Slidemeister (Chromatic & related only - no Diatonic discussion) > Custom Chromatic Stuff

converting 270/260 from nails to screws

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peevole:
Hi all
I would appreciate some help in finding the easiest-to-follow directions for the above nails to screws conversion. There was a great one on the defunct M. Timler site, but I'm sure there are some good ones among Slidemeister threads.
Thanx in advance
Peter.

PS - I'm in Denmark, so I'd prefer "generic" names as the US brands are hard to find here.

Winslow Yerxa:
I'm not where I can cite specifics, but here are some general guidelines.

First you need machine screws that are suitable. The ones that Hohner uses for its other chromatics are available as parts.

Next, you neeed a drill press, two drill bits of the correct sizes, and a tap cutter that will cut the screw threads in the bottom reedplate. The tap cutter needs to have the same thread as the screws you intend to use, of course.

The drill bit you use on the lower reedplate needs to be the right diameter to create a hole only large enough so that you can then use the tap cutter to cut threads on the holes.

The drill bit you use on the upper reedplate should have a larger diameter that will give room to move the reedplate around slightly to ajust its placement.

Once you know the correct size of the screws, you can look up on the web the correct sizes for the tap cutter, the tap drill (lower hole) and the clearance drill (upper hole).

Now you need to remove the reedplates.

Use a large knife, with a blade that is at least as long as the reedplates, and wide enough that it will not flex easily. Many inexpensive kitchen knives are available that will be suitable.

Insert the blade of the knife between the reedplate and comb, and gently pry upward. Be careful not to dig the blade of the knife into the wood of the comb. You can start with the long edge of the reedplate (the back) and then also work the sides, alternating among them to gently pry up the reedplate.

Remove both reedplates. At this point you may wish to also remove the mouthpiece assembly and sand the top and bottom of the comb flat, and seal it against moisture.

Now it is time to start drilling holes.

To drill, you need to be able to lay the comb flat on the working surface. Removing the mouthpiece assembly makes this job much easier.

But before drilling, place the reedplates on the comb, and fasten them with the nails that are closest to the end tabs of the covers. This will hold the reedplates in correct alignment. As these nails are very close to the tabs, you will not be able to insert screw heads and therefore do not need to drill those holes.

Now, use the small diameter drill bit to drill through the reedplates and comb. Lay the reedblock on a piece of soft wood if you choose.

Where to drill the holes? Follow the existing nail holes, but be careful in your choices.

* Examine where the holes on the upper and lower reedplates coincide, or where they may be close but far enough away that the integrity of the screw hole may be compromised by the alignment of an existing nail hole.
* Be careful that enlarging the nail hole will not compromise the airtightness of any of the chambers in the comb.
Now, remove the lower reedplate and use the tap cutter to cut threads in the new screw holes.

Now use the larger diameter drill to enlarge the holes in the upper reedplate and the comb.

At this point you should be ready to reassemble the reed block.

* First, reinstall the mouthpiece assembly.
* Align the reedplates with the comb and insert the screws, getting each engaged with the thread in the bottom reedplate.
* Start by turning the screw counterclockwise until it clicks, then turn clockwise, just until you feel the screw engaging the thread. Do not tighten.

* Check the alignment of the front edges of the reedplates with the backing plate of the mouthpiece assembly. This is critical, as a lack of contact will compromise airflow to the instrument.
* Starting at the middle of the reedplate, start tightening the screws until they resist your finger pressure on the screwdriver. Do not tighten excessively.
* Work your way from the middle of the reedplate out toward each edge until all screws are tightened. Check the front edge alignments again, and check each screw with a screwdriver to make sure none are loose.
* Continue with reassembly of the insturment, but play it first in case there are any problems with reeds not sounding.

Gnarly He Man:
You make it sound (relatively) easy.
So I saved this info in a word doc, just in case I find myself with time, tools, and the desire to do this task myself.
Thanks W!

llumagsara:
hello

for taking the reedplates, i file completely the nails' heads with a dremel (diamond point), take out the reed plates, then the nails of the comb with pliers...

good health

Agustín

m.marino:
Gary,

With the right equipment it is easy and a step by step process. Winslow points out many of the traps that can await and if he does not mind I might use this description on my web site (giving credit of course) as he has done a very accurate job of describing the process. The only item i would add is that it is best to sand the combs lightly, with the sandpaper on a flat plate (which can be a glass cutting board or such that is fully flat).

I have found that M2 screws work best for the conversion and we will be offering complete kits for doing the conversion shortly.


Michael Marino
free Reed foolery

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