I’m about to go into heavy production on certain of my instruments, and I want to ask other makers what production methods they think are good. First, assume that I’ll be using polymer or soft (brass) metal tubing for the bodies. No big hassles with steel this time. Here are my thoughts - PM me please, or post here with opinions…
CNC milling to bore the holes. I think I could clamp probably up to 24 tubes in the bed, and program the machine to go do each hole separately, with automatic tool changing between sizes.
Gang Drill to bore the holes. Using a fixture to hold the tube in place, one tube gets drilled at a time, with six drills running in precision-bearing guides.
Indexing the tubes in a single-drill environment. Probably the least expensive, an indexing jig is built to hold the tubes, which are fed through the drill press one at a time. the index points allow precise positioning of each tube at identical points under the drill.
The reason I’m asking this is that I’ve been asked about possibly supplying several thousand whistles per year, and I need to build them as quickly as possible, at as low a cost as possible. I do NOT intend to outsource them. I’m getting really sick of almost never seeing “Made in USA” on things I buy, and I make my whistles myself, and intend to continue that practice.
Sorry for the little rant. Anyway, opinions and actual knowledge are solicited. I’ve never had to think this “big” before about what I do.
thanks,
Bill Whedon
I’m not a whistle-maker, but I did a stint making taiko drums, and some of the lessons I learned are probably applicable.
I would encourage you to go with the CNC. If you are being asked to mass produce whistles, then mass produce them. Create a workflow and buy the tooling that gives you the greatest production efficiences. With CNC, you can alter the programming for different keys, tweak the hole sizes and placements to fine tune your whistles, and guarantee consistancy.
Gang drills don’t have that flexibility. Jigs are great only for the time it takes you to get up and running on CNC.
The real key is to do whatever it takes to save time. If you have hours in the day remaining, you can still hand craft whistles, you can pack and ship whistles, you can take a day off to play whistles.
Any kind of hand labor on anything other than “high end” instruments is a sure way to turn a nice hobby/small business into a failure.
-Just a guess from mostly pre-CNC welding/machining training, IMHO:
1)-CNC: -Numero uno for superb
repeatability/efficiency -Be sure initial output and periodic QC checks are right as parameters will be repeated en masse.
-Mistakes are replicable, and quickly. A small mistake replicated across thousands of tubes will waste lots of $$$, material & time. Once process and tooling is right its gravy, just requiring supervision so gravy continues to come out right.
-Ix-nay on the gang drilling
and single tube indexing:
-A host of places for error in process (wiggly gang chucks, debris in indexing fixture spoiling placement, etc.)
Things I think you alwready know. Drilling thin wall brass will need very sharp drills. Step drilling takes more time, and makes a very clean hole.
I have not been able to drill thin wall brass without step drilling. Trying to drill the hole to size on the fist time, results in the point pushing the metal before cutting. I do not trust or have a drill doctor for sharpning my drills. I use a slow speed wet grinder that I put to geather with two reduction shafts and a motor. I make them very sharp with lots of relief behind the cutting edge. They would most likey dull very fast if I tried to drill steel.
I have wondered how the factorys Gereration, Waltons, Feadog, make their holes. Looking close at the holes makes me think they might be punched and then buffed to take the edge off.
My friend has a custom transmission shop where he only makes transmissions for racing. In the valve body there is a thin index plate with many holes in it. He use to pay someone to drill the holes. But now finds it cheaper and more accuret to contract them out and be done with a laser.
Theres some good answers here. All I’d say is - do your numbers. After costs and prices are factored over 1 year also look at risk. Factor in all the costs including yer ABOs (Air-Breathing Overheads) - a starving machinist tends to increase the error rate - and you may need an accountant for sanity and a legal for the contract.