Chrome Plating the DM48 Mouthpiece
Ivan Johnstone
I have been playing a series of Hohner chromatic harmonicas from the age of 9 in the late 1950s and I am used to playing on the slippery chrome plated mouthpieces. The way that I play is totally self-taught. Even the way I hold a harmonica is different from anyone else I have seen on YouTube. I am right handed and I place my harmonica on top of my left thumb and palm with my fingers wrapped over the top. My left wrist is at 90 degrees to my forearm and my left elbow is hugged into my body and slightly over the front of my lower ribs. In my right hand my first finger is raised and pressing on the slide while I hold my harmonica between my remaining fingers and thumb. I play my harmonica with my mouthpiece at a 45 degree tilt. It works for me, and with this arrangement I am able to create a large hollow behind my harmonica with both palms and smallest fingers against each other forming a seal. I can break the seal to create special effects. When playing I keep my lips on the mouthpiece and slide the mouthpiece across my lips while keeping my head still
I find that the matt anodised finish to the aluminium DM48 mouthpiece is not slippery enough for me unless the mouthpiece is well lubricated with spittle. When playing mainly at one end of mouthpiece the lubricant can dry at the other end. The result is that when I slide the mouthpiece to the other end my lips are pulled sideways with the friction and sometimes I initially play the wrong adjacent hole. I have therefore ordered spare mouthpieces from Erick Lekholm to experiment with.
I have tried a coating of Liquid Chrome (NZ $20 a spray can) and this is not a goer. The surface is not as slippery as a true chrome plated finish and the coating would not be durable.
My next “experiment” is chrome plating. My experience in finding a business in New Zealand that would chrome plate one of my spare mouthpieces has prompted me to report this experience to other DM48 players who may also wish to chrome plate their mouthpieces.
I finished up emailing 13 electroplating businesses in New Zealand to chrome plate the mouthpiece of my DM48 Digital Chromatic Harmonica. Some businesses did not reply, some replied they were unable (or not prepared?) to chrome plate my mouthpiece, and some provided an estimate to silver plate. Silver plating is not an option for me because it tarnishes with age. The chrome plate finishes to my Hohner chromatic harmonicas still provide a slippery surface after 20 years of use and outlast the reeds.
Given the above responses, I modified my additional request for a fixed quotation to chrome plate my mouthpiece by specifying that I wanted a quotation and not an estimate, I described the process I wanted after doing research on the Internet, and I made it clear that a high quality chrome finish to the interior of the holes in the mouthpiece was not critical or necessary. I eventually received a reply from an Auckland based electroplating business in which I have confidence and I accepted their quotation of NZ $120 plus 15% GST.
My following request for a quotation may be helpful to anyone else who may wish to chrome plate their DM48 mouthpiece:
“I have purchased a digital chromatic harmonica which has a mouthpiece made of aluminium with a black matt anodised finish which is not slippery enough for me to play the instrument without unwanted notes. My Hohner standard chromatic harmonicas have a chrome plated mouthpiece.
Please provide a fixed quotation (not an estimate) for the highest possible standard and quality of chrome plating of my harmonica mouthpiece. The mouthpiece is 165 mm long x 15 mm high by 30 mm wide and can be viewed in the attached photographs. Only the exterior surfaces of the mouthpiece need to have a quality smooth finish. The internal surface of the holes in the mouthpiece are not critical and do not need to be chrome plated. Chrome plating must include the following processes and order of process:
1. Stripping the anodising,
2. Polishing the bare aluminium exterior surfaces,
3. Copper plating,
4. Polishing the exterior copper plating,
5. Nickel plating,
6. Polishing the exterior nickel plating,
7. Chrome plating,
8. Polishing the exterior chrome plating.”
As an aside, I have found that while waiting for return of my chrome plated mouthpiece, a smearing of white petroleum jelly on my current mouthpiece provides a sufficiently slippery surface to play without unwanted notes for up to an hour without needing a second coating.
Ivan Johnstone
Ivan Johnstone
On Sunday, July 2, 2017 at 9:21:28 AM UTC+12, Ivan Johnstone wrote:
Ivan Johnstone
Agustín
good health
Agustín
Agustín
good health
Agustín
Ivan Johnstone
Over the past few years I have semi-toyed with the idea of buying a 3D printer - the cost has put me off - and in recent days I have done some more homework on the process. Using a more expensive 3D printer it is possible to laser scan a DM48 mouthpiece to create a 3D image file in stl or obj file format which can be used by a 3D printer or CNC machining. An alternative is to measure up a DM48 mouthpiece and use 3D design software to create the same 3D file. I am very impressed by FreeCAD which is freeware. https://www.freecadweb.org
I have done an Internet search on what is methacrylate and have come across a definition of a material which is better known - "Perspex: solid transparent plastic made of polymethyl methacrylate (the same material as Plexiglas or Lucite)."
I will check out the slipperiness of this material and if it is to my satisfaction, then I will either use FreeCAD or obtain a laser scan to create a 3D file for third party CNC machining. An alternative is to CNC machine brass, make sure that the mouthpiece is perfectly polished, and then use a local electroplater to chrome plate. This alternative would be more expensive compared to CNC machining Perpsex.
Augustin, please confirm whether you used a block of Perspex and the source of your material to create your mouthpiece. I am also curious as to how you crafted your mouthpiece and especially on what you did to create the final smooth finish.
Agustín
if you can find half bar you have the job near done, if not you have to buy a square bar and file the round part, the hering mouthpiece of the photo it's made like that. The better and patient way it's with sandpaper each time softer. I use the quickly way, a stone to sharpen knives that has two parts hard and soft, also finishing with the soft part the lucite it's full of scratches, but then you apply liquid ointment for polish lucite (apply with a clothe) and you have a polish surface also if some scratches were deep it's like they're hidden (for the touch but not for the view) and the lips don't notice them and believe me i have very sensitive lips, i can't play a hering mouthpiece (that's the reason for the plexiglass) and everyone can. Also DM48 new aluminium mouthpiece has sharp holes for me. For what i said look the DM48 mouthpiece plexiglass photo in the extremes and you can see the scratches but lips slide well.
good health
Agustín
Ivan Johnstone
On the 3D hobby printing front, I have decided to take the plunge now and I have ordered a Creality3D CR - 10S 3D Desktop Printer for $526.71 (US) delivered to New Zealand.
https://www.gearbest.com/3d-printers-3d-printer-kits/pp_796478.html?lkid=10695720&lkid=11570557
One of my first tasks will be to create a base for attaching the Swan 1248 mouthpice and cover plates. By doing so, the profile of the mouthpiece and sliperiness will be the same as to what I have become used to over a number of decades. The screw holes of the mouthpiece are likely to interfere with the spacing for attachment to the DM48. If so, then the base from the rear of the face plates will project by an extra 40 mm to allow a recess for inserting the base screws and using an L shaped Allen key for tightening to the DM48. When I have successfully completed this project I will post the 3D stl and obj files for other DM48 players to use.
Agustín
good health
Agustín
El sábado, 1 de julio de 2017, 23:21:28 (UTC+2), Ivan Johnstone escribió:
Ivan Johnstone
Ivan Johnstone
https://www.mwmaterialsworld.com/es/media-cana-metacrilato-transparente.html
In the meantime, I have done an Internet search on whether one can 3D print Polymethyl Methacrylate and yes, one can. The filament is called PMMA (Acrylic).
https://all3dp.com/1/3d-printer-filament-types-3d-printing-3d-filament/#pmma-acrylic
One advantage of 3D printing over modifying a rod of Polymethyl Methacrylate is that the same mouthpiece profile of an Hohner chromatic harmonica can be far more easily created. The 3D printer I have ordered does quality printing. In terms of final smoothness, at worst I might need to do some light sanding or use polishing paste. I like Augustin's idea of using smaller holes to reduce the possibility of sounding unwanted notes on adjacent holes. This would be an advantage as I like to keep the Solo Assist setting off to enable rapid transitions to adjacent notes. I am still experimenting. Some patches are easier to play without unwanted adjacent notes than others.
Brendan Power
Your mouthpiece looks nice Augustin :-)
Ivan Johnstone
An advantage of printing a plastic mouthpiece is that both the profile of the mouthpiece and the diameter of the holes can be tailored to suit the player. I have used 5.0 mm instead of 6.5 mm diameter holes as used in the DM48 aluminium mouthpiece. I have attached STL files of a bevelled and a rounded version of the mouthpiece and also the FreeCAD files which can be modified.
Blunt White
On Saturday, March 10, 2018 at 3:07:37 AM UTC-5, Brendan Power wrote:
Ivan Johnstone
Ivan Johnstone
My above postings have described what has been a bit of a saga for me to get an alternative mouthpiece which is sufficiently slippery for me when both dry and wet. The slipperiness of a Hohner chrome plated mouthpiece is the standard I have tried to achieve and chrome plating the standard aluminium DM48 mouthpiece is possible by following the specification in one of my previous postings. Silver plating the standard DM48 mouthpiece is another option, but both these options are not the cheapest options and for some player these modified DM48 mouthpieces may be too cold for their lips.
The above saga has continued. I have successfully printed a DM48 mouthpiece using PLA filament, but PLA is not slippery enough when dry and wet. Given Brendan Power’s posting that he uses ABS filament to print an alternative DM48 mouthpiece, I decided to try out the same. A 1.0 kg reel of ABS cost me NZ $33 including postage and a 100% infill mouthpiece would use 59 grams (i.e. less than $2 of ABS material) and take 13 hours to print at 100 micron quality using my Creality CR-10S 3D printer.
3D printing with ABS filament requires higher plate and nozzle temperatures, is more difficult to stick to a plate, and tends to bow unless firmly stuck down to the plate. My first 3D printing using ABS filament was unsuccessful when using hairspray or paper tape which had been adequate for PLA. After two hours of printing the paper tape came unstuck and the 3D print bowed. I sanded the bottom of the defect and used a fine haired paint brush to apply acetone as described in Brendan Power’s posting. Yes, ABS is sufficiently slippery enough for me when both dry and wet.
I have mastered printing PLA filament but not ABS. By this time I was getting impatient to get a final result, so I used 3D Hubs (middleman) to identify a professional 3D printing firm based in New Zealand to print my mouthpiece for me. A 3D printing firm based in Queenstown provide a quotation of NZ $27 including postage based on the STL file that I uploaded to the 3D Hubs website. My mouthpiece arrived a few days later, but the 3D printing firm had misread my specification to print a mouthpiece using ABS filament and had instead printed one using PLA. The firm apologised for its mistake and undertook to print again using ABS and posting to me by one day courier. A few days later 3D Hubs advised me I would receive a full refund because the Queenstown firm could not meet the quality standard of my specification.
On Wednesday last week I bypassed any middleman by requesting a direct quotation from a well-established 3D printing firm based in Auckland, New Zealand. The website provided an estimate of NZ $31 based on the STL file I uploaded. By Friday night I had not received a reply, so I ordered a heat resistant 3M mat (NZ $12 plus $5 courier) to stick to the glass plate of my Creality CR-10S 3D printer. The 3M mat arrived on Tuesday and on the same day I successfully printed my alternative DM48 mouthpiece. I still haven’t received a reply from the Auckland firm.
The specification and procedure I used to print and smooth my ABS mouthpiece are as follows. I printed my mouthpiece using 1.75 mm ABS filament, 100 micron quality, and 30% infill using a 90 degrees Celsius plate and 230 degrees Celsius nozzle. The nozzle was 0.4 mm brass. I chose 30% infill because it took 5 hours 15 minutes to print on my 3D printer compared to 13 hours for 100% infill. 30% infill is robust – no problems there. To be doubly sure that the mouthpiece would stay stuck to the 3M mat during printing, I painted a slurry mix of ABS dissolved in acetone to the mat when fully heated. This may have been an overkill. It took quite a bit of effort to remove the mouthpiece from the 3M mat when the mouthpiece and plate had cooled.
I then spent a considerable amount of time sanding my mouthpiece to a smooth and dull surface using 400 and then 1000 grit sandpaper. I had already established that brush painting my previous defective mouthpiece with acetone created a glossy but uneven smooth surface. I therefore tried an acetone fume approach to get some gloss on my sanded and very smooth but dull mouthpiece. Using acetone fumes to get a gloss finish requires experimentation. I placed toilet paper impregnated with acetone on the bottom and sides of a glass container as described on a number of websites and then placed my mouthpiece on top of a stand away from the toilet paper. A glass lid sealed the top of the container. I checked the mouthpiece periodically over a 90 minute period and there was little if any change in the upper surface. However, when I checked the bottom of the mouthpiece the surface had melted to a glossy but irregular finish. I sanded the bottom of the mouthpiece back to a smooth surface and then impregnated folded up toilet paper with acetone and lightly wiped the upper surface once in only one direction. The surface turned glossy and remained smooth to my finger touch. Success at long last. The soft and fine textured cloth to clean glasses might provide even better results.
I have just finished a practice session using my ABS printed mouthpiece and I have compared its slipperiness against my defective chrome plated mouthpiece, sections of which are peeling away. No, the ABS printed mouthpiece is not as slippery when dry and wet as chrome plating, but is definitely more slippery than the standard matte anodised aluminium mouthpiece when dry.
I tried 1000 grit sandpaper on the glossy finish of my ABS mouthpiece and this improved the slipperiness. Polishing the surface might result in an additional improvement in slipperiness. The coldness of the aluminium mouthpiece compared to the ABS mouthpiece was quite striking. The chrome plated mouthpiece felt even colder.
With my ABS mouthpiece in place, I will now focus on playing my DM48 on a more regular basis. I will continue experimenting to improve the slipperiness of the ABS mouthpiece and I might try 3D printing a mouthpiece using PMMA filament as I understand from the Internet that this type of filament is the most slippery. I might also print a rounded version of an alternative DM48 mouthpiece for comparison. The STL files for both a beveled and rounded mouthpiece can be downloaded from a previous posting above.
Agustín
Erik Larsson Lekholm
Ivan Johnstone
Ivan Johnstone
2. I slid each mouthpiece on only my upper lip backwards and forwards by one hole and then backwards and forwards across all 12 holes.
3. Ditto for only my lower lip.
4. Ditto with both lips.
My rankings of slipperiness when dry are as follows with the most slippery ranked first.
1. Chrome plating on DM48 aluminium mouthpiece.
2. Chemtech Liquid Chrome in can sprayed on matte anodised aluminium mouthpiece.
3. ZAP PT36 Z Poxy 5 Minute Epoxy Quick Shot Dual Syringe applied to PLA mouthpiece.
4. ABS mouthpiece.
5. PLA mouthpiece.
6. Matte anodised aluminium mouthpiece.
I will now 3D print a rounded profile mouthpiece using PLA, apply coats of Chemtech Liquid Chrome, sand the surface to smooth finish, and then polish. Fingers crossed that this mouthpiece will be acceptable to me when playing my DM48. Failing that, I think I will go for my first option which is chrome plating. Chrome plating can be applied directly to brass, but not aluminium unless a copper base is electroplated on first. Removing the matt anodising from a standard DM48 aluminium mouthpiece before electroplating, especially from the holes, might prove to be a problem. The safe way to go would be to obtain a CNC manufactured mouthpiece made of brass using my STL file and chrome plate this mouthpiece.
Ivan Johnstone
http://www.slidemeister.com/forums/index.php?topic=1238.0
The postings confirm my own findings. I have used chrome plated mouthpieces for 60 years and for me chrome plating is the ultimate. I have never tried silver plated mouthpieces.
A number of days ago I 3D printed a beveled and a rounded mouthpiece using PLA. I then carefully can sprayed multiple light coats of Liquid Chrome on the mouthpieces allowing plenty of time for drying between coats. Liquid Chrome takes ages to dry hard and after sanding and polishing the mouthpieces three days later I found that the surface of the Liquid Chrome coating was not as hard as that of the same coating I had applied to the standard DM48 matte anodised aluminium mouthpiece many months ago. My Liquid Chrome over PLA mouthpieces are currently less slippery when dry than the Liquid Chrome coating over a standard DM48 aluminium mouthpiece and also less slippery when dry than my ABS mouthpiece.
According to the Internet, the Hohner CX12 black mouthpiece is made of ABS (not 3D printed). I will continue trialling my ABS mouthpiece (I prefer the beveled profile). If ABS should prove not to be a long term solution for me, then to keep costs down I will 3D print an extension to my DM48 which will take the chrome plated mouthpiece and cover plates of my Swan 1248. A slight hiccup if I should do that. The round holes in the Swan mouthpiece do not match up exactly to the holes in the DM48. Over 12 holes the Swan mouthpiece holes are half a hole shorter. I could try doing without the mouthpiece and use only the cover plates in the same way as diatonic harps.
Ivan Johnstone
Ivan Johnstone
I prefer chrome plated mouthpieces for their slipperiness when dry. As per my earlier postings, I commissioned an electroplater to chrome plate a DM48 matte finish anodised aluminium mouthpiece. This approach was not ideal from the outset because chrome plating cannot be applied directly to aluminium. The anodised surface, including the interior surfaces of the holes, needs to be fully removed, the surfaces polished to a smooth finish, and then a plating of copper needs to be applied to the prepared aluminium before the final chrome plating. Silver plating can be applied directly over aluminium, but once again the anodised surface first needs to be fully removed and then polished to a smooth surface.
For reasons given in an earlier posting, my first attempt at obtaining a chrome plated mouthpiece for my DM48 was initially successful until six months later when the electroplating proved to be defective. My subsequent efforts at 3D printing a mouthpiece, including ABS filament, have also been unsatisfactory. For me, the slipperiness of chrome plating when dry is far superior. For others, a 3D printed ABS mouthpiece might be a satisfactory replacement of the DM48 aluminium mouthpiece. Being able to change the diameter of the holes in a 3D printed mouthpiece might be an advantage for some DM48 players.
My second attempt at obtaining a chrome plated mouthpiece for my DM48 has been successful. This solution adopts the same approach as that of a standard diatonic harp which uses chrome plated cover plates. A photograph of my solution is attached and I have also attached a screen shot of the 3D printed base, the STL file, and the FreeCAD file for further modification by others.
I have finished up 3D printing using PLA filament, draft print at 0.2 mm, 1.4 mm walls, and 20% infill density. It took 7 hours 15 minutes to print and used 89 grams of filament. To print at 100% infill density would have taken 18 hours 35 minutes to print and would have used 194 grams of filament. I found that ABS filament delaminated at 20% infill density at various nozzle temperatures. On previous successful ABS prints I have used 100% infill. All my PLA printed objects have been 100% successful and I don't have patience for long prints, so I used PLA instead of ABS filament. I smoothed the top surface of the draft quality PLA base with a very light sanding of 60 grit sandpaper followed by 240, 400, 800, and then 1200 grit sandpaper. I then used a small roll (reefer) of 1200 grit sandpaper to smooth the sharp edges of each hole. I didn't use polishing compound as I didn't want remnants entering each hole. The sanded surface of the top of the base is as slippery as that of my diatonic harps.
I have adjusted the positioning of the Swan 1248 chrome plated cover plates to be flush with the top of the 3D printed base and also slightly proud of the PLA surface. I prefer the second option. The cover plates from any manufacturer of 12-hole chromatic harmonicas can be used on the 3D printed base. Second hand cover plates can be sterilised in a pressure cooker.
With the 5mm diameter holes in the 3D printed base and subsequent greater spacing between holes, I am able to quickly transition notes from hole to hole without blipping or sounding of unwanted holes (MP3 file attached). The diameter of the holes in the standard DM48 aluminium mouthpiece is 6.5mm (correction to previous posting).
The round headed bolts used to secure the original DM48 mouthpiece to the DM48 electronic base are best tightened and loosened using a TEX screw driver held vertically. Given the necessary configuration of the 3D printed base, it is not possible to use any screw driver held vertically, so I tried using an Allen key which was not ideal. I have found that Phillips (star shaped) round head bolts can be more easily tightened and loosened with a screw driver held at an angle. The round head bolts I have purchased from the local hardware store are M3 x 25mm zinc plated and I have used the same M3 bolts (and nuts) to secure the cover plates.
Before screwing the 3D printed base to the DM48, I first removed the DM48 lid to expose the interior nuts. At one end an M3 X 25mm round head bolt can be used to secure the 3D printed base to the DM48 electronic base. At the other end a shorter round head bolt is required. Shorter than 25mm round head bolts might be available at specialised outlets, otherwise a 25mm bolt can be shortened by first threading two nuts for locking purposes on the bolt to the required length of bolt and then cutting the bolt with either a thin abrasive disk attached to a drill or a very fine-toothed hacksaw blade. Removing the nuts usually removes blemishes to the thread of the bolt. If not, then carefully file the end of the bolt to a pointed end to remove any remaining burs of metal from the threads.
On Monday, August 20, 2018 at 10:39:19 AM UTC+12, Ivan Johnstone wrote:
When practicing Schindler's List by John Williams I use Hole 1 in the key of F. The left edge of my 5.0 mm diameter hole in the 3D printed base is at the left edge of hole 1 of the Swan 1248 chrome plated mouthpiece that I have screw fixed to the top of the base. Using the monophonic setting I find that when I blow notes on hole 1 the sound initially blips in deciding whether to play hole 1 or hole 2. The diameter of the holes in the Swan mouthpiece is 7.0 mm so the effective separation between holes is therefore less than that of the 5.0 mm holes in the base and also less than that of the 6.35 mm holes in the standard DM48 aluminium mouthpiece.I have removed the Swan mouthpiece and I no longer have the same possibility of blipping. The separation of my current base between the Swan cover plates as 3D printed is 14.7 mm compared to 8.0 mm of an Hohner diatonic harp which I am used to playing. I will therefore print a new base with an 8mm separation between the cover plates and when I do so I will post this new STL file on the forum. I will 3D print using ABS filament so that I can smooth and polish the top of the base to a more slippery finish than is possible using PLA filament. Another advantage of using ABS filament is that I can more easily smooth the sides of a draft 3D print using acetone.
Ivan Johnstone
On Thursday, August 23, 2018 at 9:12:52 AM UTC+12, Ivan Johnstone wrote:
I prefer chrome plated mouthpieces for their slipperiness when dry. As per my earlier postings, I commissioned an electroplater to chrome plate a DM48 matte finish anodised aluminium mouthpiece. This approach was not ideal from the outset because chrome plating cannot be applied directly to aluminium. The anodised surface, including the interior surfaces of the holes, needs to be fully removed, the surfaces polished to a smooth finish, and then a plating of copper needs to be applied to the prepared aluminium before the final chrome plating. Silver plating can be applied directly over aluminium, but once again the anodised surface first needs to be fully removed and then polished to a smooth surface.
For reasons given in an earlier posting, my first attempt at obtaining a chrome plated mouthpiece for my DM48 was initially successful until six months later when the electroplating proved to be defective. My subsequent efforts at 3D printing a mouthpiece, including ABS filament, have also been unsatisfactory. For me, the slipperiness of chrome plating when dry is far superior. For others, a 3D printed ABS mouthpiece might be a satisfactory replacement of the DM48 aluminium mouthpiece. Being able to change the diameter of the holes in a 3D printed mouthpiece might be an advantage for some DM48 players.
My second attempt at obtaining a chrome plated mouthpiece for my DM48 has been successful. This solution adopts the same approach as that of a standard diatonic harp which uses chrome plated cover plates. A photograph of my solution is attached and I have also attached a screen shot of the 3D printed base, the STL file, and the FreeCAD file for further modification by others.
I have finished up 3D printing using PLA filament, draft print at 0.2 mm, 1.4 mm walls, and 20% infill density. It took 7 hours 15 minutes to print and used 89 grams of filament. To print at 100% infill density would have taken 18 hours 35 minutes to print and would have used 194 grams of filament. I found that ABS filament delaminated at 20% infill density at various nozzle temperatures. On previous successful ABS prints I have used 100% infill. All my PLA printed objects have been 100% successful and I don't have patience for long prints, so I used PLA instead of ABS filament. I smoothed the top surface of the draft quality PLA base with a very light sanding of 60 grit sandpaper followed by 240, 400, 800, and then 1200 grit sandpaper. I then used a small roll (reefer) of 1200 grit sandpaper to smooth the sharp edges of each hole. I didn't use polishing compound as I didn't want remnants entering each hole. The sanded surface of the top of the base is as slippery as that of my diatonic harps.
I have adjusted the positioning of the Swan 1248 chrome plated cover plates to be flush with the top of the 3D printed base and also slightly proud of the PLA surface. I prefer the second option. The cover plates from any manufacturer of 12-hole chromatic harmonicas can be used on the 3D printed base. Second hand cover plates can be sterilised in a pressure cooker.
With the 5mm diameter holes in the 3D printed base and subsequent greater spacing between holes, I am able to quickly transition notes from hole to hole without blipping or sounding of unwanted holes (MP3 file attached). The diameter of the holes in the standard DM48 aluminium mouthpiece is 6.5mm (correction to previous posting).
The round headed bolts used to secure the original DM48 mouthpiece to the DM48 electronic base are best tightened and loosened using a TEX screw driver held vertically. Given the necessary configuration of the 3D printed base, it is not possible to use any screw driver held vertically, so I tried using an Allen key which was not ideal. I have found that Phillips (star shaped) round head bolts can be more easily tightened and loosened with a screw driver held at an angle. The round head bolts I have purchased from the local hardware store are M3 x 25mm zinc plated and I have used the same M3 bolts (and nuts) to secure the cover plates.
Before screwing the 3D printed base to the DM48, I first removed the DM48 lid to expose the interior nuts. At one end an M3 X 25mm round head bolt can be used to secure the 3D printed base to the DM48 electronic base. At the other end a shorter round head bolt is required. Shorter than 25mm round head bolts might be available at specialised outlets, otherwise a 25mm bolt can be shortened by first threading two nuts for locking purposes on the bolt to the required length of bolt and then cutting the bolt with either a thin abrasive disk attached to a drill or a very fine-toothed hacksaw blade. Removing the nuts usually removes blemishes to the thread of the bolt. If not, then carefully file the end of the bolt to a pointed end to remove any remaining burs of metal from the threads.
<w:LsdException Locked="false" Priority="52" Name="List Table 7 Colorful Accen
Brendan Power
Ivan Johnstone
On the basis that a greater separation between holes would reduce the possibility of low breath pressure on adjacent holes, I removed the mouthpiece from the base but retained the cover plates. The resulting mouthpiece profile is now identical to that of a diatonic harp. Removal of the mouthpiece resulted in fewer occasional blips when shifting from one hole to a more distant hole.
Ideally, I would like to totally eliminate blips when playing my DM48. One solution is to block out adjacent holes to the one being played and I have carried out experiments as described in my previous diary entries which confirm that this approach is feasible, but not necessarily viable. A week ago, I emailed a price request to Kettlewell Frictionless Mouthpiece for his slider and mouthpiece combination which blocks out adjacent holes. Kettlewell has not replied to my email. I have therefore carried out further experiments 3D printing sliders which fit over the chrome plated Swan 1248 mouthpiece. To ensure a tight seal between slider and mouthpiece, I have immersed each slider in boiling water and then pressed the slider over the mouthpieces while sliding back and forwards to ensure it moulded to the exact same profile. Using my lips alone, the friction between slider and mouthpiece is greatly reduced to the extent that the combination of slider and mouthpiece is playable. However, there is a problem. To ensure there is a tight seal between slider and mouthpiece, one’s lips need to constantly press the slider firmly against the mouthpiece and the slider will not stay on the mouthpiece by itself. I find this to be cumbersome and restrictive. A slider approach similar to the Kettlewell Frictionless Mouthpiece to eliminate blips when playing the DM48 is not a solution for me.
Going back to the greater separation between holes approach, I have 3D printed a base with 2mm diameter holes which further increases the separation between holes. However, I found that 2mm diameter holes are too small. It took too much effort to produce a sounding note when blowing and I couldn’t produce any sounding note when sucking regardless of any DM48 setting. A few days ago, I 3D printed a base with 3mm diameter holes. The result so far seems to be an improvement over the base which uses 5mm diameter holes and I seem to have greater control over the occurrence of blips using the Sensitivity and Trigger Level settings. A balance of settings is needed to provide a wide dynamic range of volume and ease of playing because the smaller holes not only result in greater separation between holes, but also require greater breath pressure to blow or suck air through each hole. I have come across a research paper titled Characterisation of Flow-Resistant Tubes Used for Semi-Occluded Vocal Tract Voice Training and Therapy which states:
“… resistance can be characterized for any tube based on diameter, length, and flow rate. With regard to the original questions, we found that … for commonly used tubes, diameter is the critical variable for governing flow resistance”.
There might be a fluid dynamics parallel between flow resistance of a tube and the threshold resistance of a reed in a standard chromatic harmonica to sound a note. To make a comprehensive comparison between using a base with 5mm versus 3mm diameter holes and the prevalence of unwanted blips I would need to have two DM48 instruments with the two bases attached. Swapping bases over is too cumbersome and time consuming to make quick comparisons. In the meantime, I will continue using the 3mm diameter hole base.
I have also carried out an experiment playing my DM48 using the outlet holes at the back of the instrument. I was able to play with far less resistance than through the base mouthpiece. I then taped over the holes in the base mouthpiece and I was still able to play notes with the same reduced resistance. I initially wondered where my air was escaping to and how effective the separation between the channels and the air seals are within the DM48 until I remembered that I can maintain air pressure in my lungs underwater without blowing any bubbles. Maintaining air pressure to sound a note inside the DM48 doesn’t require a flow of air. I hadn’t full sealed the exit holes with my lips, so after initially setting a new level of pressure in the DM48 my breath would have escaped from the sides of my lips. Although I was able to play the DM48 using the exit holes, I sometimes played blips when shifting to play on adjacent notes. This never happens when I play through the base mouthpiece. It was also possible for me to deliberately play a series of blips without moving my DM48 from one position. It is of note that the separations between the exit holes are minimal.
A few hours later
Erik Lekholm
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Ivan Johnstone
Yesterday I tested out the 3mm diameter hole base using the SWAM Violin instrument and I found the response of the instrument to be natural with Sensitivity set to 15 and Trigger Level set to 6. Today I practiced snippets of melody using the SWAM Flute followed by the SWAM Violin. With the SWAM flute I found that the breath resistance was too great to easily trip from note to note at a faster tempo and I had to change the Sensitivity Setting to 30 and the Trigger Level to 2 in order to play the melody snippet to my satisfaction. I then played the same melody using the SWAM Violin and felt that I had much greater control with Sensitivity set to 15 and Trigger Level set to 6.
Different instruments require different DM48 settings, and with the flute I am at the DM48 limits of settings and near the closure limits of the exit holes. I might need to do a rethink as to the final diameter of hole that I settle down to using before ordering a CNC chrome plated mouthpiece. I will try increasing the closure of the exit holes and if that doesn’t work out OK for the SWAM Flute, then I will 3D print another base using 4mm diameter holes before going back to a 5mm diameter base.
Erik, with regards to suppressing unwanted notes using DM48 settings, yes, I agree that is possible, but all along I have used settings that provide for me a natural response and a wide range of volume. For me that involves a compromise between achieving a natural response and occasionally playing an unwanted blip when shifting from one hole to a distant hole. Lifting my lips and landing on a distant hole instead of sliding to the distant hole eliminates blips, but that style of playing is not natural for me and is more difficult to do when playing at a faster tempo. Given the choice of playing naturally or sounding the occasional blip, I choose to play naturally. This choice is easy for me to make because I am a keen amateur who plays for my own enjoyment without an audience and not a professional where unwanted notes or blips would be an embarrassment. For example, before the monophonic mode became available and we used what is now called the Assisted Polyphonic Mode to suppress triggering neighbouring notes, I never used the full strength setting because this setting didn't feel natural when transitioning to adjacent notes.
With regards to separation between holes, absolute separation between holes using a Kettlewell Frictionless Slider or similar device to cover up adjacent holes does absolutely suppress triggering neighbouring notes both at the sounding level and MIDI unsounded notes level - there are no blips or unwanted very low volume and very short duration notes in a MIDI file. I found that a slider device over the mouthpiece is not for me.
The next best form of separation is separating the distance between the outer perimeter of each hole - i.e. smaller holes while maintaining the same centres between each hole. I have found that when using DM48 settings which enable a natural feel of play for me that a 5mm hole and then a 3mm hole further reduces the frequency of occasional blips when shifting from a hole to a distant hole.
The separation between holes of a chromatic harmonica and especially a diatonic harp means that most players envelop three holes simultaneously (unless they are seriously puckering their lips) while intentionally sounding notes in only the central hole. Because the centres of the holes in a diatonic harp are closer together than that of a chromatic harmonica, I am able to play faster tempo single note melodies more easily on a diatonic than on a chromatic. I have also played a 4-hole diatonic harp which fits entirely in my mouth and I can play single notes on this tiny harp as equally as well as that on a standard 10-hole harp. The presence of adjacent holes in a reed instrument even with very small centre spacings between holes does not impede reliable playing of single notes.
Although each of the above instruments has a series of holes at different centre spacings, the brain enables an immediate adjustment to the different spacings. It would be possible to construct a base with widening splayed holes from the DM48 to a mouthpiece with holes at greater centres. Brendan Power has done the reverse with his 10-hole diatonic base connected to the DM48. In the extreme, the centres of the holes could be so far apart that there would be an absolute effective separation between holes when playing. The mouthpiece would be playable, but not easily at a fast tempo, and one would need to use a sustain pedal for some melodies when transitioning from note to note. I am not suggesting that anyone should construct such a base. The above description is just a thought experiment.
It would be interesting to have measurements of breath pressure at 1mm intervals over 30mm (the width of lips enveloping 3 holes) while a player is intentionally sounding the central hole. I suspect the profile would be a bell curve with high kurtosis which would be different for different players and which would be different with different degrees of puckering for each player. Now place that bell curve over a mouthpiece with holes of different diameters and hence different spacings between holes. Lower breath pressure on the bell curve would land on the smaller diameter holes. Less breath pressure again would land on smaller diameter holes at greater centres between holes. In the extreme no suppression would be needed if the centres of each hole were 35mm apart instead of the DM48 9.55mm centres. Once again, the above is just a thought experiment.
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Ivan Johnstone
I get a great deal of enjoyment playing my DM48 with the above mouthpiece configuration, but nonetheless this configuration is a compromise compared to using a 3D printed base with chrome cover plates and chrome plated mouthpiece with 4mm holes. Each time I occasionally play my 16 hole Professional 16 chromatic harmonica by Hohner, I am reminded of what could be in terms of ideal slipperiness and when I play this reed based harmonica I am also reminded that I am able to play without any unwanted notes.
Out of curiosity, are there any players of the DM48 who use a chrome plated CNC manufactured mouthpiece made of brass either attached to a 3D printed base or directly to the DM48?
My next experiment will be to 3D print a base with holes the same size as the DM48 and a separate 3D printed mouthpiece with 3mm holes and smaller to test the pressure resistance of blowing and especially sucking while keeping the screw closures at each hole in the DM48 at 50%. The principles of airflow through a tube tells me that a large proportion of air flow resistance is due to the length of the tube as opposed to the diameter. For me, I find the greater the separation of the holes (i.e. the smaller the holes) when playing the DM48, the less likely I play unwanted notes adjacent to the note I want to play while retaining the full range of volume instead of suppressing unwanted notes by increasing the pressure threshold for triggering notes.
As an aside, I enjoy whistling when I am in the right frame of mind (happy) and I find that whistling is great practice for breath control. How many other DM48 players also enjoy whistling and use whistling to practice breath control when not near their DM48?
On Tuesday, September 18, 2018 at 8:20:36 AM UTC+12, Ivan Johnstone wrote:
Yesterday I tested out the 3mm diameter hole base using the SWAM Violin instrument and I found the response of the instrument to be natural with Sensitivity set to 15 and Trigger Level set to 6. Today I practiced snippets of melody using the SWAM Flute followed by the SWAM Violin. With the SWAM flute I found that the breath resistance was too great to easily trip from note to note at a faster tempo and I had to change the Sensitivity Setting to 30 and the Trigger Level to 2 in order to play the melody snippet to my satisfaction. I then played the same melody using the SWAM Violin and felt that I had much greater control with Sensitivity set to 15 and Trigger Level set to 6.
Different instruments require different DM48 settings, and with the flute I am at the DM48 limits of settings and near the closure limits of the exit holes. I might need to do a rethink as to the final diameter of hole that I settle down to using before ordering a CNC chrome plated mouthpiece. I will try increasing the closure of the exit holes and if that doesn’t work out OK for the SWAM Flute, then I will 3D print another base using 4mm diameter holes before going back to a 5mm diameter base.
Erik, with regards to suppressing unwanted notes using DM48 settings, yes, I agree that is possible, but all along I have used settings that provide for me a natural response and a wide range of volume. For me that involves a compromise between achieving a natural response and occasionally playing an unwanted blip when shifting from one hole to a distant hole. Lifting my lips and landing on a distant hole instead of sliding to the distant hole eliminates blips, but that style of playing is not natural for me and is more difficult to do when playing at a faster tempo. Given the choice of playing naturally or sounding the occasional blip, I choose to play naturally. This choice is easy for me to make because I am a keen amateur who plays for my own enjoyment without an audience and not a professional where unwanted notes or blips would be an embarrassment. For example, before the monophonic mode became available and we used what is now called the Assisted Polyphonic Mode to suppress triggering neighbouring notes, I never used the full strength setting because this setting didn't feel natural when transitioning to adjacent notes.
With regards to separation between holes, absolute separation between holes using a Kettlewell Frictionless Slider or similar device to cover up adjacent holes does absolutely suppress triggering neighbouring notes both at the sounding level and MIDI unsounded notes level - there are no blips or unwanted very low volume and very short duration notes in a MIDI file. I found that a slider device over the mouthpiece is not for me.
The next best form of separation is separating the distance between the outer perimeter of each hole - i.e. smaller holes while maintaining the same centres between each hole. I have found that when using DM48 settings which enable a natural feel of play for me that a 5mm hole and then a 3mm hole further reduces the frequency of occasional blips when shifting from a hole to a distant hole.
The separation between holes of a chromatic harmonica and especially a diatonic harp means that most players envelop three holes simultaneously (unless they are seriously puckering their lips) while intentionally sounding notes in only the central hole. Because the centres of the holes in a diatonic harp are closer together than that of a chromatic harmonica, I am able to play faster tempo single note melodies more easily on a diatonic than on a chromatic. I have also played a 4-hole diatonic harp which fits entirely in my mouth and I can play single notes on this tiny harp as equally as well as that on a standard 10-hole harp. The presence of adjacent holes in a reed instrument even with very small centre spacings between holes does not impede reliable playing of single notes.
Although each of the above instruments has a series of holes at different centre spacings, the brain enables an immediate adjustment to the different spacings. It would be possible to construct a base with widening splayed holes from the DM48 to a mouthpiece with holes at greater centres. Brendan Power has done the reverse with his 10-hole diatonic base connected to the DM48. In the extreme, the centres of the holes could be so far apart that there would be an absolute effective separation between holes when playing. The mouthpiece would be playable, but not easily at a fast tempo, and one would need to use a sustain pedal for some melodies when transitioning from note to note. I am not suggesting that anyone should construct such a base. The above description is just a thought experiment.
It would be interesting to have measurements of breath pressure at 1mm intervals over 30mm (the width of lips enveloping 3 holes) while a player is intentionally sounding the central hole. I suspect the profile would be a bell curve with high kurtosis which would be different for different players and which would be different with different degrees of puckering for each player. Now place that bell curve over a mouthpiece with holes of different diameters and hence different spacings between holes. Lower breath pressure on the bell curve would land on the smaller diameter holes. Less breath pressure again would land on smaller diameter holes at greater centres between holes. In the extreme no suppression would be needed if the centres of each hole were 35mm apart instead of the DM48 9.55mm centres. Once again, the above is just a thought experiment.
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