Drill Press Information and "How to replace nails with bolts on 270's"

SOMEWHAT NEW NEWS: Brendan Power is making replacement combs for the 270 deluxes and for most other models, including the recent addition of the combs (and slides) for CX12s. I've installed about fifteen of Brendan's Powercomb on my Hohner 270 Deluxes, with stellar results.

Brendan has a slightly different way to drill the holes, which is not needed on the Deluxe, of course. His method doesn't use the template that's linked to below here someplace. It looks like it works just fine. His video is here.

A Drill Press is a pretty cool tool for a repair-minded chromatic harmonica owner to own. Not mandatory, but really nice to have in a few situations.

On instruments that have wooden combs and use nails to hold the reed plates in place (I'm looking at YOU, Hohner 270's), it's nice to have the drill press to drill out the holes getting them ready to accept bolts.

Drill presses are also good for tapping the holes in the bottom plates to accept the bolts, but you do it by hand, the press serves to make sure things are at the correct angle. You just turn the bits by hand, OR, for those who hate being told what to do, you could turn the harmonica, I suppose.

There are two typical types of Drill Presses:


DREMEL'S WORK STATION $39.99	MICROLUX'S DRILL PRESS $199
If you want OVAL holes	If you opt for the more traditional ROUND holes

HINT: Buy the one that makes ROUND holes.

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There used to be a site, called HarpOnLine, where they very nicely showed us all how to replace nails with bolts. There was a template and some warnings, but I used it with great success on my keyed 270's.

My main "C" instruments are the Deluxes, which come with the bolts, a nice featiure.

Before they closed that site, I downloaded parts of it. Perhaps I can duplicate the "how to replace nails" section. It was really helpful.

Ok, here goes.... no guarantees that you won't screw up your instrument, though.

VERY IMPORTANT..;...download this jpg file and be sure it's the correct size when you print it. The size is mentioned in their text below.

FOR THE 270, THE TEMPLATE MUST MEASURE 142.5 mm exactly. YOUR INSTRUMENT WILL DIE A TERRIBLE DEATH, GOING DOWN IN FLAMES AND BE FAIRLY USELESS IF THIS IS NOT DONE CORRECTLY.

This is SO important that some nice people planned ahead and composed a useful song about what to do IF you screw this up.

That said, I've done it a number of times from the following directions, and had no problems, at least any Problems I've had are not related to this subject.

note: Originally in German, translated by someone at the original site, the English on this set of directions is just a bit quirky but pretty good.....its a lot better than if I had to translate it from English to German, so I've fixed a few places, but most of it is as it was on the site.

I've used this without permission, and I hope they don't mind, inasmuch as I don't know who "They" actually are, but they have my thanks, since their site was the very best.

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THE PROBLEM:

Concerning the M260 and M270 Chromatic Harmonicas, the reedplates are fixed to the comb with nails.

This means: There is no chance of replacing the inner valves, or working on broken inner reeds, etc.

THE SOLUTION:

We are offering:

A set of screws enabling you to rebuild these reedplates into a screw-locked version..

NOTE FROM KIP: Since that site is out of business now,
you'll have to find the bolts yourself, and be sure to get a matching tap
for threading the bottom plates.
IF someone finds the bolts or has suggestions, please email me.

	Before
	After

TOOLS AND AIDS

A bench-drill would be useful, but not absolutely necessary. The work can also be done with a hand drill tool.

The rebuilding process is shown here on a Hohner Hardbopper, however it also works well on every 12hole- 270er Model . 10 hole-chroms, like the Chromatic Koch , the Slide Harp , as well as the Chrom I 260 can also be rebuilt this way, but you'll need the the small stencil on the downloadable sheet provided in the next chapter.

DISMANTLING

First you must remove the slide package by unscrewing the mouthpiece screws.

Caution!
Behind the mouthpiece you'll find the Buffers, These can easily slip away and if they fall on the floor you'll never find the little corner they've rolled into...

So store your spare-parts in a box, like this.


Dismantling The Covers

Remove of the Cover Supports.

The supports are wedged into the timber of the comb, so you'll need a pair of pincers unlock them.

THE DRILLING STENCIL

The Reedplates and comb must be redrilled to provide new holes.
The graphic below shows the
order of the drill-holes on the 270-comb

	The new drill-holes will be marked using a paper stencil. Download the drilling stencil by clicking HERE and printing yourself a copy. Again, (from jon) BE SURE IT"S CORRECT SIZE 142.5 mm exactly, for the 270.
	The print-out of the 270 model/12 hole must match the width of 142,5mm exactly
	The stencil is then cut to size using a pair of scissors....
	.and it must exactly fit the surface of the upper reedplate. Caution ! If the stencil doesn't fit exactly and you continue working, you will destroy your harmonica. In the case of a stencil not being properly printed out, the fault lies with your PC and its connection to your printer-driver, a feature we have no influence over.
	The stencil is now carefully fixed on the upper reedplate, using adhesive tape. The stencil is not only good for marking new holes but it also helps to protect the valves during the operation However, you should be aware that valves can occasionally be damaged.

DRILLING THE INNER HOLES

	A vertical drill including a spanning device is very much recommended here. Okay, you've fixed the stencil to the comb and now the 5 new holes for theScrews M2 x 16 must be drilled. Therefore insert a twist drill bit with 1,6mm diam into your drill. This will produce the core hole for the thread M2 required for tapping the lower plate.
	Place the Harmonica on a flat surface which can also be drilled into (ie. a piece of timber). However it would be better to use the bench-vice shown in the illustrations.
	Now drill the 5 holes, one after another. Taking care to drill only the holes marked on the stencil, drill the whole package. The new holes are situated beneath the nails which are still holding the plates to the comb.
	Holding your package firmly with your hand, allow the drill to continue at high speed.
	Caution ! At driving up the drill bit it tends to get stuck. It is not possible to drill the 4 outer holes, because the nails have not yet been removed.

TAPPING

Now, using the M2 Tap Bit and Universal Holder tap the M2 thread into the
lower reedplate

Removing the nails (lower plate only
	With the aid of a sharp flat knife, prize the lower plate carefully from the edge of the comb.
	Using this method the nails are lifted, but avoids having them fall out.
	Caution! Take care! Neither the comb nor the plate must be damaged during this operation.
	Using your pincers remove only the 4 outside nails on the lower plate. The upper plate must remain in position under the stencil.

Drilling the outside 4 holes

After removing the nails, drill the 4 outside holes, but from the opposite direction -
from downside to upside.
During the drilling process, do not remove the inside nails because they are holding the lower plate in place.

Caution:
The package cannot be drilled all the way through, because the nails on the opposite side are still in position.

Now, the 4 remaining threads of the lower reedplate can be cut, using the tapper bit M2.0 and the universal holder

DRILLING THE UPPER PLATE
	After removing the remaining nails, we now remove the lower plate....... .....plus the centring-bolt, which holds the slide spring in place.
	The stencil can also be removed.
	Now, a Twist Drill Bit Twist-Drill Bit with a 2.0 diameter is inserted.
	The new holes in the upper plate are now drilled to a diameter of 2.0mm.
	However. during this process, the entire package would be drilled through. Therefore, the lower plate is dismantled and only the upper plate and comb are drilled.

REMOVING THE NAILS AND DRILLING THE UPPER PLATE
	Carefully lift the upper plate with your knife, ensuring the nails do not fall out.
	Remove only the outer 4 nails
	Now we drill the 4 outer holes to a diameter of 2mm.

COUNTERSINKING THE OUTER HOLES
	Remove the Twist drill bit and replace it with one measuring about 5.0mm.
	Now, using this tool countersink the 4 outer holes of the upper plate.
	The upper plate is still fixed to the comb with the inner nails. Yes, we are aware that an expert would never countersink a hole using a twist-drill bit, the job requires an additional tool, (a countersink bit) and the cost of such a tool is high, so we believe this way of doing it is defensible.
	The flat headed M2 x 16 screw must lie totally inside the countersink, because the cover will be tightened over the area and must be allowed to lay absolutely flat on the surface of the plate.

NOTE, FROM ME AGAIN. That last step, adding the countersinking step, is one that I don't usually do. It's not really needed, as the cover plates tend to do the same job as the countersunk bolts. That's just me, of course. I hasten to add that I do, upon occasion, play wrong notes. The lack of extra bolts may be the cause. Or not.

FINISHING THE HARMONICA
	Now, the upper plate can be lifted and its nails removed.
	After carefully removing all shavings and cleaning the comb thoroughly, we can begin reassembling the plates. However it's possible we may need to exchange some damaged valves too.
	Replacing the plates
	Putting the Allen screw M2 x 16 VA in place.
	Tightening with the Allen screwdriver
	Placing and tightening the Flat Head Screw M2 x 16 . Caution ! It may be possible, that you have to cut this screw depending on the thickness of the reedplate-comb. The screw must not protrude above the surface of the plate (on both sides, remember !), because the covers have to lay flat on the surface of the reedplate on both sides of the harmonica.
READY
We do not include the reassembling of covers and mouthpiece here, because the workshop would become overcrowded with pictures, causing huge loading times.