The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

e015475 · 06-12-2019, 02:03 AM

For the most part, using cutting oil when you are hand drilling just serves to help you clear chips out the flute of the bit. It is very unlikely you put enough heat into the fastener to 'heat treat' it

A lot of larger bits have a chisel point in the middle and only work well with a pilot hole. Did you run out of pilot hole? I start mine with a sharp 1/8" bit all the way to the bottom of the hole.

While it'd be almost impossible to change the hardness of the fastener, you can dull a drill bit pretty fast by overheating it at too high of RPMs and putting a drop or two of oil on it isn't going to make much difference. Different drill bit brands will have different coatings and materials and one might be more robust to higher speed than the other. Look at the cutting edge of the bit and see if there's chunks missing out of the cutting edge or it is a straw color.

Learn how to sharpen a bit on your grinder or buy yourself a DrillDoctor.

06-12-2019, 02:03 AM	#3
e015475 Registered User Join Date: Nov 2013 Location: Show Low, Arizona Posts: 762	Re: question about metal for machinists For the most part, using cutting oil when you are hand drilling just serves to help you clear chips out the flute of the bit. It is very unlikely you put enough heat into the fastener to 'heat treat' it A lot of larger bits have a chisel point in the middle and only work well with a pilot hole. Did you run out of pilot hole? I start mine with a sharp 1/8" bit all the way to the bottom of the hole. While it'd be almost impossible to change the hardness of the fastener, you can dull a drill bit pretty fast by overheating it at too high of RPMs and putting a drop or two of oil on it isn't going to make much difference. Different drill bit brands will have different coatings and materials and one might be more robust to higher speed than the other. Look at the cutting edge of the bit and see if there's chunks missing out of the cutting edge or it is a straw color. Learn how to sharpen a bit on your grinder or buy yourself a DrillDoctor.