Re: [Harp-L] Fw: Was American Chestnut combs, now stainless steel combs



I would suggest that the test is whether or not you own a drill press and are accustomed to drilling metal with it. The second test is whether or not you have ever tapped a hole in metal. If not...then definitely go to a machinist for the work. You don't want to obtain your training and experience by breaking a drill or tap in your expensive SS harmonica combs.

Although tougher than mild steel, most grades of 300-series SS present no special drilling problems. If you are using a #50 drill, a 6mm thick comb is not especially deep...only about 4 diameters. It is very unlikely that harmonica combs are 400-series SS, hardened by heat treating.

Do you mean tungsten carbide instead of titanium for drill material? Carbide is very hard and will drill hard metals, glass and ceramics. However it is brittle and must be used very carefully or it will break. In the larger drill sizes the drills have steel shanks and carbide tips.

Vern

----- Original Message ----- From: "David Payne" <dmatthew@xxxxxxxxxxxxxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Tuesday, June 09, 2009 10:51 PM
Subject: [Harp-L] Fw: Was American Chestnut combs, now stainless steel combs




I meant to add that you need to find the proper lubricant for drilling stainless. I have no idea what that is.

Dave Payne
Elk River Harmonicas
www.elkriverharmonicas.com


________________________________
From: David Payne <dmatthew@xxxxxxxxxxxxxxxxxxxxxx>
To: harp-l@xxxxxxxxxx
Sent: Wednesday, June 10, 2009 1:48:31 AM
Subject: Was American Chestnut combs, now stainless steel combs



I wouldn't do it myself, even if it were my idea to make the comb. What I would do is talk to the gang at your friendly neighborhood machine shop, any of us fooling on the tech side of things should develop a relationship with the guys at the local, independent machine shop. My local shop, Parkersburg Tool, is very friendly. They think I'm a nut, which I am.
The deal is stainless steel is not the best stuff for drilling. FOr Vern, it's second-nature I'm sure and I'm sure it's now becoming second nature for Chris Reynolds as I think he's working with some steel now. I like Vern's idea of the tapped holes, if you are gonna do this, you ought to do it so you have the A NO. 1 comb in the end.
I've drilled through steel quite a bit on grandpa's old drill press. Never anything as thick as a comb. You're gonna have to drill slow rpm and you'll have to use a lubricant. This does not mean motor oil. I use, in the Elk River Fortress of Harmonica Solitude, turbine oil.. cause it's what I have and the steel I drill through isn't that thick and it's not stainless, it's spring steel.
One of the harmonica/machine shop greats has suggested titanium bits for this job and says, if you're lucky, your bit might last about four holes. After you've broken through, check the point of the bit to make sure you still have one.


Dave
______________________
Dave Payne Sr.
Elk River Harmonicas
www.elkriverharmonicas.com






Vern says:


David Payne gave you the best idea. For "good old-fashioned
SS" there is the "good old fashioned twist drill and drill
press." Oil-emilsion coolant or oil keeps the bit cool
while drilling.


Having an un-drilled metal comb gives you another option.
Instead of using the long screws that reach through to the
opposite reedplate or the opposite cover nut, you can tap
(cut screw threads in) the holes and use short screws for
both the reedplates and the covers.  I suggest a #50 tap
drill and a 2-56 tap and screws.  All are available from
McMaster Carr http://www.mcmaster.com/ The drill bit, tap,
tap handle and SS screws will probably cost about $40.
OR...any competent harmonica tech can do the work for you.

The advantage is that when you wish to work on the reeds to
tune, gap, or replace them you can remove one cover and one
reedplate without the opposite ones falling off. Also, with
steel screws and threads, you can really crank down on the
screws without danger of stripping the threads. Admittedly,
this advantage is more important on a chromatic harp than on
a diatonic harp.


Because you have gone to a lot of cost and trouble to have
the strongest and most stable comb, and you might wish to go
"all the way" with tapped screw holes.


Vern
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