drawing of a chest organ

    Hello everybody, I am from China and I would very much like to build a chest organ, I think I shall start by making the 3D drawings first.

    My goal is to follow the design by Mr. Theo Koele opus 5 https://www.kistorgels.nl/

    I would very much appreciate your help and give advice during the process, I wish I could finish this by a year I know it is extremely challenging but worth trying.

    I would like to start with the keyboard, I put some picture of the design, looking forward to receive advice and comments, thanks in advance.

    Best regards,

    Xiaohu Wang


    Hello Xiaohu,


    congratulation to your decision to build an instrument. Theo Koele was also an inspiration to me; he makes nice sounding instruments and the many images and videos on youtube and on his website helped me also a lot.


    Your drawings look fine, I think that they will work. I didn't check the exact measurements, but when you follow some norm, such as the BDO norm or the AGO norm of keyboards (or measurements near those norms), it will work. Taking measures from existing instruments is of course also an option.


    Finishing it in one year is indeed challenging. I would rather say that about 5 years is more realistic. Let's say, a professional organ builder finishes an instrument like that in a quarter of a year, working 7 hours a day on it. This would be about 90 days time 7 hours = 630 hours. When you have about one hour per day to build, this would equal 630 days, which is almost two years. If you have only about half an hour, this doubles to about 4 years. That's only a rough estimation. It also depends on the family situation and if you can work on it at the weekends or vacation or if you are going to use existing parts. But sorry, I didn't want to discourage you. Just try and start and have fun, but don't be discouraged when it will take longer than expected ;-)


    I didn't build my keyboard all by myself. I got a used one out of eBay and made new key toppings. I used plastic key covers like these: https://organparts.info/en/21-manual-keyboard?p=2 and made the accidental covers (C#, Eb, F#, G# Bb) by myself out of wood.


    Regards,


    Jens

    Hi Jens,


    Thank you so much for your encouragement, it will take much longer time for me than the professional builder thus 630 hours is a minimum estimate😂 I think it would take twice the time. But it is real pleasure and fun to share and learn about the chest organ during the process, and kind builders like Mr. Koele and you and many others to offer generous help, otherwise it is simply impossible to built one.

    I am now trying to figure out the transposing mechanism, I came up with a solution but still working on the CAD drawing, I will post the solution later and I hope to receive your further comments, thanks in advance.


    Best,

    Xiaohu

    That will work. Consider that you may need to lift the keyboard at the front while shifting to not "scratch" the keyboard at the bottom with the rods/stickers. Another simple solution is just to have a block of wood with the thickness of one key which can be added at the left or right of the keyboard. Then, you don't even need a dowel pin. I saw this on harpsichords:

    I have a harmonium from the 1850s that has a very simple but effective transposing device. The key frame runs in a groove at the back and can be lifted at the front and then fixed with the pin in one of the holes. This way you can transpose a whole octave, but you need a lot of extra keys which disappear under a flap when not in use. The pin does not release the shifting of the key until the keys are raised far enough to no longer scratch on top of the rods. This also takes Jens' hint into account.

    Greetings! Samuel


    Zitat von SamES

    I have a harmonium from the 1850s that has a very simple but effective transposing device. The key frame runs in a groove at the back and can be lifted at the front and then fixed with the pin in one of the holes. This way you can transpose a whole octave, but you need a lot of extra keys which disappear under a flap when not in use. The pin does not release the shifting of the key until the keys are raised far enough to no longer scratch on top of the rods. This also takes Jens' hint into account.

    Greetings! Samuel


    Thank you so much Samuel,


    I roughly understand the mechanism, but could you possible show more photos or maybe show a short video could be more helpful?^^


    My idea is that the keys together with the key frame shift during transposing, similar to the harpsichord video show by Jens.


    But I think the conventional method is by lifting up the keyboard at the front and then make the shift. But I don't know the exact mechanism.


    Best regards! Xiaohu

    Hello Jens,


    Thank you for the video, it is very useful. The reason I choose to shift the keys and the key frame together is because I didn't know how the conventional method works: first lift up the keyboard at the front and then make the shift.


    I made a slight adjustment at the back of the keys according to the design by Mr. Koele's, I think this would help to confine the keys undesired horizontal movement.


    Next I will draw the rods connecting the keyboard and the pallet.


    Greetings, Xiaohu


    Hello Xiaohu!


    You should lift the whole keyboard frame when transposing because the keys lie on the rods in order to have the most direct contact possible with the valve. If you then move the keys without lifting them, there is a risk that they will jam on the rods. With the harpsichord, you have to be very careful, because the contact point is at the back of the key, so lifting is not possible. If something is not neatly worked, or you accidentally press a key when moving it, something often breaks... But I also know the variant of chest organs where the rods under the keys are moved without lifting anything. In this case, you probably have to build very clean transitions between the keys and round off the contact surfaces well.


    By the way, your upper keys seem very high to me. That is not exactly helpful for a smooth playing...


    Best wishes
    Samuel

    Hello Samuel,


    Thanks for the information, it is really very helpful indeed, I will remember to make the surfaces smooth for a clean transition.

    Meanwhile, do you mean that the sharp and flat keys are too high? It centainly appears so, I will reduce the height of those keys. what is the suggested height?

    I would also like to ask what is the normal displacement of the key when pressed down? now my design is around 10mm, it is too large? I find in Jens's design is 6-8mm.

    And the octave span distance for my drawing is 147mm, is it a bit small? comparing to that of the modern piano which is around 165mm for an octave.


    Thank you and have a nice weekend, Xiaohu

    Dear Xiaohu,


    the dimensions of keyboards are historically quite variable. However, they are usually wider rather than narrower in terms of octave compared to today's pianos. You are almost one key narrower than normal on the octave! That's fine if you have small hands and can't grasp an octave on normal keyboards, but if someone else wants to play on your organ, he will at first have big problems to adjust to this short measure. The "Bund deutscher Orgelbauer" (Association of German Organ Builders) has set standard measurements and these are exactly the same width as the modern piano. In deepness at pressing down, they sy 7-11 mm depending on the size of the organ. So for chest organs I would rather take 7 or 8 mm to allow agile playing.

    As for the height of the upper keys, however, the BDO is of the opinion that it should be 12.5 mm. I come from historical harpsichord building and there the pressed upper key is almost level with the unpressed white key, so rather lower. Here is the page with the standard dimensions! Everything in German of course, but the drawings are understandable even so:


    https://www.midiboutique.com/i…load/download/get&did=158


    Kind regards
    Samuel

    嗨塞缪尔，

    非常感谢您提供这些详细信息，这真的很有帮助。我将八度音阶尺寸调整为 160 毫米。上键高度降低到8mm。

    正如您建议的那样，我正在尝试通过在实际组装时添加 2 毫米的毡层来将压下的深度降低到 7-8 毫米。


    我仍在研究键盘框架和移调机制，希望我能尽快提出解决方案。

    最好的祝福，

    Xiaohu

    Ein Gruß in die Runde!

    Falls noch nicht alle die Seite deepl.com kennen. Hier ist die automatische Übersetzung des Beitrags von Xiaohu. Klingt zumindest plausibel. Es können sich in dieser Frage aber gern auch andere zu Wort melden. Ich halte mich nicht für den Experten, der die alleinige Weisheit im Besitz hat!


    对这一回合的问候!

    如果不是每个人都知道deepl.com这个网站的话。以下是小胡的帖子的自动翻译。至少它听起来是合理的。但请随时向其他人询问这个问题。我不认为自己是拥有唯一智慧的专家！我认为自己是拥有唯一智慧的专家。


    Hello Xiaohu!

    I prefer writing in English with machine help because then I can better control how the translation turned out. Felt is always good to reduce noise, only if it becomes too thick, it could give an uncomfortable feeling when you can't feel exactly when the key is pressed. With 8 mm press depth, I'd stick with at least 10 mm key height after all, otherwise you'll be flat when the top key is pressed, which could be irritating, especially for modern players.

    Many greetings

    Samuel

    Hello Xiaohu and to the round. I have always used the drawings from Laukhuff as a guide for the dimensions: "Laukhuff". Luckily I still have the catalogue as a PDF on my computer. The octave width of my chest is 162mm. The upper keys are 12.5 high and slope down to 11 at the back.

    My small contribution to the matter and good luck, Xiaohu

    Greetings Jürgen


    Hallo Xiaohu und in die Runde. Ich habe mich bei den Abmassen immer an die Zeichnungen von der Fa.: "Laukhuff" orientiert. Den Katalog als PDF habe ich zum Glück noch auf dem Rechner. Bei meiner Truhe bin ich bei der Oktavbreite mit 162mm dabei. Die Obertasten sind mit 12,5 hoch nach hinten auf 11 abfallend.

    Mein kleiner Beitrag zu der Sache und viel Erfolg, Xiaohu

    Grüße Jürgen

    Hello Xiaohu, your keyboard is ending on note E. That's a bit strange because the "usual" compass is rather up to a2 (renaissance), c3 or d3 (baroque) or f3/g3 (later). If you prefer to play music after the baroque era, I would suggest to go up to at least f3 which is one note more as far as I can tell. Regards, Jens

    Zitat von JGB

    Hello Xiaohu, your keyboard is ending on note E. That's a bit strange because the "usual" compass is rather up to a2 (renaissance), c3 or d3 (baroque) or f3/g3 (later). If you prefer to play music after the baroque era, I would suggest to go up to at least f3 which is one note more as far as I can tell. Regards, Jens

    Dear Jens, thanks so much for your kind suggestion. I am planning to build this chest organ mainly for the purpose to play hymns or Bach's works or maybe could borrow to the local baroque ensemble as continuo. I ended with note E as copied from Mr. Theo Koele's organ e5. Thanks and best regards, Xiaohu

    Hello Juergen!

    So nice to talk to you and thank you for this information, I will consider changing the height of the upper keys, but at present I will stick to Samuel's suggestion to make the height to be 10mm and 8mm press depth as shown in the graph below. I also make a little adjustment at the back which the keyboard frame can be lifted up and rotate a little that facilates the transposition.

    Thanks again and best regards, Xiaohu



    Hello Samuel and other fellow organ builders,


    Ich kann nur ein bisschen Deutsch sprechen, therefore I use English to write and I don't know why in the previous post the language switches to my mother tongue Chinese and thank you for letting me know the deepl website, I use google translate8o


    I am now searching for the suitable blower for some time on the online shops in China, there is no suitable organ blower for sale in China and I am searching for the alternatives.

    I found that the pressure of 450pa or 45mm of water would be enough and try to make the blower as small as possible, my plan is to build two stops with 8foot and 4 foot pipes. I found two blowers cost around 20 euros, but I don't know whether this will meet the needs, but it is the best I could found. The first one has very small dimension:


    The parameter of the second one is better but it is too high (260mm) for a chest organ?


    Looking forward to your comments and advice,

    Best regards,

    Xiaohu





    Hi Xiaohu, pressure in Pascal is about ten times the pressure in millimeter of water column. If you want 45mm or 450 Pascal in your instrument you have to add a little bit in order to have some margin for pressure regulation with the bellows/ventil combination. So I would suggest having a blower that can deliver 60mm or 600 Pa. There are also special organ blowers in the market like the ones from organparts.info but they are rather expensive. If you can afford it, take such a special blower: they just work as intended. Else, you have to experiment a little bit. I use a 2nd hand ebm RG148 blower (now ebmpapst) that can be regulated. But it can only handle about 1 or 2 organ stops. Regards, Jens