dent balls

[bigtubby]

I've been buying from these folks: http://stores.ebay.com/toolsupply" target="_blank" target="_blank decent prices but ...

... paying for ball bearing quality when you need "fairly round" quality doesn't make much sense. There are two bearing factories within 75 miles of me and it seems as if there should be seconds (and thirds, etc.) available. Looking into that, will keep you posted.

[Ken Herrick]

Dent ball sets get expensive in a hurry. While not as good or durable as steel, hardwood dowelling turned down to the sizes and shape you want, with a hole drilled through can be quite effective.

Maybe Jordan could post the pics I sent him to give you some ideas for alternative tools. Or if you pm or email to me I can email them to you.

Added

well, not real good with magnets.. A repair shop for heavy machinery might have some scrapped bearings for next to $0.

[Dean E]

Can anybody thing of a source ?
Well, I'm trying to figure out how to repurpose, recycle, or otherwise fake, some dent balls on the cheap.
My man at Fastenall seems to have given up and neither of the local welding shops have anything close, so
How can I get a 3/4", 1", and 1 1/4" dent balls cheap ? The fastenall guy said that if he could get them, a
1 1/4" ball bearing would only cost me $6.75. I don't expect to be that cheap but what do you guys think ?
Can anybody thing of a source ?
Thanks !

I seem to remember Tubatinker suggesting a commercial source for magnets several years ago. Speaker magnets might give enough power.

I have bought steel balls from the auction site. FWIW, from my experience it is too easy to damage a horn even with a real magnetic dent ball set. Good luck.

[Ken Herrick]

Chris Olka had a lot of repair gear for sale. Maybe he would have what you want at a good price.

[PMeuph]

The ebay site posted above is where I got mine. You can search dent ball and get the following results.

http://stores.ebay.com/ToolSupply/_i.ht ... d=74456173" target="_blank" target="_blank

I paid between $8 and $16 per ball for sizes between 1/2" and 2"

(1/2" has been useless for me, ymmv)
_____

I believe that Tubatinker once referred to buying several steel balls from Mcmaster-carr.

viewtopic.php?t=49461&p=427224#p427211" target="_blank" target="_blank

[bigtubby]

Can anybody thing of a source ?
Well, I'm trying to figure out how to repurpose, recycle, or otherwise fake, some dent balls on the cheap.
My man at Fastenall seems to have given up and neither of the local welding shops have anything close, so
How can I get a 3/4", 1", and 1 1/4" dent balls cheap ? The fastenall guy said that if he could get them, a
1 1/4" ball bearing would only cost me $6.75. I don't expect to be that cheap but what do you guys think ?
Can anybody thing of a source ?
Thanks !

I seem to remember Tubatinker suggesting a commercial source for magnets several years ago. Speaker magnets might give enough power.

I have bought steel balls from the auction site. FWIW, from my experience it is too easy to damage a horn even with a real magnetic dent ball set. Good luck.

I don't think that speaker magnets will cut it: not enough horsepower unless huge. If huge, they will scarf up everything around what you are working on. A magnet that is really good for almost everything beyond the valve cluster in a tuba is this 1-1/2" X 1-1/2" N45 neodymium for a little over forty bucks:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0532810419" target="_blank" target="_blank" target="_blank

It is the one that the tool I posted in this thread was based around: viewtopic.php?f=11&t=50574&start=12#p459366" target="_blank" target="_blank

In that guy's non-ebay store he has a 2" X 2" N42 for a little over seventy bucks:
http://www.magnet4sale.com/On-Sale-N42- ... gnets.html" target="_blank" target="_blank" target="_blank

The 1-1/2" magnet is rated at 219lbs pull IIRC - the 2" is 368lbs. If you want to work on smaller tubing (e.g. first branch, valve cluster and leadpipe) you probably want the bigger one. The smaller the dent ball, the less mass so the stronger magnet makes a difference. OTOH, the bigger magnet seems to be too strong for larger balls in more delicate (non-student model) instruments. I don't regret having bought both of them.

HTH

[Tubajug]

I just searched "steel balls" or "ball bearings" on Ebay and looked for the best prices on the different sizes. I bought them from a few different folks, whoever had the best price.

[Dan Schultz]

.....I also wonder how you can release a 368 lb attraction ! ?
I want to say I appreciate you telling about the strength of magnets available. Quite eye opening.
For right now though, I just want to get some proper sized balls to try. I figure if a spoon works, spheres should be
awesome.

That 'high' force is only at straight-on attraction. The force diminishes greatly when you roll the ball to the side of the magnet.

The force depends on the size of the magnet and the mass of the ball. Little balls don't do much (but you already knew that, didn't you? ).

In some cases... when a large ball won't do the job... a somewhat smaller one will. It has to do with the rolling geometry and the actually surface contact of the ball on the inside of the brass. You can work all day trying to remove a small wrinkle with a 3" ball and then try a 2" one and get the job done.

Working with magnets is one heck of an education. You're gonna get hurt a couple of times and gonna tear up a few horns until you get it right.

[imperialbari]

As for the topic title my comment would be:

Don’t. It hurts.

[bigbob]

......

Working with magnets is one heck of an education. You're gonna get hurt a couple of times and gonna tear up a few horns until you get it right.

What do you mean about getting hurt...How??

[PMeuph]

......

Working with magnets is one heck of an education. You're gonna get hurt a couple of times and gonna tear up a few horns until you get it right.

What do you mean about getting hurt...How??

Just replace the object with your finger. Crushed bones are a possibility...

http://www.youtube.com/watch?v=ClkP-QwIOAQ" target="_blank

[jsmn4vu]

Crushed bones are a possibility...

... and blood blisters are highly likely.

[Dan Schultz]

......

Working with magnets is one heck of an education. You're gonna get hurt a couple of times and gonna tear up a few horns until you get it right.

What do you mean about getting hurt...How??

I have TWO 1 5/8" diameter x 1 1/4" magnets stacked against a same size steel backing plug and shoved into a piece of reinforced vinyl tubing. Getting this thing in the proximity of loose tools on my workbench sort of reminds me of an old 3D Abbott and Costello movie where meat cleavers and knives were flying through the air!

And yeas... as one poster already said.... blood-blisters will eventually happen!

[bigtubby]

bigtubby,
All I can say is Wow ! Those magnets you bought are amazingly powerful.

Actually they are the economy size. I'm a bang for the buck kind of guy - N50 and N52 magnets in the same size have more pull but the price curve is pretty steep.

I'm starting out with smaller stackable magnets that hopefully won’t damage my horn by snapping together.
With my 1"x1" magnets I only get around 98 lbs pull. Stacked they add about 70% above that and I have an old
stack of coin sized magnets that probably add another <50 lbs. So far I have only stacked the little ones inside
a table spoon and used the two bigger ones to pull the spoon over the bumps. Where the bumps matched the
radius of the spoon, it was amazing how well it worked. It was like polishing out the dents. I can't wait to do more !
I suspect that if I ever get into higher strength applications, I will probably want to stack magnets rather then
chancing the destruction of my horn's appearance.

I'm pretty happy with the N45 1-1/2X1-1/2 and N42 2X2 combination with a combined price of about $120.00. Good thinking on not going overboard with power. The 2" magnet is too much with larger balls but has its place there (reinforcements, etc.). On normal body metal I use the 1-1/2" magnet with balls over one inch or so.

Also: "... my horn's appearance ...": I had some school horns for practice (my horns; but old strong, heavily dented ex-school horns). If you pick up a junker for a couple hundred bucks on ebay you can practice on it and probably increase its value enough to pay for the shipping or more ...

I also wonder how you can release a 368 lb attraction ! ?

That can be tricky. You have to be very careful when separating them that you don't cock or twist the magnet or you will end up with a new dent. And usually a new dent with a crease from the hard edge of the magnet. You can work the ball up under a reinforced area which will help insure against that. But even then, the act of pulling the ball under it can balloon the body metal near the reinforcement.

I want to say I appreciate you telling about the strength of magnets available. Quite eye opening. For right now though, I just want to get some proper sized balls to try. I figure if a spoon works, spheres should be awesome.

Yes, I put a lot more money into balls than I did into the magnets. Again, I hope to find a way to acquire seconds or overruns from one of the local bearing manufactories.

Sounds as if you are proceeding in a great direction and with caution, best luck with your experiments!

[bigtubby]

Working with magnets is one heck of an education. You're gonna get hurt a couple of times and gonna tear up a few horns until you get it right.

In my education I used that as a training device: After leaving an ugly ball track by getting too far up into the bell flare, I found a method of preventing that:

When working near the bell, keep your free hand just below the beginning of the flare and in the area in which you are working. It is sort of like those dog collars that give a shock when Fido crosses the line: after losing a couple of fingernails I got much better at knowing where the flare starts.

[bigtubby]

This is very interesting, especially since the "kit" starts at $450.

I pretty much replicated that starter "kit" for around $200.00 using bits from ebay Links earlier in this thread).

Any luck finding a convex magnet or steel half-sphere?

It reduces the pull somewhat but $15.00: http://www.votawtool.com/zcom.asp?pg=pr ... =jnenpqdoo" target="_blank

They have a 2" version too: http://www.votawtool.com/zcom.asp?pg=pr ... =jnenrogpm" target="_blank

[imperialbari]

As I understand posters here the right dosage of magnetic energy is a problem.

Why stay with solid physical magnets?

Couldn’t an electromagnet with adjustable strength be shaped into a manageable hand tool with pedal control?

Klaus

[tubarepair]

As I understand posters here the right dosage of magnetic energy is a problem.

Why stay with solid physical magnets?

Couldn’t an electromagnet with adjustable strength be shaped into a manageable hand tool with pedal control?

Klaus

Electro-magnets were used in the band repair industry as far back as the 1950's. From the reports I've received from the folks that tried them back then, they were mostly unfavorable. Perhaps some new experiments could be done, but my experience with the MDRS is it just like any other form of dent removal - you have to learn to feel (instantly) what is happening to the metal and adjust. Not sure that would work with electromagnetics.

As an aside, Votaw had a pneumatic dent removal tool for saxophone called "The Elimator" or "Terminator" or something that I had access to for years. While it had some use, control of force was always an issue, no matter who tried it. If you can't feel what is happening, it's too late when the dent now occurs from the inside of the horn to the outside.

Note to all you new magnet users: Stay away from the ferrules and guards. You'll be disappointed when the tubing on either side ends up higher than the ferrule/guard itself.

[Lee Stofer]

If one wishes to experiment, and doesn't mind if the subject instrument, or parts thereof, are ruined, then all is well.

I would suggest not trying any of this on something that you need to play tonight, or tomorrow.

I've spent many years trying to perfect the art of dent removal, and there is a lot more to it than is immediately observable.

One thing DP alluded to is being angry about a repair shop transforming the finish of his instrument to "hammerite" (whatever that is), what I would refer to as an orange-peel texture where the magnetic dent removal happened. The only fault of the technician was not knowing that this would happen with this particular instrument. Older instruments, and newer instruments that were made by branches being burnished on mandrels are generally smooth inside, and respond wonderfully to the magnetic dent removal technology. However, the majority of newer instruments are of thinner and harder metal. These were made by hydraulic blowing of branches to fit the inside of a mold, and then the exterior is media-polished to a mirror finish, while the inside remains relatively rough. So, when you introduce the ball and magnet to this finish, the rough inner texture transfers to the outside of the instrument, compromising the outer finish and making the portion of an otherwise wonderful looking instrument look terrible. And, there is really no fix to that orange-peel texture short of sanding and buffing the area, and refinishing it.

And, as to the hardness, softness, and/or thickness of metals, different branches on the same instrument can respond quite differently, so I find that I always have to be on guard for what might happen next, using the greatest of care at all times.
It is possible to do quite a lot of damage to a brass instrument, and very quickly, with magnets and dent balls. Now, you've been warned.