spring in the milling machine and it cuts it like butter using cutsol as a
lubricant (the stuff you mix with water that adds just enough oil to stop
rusting).
I remember the first steel spring I tried to drill back in '95 and burned
out many a bit... a trip to the local machine shop and with the spring
thrown in the mill the guys said "what's the big deal"!
I just go straight to the mill now, with a 4 tooth cutter.
Wayne
----- Original Message -----
From: <schaumr@dcsol.com>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, August 31, 2010 6:22 AM
Subject: Re: [rebel-builders] Drilling through steel leaf springs:
work-hardenin
Thanks to all on the advice,
Got the job done with some overpriced "titanium" bits from the local
hardware
store (said they were for stainless steel, so I thought they would be
adequate). Stepped up from 1/8, 1/4, 9/32, and finally 3/8" (on the
drill
press)
Used 2-stroke oil as cutting fluid and stopped routinely to re-apply oil
to the
work piece and/or change bit size. With the largest bit, I got the sense
it
had to struggle more and started to sound like it was grinding again (no
chips
being produced). It got through, but I'm not sure how the bit faired.
Regardless, it was educational. I like the idea of resharpening....
Ken.....does
one use a jig?
Rob
On 8/30/2010 5:05 PM, klehman@albedo.net wrote to rebel-builders:
-> If it is truly harder than the already hardened spring and it is the
-> fuselage end you can always anneal it by heating just the end to red
hot
-> and letting it cool slowly. I would not do that to the tailwheel end
though.
->
-> First I'd dry a carbide tipped concrete bit as per Dick's suggestion
-> (slow, hard pressure, oil) Don't be afraid to touch up the carbide a
few
-> times if needed. I use a green grinding stone. Buy a couple of bits.
-> They are cheap.
->
-> There are also carbide twist drills but they are pricey. I've done this
-> sort of thing with hardware store cobalt bits but again be prepared to
-> sharpen it several times. When sharpening keep the cutting angle as
-> close to 90 degrees as you can.
->
-> I'm assuming you have access to a drill press. Drilling springs with a
-> hand drill would be rather difficult.
->
-> Ken
->
->
-> Dick Wampach wrote:
-> > Oh, Oh! So did you try to drill a big hole all in one pass? Try a
small
-> > diameter carbide # 40 or so, slow turning, heavy pressure, cutting
oil, &
-> > don't side load the bit to break it. Good luck
-> >
-> > Dick Wampach SR-108 N331RW
-> >
-> >
-> >
-> > -----Original Message-----
-> > From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
-> > schaumr@dcsol.com
-> > Sent: Monday, August 30, 2010 9:19 AM
-> > To: rebel-builders@dcsol.com
-> > Subject: [rebel-builders] Drilling through steel leaf springs:
-> > work-hardening
-> >
-> >
-> > Hi All,
-> >
-> > Tried to drill through my steel tail spring this morning but managed
to
-> > render
-> > half the hole "work-hardened" (not enough lube and/or cooling). What
do I
-> > do now? Carbide tipped bits? Other bits?
-> >
-> > Hope someone can help me avoid buying a new tail spring!!
-> >
-> > Rob
-> > Rebel 786
-> >
-> >
-> >
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