Bassoon reamers -- what length is desirable? - created 08-27-2007

Froelich, Eleanor - 08/27/2007.05:46:00

I'm about to make metal bassoon reamers, and would like to know what length to make them. I presume that they should not be as long as the joints, and I presume that the length stands in relationship to the diameter. To give you an idea, I have weak cones, varying from 8.8mm to 14.5mm over 464mm (I haven't done my math yet, sorry) to 24.4mm to 32.2mm over 576mm. I have already stepped out the bores with Löffelbohrer.

Would a cheap steel be fine for my first try, or should I use tool steel (silberstahl?)

I am no bassoon maker; but I have made some reamers, and usually you need to make them longer than the work piece, otherwise they will make grooves in the bore. Tool steel is best; it will be about as much trouble to turn and shape as mild steel. The difficult part is hardening a long reamer. There are different recipes for different tool steels, but for normal water-hardening high-carbon steel ( type W-1) you would heat the reamer to an orange color, quench it in brine, rub the steel clean and bright with sandpaper and then carefully heat it to a dark straw color ( or, you can actually bake it in a kitchen oven for several hours at 400 degree F). It can be hard to avoid having the reamer warp during the oil quench, and though you can heat it to straw and bend it a little while it's hot, to straighten it, you might want to find a knifemaker or good blacksmith/kunstschmied who's used to doing it show you the technique.

Another way to work would be to use an air hardening steel, type A-2. With A-2 you would make the reamer, heat it to the right temperature, then simply let it cool; so it is less likely to warp. But A-2 is at least 3x more expensive than W-1, in small sizes, more in large ones.

Eleanor, congratulations for your progress. Everyone I know on the west coast here uses water hardening tool steel or aluminum bodies with inset tool steel blades. What type of reamer will you be making. Soft steel will not work as it will not hold an edge long enough to do the job. You don't need to temper the tool steel as long as you haven't burnt it in the shaping process. It will hold a fine edge as is and you run the risk of warping it when tempering it. As Nicolas stated most reamers exceed the length of the bore or cut. You can do shorter reamers but must reduce the cone at the overlap so to avoid unintentional steps in the bore. You might be interested in the photos of Charles Collier shawm making I recently came across. You will have to google him and publicinterest. It would be a great time to contact Michael Hubbert as he is an excellent reamer maker and has some interesting techniques.

I use toolsteel, but avoid tempering it for fear of warping. Warping is worst for long thin things. You will want to temper tools used in production, especially if they have complex shapes. For prototypes or one-offs this is not necessary. You will find commercial establishments that can do the tempering for you, before deciding on which kind of tool steel to use I would ask them what they think best.

Large reamers and drills can be made in two parts, a head and a shank, the shank screws into the head and allows you to work deep inside a bore, perhaps to expand the bore near a particular set of finger holes. You dont have to worry too much about concentricity of the assembled reamer as it will be used by hand in most cases.

If you can partner up with a blacksmith/welder, you might make the head from sheet foge-rolled around a core that is drilled. You will turn and tap the head after the forge work has roughed it into shape. A jam-chuck might be enough to hold the roughed-head for reaming and tapping the shank hole, a stub into that can be chucked for truing the outer surface. This last need not be done on a lathe, it can also be done on a grinder.

If you are working thru a tailstock, the assembled length will be longer than the joint. Some thought must be given to what you will use for a handle. I find the handles used by machinists and plumbers for large taps very useful, so my reamer and drill stocks have a squared end. These tap handles are large, heavy, and new ones are expensive, I was lucky and found some for sale at a used tool store.

Thanks for all the information! I was wondering if I could make a reamer as long as the wing joint (plus pilot at the front and shank and handle at the back) or if I should do it in 2 or more pieces. Stephen, your tip about reducing the cone at the overlap when I use more than one piece is great -- I wouldn't have thought of that. And I will write Michael. The Collier pictures are great, but I can't get them larger on my computer -- I'll have to look at them on another machine.

I would use a length of tube as core for the head, diameter chosen to be a slip fit inside the bore left by a drill you make to go thru. Other end of this tube has a plate soldered across it which is drilled and tapped for the shank, long enough to go thru. A couple heads like this will allow you different tapers for complex bore profiles. If you are using a simple conical profile it could be just one. A series of large 'washers' would be tack-welded along the length of the tube to then be tack-welded to the conically rolled sheet that becomes the cutting edge. Two such washers will do for short heads, longer ones might want 3 or 4. lots of room for chips this way. The welding will distort the sheet some, so plan to do a cleanup cut on the lathe. If the sheet is thin enough it should be possible to use mechanical rollers to form it. I would plan on the sheet being no more than 2/3 of a circle.

Sorry Eleanor, I play Dulcian, not Bassoon, and I was thinking about the larger reamers used to shape the ascending joint. The wing joint goes from perhaps 20mm to perhaps 8mm, tho the very end is expanded from the other end to socket the bocal. I would not attempt to go thru from either end in one go. Try step drilling from the large end, and connect thru from the small with a long small drill, then smooth it out with reamers, taking partial turns to drift the reamer and keep it from breaking out.

I would make the wing joint reamer in two parts, which could be joined using pins. No need to align the cutting edges, probably best if they were staggered and slightly overlapped.

Most of my research indicates that the Dulcian/Curtal/Bassoon instruments were made in two halves using scrapers for an oval bore. The two halves were then glued together and covered in thin leather and hide glue and the ends are capped with brass plates for strenth. The bell shapes were used mostly to align the nodes of the registers. Recorders do this by adjusting the angle of the tapered bore and flutes use the adjustable plug.

A "salt shaker" cover plate is sometimes added to the bell for register tuning. It works like a fireplace vent. 2 plates with perforated holes and the top plate can rotate, closing off some of the holes. This creates acoustic "feedback".

A simpler method is used for Shawms/Chanters. A set of holes, drilled in the bell are closed/opened by wax cover/uncover to tune the bell note AND adjust register cross-over frequency.

I suggest reading the chapters on bores and bells in Arthur H. Benade's books on Brass winds and Acoustics and see if you can find a Library copy of "Ancient European Musical Instruments" by Nicholas Bessaraboff. These cover some aspects of bore/bell design. There are also some woodcut plates in "De Organographica, vol#2" by Michael Preatorius showing old style spoon/shell reamers.

I believe there is 1 book available here at MIMForum Bookstore on making reamers, "The Amateur Woodwind Instrument Maker" by Irving Sloane. The "Recorder/Flute" section in the Links area(below)has a weblink to "Tools for Making Recorders" with a chapter on Reamers as well.

If you wish to design tuned bore/bell shapes with mathematics, I suggest the Books of Lew Paxton Price. It is easier than you think and requires only a scientific calculator.

Thomas, thanks for all your information! The few original Dulcians I have seen were made in one piece, but that is just small numbers statistics.

Bell shapes align the nodes of the registers -- that fits well with my experience. I need to measure a lot more instruments and compare.

I never even thought of plugging up some of the holes in the salt shaker top of my Denner Dulcian! I have a lot of experimenting to do this coming week...

I can´t find my Benade at the moment, it must be in the workshop. But I´ll do my homework.

Dana, I don´t have the skills to forge a reamer, but I sure wish I did. I know someone with those skills, but he has way too many projects going on. (He did make me 3 really good spoon reamers.) I was planning on making metal reamers with a slot, on the D-bit principle. (I have a metal lathe and a router (don´t know if that´s the right word -- it´s called a Fräse in German.) In any case, the necessary tools for the job. Now I´m waiting for the metal...

Thomas,

Eleanor , how do plan to put the slot in the reamer?

With a router attached to my metal lathe.

Wow radical. I thought you might mean that . So will you use a router bit or a milling bit.

At that speed you will want to only take off little material at a time. Get good ear protection and a good face mask. Don't let your 'reamer in progress' get too hot.

Stephen: Off the top of my tiny head, here is a start. I will dig up more later.

One cheap source for Dulcian/Curtal research is Anthony Baines "Woodwind Instruments and Their History" Dover Pub. Try to find a library with a copy of "Ancient European Musical Instruments" by Bessaraboff. The plates of Michael Preatorius are scale drawings but must be converted to English inches. There are plates and a "conversion key" in the Bessaraboff book.

If my memory is correct,...The MIMForum Archives have info, with photos, of a Basoon/Curtal made by bakeing Polyclay/PVC around a wooden manderel shaped like the Bassoon/Curtal bore. This material (PVC) is used for most of the modern Didjeridhu's today.

You may wish to get some inspiration from organ pipe construction. (google "Encyclopedia of Organstops" and click on the "Index of Illustrations". I will post the site below, but fear it will be removed for some reason)

http://www.organstops.org/_apps/Illustrations.html

Thomas,

Stephen, I had to return my ILL copy of the Kilbey Curtal checklist book, but I recall a number of them having been leather covered, and several were mentioned as being fabricated from two (or more) parts later glued, all looking as one.

The first issue facing a maker is how to set up the boring operation, two nearly parallel bores, each expanding in opposed directions, a rather thin wall between, rather a challenge today. Most modern makers are set up with a lathe and hollow tailstock, but this implies a very awkward setup with a dangerously unbalanced billet.

An alternative is a rotating cage inside of which the billet is wedged, and which can by dynamically ballanced by weights. This could be attached to a faceplate at the headstock of a lathe, and some kind of ball-bearing steady rest would support the far end. Slow speed is no novelty in this kind of boring work, and would clearly be called for.

Another approach might be more historical, a table with a sliding carriage holds the billet, which is advanced by weighted ropes into a rotating drill/reamer. I think a similar system was used to bore wooden water pipes.

I have found that D-bit style drills tend to get fouled by their own cuttings if rotated, perhaps this is less true of spoon bits which are more likely to make chips than dust.

Dana ,

Maggie Kilbey ‘Curtal, Dulcian, Bajón: A History of the Precursor to the Bassoon’

(St Albans, 2002). Glad to be corrected on the historic aspect of approaching the curtal as a cornetto.

In doing research on attempting to come to my own concussion on the Myers /Segerman argument on pitch I recently came across an article comparing bassoon and dulcian bores. The bores are similar, but the bassoon tends to have a overall smaller bore and the dulzian flares out more at the bell. Bassoons are as well longer for the lower 'French' pitch. Similar to the shawm to oboe transition. I also saw in Galpin that the dulzian continued along side of the bassoon in Spain. As shawms, recorders, and flutes had a transitional period in the seventeenth century I wonder if it is correct that dulcians did as well. I will site the articles as I wade thru my notes.

For boring , the tool-rest and a steady are also used as you know. To counter balance the the body a piece of wood is attached to the light side.

Hollow ground your d bits so they slice rather than scrape. The gun drill type of off centered 1/3 milled out bit is better than a d bit. As the double bore section on the bassoon is slight a piece of wood straped on creates no danger.

Price of steel tubing and a good nights sleep have given me to rethink the scheme I had planed, instead of a steel cylynder, a face-plate mounted jam chuck and a ball-bearing collar/steady rest. The billet should be stiff enough to support itself.

The Kilbey book has a major shortcomming, no hard data except Loa.

From the comments in Kilbey, I got the impression that most of the multi-part Dulcians were assembled from bored tubes, which implies two things to me. First is a reluctance to trust glued-together bores to not leak (a reluctance I share, nothing worse to repair than a leak between the up and down bore). Second, it must have been a real challenge to make parallel bores in one piece using renaissance lathes. Eventually what was conveniant for the maker yielded to the perceived conveniance of the user (fewer parts to be lost or gotten confused in the chest)

The 'transitional " instruments that continued alongside of the bassoon were becoming like bassoons yet with out the choke toward the bell, still the expanding bell. The pictures indicate socket and tenon connection. To avoid a bad glue joint on a 'carved' two part bore use a large sanding board to insure both sides are even. Though not period epoxy might let you sleep better.

As we know from the 18th century , woodwind makers used bore plates as a tail-stock to hold their work drilled on the lathe. There is iconographic evidence that this took place in the sixteenth century as well. A bore plate of a dulcian would be a thick plate of forged iron with a large whole it it to accommodate a tenon turned on the roughed out dulcian body. Probably lubed with lard or tallow. When one hole was bored the centers of the new bore would be marked and a new ,perhaps smaller tenon would be turned. I suspect these tenon were on the narrow part of the instrument and were just waste wood of the finished instrument. The counter balance might not make such a difference on a bow lathe of slow speed. In both operations the bell side of the instrument would necessitate a true surface to carry the driving cord on . Or it could have been done on a large wheel run lathe with an assistant, or a treadle though we have little evidence of this in the sixteenth century.

A bore plate with a tapered hole is something I could see working, hadnt thought of that. Taper would be easier to manage for a blacksmith, formed on a hot punch-like tapered stake. The taper would help to keep the billet on the drive point.

Drive point might be set up as a jam chuck, or possibly screw/nailed to the side of the billet (on wood to be wasted later).

One problem with this is the need for a much larger billet (which would need less ballancing). Maybe a glued on collar?

The concept of roller bearings is known in ships blocks at a later date, ca napoleonic wars if I recall correctly (Steel's masting and rigging), might well be used earlier, not a huge stretch from using rollers under ships keels and moving stone blocks which is at least roman era tech. Was thinking of home-made roller bearing using 6" and 7" steel tube (online source for inch lengths) with rollers from steel drill rod.

If one carves a dulcian's bores in two halves as cornetto's are done, I would think it necessary to orient the grain by using bookmatched quartersawn wood, but even then, the uneven moisture in the bore (players breath wetting the upper part of the descending bore, leaving the rest progressivly drier) would cause movement that would stress both the glue joint and adjacent wood. Better than epoxy might be to size the finished bore with diluted hide glue.

Hide glue would make a mess as it is water soluble . Seal the bore with shellac or tallow(traditional). Cornetto makers have experimented with various traditional water proof glues. Variants of milk glue as well as hide glue with urea have been used. As cornettos the pieces must have been bound with chord.

As I have rebuilt the bottom of rotted out bassoon bores am aware of the problem . The solution is storing your dulcian upside down. Binding by cord and perhaps a metal end cap will keep the wood together in use . Think water barrel, the staffs swell to the hoops.

I would never size a bore with epoxy.

I guess impregnation with wax/tallow is better, but then you have to be careful not to leave the instrument inside a closed car parked in the sun (which nearly ruined a friends bass recorder when he did that).

Hide glue with urea, heh, one traditional role for apprentice in any woodworking shop is maintenance of the glue pot. I beleive it was urine from young boys that was preffered in days of old for that additive, no? Well, I hardly qualify, and not sure if urea (for fertilizer mixing) is considered a restricted item these days or what, I guess I will find out next shopping expedition.

As to storing the instrument, I think the issue is more one of letting the moisture evaporate, leaving it out of the case long enough is more the point; swabbing it with a silk pull-thru helps a great deal.

Dana ,

If you recall in 19th century flutes the metal sleeve is glued into the flute head joint with shellac as were, till relatively recently, flute pads. Why don't you just seal your bore with shellac, It is more moisture/water proof than lacquer .