Slipping countwheel drive pinion

[Seth Thomas Fan]

For a long time now the strike on my Seth Thomas quarter-hour bim bam mantel clock (ST 89I countwheel strike) would strike erratically. Finally, today I took the movement out and moved the minute shaft through its paces and observed.

I think I found the cause.

The pinion on the no. 2 strike arbor which drives the countwheel, slips on the arbor (slipping pinion indicated by red circle below)

http://static.flickr.com/92/281732080_6d64abcb6a_o.jpg

That of course causes unpredictable advancement of the countwheel and consequent screwy striking. What I would like to know is: how does one correct that? Is there an easy way to secure the pinion to the no. 2 arbor? By staking? If so, how? For now, I've rotated the countwheel drive wheel (the one parallel and adjacent to the count wheel) which meshes with the pinion till the loose pinion found a place on the arbor where it met some degree of resistance and for now is striking correctly. But I know it's only a matter of time before it slips again.

Any advice is welcome and valuable. I am a novice and have much to learn.

[Bryan Prindle]

Well Seth,

I’m going to probably get clobbered for this, but I had the same slipping problem on gathering pallet on a Junghans, it just wouldn't stay in time. I tried to stake it, etc. just wound up boogering it up.

Finally used Blue Locktite, hasn’t moved since. Just carefully put a smidgeon on both sides of the pinion. Don’t slather it everywhere. Done this way you won’t even be able to see it. Later if you need to, you will be able to remove the pinion, it’s not permanent.

Don’t use Red Locktite, I’ve never used it, put it’s my understanding it’s simi-permanent, that you have to use heat to break it loose. :redface:

Good catch on the pinion though…

Also, note to myself and others, picture is nice and really helps.

Bryan

[wilfr]

Drill 1 or 2 small holes in pinion and wheel put a small pin side to side and rivet both ends, this will solve your problem forever just be carefull to file ends so the do not touch anything.

http://static.flickr.com/91/282366413_c5acbce314_o.jpg

[LaBounty]

You could also knurl the area of the shaft where the pinion resides. This can be easily done with a file but requires you to take the 2nd wheel out of the movement and drive off the pinion.

[bangster]

WOW! Scroll that picture up or down, and you can watch the wheels turn!

bangster

[ticktock]

David,
what tool or tools does one need to knurl the arbor on a lathe?

[LaBounty]

Hey Ticktock-

I don't actually use a lathe for this particular type of knurling. I roll the shaft on the upper edge of a drawer using the edge of a file. This will raise a delicate burr on the steel and the wood underneath won't damage it as it rolls.

But, to answer your question of what to use on a lathe to make a knurl...

If we are talking about a miniature lathe, there are small knurls (wheels with sharp teeth) available from machinist supply houses. I just ordered several from KBC at kbctools.com. The EP series has a hole diameter of 3/16", a diameter of 1/2", and a width of 3/16" (I use part # 1-580A-015 the most). You can attach one of these to the side of a piece of square bar stock, which will fit in your lathe tool post, using a shoulder screw that allows the knurl to spin. Then, the knurl is presented to the material with the cross slide and it will produce a raised pattern (knurl) on the surface of the stock as it is rotated.

I've made several of these to fit my Levin tool post and they come in very handy.

Hope that helps!

[ticktock]

Seth Thomas Fan, that is a nice picture. What kind of camera you using to take those pics?

[Seth Thomas Fan]

Bryan,

I was actually thinking about blue loctite. I may try that if it starts slipping again. I don't want to try drilling, knurling, etc., as my clock skills aren't that great and I stand a great risk of making it worse, not to mention lowering its value.

I actually thought of wiping the pinion and arbor area with some denatured alcohol and putting some shellac there to lock it in place. I could easily remove it with alcohol in the future, while not modifying the movement in any way. Since there's not a lot of force applied by the pinion, I thought it would work.

Does that sound OK?

Ticktock, I used my son's Kodak digital camera, 4 megapixel resolution, I think. Close-up setting with flash. It's just a standard digital camera that he paid I think $140 or $150 for on Ebay (brand new). Takes better pictures than my expensive Olympus single-lens reflex 35 mm camera that I got in 1976!

[shutterbug]

If you're sure it's slipping, the locktite trick might work. If it's just out of place and missing a tooth from time to time it will need to be moved to engage more accurately. It looks pretty far back from the wheel.

[Bryan Prindle]

Seth,

Whats good about Blue Locktite is that you could use it without taking your clock apart. It may not be the most original, but it does work and if applied carefully, you won't be able to see it. It dries pretty clear. You could use a needle, piece of pinion wire or a piece of straw to apply it. The tube applicator is way too BIG.

Hey I just noticed that the BBS has a spelling checker on it now! Good show guys. :smile:

Now how about a few more emoticons for different situations. :biggrin:

Bryan

[Seth Thomas Fan]

If the pinion starts slipping again (and it was definitely slipping) I may try the blue loctite treatment. Thanks for the suggestion. I've used that product before for securing riflescope mounting bases onto rifle receivers, and I know it keeps screws from working loose under recoil, yet screws are easily unscrewed with just a bit of extra torque.

[Bryan Prindle]

Hey Seth, how about a name? You're a frequent poster here. You're among friends.

Bryan

[Seth Thomas Fan]

Thought I'd share what I did about the slipping pinion. I tried blue loctite. My bottle was almost empty and maybe it had expired. Anyway, the liquid never dried after waiting several hours after applying it. I then tried a droplet of my wife's nailpolish (applied with a piece of wire). I allowed it to dry and it's been working fine for a few weeks now, after making an initial fine adjustment on the count hook.

[Bryan Prindle]

Seth:

Could be your "blue" was expired, but when I used the stuff I always let it dry 24 hours.

However, here at work I have also used the fingernail polish trick to secure screws. For others I place a drop between the head of the screw and the plate. Pretty well locks it down, but is easily removable when necessary.

I use "Cha Cha Red" I've had a lot of fun with that over the years. :razz:

Bryan

[Joseph Bautsch]

All of these recommendations will work. However, I would go for a more permanent repair that will not come off until you want it to. I not only repair clock works but also do a lot of antique auto restoration work. That industry has developed some amazing epoxy glues that will give you a permanent repair. These glues have strengths of 2,400 psi and up. Depending on the type you purchase the repair job can be done in 60 seconds to 5 minutes. The beauty of this is that if you ever need to remove the glue apply a some heat and it will come right off. The amount of heat needed will not harm the temper of the arbor and will not discolor the brass.

[TEACLOCKS]

Joseph Bautsch, Can you give some names of suppliers of the epoxys

[Joseph Bautsch]

Teaclocks - The epoxys can be found at most any auto supply store. Also a great place to find all kinds of material and tools and epoxys for clock work is ENCO. This is a machine shop supplier. I found them while doing repair work on antique cars. The e-mail address is: use-enco.com. You can also call them for a catalog at: 800/use-enco.

[Ralph]

If you applied the blue locktite outside the mating surface of the arbor and gear, that is the reason it failed. It cures, when it is deprived of oxygen. You would have to move the gear on the arbor, apply some locktite and return the gear to the original location.

I don't believe it will wick in.

Ralph

[Mike Phelan]

TC
Have a look at this (http://www.bhi.co.uk/hints/loctite.htm).

Over here, most of the Loctite range is available at engineers' suppliers and motor factors - would think it is the same over the pond, but the names may change! :wink:

Ralph is correct about the lack of capillary action; only thread lock will do this.

Loctite 601 bearing fit will take up quite some clearance; two years ago I replaced one of the kingpins on my wife's car where it should have been driven into the arm but could slide in; I Loctited it.
It has done 1000s of miles all over Europe and in temperatures up to 40C and on very rough Belgian roads and the Loctite has not budged.