Unscrewing Stuck Coverplate Screws
Hello Kinya Pollard,
The other day I tried to take my harp apart so that I could clean it. Unfortunately, I could only loosen one of the the coverplate screws. The other screw was stuck to the clasp thingy on the bottom side. I attached a couple pictures that might clarify my post a bit more. How would you go about loosening a stuck screw?
One more question: what kind of tool should I use to loosen the screws? The tool I was using ripped up the top of the screw which the picture below shows.
Thanks
Thanks for the feedback, Kinya. I appreciate the response and will test your advice out.
Great. Let us know how things work out for you.
Your Harpsmith, Kinya
Are miniature wrenches hard to find at hardware stores? Are they more of a specialty item because I would prefer to buy them locally since I live in Malaysia and shipping can add a hefty sum to anything I buy online?
I tried using WD 40 to get rid of the rust. It didn't work, and it left a horrible smell. Two questions. Will the smell go away? And two, should I be worried about WD 40's toxicity?
Sorry, that was a mouthful for one post!
harpsquealer
Hi HarpSquealer
My apologies for the confusion regarding the WD40. The idea was to use a "drop" of WD40 to soak and help disolve the rust on the cover plate nut/bolt ;o(
WD40 is a petroleum distillate type project, so you wouldn't want to mix a Teh Tarik drink with WD40! With the covers removed from the harmonica, soak them in dish washing liquid, then scrub the WD40 film off the cover plates.
Rust behaves like cancer, once the process starts, it will continue to deteriate the metal. Remember, your vintage Hohner Special 20 cover plates are basically "tin" (the new models do not rust). In the meantime, however, you can "polish" your plates with SemiChrome paste by Happich--and make it look almost new. One small tube will last you a lifetime of harmonicas.
TIP: when stock harmonica cover plate bolts (screws) become damaged, at .375" (3/8") long, many Harp Techs swap out the old for new 2-72 or 2-56 nuts/bolts for the cover plates.
As for online purchases, have you tried Alibaba and shipping from Asian destinations? Miniature open wrenches, along with "adjustable" miniature wrenches (also known as Cresent Wrenches), and SemiChrome polish should be universally available.
Your Harpsmith, Kinya
Hi Kinya,
First of all, how do you know about teh tarik! It's such a great drink. Have you been to Malaysia much?
Without the miniature wrenches, I attempted to loosen the screws. I used some WD 40 but had no luck. About a week later (today), I tried again and I guess WD40 worked his magic. I got the harmonica open.
I took off the cover plates and soaked them in some soapy water. The rusted screw is too bad to use anymore. In your previous post, you mentioned that harp techs will use new 2-56 or 2-72 nuts/bolts. I am in no way, shape, or form a hardware guru. Is that just a specific size of nuts and their corresponding bolts?
Thanks for the loads of help :)
harpsquealer
Hi Harpsqueler
That is correct. So, to interpret this string of numbers, 2-72 x 3/8":
- #2 is the "diameter" of the shaft of the bolt or screw
- #72 refers to the "threads" count per inch
- 3/8" is the length of the bolt or screw, measured from underneath the head of the bolt to the end of the shaft.
When you are at the DIY hardware store (Home Depot, Lowes, etc.), simply match 2-72 x 3/8" with the blister pack labels (located in the hardware dept). Keep in mind that many of the employees who are employed at the DIY stores, don't know half as much as you, and will expect you to "Do It Yourself" ;o) Was that too snarky?
Your Harpsmith, Kinya
It makes so much sense! Who would have thought that that scary--dare I say--terrifying collection of numbers could make sense! Thanks for your great help, Kinya! You did a great job explaining everything.
harpsquealer
but seriously,
how do you know about teh tarik?
Seriously, Yum!
Your Harpsmith, Kinya
Hello HarpSquealer, good to hear from you. Terrific photos (I luv that)
Yikes, your Hohner Special 20 is vintage indeed! The original cover plates were made with tin, and the slightest amount of residual moisture would oxidize into a rusting mess--locking up screws, etc.
I use a 3/16" open ended wrench to secure the nut, then use a Wiha straight blade screwdriver to loosen the bond. Everything can be purchased from Micro-Mark:
http://www.micromark.com/6-piece-miniature-wrench-set,7950.html
http://www.micromark.com/7-piece-precision-screwdriver-set-with-stand,75...
Tip: a spot of WD-40 solution works great to breakdown the rust!
Your Harpsmith, Kinya