[bigfred1958]

Ok,
It's not like I haven't been building bikes cars and scooters for 12 years, but I'm running into something really wierd and I'm not sure what to make of it.

I'm trying to widen a hole in a piece of 1/4" Steel plate in my drill press. I've got everything set up nice and tight. Normally, this is no problem, however, I keep dulling out drill bits!

It seems like I'll make some progress, then I'll just be spinning my bit.

I'm suspecting that since the bit is only cutting on the very edge of the tip, it's getting really hot in a small area and dulling out quickly.... I'm on my 2nd bit and about to go to the store to buy another one. I've tried sharpening the bits, but it doesn't seem to help.

BTW, I suspect the holes were originally cut with a plasma cutter, maybe the heat from the cutter is making the metal hard to drill?

Any advice about how to do this?
Any thoughts on why I keep wrecking bits....
Sorry about the stupid questions!
-alfie

[BOBCRMAN@aol.com]

Yes your material is hard and you are not cutting enuff surface to support the cutting edge of the bit. A piloted reamer would probably work better.

[bigfred1958]

Bob,
What's a Piloted Reamer and where do I get one?
Thanks
-alfie

[troy-curt]

What kind of material is your plate?

Troy

Ok I reread your post, you said steel plate, should be soft. Are you sure it's not stainless steel?

[Kevin45]

A piloted reamer is almost like a counterbore. What you can do if possible is slow down the drill press as slow as it goes and use some oil on the piece. If that don't work let me know. I might have one more trick up my sleeve

Kevin

[bigfred1958]

Kevin,
I'll try slowing it down.
I've been keeping the bit well oiled, but it's still dulling, Maybe the combo of extra-slow drilling w/oil cooling will work!?

What's your other trick?

Do you think they have piloted reamers at home depot (it's on my way home from work), or am I going to have to go to a specialty tool store?

Thanks again for all the response!
-alfie

[adtkart]

You could also try a Uni-bit (step bit) to enlarge the hole. They are designed to cut only a little at a time, and may do better at it.

[BstMech]

Kevin's method is what works for me when drilling holes in thick steel (frame rails etc.). I've found that slow drilling with lots of force cuts the fastest and doesn't dull or burn the bits up.

You probably wouldn't want to put too much force against the bit in this case though as the risk of binding up is higher. Slower is actually faster sometimes.

[Kevin45]

Off topic but BST...what does this mean under your name...NYOFP4RJ3CHRIS

[will's53chevy]

One thing that i have tried and does work when cutting on a drill press on flat surface, is use a little cutting oil. Just have someone else give a continuous squirt or two as you drill. If you are doing the drilling by yourself squirt a little oil every ten seconds or as you see fit. It'll smoke but it also helps keep the bit a little cooler and lubricated so that they cut better and last longer.(if you don't have cutting oil just use oil)

I just read that you've been using oil, the slower speed and oil should do the trick, though.

where is the plate from, I had this problem when i drilled out bumper brackets. it was because they were made out of spring steel which is harder. I went through 3 or 4 bits before i got through the steel. btw what brand bits are you using I've found that Dewalt bits aren't as tuff as some other brands that you can get.

the reason you keep wrecking the bits is that they are more than likely heating up and actually causing the tip to wear extremely bad. Are the tips just dull when you get done or do they look smoothed out and slightly rounded.

[iiibdsiil]

Originally posted by Kevin45
Off topic but BST...what does this mean under your name...NYOFP4RJ3CHRIS

I'm gonna guess...

It is his number thing for ASE certification.

I am not sure though, just a guess.

[mferris72]

If in fact your piece was cut with a plasma, the area is hardened. You must keep it cool and us slooow speed with heavy feed. Of course you must also have a goood bit. No cheep-o's here. Lub the bit with bee's wax or in a pinch a bar of soap will work. Don't use water as it cools to quickly and will du;; the bit. You can also do whats called a back cut on the bit, but without pictures it would be difficult to explain. I notice you were in NM, where. I'm in Albuquerque. Maybe we can get together and I can help out.

[BstMech]

Originally posted by Kevin45
Off topic but BST...what does this mean under your name...NYOFP4RJ3CHRIS

It's my ASE certification number. Not a master......still "cuttin' my teeth".......

[adam9741]

I'd use a step bit (uni-bit) as said above. They've always worked well for me, even used a couple times for widening a hole in stainless.

[advantage drills inc]

[QUOTE=bigfred1958]Ok,
THIS IS NOT A STUPID QUESTION! YOU HAVE TO REMEMBER ,A DRILL BIT IS DESIGNED TO CUT FROM THE CENTER FULCRUM OUTWARD. IF YOU ARE ENLARGING A HOLE YOU NEED TO USE EITHER A CORE DRILL OR REAMER, WHICH ARE DESIGNED TO CUT ON THE OUTSIDE DIAMETER. GIVE US A CALL.
WWW ADVANTAGE-DRILLBITS.COM 1-407-478-2487