopefully the products we are using today will have proven themselves to still be useful well into the future. Thanks for sharing your result and good luck with the task at hand.
Bruce

 

[R. Croswell]

Regarding LocTite, a mentor of mine used the red formula (for threads) LocTite on all of his press fit bushings. I started doing that about 10 years ago and then got away from it. I have recently resumed using it routinely on most bushings...... I use LocTite 680 retaining compound. I have no doubt that it improves the retention of my bushings to the point that they'll need to be reamed out if or when the need arises (hopefully only due to wear and only after a long service life). I don't think its use is absolutely necessary, and if I ever came across a bushing loose enough to require it, I would not place that bushing. ......I view it as an extra measure, not a substitute.

Having said all of that, I don't think I would entertain the thought of using it here..........

So you started using red Loc-tite on press fit bushing because of your mentor, so why did you "get away from it"? And why did you recently resume using "it"? Do you mean you resumed using Loc-Tite that you resumed using red thread locker or started using 680 retaining compound? Generally, I believe that the retaining compounds expect a close slip fit so there is some space for the compound between the parts to be retained. I'm wondering how well this will work with a press fit bushing? have you actually compared the force required to remove identical press fit bushings with and without Loc-Tite?

As for the current repair Loc-Tite might actually work if enough of it finds its way into the actual joint where it should cure. The excess uncured material would need to be removed, but the repair would be invisible. I don't think that this would be the ideal method but there isn't much to be lost in trying unless of course one wants to use solder which would not work with Loc-Tite in the joint.

RC

 

[Jerry Kieffer]

Many thanks for all the input guys and I respond as follows:

The EW is not so loose that it's flopping around, the movement perpendicular to the arbor is barely detectable and I would say no more than would exist between pivot and bushing, similarly with lateral movement. The most movement is radial by maybe 2 or 3 degrees.

I'm sorry Jerry, but I'm not sure what you are saying, can you provide a little sketch please?


As I indicated above in my repose to Shimmystep, there is not enough movement to do as you suggest.

Richard

Richard
As mentioned, Typical clock movements are far from precise as precise is defined in the word of metal working. So is the minimal amount of machining on parts to the point that often parts are not machined identical even in identical movements.
It is rare to encounter a staked wheel that comes loose, but it does happen per your example. Typically when this happens, the pinion leaf area to be staked will not extend past the wheel to allow the metal to be expanded and rolled over the edge of the wheel during the staking process, locking the wheel in place. My personal solution for this is to machine the pocket about .010" deeper or less providing more metal for the staking process per the attached sketch.

The first photo simply shows a pocket in a pinion where a wheel can be mounted and staked.

The sketch of a single leaf should be self explanatory where it applies based on other identical movements without issues.

The second photo shows my personal setup Utilizing a small Mill as as a Staking tool. Third photo shows a closeup showing the use of a watchmakers staking tool stake to stake the wheel. The process involves locking the anvil to the bed as shown. Then mounting the staking tool in a WW collet in the Mill to a snug slip fit and tapping the top of it with a driver that extends out the top of the spindle shown in the second photo. Fourth photo shows a verity of stakes available for this procedure from a watchmakers staking set. This allows you to duplicate most staking patterns with the work piece safely and securely locked in place.

Jerry Kieffer

 

[Bruce Alexander]

Jerry, I'm just going to have to get myself some type of Mill. I have a Watchmaker's Staking Kit but the Anvil is often too limited in size for clock wheels and parts. Thanks for that explanation. It just wasn't clear to me what you meant by "pocket".

RC I was kind of expecting you to jump in with your usual probing questions. You seldom disappoint.

In no particular order;
No, I don't use LocTite 262 anymore. Mostly because the tube I had on hand was too old and the little plastic nozzle was always plugging up. I would constantly need to poke or drill through a cured plug in the application nozzle in order to dispense product. I then decided to try Loctite 638, which is specifically formulated for sleeve retention. However, I had the same problem with the application tube plugging up since the packaging/dispenser was basically the same as before. I have tossed both of those tubes out because they were too old and the nozzles were getting pretty "chewed up" with my constant efforts to re-open them back up. Evidently the packaging was not intended to be used for small, frequent applications of the product. Most recently, I've purchased the 680 formula and have been very pleased with an improvement in the package dispensing tip. It does not clog and gives me the ability to apply very small amounts to my bushings.

The 680 Formula has directions for slip, press and shrink fitted assemblies. It is designed for fitting of cylindrical parts where low viscosity is required. I really like the stuff. Have I set up an engineering lab to test its effectiveness, RC? Nope, I sure haven't. Have I looked at specs reported by their Engineers and Tests on the product? Yes, I have. Do I know that some press fit bushings without additional retentive measures are relatively easy to displace? In my experience, yes they can be. That's not to say they are loose. I have chosen to have some of the 680 on hand, and I have decided to use it rather than lose it to an expired shelf-life.

Why did I get away from using LocTite? For a while I worked with peening and reaming press fit bushings, but only when they fit didn't feel as tight as I would like it to. I experienced this most often with a batch of bronze bushings I ordered from Timesavers (as I recall). It's a fast and effective method of setting a slightly marginal bushing and I think it is good for me to have it in my toolbox.

I wouldn't use LocTite on the joint in question unless the Gear is to be removed for adequate application of the product. Even then, the joint is not a Cylinder, nor is it a series of threads so I don't see it as lending itself to the use of LocTite. If, for whatever reason, the pocket is not to be deepened to expose additional metal for staking, and if I couldn't stake securely with the current joint form, I would probably use very small amounts of silver bearing solder instead of LocTite. This is an EW so even a soft solder like Tix would probably provide more than enough bonding in the joint.
Did I miss anything RC?
Regards,

Bruce

 

[R. Croswell]

No, I don't use LocTite 262 anymore. Mostly because the tube I had on hand was too old........ Most recently, I've purchased the 680 formula and have been very pleased with an improvement in the package dispensing tip. It does not clog and gives me the ability to apply very small amounts to my bushings.

You make a very important point that everyone who uses Loc-Tite needs to be aware of regarding the expiration date. In my shop it always reach the expiration date before I use it all. "The 680 Formula has directions for slip, press and shrink fitted assemblies". I think 680 would seem to be a good choice but there are so many choices, if one can find them. Where did you find it available?

]Have I set up an engineering lab to test its effectiveness, RC? Nope, I sure haven't. .....Do I know that some press fit bushings without additional retentive measures are relatively easy to displace? In my experience, yes they can be. That's not to say they are loose. I have chosen to have some of the 680 on hand, and I have decided to use it rather than lose it to an expired shelf-life..........Why did I get away from using LocTite? For a while I worked with peening and reaming press fit bushings, but only when they fit didn't feel as tight as I would like it to. .........It's a fast and effective method of setting a slightly marginal bushing and I think it is good for me to have it in my toolbox.

Isn't that a bit like taking pills when you aren't sick just to use them up before the expiration date? A good quality press fit bushing in a properly sized hole with parallel sides (not reamed by hand with a tapered reamer) should have sufficient friction to retain the bushing. I can see how 680 Loc-Tite would add a margin of safety if the dimensions or shape or the bushing or the hole were at all compromised. I'm more interested in whether, and to what degree a retaining compound like 680 Loc-Tite might increase the "hold" of a properly fitted pressed in bushing in a properly sized hole with parallel sides. I don't have problems with bushings popping out on their own but I have had a bushing slip when pressing on or removing a gathering pallet, cannon pinion, or minute hand, etc Perhaps I'll experiment with it and see what I can see.

I wouldn't use LocTite on the joint in question unless the Gear is to be removed for adequate application of the product. Even then, the joint is not a Cylinder, nor is it a series of threads so I don't see it as lending itself to the use of LocTite. If, for whatever reason, the pocket is not to be deepened to expose additional metal for staking, and if I couldn't stake securely with the current joint form, I would probably use very small amounts of silver bearing solder instead of LocTite. This is an EW so even a soft solder like Tix would probably provide more than enough bonding in the joint.
Did I miss anything RC?
Regards,

Bruce

Tix or soft solder would hold but I don't like using the required corrosive flux in a place like this because it can be hard to remove all the flux and we wouldn't know for some months when corrosion sets in. As for "plan-B" options to make it work without regard to creating an invisible repair, A little JB-Weld will hold it in place and be not much more obvious than solder. It really depends on one's objective, outcome criteria, and ability to execute the plan. It is great to have options and various opinions and experiences which are usually abundant here.

RC

 

[Bruce Alexander]

Isn't that a bit like taking pills when you aren't sick just to use them up before the expiration date?

More like vitamins I suppose. Doesn't take much time but it is an additional step so if speed is important, one is probably not going to be interested in putting on a belt and suspenders when one or the other will keep the pants up.

A little JB-Weld will hold it in place and be not much more obvious than solder.

JB-Weld is pretty viscous. I think one has much more control over the placement of an adequate amount of solder. Plus solder has a metallurgical alloy component in the joint. JB Weld is a steel particle filled epoxy (as I recall.) As far as the Flux is concerned, just run the wheel back through your standard cleaning process. That should take care of it I think.
Regards,
Bruce

 

[Bruce Alexander]

Where did you find it available?

Sorry, I missed that question RC.
I found it on Amazon. It should be widely available

 

[shimmystep]

The EW is not so loose that it's flopping around, the movement perpendicular to the arbor is barely detectable and I would say no more than would exist between pivot and bushing, similarly with lateral movement. The most movement is radial by maybe 2 or 3 degrees.

Hi Richard. Any movement away from the concentric will mean it will be unable to be put in beat, even if slight.
You can't compare it to the play 'between a pivot and bushing', the pivot isn't fixed to the bushing, and there needs to be some play there.

Glue, solder, JB weld etc should all be plan Z

 

[Bruce Alexander]

Any movement away from the concentric will mean it will be unable to be put in beat

Hello Shimmy. You've fabricated EW's so your time and input carries some gravy-toss here.
Seriously, isn't it sometimes recommended that an EW's teeth be "tipped" or carefully turned even as routine maintenance during an overhaul? If the gear is loose, I would suspect that tipping the teeth would be advisable regardless of what method Richard uses to tighten the joint. Re-staking included.

 

[shimmystep]

Hello Shimmy. You've fabricated EW's so your time and input carries some gravy-toss here.
Seriously, isn't it sometimes recommended that an EW's teeth be "tipped" or carefully turned even as routine maintenance during an overhaul? If the gear is loose, I would suspect that tipping the teeth would be advisable regardless of what method Richard uses to tighten the joint. Re-staking included.

Aha, a tempting trap to fall into Bruce!

I agrees that sometimes the EW needs 'tipping', but the EW must be concentric for this to be done when turned on the arbour.

See the sketch below. As you move up or down the radial lines A B, you can see that the distance (1,2,3) between them obviously changes.This remains a consistent through all, as long as the radial lines are taken from dead centre.

Now if you move the dead centre, i.e. have the EW mounted on the arbour out of true, when you tip the ends, the distance between the teeth tips will differ depending on what side of the 'off' centre it is mounted.

 

[Jerry Kieffer]

Interesting discussion

Escape Wheel maintenance is critical if required and often overlooked.

When I have completed a repair, I listen for any variation of beat over one or more complete rotations of the escape wheel amplified if required.
If any variation can be detected, I then service the escape wheel as follows.

(1) First, It is critical that the escape wheel OD run true in relation to the pivots. I check this in the Lathe by comparing runout under optics by hand rotating the wheel in comparison to a sharp pointed lathe tool per the first attached photo. One pivot is mounted in a collet and the other pivot is supported. If variation is detected, the wheel is slowly ramped up to about 2000 rpm as not to place stress on the pivot. Then the sharp pointed lathe tool is used to just touch the teeth until all have been touched usually less than .001" on a untampered wheel. At this depth and speed, the cut is extremely clean with no detectable cutting stress on the driven pivot. The speed is then slowly decreased to again to eliminate any stress on the driven pivot.

(2) You can bend or tip any tooth for any reason, but you then risk loosing equal indexing to other teeth that in some cases effects proper setting of the beat. My personal method of dealing with teeth is to set the wheel up in the Mill in the same manner as if I were to cut the wheel per second photo. I then install a escape wheel cutter that I generally have, but one is easily ground free hand on a bench grinder as seen in the third photo. After the cutter is positioned per the third photo, I rotate the cutter up and index to each tooth where spacing and indexing can be adjusted to match the cutter position if required. Thus, both spacing and indexing are addressed.

Jerry Kieffer

 

[Bruce Alexander]

Thanks for that Shimmy. I know that your illustration is scaled to explain and prove a point but Richard did mention that the EW is a...

little loose on it's arbor

...
I get the impression that it's not loose enough to remove, at least not easily removed anyway. Staking could easily move the wheel slightly off center too but thanks for taking the time to illustrate your point (well taken).

Jerry, I would be awfully nervous driving a pivot. That's probably because I'm still kind of like a bull in a china shop on when it comes to doing ultra-fine machine work on my Lathe. Thanks for sharing those photos.

 

[Willie X]

rgmt,

You can use a pair of simple "V" blocks and your fingernail. Your fingernail will drag the high spot. Mark it, and stake one light blow opposite your mark. Rinse and repeat as necessary to center and tighten.

If you find more than one high spot, or low spot, you will have to "top" the wheel. This to can be done by hand using a throw and a fine stone. Or you can use a Fordham tool and a wooden "V" block. When topping, you usually have to do a slight clean-up afterwards with a small fine barrett file. This is not to reshape anything to much, but to remove any tiny burrs. Unless the wheel is damaged, the topping operation will only need to remove a tiny amount of metal.

Note, always do the topping with the pointie side of the teeth turning into the stone.

Willie X

 

[Jerry Kieffer]

TAT
There are a few times when driving the pivot is required such as this example if accuracy is a concern. For safety and security of the part, They should only be driven in a proper fitting collet with opposite end support and variable speed drive as described. Under these conditions with little detectable load, there is little issue driving a pivot when common sense is applied.
Practice in a junk wheel will surprise you with how strong pivots actually are.

Jerry Kieffer

 

[Bruce Alexander]

Practice in a junk wheel will surprise you with how strong pivots really are.

Thanks. Will do.

 

[kinsler33]

Green Loctite ought to work. It'll penetrate very small openings so you wouldn't have to disassemble anything and, though classified as a low-to-medium strength product, holds very tightly in my experience. It smells horrible and will migrate anywhere you don't want it to go, but if your escape wheel is out of the clock anyway, one drop of the stuff will hold for the forseeable future.

M Kinsler

 

[R. Croswell]

TAT
There are a few times when driving the pivot is required such as this example if accuracy is a concern. For safety and security of the part, They should only be driven in a proper fitting collet with opposite end support and variable speed drive as described. Under these conditions with little detectable load, there is little issue driving a pivot when common sense is applied.
Practice in a junk wheel will surprise you with how strong pivots actually are.

Jerry Kieffer

I think the greatest risk to the pivot, especially if its a very hard pivot, it that it can be accidentally snapped off or bent during the setup. As Jerry said, apply "common sense", and obviously the means of supporting the opposite pivot needs to be "on center" as well. In cases like this I have fitted a bushing on the opposite pivot and chucked the bushing in the tail piece or in a study rest. Perhaps Jerry has a better way?

RC

 

[rgmt79]

WOW, once again I'm overwhelmed by so much input and much information and advice to absorb. I respond as follows:

As mentioned, Typical clock movements are far from precise as precise is defined in the word of metal working. So is the minimal amount of machining on parts to the point that often parts are not machined identical even in identical movements.
It is rare to encounter a staked wheel that comes loose, but it does happen per your example. Typically when this happens, the pinion leaf area to be staked will not extend past the wheel to allow the metal to be expanded and rolled over the edge of the wheel during the staking process, locking the wheel in place. My personal solution for this is to machine the pocket about .010" deeper or less providing more metal for the staking process per the attached sketch.

The first photo simply shows a pocket in a pinion where a wheel can be mounted and staked.

The sketch of a single leaf should be self explanatory where it applies based on other identical movements without issues.

The second photo shows my personal setup Utilizing a small Mill as as a Staking tool. Third photo shows a closeup showing the use of a watchmakers staking tool stake to stake the wheel. The process involves locking the anvil to the bed as shown. Then mounting the staking tool in a WW collet in the Mill to a snug slip fit and tapping the top of it with a driver that extends out the top of the spindle shown in the second photo. Fourth photo shows a verity of stakes available for this procedure from a watchmakers staking set. This allows you to duplicate most staking patterns with the work piece safely and securely locked in place.

Jerry, thank you for that master class I have a mill and I will follow your procedure for staking. However, I think there is enough metal there to do the re-staking without the need to deepen the pocket as you suggest. The ES has only become slightly loose and has not broken away from the original staking. Otherwise, I would need to machine away the original staking and start from scratch.

I agrees that sometimes the EW needs 'tipping', but the EW must be concentric for this to be done when turned on the arbour.

shimmy, I'm not sure if I understand what you and TAT mean by 'tipping'? I assume it means 'dressing' the circumference of the wheel, but surely if the wheel is concentric there should be no need to do this and if it isn't concentric, then simply 'dressing' the wheel will achieve nothing?

When I have completed a repair, I listen for any variation of beat over one or more complete rotations of the escape wheel amplified if required.
If any variation can be detected, I then service the escape wheel as follows.

Jerry, again thank you, I will do as you suggest when I come to reassemble the movement.

Richard

 

[Bruce Alexander]

Common sense implies common experience. Every instruction I've previously come across cautions against chucking a pivot. For beginners, with little common experience, that's probably a good rule to observe. I've got plenty of bone yard gears. I'll play with it. Regarding use of a bushing, I did employ the drive dog approach you and banster have detailed RC. A simple pivot-polishing aid for your lathe The intent of which is specifically to avoid chucking a pivot with insufficient length of exposed arbor before the gear or pinion to get a hold of with your chuck or collet. I've found that a straight nail head serving as a tie point for a rubber band gives one more flexible set up options for odd wheel and pinion shapes, sizes and placements. But, that's getting off topic.

I assume it means 'dressing' the circumference of the wheel

Hello Richard. Yes, that's how I'm using the term. I think that the more the EW is off dead center, the less you want to attempt to use this approach. I've only come across its use in "dressing" an EW that has had some bent teeth straightened out. I think Shimmy is saying that the more you flatten an EW tooth profile, the more you'll change spacing and timing through the pallets. You certainly want a sharp tip at the end of a tooth, not a plateau. I suppose you can always go back and re-sharpen the tooth but the EW set up pretty critical as you well know.

Please let us know how you go about addressing the issue.

 

[R. Croswell]

.........Every instruction I've previously come across cautions against chucking a pivot. For beginners, with little common experience, that's probably a good rule to observe. ......Regarding use of a bushing, I did employ the drive dog approach you and banster have detailed RC. A simple pivot-polishing aid for your lathe The intent of which is specifically to avoid chucking a pivot with insufficient length of exposed arbor before the gear or pinion to get a hold of with your chuck or collet. I've found that a straight nail head serving as a tie point for a rubber band gives one more flexible set up options for odd wheel and pinion shapes, sizes and placements.........

The dog and bushing approach is fine for pivot polishing. Can also use tape and bushing. But if we are actually going to machine the diameter of an escape wheel I would rather chuck the pivot so there would be zero looseness in the drive. Even the bushing at the tail should have minimum clearance, and of course if the hole in the bushing isn't perfectly centered that can be an issue. I don't think I would use an elastic drive for actual turning but haven't tried it. To some extent the method will depend of the individual part and how much precision is necessary or desired.

RC

 

[shimmystep]

I think Shimmy is saying that the more you flatten an EW tooth profile, the more you'll change spacing and timing through the pallets.

Kind of Bruce Though it's not so much about changing the EW tooth tip profile as you say. What I'm trying to say is that you can not tip/dress/top (whatever term we use) if the wheel is not concentric, unless you are able to address the indexing/pitch afterwards. Because if the wheel is not turned at exactly dead centre on the lathe, one side of the wheel will have more material removed that the other side side. hence the pitch will be different on one side of the wheel, as per sketch, see what I mean?

On the subject of driving from a pivot...done this plenty of times without disaster to dress an EW. I take such a tiny advance into the wheel with a very very sharp tool, that the pivot is not really under too much threat.

 

[Bruce Alexander]

I'm familiar with the use of tape. I've tried using elastic bands for pivot polishing and I like them but I agree that it's probably not a good, solid drive for most any kind of turning. I just brought it up as an example of how chucking pivots is normally discouraged.

 

[Bruce Alexander]

see what I mean?

Yes I did Shimmy. As per Richard's situation If the EW is not on dead center one "side" of teeth will be trued (or flattened) while the teeth on the opposite side of the gear will be untouched (or only very slightly machined at the stopping point of the process). The more out of true the wheel is mounted, the more this will be the case. That will change the shape of the teeth as well as the distance between the effective "tip" of the teeth which have been the most heavily machined in dressing the gear. Is that right? I kind of doubt that we're talking significant tolerances here though. Richard is only seeking to tighten the joint, not re-establish it.

Regarding pitch, if a slight change in pitch of the teeth in question doesn't interfere with the pallets' motion (locking and impulse) and if the distance between the teeth are uniform, will there be any significant effect on the escapement's operation?

 

[shimmystep]

Yes I did Shimmy. As per Richard's situation If the EW is not on dead center one "side" of teeth will be trued (or flattened) while the teeth on the opposite side of the gear will be untouched (or only very slightly machined at the stopping point of the process). The more out of true the wheel is mounted, the more this will be the case. That will change the shape of the teeth as well as the distance between the effective "tip" of the teeth which have been the most heavily machined in dressing the gear. Is that right? I kind of doubt that we're talking significant tolerances here though. Richard is only seeking to tighten the joint, not re-establish it.

Regarding pitch, if a slight change in pitch of the teeth in question doesn't interfere with the pallets' motion (locking and impulse) and if the distance between the teeth are uniform, will there be any significant effect on the escapement's operation?

I would put aside in your mind how 'flattened' the end of the teeth will be
That is not the real issue here. Only the leading edge of the tooth will contact the impulse face.

It is about the reducing the distance between A + B unevenly on different sides of the wheel if the wheel is not concentric when dressed. ANY tolerances on the EW, due to it not being concentric when dressed in this regard will mean it will be out of beat.

Richard will have difficulties 'tightening the joint', and leaving it concentric. The teeth of this EW were cut after it was staked onto the arbour, if it is now loose on the arbour even by a little, that advantage is lost and it's a tough job to make it right again without going through sound mechanical remedial processes. That's not to say that were it fitted to the arbour out of true, (with glue, JB weld or solder) that it wouldn't run, but you'll only get it in beat for a percentage of the circumference....and that would drive me potty

 

[Bruce Alexander]

I would put aside in your mind how 'flattened' the end of the teeth will be

Okay. I think we're talking about the same thing, I'm just focused more on the tip of the tooth as that's how distances between adjacent teeth are measured, no?

That's not to say that were it fitted to the arbour out of true, (with glue, JB weld or solder) that it wouldn't run, but you'll only get it in beat for a percentage of the circumference....and that would drive me potty

I have seldom seen escapements with absolutely 0% instantaneous beat error throughout the entire circumference of the EW. I'm most familiar with mass produced American Mantel Clocks. What percent beat error are you willing to accept?

 

[shimmystep]

Okay. I think we're talking about the same thing, I'm just focused more on the tip of the tooth as that's how distances between adjacent teeth are measured, no?

I have seldom seen escapements with absolutely 0% instantaneous beat error throughout the entire circumference of the EW. I'm most familiar with mass produced American Mantel Clocks. What percent beat error are you willing to accept?

yes, we are. If the wheel is concentric and the wheel is dressed, it will change the geometry a little, the drops will be a little increased. Though dressing only needs to remove a mirco smidgen, enough to remove the accumulated embedded detritus that wears the impulse faces.

tbh Bruce, I rarely see American Mantel clocks this side of the pond, I'm sure you're right, of the few I've worked on, I remember them being very noisy! I'll remember what you say if I see another one though and I'm chasing my tail over 100% circumference beat

 

[rgmt79]

Green Loctite

M Kinsler, do have a reference number for this Loctite ###?

Richard

 

[rgmt79]

After some distractions, I finally got around to sorting out the loose EW. To minimise the risk of losing concentricity between the arbor and the wheel, I made a staking tool to fit over the arbor so that the re-staking could take place around the circumference simultaneously. I intended using my Mill to do the staking as per Jerry's suggestion, but unlike the Sherline, my Mill (Unimat 3) does not allow me access to the staking punch through the centre of the spindle....so I did it by hand as seen in the photo. 3 or 4 sharp taps seem to have done the trick. I checked for concentricity by mounting in a collet in the lathe and turning by hand against a sharp pointed tool and all seems well

Thanks again for all the input.

Richard

 

[kinsler33]

M Kinsler, do have a reference number for this Loctite ###?

Richard

Whoops. I forgot to answer this. Lemme go see if I can read what's left of the printing on the tube....
...well, for one thing, it's not Loctite. It's Permatex 29000. I probably got it at Advance Auto Parts, which is a thoroughly generic national auto parts chain. Smells horrible but penetrates nicely and will let go when you need it to.

I have been fighting with a stubborn gathering pallet that refuses to stay locked to its shaft. I even bushed the hole in the fool thing. I think I've finally gotten it to hold with a drop of thoroughly-mixed Super Weld (if that's the name) Epoxy from Harbor Freight. It's a white + black = gray two-tube epoxy that takes at least overnight to set, but I haven't had any failures thus far.

Mark Kinsler

 

[Bruce Alexander]

Glad you got it sorted out Richard.
Great Thread with many helpful suggestions!