Exhibition needlebar adjustment problems

[Brad]

I think this discussion took place a while back on the previous board. The heat from a soldering iron will not hurt the needle bar or the mica. After all, both materials were created at much higher temperatures.

As stated above, the beeswax is to prevent the screw from vibrating loose. Sealing against air leaks is probably a secondary benefit, but probably isn't needed for that.

In order to get good adhesion of the beeswax to the various surfaces (screw and mica), those surfaces must get hot as well. Think of soldering copper pipes. You heat up the copper and allow the solder to melt and flow, you don't apply molten solder to cold copper.

Placing a little blob of beeswax on the screw head, then applying heat from a soldering iron to the needle bar will heat the area of interest and allow the beeswax to flow with good adhesion.

[Steve]

In order to get good adhesion of the beeswax to the various surfaces (screw and mica), those surfaces must get hot as well. Think of soldering copper pipes. You heat up the copper and allow the solder to melt and flow, you don't apply molten solder to cold copper.

Sorry, I simply do not agree. If you think I haven't got good adhesion between the wax and my mica diaphragms, you're welcome to come and help me try and remove some of my "spills" where I made a mistake!

We're not welding two materials together here, folks, and maybe that's part of the misunderstanding? All you're doing is sealing a potential air leak and trapping the screw, preventing it loosening (in theory). Hot liquid wax melted over the screw thread / stylus bar will do the job just as well on a cold mica and stylus bar. I use a small optician's screwdriver with a wooden handle. It only takes half a minute in a naked flame (gas hob works well)to get the tip "red hot" and it makes it easy to control the application of heat. Well I think so anyway.

[Henry]

Steve, your way is essentially the authentic Victor way, as specified in their Exhibition rebuild literature, which I have in reprinted form. They even made a special tool for the purpose; it resembles nothing so much as an ordinary awl, with a slight hook on the tip. The instructions say to heat the tip in a Bunsen flame, touch it to a hunk of beeswax, and apply to the needle bar at the diaphragm. The wax should flow onto the mica surface, sealing it to the needle bar. There is nothing said about applying wax to the back side of the diaphragm. When I rebuilt my Exhibition, the wax flowed through the hole and onto the back anyway. I should point out that the original sound box had a small paper washer that went under the screw head; I suppose one could try to fashion one of these, but I just omitted it. I was and am very pleased with the results using these methods.

BTW, if you don't have access to a gas flame (!) you can use the flame produced by a cigarette lighter. Though I no longer smoke, I still have my trusty Zippo lighter, and I keep it in working order for the little odd jobs around the house that might require a clean-burning flame. The lighter fluid itself (naphtha) is an excellent solvent and degreaser.

[Steve]

Thanks, Henry, I'm glad to learn that Victor would've given their seal of approval (ouch...sorry...couldn't resist that pun! ) to my methods.

BTW, I like your smart avatar. I trust this mode of transport is fairly commonplace to your particular part of the world?

Steve

[richardh]

This is useful information - and it seems that no matter which technique you use - it is sucessful. BBB hope your exhibition rebuild works out. Let us know how it goes.

RJ

[Henry]

Steve, I have John and David to thank for the avatar, as this image of the streetcar was one of the choices they made available. Yes, I live near Philadelphia, which has one of the most extensive trolley networks remaining in N. America (along with San Francisco, Boston, and Toronto), even though it is but a shadow of its former self. And I spent some boyhood years in New Orleans, where I rode streetcars very similar to the one in the avatar; these are still running down there, having survived hurricanes and much else.

[Phonolair]

Steve, your way is essentially the authentic Victor way, as specified in their Exhibition rebuild literature

Henry has nailed it and right from the horse's mouth (or Victor's mouth) There are many ways to rebuild reproducer's and most of them will work fine. But in the Victor service notes and instruction for repairing the Exhibition Sound Box it has you use a heated awl and suitable wax (I to use broken 2 minute cylinders) and touch it to the head of the screw and then turn over the reproducer and repeat the operation. This wax is all about sealing air leaks and while many people rebuilt Exhibition reproducer few know that when you install the white rubber gaskets the joints should be opposite, one top and one bottom to reduce the chance of air leaks. Of course there are other steps listed also but the heated debate(pun intended) here was the heating of the needle bar. And when you have what sounds like a new rebuilder with a soldering iron around the needle bar and foot which is soldered on you just need to be careful as the foot is soldered to the needle bar. It only takes a small amount of heat to melt wax and if you have ever tried to clean up melted wax from your table or candle sticks you know it holds very well. Over the years I've rebuilt many Exhibitions, Victor's way and have never had a problem.

Best Regards, Larry

[MordEth]

Walt,

Thanks for the detailed information in your post. I should track down the patent images and post them here...

I use a 200mw 650nm laser assembly that I salvaged from a DVD recorder that was struck by lighting a few years ago and some lenses salvaged from the focusing assembly.

Could you take a picture of this? I’d be really curious to see it.

— MordEth

[Brad]

Steve, your way is essentially the authentic Victor way, as specified in their Exhibition rebuild literature, which I have in reprinted form. They even made a special tool for the purpose; it resembles nothing so much as an ordinary awl, with a slight hook on the tip. The instructions say to heat the tip in a Bunsen flame, touch it to a hunk of beeswax, and apply to the needle bar at the diaphragm. The wax should flow onto the mica surface, sealing it to the needle bar. There is nothing said about applying wax to the back side of the diaphragm. When I rebuilt my Exhibition, the wax flowed through the hole and onto the back anyway. I should point out that the original sound box had a small paper washer that went under the screw head; I suppose one could try to fashion one of these, but I just omitted it. I was and am very pleased with the results using these methods.

I recall the previous boards thread went down a similar path.

One thing we should keep in mind is that just because it was done certain way 100 years ago, that is not necessarily the best way. Electrical iron heating elements were not common and they did a lot of things with fire then just because it was easier. Today there are some building framers that still use a hammer rather than air nailer. Both will hold together a wall, but one will give better/stronger results with less effort. While it is true we are not welding materials here, better adhesion will result if the surfaces are heated and cause the wax to flow. Whether that level of adheasion is required is another topic and one worthy of tipping back a few cold ones over.

Using a laser to do it has that new age CD technoglogy meets acoustic technolgy zen that any engineer would appreciate.

Now, where did I put that walk behind plow? I have a hundred acres to plant before the show at Wayne this Sunday

[Brad]

.... I've hired some Amish builders to do some construction for me. ..... and a few weeks later I pay them about half ......

So, you admit to exploiting the Amish? Sorry Walt, a cheap shot, but I couldn't resist! Though I fully admit that I do not know much about the Amish culture, I wonder, are wind up phonographs popular among the Amish? If so, there must exist a treasure of rare and well maintained machines that will never make it to collectors hands.


But wait, wasn't this thread about a needle bar adjustment???

Hey Triple-B, did you resolve your issue?