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A smiple Problem

A smiple Problem

A smiple Problem

(OP)
I have a piece of steel in the shape of the disk. 10" diameter .25" thick. I need to drill 7/64's holes into the side of the disk. I punched indentions where I needed.  The holes I drilled on the flat side of the steel worked fine. However as soon as I tried the curved side holes, I had a problem.

The drill bit will not engage. It simply rides on the surface.

I tried a drill press at each speed and then tried a hand drill.  I used cutting oil.

Is there any way to make the drill bit go in?

RE: A smiple Problem

You probably work hardened the material.  What kind of steel?  Try a smaller diameter drill and more force.  You may need to use a carbide drill to break through the hardened surface.

RE: A smiple Problem

(OP)
The steel is nothing special.  I managed to get a hole directley in the center with minimual difficley.  I used a 3/32 bit to start.  Perhaps this is because the side was machined. I'm not sure.  The bit I used is a cobalt steel bit.  I used enough force that the bit almost broke.  It bent over nicley under stress.  

I thought that maybe the center punch hardened the steel at that precise point.  So I took my dremel and ground off the indentation flush.  That didn't help much.  It speeded up the initial penetration on the flat side but not on the round side.

RE: A smiple Problem

Have you tried a split-point drill.  That's basically what they're for.

Don
Kansas City

RE: A smiple Problem

(OP)
No I havn't.  Don't seem to have one of those in my collection.  However I do have a dril doctor that is supposed to be able to turn ordinary bits into split points. I think I might try that.

RE: A smiple Problem

How was the disc made?  Laser Cut?  Plasma cut?  Stamped?  First two could have a lot to do with your problem.

Griffy

RE: A smiple Problem

(OP)
I'm Not sure. However, I believe it was cut on a milling machine?

RE: A smiple Problem

(OP)
I split point the bits.  That worked niceley.  However, what I found is that the first 1/8" down or so was hardened.  I am guessing this is because it was cut using a laser.  Well at any rate after the first four holes the bits would either dull or break.  Also I could not tap threads, the tap would simply not engage into the hole.  So I've decided on plan B.  Use jb Weld.

Thanks For everyones Advice.

RE: A smiple Problem

Since the first 1/8" is hardened, could you drill that portion a clearance drill size, then you'd only have to get thread in anything deeper than 1/8"?

Ken

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