A smiple Problem 1

[power453c]

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?

 

[BobM3]

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.

 

[power453c]

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.

 

[eromlignod]

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

Don
Kansas City

 

[power453c]

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.

 

[griffengm]

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

Griffy

 

[power453c]

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

 

[power453c]

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.

 

[brengine]

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