I’m currently setting up shop to make flutes and pipes. I know from the pipes that step-drilling is not necessary for the relatively narrow bores of the pipes, but I wonder if flute bores need step-drilling. Terry McGee doesn’t mention it on his web site, but I guess that step-drilling will be necessary for flute bores. It might also depend on the reamer, though, as a flat reamer made from steel sheet should be far less stable than a turned D-shape reamer.
The middle joint’s bore of a typical Pratten flute goes from ~18mm to ~14mm which means that 2mm of material have to be removed at the widest side, and less the more the bore narrows, if a single cylindrical pilot hole is drilled at or slightly below the diameter the narrower side requires. If the reamer is stable enough (i.e. made from solid metal rod, turned on a metal lathe, d-shaped on a mill and hardened finally), it actually shouldn’t require step-drilling, or will it?
I’m also interested in different drilling methods. I know that a gun drill should do the job most efficient and easy, but gun drills and the necessary machinery are probably quite pricey, so cheaper methods would be of interest. I know a method where the drills are made from solid metal rod and cut to certain angles, which works quite well (esp. because the drills are more or less self-centering), but is slow and a bit demanding.
I hope that I don’t dig into professional secrets here and that maybe some of you who are making flutes are willing to share
You may not know about the Flutemakers Group on Yahoo groups - it has over a thousand members and extensive archives which will give you a lot of insight into the kind of thing you’re asking about here.
You can step-drill flute bores or you can use a flat roughing reamer to get to where you can use a finishing reamer (not necessarily D-shaped) to get the final bore - either way as you say, you can’t just go straight from the pilot drilled hole to the finished bore as a proper finishing reamer only takes out a small amount of material.
Gundrills are available cheap enough second-hand on Ebay and the ones designed for steel work well for wood and delrin too - for flutemaking purposes anyway. There are the more traditional alternatives to gun drills too which you mention - just search the Flutemakers archives with "reamer"or “gun drill” and you’ll see a lot of previous threads…
Hi,
What I do, is grind a old file or one made in China, to the contour of the bore, making it a little smaller. This is fixed to the tool holder, then introduced into the drilled blank. This removes quite a bit of wood, then I finish the last couple of mm with a reamer.
I buy my gun drills off of eBay for around $30, I fix this to the tool holder, compressed air is channeled through the cooling hole for cooling and chip removal. Both these techniques are tried and true, garnered from the internet research, over the years. Thanks Casey, Terry and all the other contributers! I agree, go to the Yahoo.groups- flute making site, and check out the archives.
Good luck!
I agree, go to the Yahoo.groups- flute making site, and check out the archives.