Pivot polishing compound alternatives

[Salsagev]

Is there any polishing compounds that would work for pivot polishing after a series of sand papering? I've got Brasso, Pre-lim, and Toothpaste. What amount of increments of sand paper should I use? I have grits to the thousands.

 

[Kevin W.]

https://mb.nawcc.org/threads/any-tips-on-pivot-polishing.135416/

There is lots on the subject on this web site, just do a search.

 

[Salsagev]

Thanks for the link but nothing mentions the use of different polishing compound alternatives to (such as) Semichrome or some block polish.

 

[Willie X]

Tripoli on a hard leather buff, or Tripoli on a 4" high speed muslin buff, works for me. Note, the first option is much slower but much safer, for you and the clock parts.
.
When the the pivots have grooves, that's another story, where a lathe, or some kind of throw, is necessary. A fine pivot file, to 400 wet-n-dry, to 800 wet-n-dry, to Tripoli is good for most.

Then there is re-pivoting. This is not that common in my shop. But it's definitely a necessary thing at times.

Smoooooothe ...

 

[Salsagev]

Nothing needs to be done if the pivots pass the fingernail test? Some pivots have very "sharp" grooves in them and some are filed away. A drill is the rotary tool I have now or I have a 5 dollar rotary tool from Harbor freight but thats too fast. I don't have Tripoli now. Can the sandpaper be even higher grit than 400?

 

[Salsagev]

Actually, I do have Tripoli in the Art bin.
Edit: it's so satisfying when you have things you didn't know you had!

 

[Schatznut]

I use Meguiar's car polish. Works wonderfully well and you can buy a quart of it at Harbor Freight for not much money. I use a felt wheel on my Dremel tool and get a finish that shines - even under a microscope.

 

[R. Croswell]

Nothing needs to be done if the pivots pass the fingernail test? Some pivots have very "sharp" grooves in them and some are filed away. .................. Can the sandpaper be even higher grit than 400?

I prefer to examine the pivot under optics. I do not want to see grooves, scratches, chips, etc. The pivot should also not be tapered. Sometimes a pivot will be worn just where the pivot hole is leaving the outer end unworn and larger. The fingernail test will only reveal the larger imperfections. A pivot with grooves may run OK in some clocks but will rapidly wear your new bushing.

If there are no grooves, I start with 1000 grit wet-or-dry paper, followed by 2000 grit wet-or dry paper. I spin the pivot in my lathe. You can turn the wet-or-dry paper over and use the back side (or a piece of brown paper bag) and an alternative polishing method. I use Semichrome polish - expensive but works pretty well. Wit any abrasive polish it is most important to be sure all the residue, wax, ete. is completely removed.

You will be more likely to find 1000 and 2000 grit paper at an automotive supply store in the paint department. Regular paint and hardware stores sometimes do not have the finer grit paper.

I have found that a drop of thread cutting oil on the 1000 grit (or 800 grit) paper will help cut faster and prolong the life of the paper.

RC

 

[shutterbug]

Check these out. They work well. You could also make your own if so inclined.

 

[Salsagev]

Thanks for the replies. So is it like a rule that all pivots are to be polished even when cosmically good condition?

Is the Tripoli stuff like the yellow chalk like stuff for sharpening knives what we mean?

Do I need all those emory buffs?

Im guessing crude and common American movements don't necessarily need any special pivot treatment to run perfectly?

If the Tripoli is the final polish touch to the pivot, do I still need any other compound such as Semichrome and such?

Almost got it. Thanks everyone.

 

[Altashot]

I use sand paper glued to very carefully selected popsicle sticks.
Sometimes I use my pivot file/burnisher double ended tool but I found that I get better, faster results with sand paper.
The sand paper I use is from a local hobby shop. They all come in 1 package. Grits are as follows:
320, 400, 600, 1000, 2000, 4000, 6000, and 12000.
I don't always start with the coarser grits but I always finish with the 12000.
The wheels are spun in my lathe to a mirror finish.

M.

 

[bruce linde]

what does cosmetically ok mean? to the naked eye? 5x magnification? more?

https://abouttime-clockmaking.com/pdfs/whiteman_pivot_analysis_1_labounty.pdf

https://abouttime-clockmaking.com/pdfs/whiteman_pivot_analysis_2_labounty.pdf

 

[shutterbug]

I have seen pivots in very old clocks that appear to have never been smooth. It's like machining marks on them. So my personal view is that smooth to sight (un-magnified) and passes the thumbnail test is good enough. I agree that a perfect surface is ideal. But a good surface will provide a good bearing surface and will last a very long time.

 

[R. Croswell]

...........So is it like a rule that all pivots are to be polished even when cosmically good condition? .........Im guessing crude and common American movements don't necessarily need any special pivot treatment to run perfectly? If the Tripoli is the final polish touch to the pivot, do I still need any other compound such as Semichrome and such?

We polish pivots for two primary reasons - to reduce friction, and to reduce the rate of wear. The more you reduce friction the better and stronger the clock will run. The smoother you make the pivot the longer the bushing will last before needing to be replaced again. "Common American movements" are often over powered and will run when the pivots are less than perfect but the same principle applies. So how good is "good enough"? When we say something is "good enough" we are acknowledging that it isn't as good as it could be. I would urge you to set your goal to be "good" not just good enough.

You usually do not need to work work up through all the grit stages or use multiple polishing agents, but if the pivot has visible defects the courser grit papers (or even a pivot file) will remove metal faster to begin work. If you start with one of the finest grit papers it will take a long tine to do the job on a rough pivot. If the pivot already "looks good", you might start with 2000 grit paper. If it already looks good and shinny you might just go right to the polishing compound, or just clean it and leave it alone unless you think you can improve it. Note that 2000 grit paper (or any other) soon wears down and effectively acts like a finer grit. I would only use one final polishing compound, try several and see which one you like best.

RC

 

[Rod Schaffter]

Call me a rebel, but I use Butterworth's polishing disks...

 

[Ralph]

No one has challenged pivot polishing using abrasives and polishing compounds? There has been a lot of discussion in the past, here and elsewhere. There's more to a polished pivot then cosmetics.

The attached PDF document sheds some serious light on the subject.

Dave Labounty has an article on the subject as well.

https://abouttime-clockmaking.com/pdfs/burnishing_labounty.pdf

As in most things, mileage may vary.

Just noticed, Bruce posted the same stuff. Burnishing is the time honored procedure.


Ralph

 

[Kevin W.]

Craytex sticks give a good polish to pivots.

 

[D.th.munroe]

A bit like what Ralph said, though, I don't think Salsa has a lathe yet and what people have suggested will work fine as long as care is taken for the shoulder and well cleaned of abrasives after.
I only use abrasive compounds simichrome or autosol to polish plated pivots, with just a popsicle stick, for everything else I use a pivot file and/or fine stones I shaped for pivots to remove grooves and wear, and depending on the hardness of the pivot burnished with a steel or carbide burnisher.
I made my carbide one at the direction of Dave LaBounty at least 15 years ago, by hand on diamond laps, took many hours to get the proper surface but rarely needs resurfacing.
The stones I shaped were dirt cheap ones unsuitable for most uses when new, but a bit of time at a lapidary wheel made perfect pivot files. I grew up very poor so always made most of what I needed.
Dan

 

[Salsagev]

(No notifications for some reason so sorry I missed all this discussion!)

what does cosmetically ok mean? to the naked eye? 5x magnification? more?

Means visually smooth. Perhaps some cheap movement wont require an hours of polishing work.

I have seen pivots in very old clocks that appear to have never been smooth. It's like machining marks on them. So my personal view is that smooth to sight (un-magnified) and passes the thumbnail test is good enough. I agree that a perfect surface is ideal. But a good surface will provide a good bearing surface and will last a very long time.

We polish pivots for two primary reasons - to reduce friction, and to reduce the rate of wear. The more you reduce friction the better and stronger the clock will run. The smoother you make the pivot the longer the bushing will last before needing to be replaced again. "Common American movements" are often over powered and will run when the pivots are less than perfect but the same principle applies. So how good is "good enough"? When we say something is "good enough" we are acknowledging that it isn't as good as it could be. I would urge you to set your goal to be "good" not just good enough.

You usually do not need to work work up through all the grit stages or use multiple polishing agents, but if the pivot has visible defects the courser grit papers (or even a pivot file) will remove metal faster to begin work. If you start with one of the finest grit papers it will take a long tine to do the job on a rough pivot. If the pivot already "looks good", you might start with 2000 grit paper. If it already looks good and shinny you might just go right to the polishing compound, or just clean it and leave it alone unless you think you can improve it. Note that 2000 grit paper (or any other) soon wears down and effectively acts like a finer grit. I would only use one final polishing compound, try several and see which one you like best.

I understand the effort that goes into polishing but would we classify "Good" as running well? Of course, my goal is always "optimal" but that is very very challenging without a full shop. I must make whatever I have work. I have a set of files from a box of clock stuff (shown on the forums before) and bought a set of bushing reamers no too long ago. Again, I have sand paper with high grits (1000+) and various polishes, and a block of Tripoli (should it be a block or some type of paste?).

No one has challenged pivot polishing using abrasives and polishing compounds? There has been a lot of discussion in the past, here and elsewhere. There's more to a polished pivot then cosmetics.

The attached PDF document sheds some serious light on the subject.

Dave Labounty has an article on the subject as well.

https://abouttime-clockmaking.com/pdfs/whiteman_pivot_analysis_1_labounty.pdf
https://abouttime-clockmaking.com/pdfs/whiteman_pivot_analysis_2_labounty.pdf

Thanks for the link everyone. Would some pivot microscopically polished really make a huge difference? If the pivot is good (not "good enough") and polished, wouldn’t it last 10-15 years before the next repairman re polish it? Wouldn’t it be also about the balance between the "extra" step and what’s effective?

Craytex sticks give a good polish to pivots.

That stuff is quite expensive for its size.

A bit like what Ralph said, though, I don't think Salsa has a lathe yet and what people have suggested will work fine as long as care is taken for the shoulder and well cleaned of abrasives after.
I only use abrasive compounds simichrome or autosol to polish plated pivots, with just a popsicle stick, for everything else I use a pivot file and/or fine stones I shaped for pivots to remove grooves and wear, and depending on the hardness of the pivot burnished with a steel or carbide burnisher.
I made my carbide one at the direction of Dave LaBounty at least 15 years ago, by hand on diamond laps, took many hours to get the proper surface but rarely needs resurfacing.
The stones I shaped were dirt cheap ones unsuitable for most uses when new, but a bit of time at a lapidary wheel made perfect pivot files. I grew up very poor so always made most of what I needed.
Dan

Right, I do not have a lather but attempted many many times to get one but seller ended up screwing me over (meaning multiple times). Since the pivot files are one dollar, should I buy all of them.


Thanks for the replies!

 

[shutterbug]

I've used a combination file/burnisher for many years. About $15.00 or so then.

 

[R. Croswell]

Since the pivot files are one dollar, should I buy all of them.

If you find a pivot file for $1.00 it is likely either worn out or a piece of junk from India.

I think the most important thing for any pivot work is a means to rotate the pivot at a constant rate while it is being filed, buffed, polished, burnished, etc. One must be careful not to create flat spots on the pivot, which is very easy to do with a pivot file. There have been a number of contraptions, sometimes called "turns", described in this forum to turn pivots during polishing operations but a small lathe is probably the best option because in most cases it is faster and can perform other tasks. Don't give up looking for a lathe, and yes, it is easy to get screwed buying used and looking only for a cheap price. "New" may actually be cheaper than used if you have to spend a lot to fix up a worn out piece of junk.

As for burnishing pivots, perhaps the two most important things for you to know at this point are; 1) a properly polished pivot will have a surface that is equally smooth to and undistinguishable from a properly burnished pivot, and; 2) a properly polished pivot will have a better surface than a poorly burnished pivot.

RC

 

[shutterbug]

For pivot polishing, you could use a good drill and devise a way to stabilize it while you work. You can't substitute a drill for a lathe in most cases, but for pivot work they will do the job fine. Don't ever try chucking on a pivot though. You can carefully chuck on a pinion, but be careful not to damage it.

 

[Kevin W.]

Tool made from a hinge to polish pivots, cheap and it works.

 

[Kevin W.]

https://mb.nawcc.org/threads/homemade-pivot-lathe-polisher.101225/

 

[kinsler33]

Check these out. They work well. You could also make your own if so inclined.

After my own heart. I began using Timesavers buffs after I finally gave up fooling around with burnishing. They work well. If there's rust or severe wear, start with a 1/0 buff, which is pretty rough. Then a stroke with a 2/0 buff cleans and smooths the pivot amazingly. Follow this with a 3/0 and you'll begin to see it shine. A 4/0 buff makes it shinier, and the 5/0 buff gets you into jewelry finish territory. A final stroke with the 6/0 buff leaves a gleaming pivot. A few lines remaining won't hurt anything. These buffs are $1.00 US each, or .85 if you buy six or more of each kind. So about thirty bucks will get you enough of these for quite a long while. Note that these buffs do a good job even after they're truly bedraggled and stained with metal. I spin pivots in my bogus drill-chuck lathe, using five or six consecutive buffs on each one.

Mark Kinsler

 

[kinsler33]

I understand the effort that goes into polishing but would we classify "Good" as running well?

Nobody knows because nobody's ever done the decades-long controlled experiments necessary to confirm the theories posted here. Polished pivots may or may not be a great idea for plain bearings at extremely slow speeds. We won't ever find out about best practices in bushing, lubrication, burnishing holes in brass plates, or if closing holes with a punch works as well as anything else because nobody's going to live long enough.

So we do our best.

Mark Kinsler

 

[DeanT]

No one has challenged pivot polishing using abrasives and polishing compounds? There has been a lot of discussion in the past, here and elsewhere. There's more to a polished pivot then cosmetics.

The attached PDF document sheds some serious light on the subject.

Dave Labounty has an article on the subject as well.

https://abouttime-clockmaking.com/pdfs/burnishing_labounty.pdf

As in most things, mileage may vary.

Just noticed, Bruce posted the same stuff. Burnishing is the time honored procedure.


Ralph

What Ralph said.

 

[Salsagev]

This is what I got so far:
I spin the pivot on the drill, with the block of Tripoli at a constant speed for about 15 seconds. Then I rub the blackened dust off with a dry paper towel. Please let me know if I should fix anything. Thanks.

 

[DeanT]

This is what I got so far:
I spin the pivot on the drill, with the block of Tripoli at a constant speed for about 15 seconds. Then I rub the blackened dust off with a dry paper towel. Please let me know if I should fix anything. Thanks.

View attachment 643557 View attachment 643558 View attachment 643559 View attachment 643560

Did you read the article? And other comments? Polishing isn't burnishing.

 

[leeinv66]

I finally gave up fooling around with burnishing.

Ditto!

 

[DeanT]

One plus to this approach is it will provide more work for the current restorers and the next generation of clockmakers.

 

[Willie X]

Sals,
That's not the way it's done. You need charge a leather buff with the Tripoli and make a few even strokes, against the direction of rotation of the pivot, use moderate pressure. Just one light rub with the tripoli ON THE BUFF will do maybe 10 pivots. A leather buff stick can be made from any straight smooth piece of close grain wood. About 3/16" x 1/2" x 6" will be good. Cut the leather strip with a metal straight edge and a razor knife. Then glue on the leather strip and clamp it lightly in a vise overnight. The leather needs to be thin and hard, and it should overhang the working edge slightly, maybe 1/2mm.
I have used a 4" muslin buff for many years. A 4" buff on a standard jewelers dust collector will have a surface speed about 100 times that of a push buff stick used with a high speed jewelers lathe. This can be dangerous for both the clock part and the operator, so be extra careful until you get some experience. This only takes a few seconds on each pivot and you charge the buff by occasionally touching the rotating buff with the Tripoli stick. A Dremell rotary tool can be used in a similar manner but a hard felt buff, at a moderate speed, will work better with this much smaller wheel. This is also much less dangerous than the high speed 4" buff and almost as good but only if you can solidly mount the Dremell tool. Willie X

 

[kinsler33]

That pivot looks quite good. If it's cylindrical, visually smooth and shiny you're done. It's not such a scientific procedure, and there are many ways to achieve good results.

Mark Kinsler

 

[DeanT]

Nobody knows because nobody's ever done the decades-long controlled experiments necessary to confirm the theories posted here. Polished pivots may or may not be a great idea for plain bearings at extremely slow speeds. We won't ever find out about best practices in bushing, lubrication, burnishing holes in brass plates, or if closing holes with a punch works as well as anything else because nobody's going to live long enough.

So we do our best.

Mark Kinsler

Scientific experiments have been conducted to determine the hardness and smoothness of pivot after burnishing vs not burnished.

Suffice to say that the burnished pivot was superior.

 

[kinsler33]

Does 'better' mean that the pivot hole in the brass plate lasted longer than, say, a pivot polished in a different manner? That test, which would require decades of waiting around, would be the only way to judge the benefits of burnishing, which is a technique mentioned in none of the metal-finishing literature used by the rest of industry.

I looked up 'superfinishing,' which is a fairly old and established method for finishing surfaces in plain bearings (e.g. the classic South Bend engine lathes.) Turns out that ultimate polishing doesn't help, and a tiny bit of roughness is preferable. Wikipedia has an article on it.

All of which to say that the relative merits of competing clock repair techniques are very difficult if not impossible to determine because of the length of time it takes for wear to appear in a clock movement. There's really no way around it.

Mark Kinsler

 

[shutterbug]

Not all pivots will be so easy, Sals. Eventually you'll find one that is really chewed up. So what we call polishing is really a process that smooths out the rough spots, establishes parallel surfaces, and polishes.

 

[Salsagev]

Thanks for the comments everyone!

That's not the way it's done. You need charge a leather buff with the Tripoli and make a few even strokes, against the direction of rotation of the pivot, use moderate pressure. Just one light rub with the tripoli ON THE BUFF will do maybe 10 pivots. A leather buff stick can be made from any straight smooth piece of close grain wood. About 3/16" x 1/2" x 6" will be good. Cut the leather strip with a metal straight edge and a razor knife. Then glue on the leather strip and clamp it lightly in a vise overnight. The leather needs to be thin and hard, and it should overhang the working edge slightly, maybe 1/2mm.
I have used a 4" muslin buff for many years. A 4" buff on a standard jewelers dust collector will have a surface speed about 100 times that of a push buff stick used with a high speed jewelers lathe. This can be dangerous for both the clock part and the operator, so be extra careful until you get some experience. This only takes a few seconds on each pivot and you charge the buff by occasionally touching the rotating buff with the Tripoli stick. A Dremell rotary tool can be used in a similar manner but a hard felt buff, at a moderate speed, will work better with this much smaller wheel. This is also much less dangerous than the high speed 4" buff and almost as good but only if you can solidly mount the Dremell tool. Willie X

I'm not sure what you mean by "few even strokes against the direction of the pivot". The tripoli is like a chalk and not a lot of patterning can be achieved. Am I not spinning the pivot itself? I don't have a Dremel but I do have a couple dollar rotary tool from harbor freight. Also, is this tripoli toxic?

That pivot looks quite good. If it's cylindrical, visually smooth and shiny you're done. It's not such a scientific procedure, and there are many ways to achieve good results.

Mark Kinsler

Scientific experiments have been conducted to determine the hardness and smoothness of pivot after burnishing vs not burnished.

Suffice to say that the burnished pivot was superior.

The pivot was a bit dull and when I spun the pivot on the tripoli, it got pretty shiny.
These pivots were fine, I think. Is it really worth it to go through all this process for a this? I keep thinking if the pivot holes would wear out both ways and the pivot will stay fine. I would only think burnishing is necessary when a clock was not serviced for 50 plus years when the pivot was badly damaged. Have pivots gotten damaged in a span of 10-15 years? By then, the next repairman will (assumption) clean the movement, remove any gunk that will eventually wear out the pivots, polish, then reassemble and oil. If a pivot was badly damaged, it would require burnishing since its structural integrity has been decreased. Will this clock run for 15 years? It's very troublesome to think that the clock you repaired had issues relating to many reasons.

 

[shutterbug]

What kind of movement is it? It looks and sounds like it might be a coated pivot. If the coating is good on those, I barely touch them to shine them up and leave them alone....just like you did

 

[Salsagev]

Seth Thomas 89.

 

[Willie X]

Sal's,
OK, "against the rotation". Normally the top of the rotating piece is coming toward the operator (you). You push the buff stick across the top of the rotating piece, this increases the effective surface speed. If you don't do it this way your surface working speed will be decreased. Under a certain condition your surface speed could be slowed to zero!

For me, burnishing is a hit or miss operation where polishing always works.
Some prefer one, some the other ...

No, Tripoli isn't toxic but you never know exactly what's in the products you buy. For occasional use, with a high speed wheel, a dust mask should be fine. For constant use, that's a different story. Occasional use of Tripoli with a buff stick should not pose a health problem.

if your pivot is scored, or rough, polishing (or burnishing) will not help you in any way.

Hope this helps, Willie X

 

[Kevin W.]

I would like to try burnishing one day. Most likely on a French clock. As for most other clocks they were never burnished when they left the factory. I polish my pivots. One day too i will attempt a re pivot job. Its a big subject pivots.

 

[Salsagev]

OK, "against the rotation". Normally the top of the rotating piece is coming toward the operator (you). You push the buff stick across the top of the rotating piece, this increases the effective surface speed. If you don't do it this way your surface working speed will be decreased. Under a certain condition your surface speed could be slowed to zero!

Ok. Is this perspective from a lathe?

if your pivot is scored, or rough, polishing (or burnishing) will not help you in any way.

OK. Is this when physical filing is necessary?

 

[shutterbug]

Burnishing work hardens the pivot. Not a great deal, but it helps. It also helps fill any valleys left by the pivot file. But since pivots are steel, they're probably going to be fine with a good polishing technique anyway.