How to free frozen Exhibition screws

[tomb]

I found kroil on amazon for $ 9.00 for eight oz. plus shipping. I ordered some to try it. Thanks for the information on this product. Tom B

[jboger]

About two hours ago I removed the three small screws from the back of an early Exhibition, the type with the slightly rounded screws that tighten the two halves together. These screws are somewhat countersunk and are smaller than the later Exhibitions. This particular Exhibition has the ferruled tension nuts, not the hexagonal nuts, and has a round needle hole. Two of the screws came out easily with the proper screwdriver as described above. The third did not budge and in fact was quite rusted. The iron is soft, and from past experience, it is quite easy to irreparably damage the slot with the screwdriver. This is the second time now that I have successfully removed these frozen screws and with no damage to the soundbox, so I believe my method is sound. It does demand that you sacrifice the screw, however.

It takes about an hour or so of careful work with a lot of patience. Do this when you are mentally prepared to do so. And don't rush. You will get that screw out and you won't create any bright brassy scratches from a slipped screwdriver. You need some masking tape, some small needle files--a round pointed one and a flat one--and you will need a certain dremel bit that I will photograph if you are interested in this technique, otherwise it is hard to describe other than that it is a bit with a small bulbous head.

So if all else fails:

First surround the screw head with masking tape so that only the head is exposed. The tape will prevent you marring the surface of the surrounding area should something slip. Take the round pointed file and use it as a drill to start a hole as dead center to the screw shaft as you can. Then with the flat file, carefully file down the head of the screw. Take it down as low as you can. Keep that file flat. You are successful when you do not dig into the masking tape. Do this with a 10x or so loupe. Change the masking tape if you need to. Constantly monitor your progress. Next chuck up the dremel bit in a small hand-held vise. Do not use the power tool; that's a recipe for disaster. You do this by hand with a 10x loupe in your eye to monitor your progress. Drill carefully and slowly straight down with the dremel bit where you had previous started a hole with the needle file. Stop often to check your progress. You may be surprised how soft the iron screw is. Take off the masking tape and clean the work area to see how things look. Rotate the head of the bit around to remove more of the screw head. If there is still a screw slot, see if a screwdriver will now remove the screw. Don't be surprised if it doesn't. You will eventually remove most of the screw head. You are not trying to drill the entire length of the screw. You are trying to remove most of the screw head so that it breaks off with some gentle force. I may use a razor blade and carefully insert it between the two halves in order to help separate the parts. If you run out of patience, find something else to do, then come back to the task when you are ready. There's no hurry.

I've described the basic process. You may want to vary it to suit your work habits. Remember, this is a labor of love.

I will photograph my tools, the screw, and the back of the reproducer if anyone asks. Otherwise, well, I won't.

[JerryVan]

Well Nick, have you tried any more of this? Had any luck at it?

[need4art]

Hey JBoger,
Just catching up-it would be great if you photograph tools the back of reproducer and screw
Thx Abe

[jboger]

I will do so this weekend. I'm glad you asked. I didn't think anyone was interested.

[jboger]

Here are some photos. I tried to take close-ups, not always with great success. After filing the screw head down, I tested with a screwdriver to see if it would turn. In this case, it did. (Such was not the case the first time I did this.) I would recommend always trying that. But if that doesn't work, the dremel bit is used to "scoop out" most of the screw head so that it collapses or a ring breaks off when the two halves of the soundbox are carefully separated. If you are careful and closely monitor your work with a loupe and use masking tape around the screw, you can take the screw down even more. The little vise to hold the dremel bit is called a pin vise. You should be able to buy one on eBay under watchmaker tools. Now I got to find a screw. But I'd rather have that problem than a permanently marred backplate.

[Henry]

Pin vises are usually sold at hobby shops, maybe also craft stores or well-stocked hardware stores. They do come in different sizes, depending on the drill sizes. Some are double-ended to accommodate a range of drill sizes, others have changeable collets for the purpose. The most comfortable kind are single-ended with collets for one end and a rotating swivel on the other; the swivel rests in the palm of the hand while turning the drill body with your fingers.

[need4art]

Well as luck would have it-my dad was a diamond cutter and watchmaker. He passed away about a year ago at 96 and I have been putting together his tools. I have sold their house and moved my mother closer to us. After going through the tools I have everything I need to do this on hand. Thx for the pictures I have just printed them out to put in my reference book.

Thx Abe

[justin ball]

To break the friction on my old bikes, with obviously larger screws and bolts, I find that after penetrating oil, turning them IN just a few degres, like 3, breaks them free.

The bit about having a screwdriver that fits EXACTLY, and this might mean dressing it to fit with a file, is mandatory. Old British bikes have slotted screws made from hard cheddar, and I learnt it the "crying with frustration" way.

[Nick Charles]

Thanks one and all for all the help. A lot of advice will be invaluable for future reference. I finally was able to free the screws through many rounds of penetrating oil, freezing and heating. It took me three days of this regimen. The next time I'll use the helpful tips and materials suggested and hopefully it will go easier.