drill doctor

[Sal Lubrano]

I was looking at getting a drill doctor but there are 4 of them. Can anyone give me a good reason to purchase the top of the line one whichis $130 vrs $50 for the basic.

 

[INEEDAGN]

One of the differences is the ability to do larger than 3/8s drill bits. I've used one before, they aren't idiot proof but they do work ok on most bits. There's guys out there that could do a better job on a bench grinder, but I am not one of them.

 

[EightSecV6]

I was looking at getting a drill doctor but there are 4 of them. Can anyone give me a good reason to purchase the top of the line one whichis $130 vrs $50 for the basic.

I have the top of the line one I bought from Matco, it is the biggest piece of crap in my tool box.

 

[mhogan6]

I have the top of the line one I bought from Matco, it is the biggest piece of crap in my tool box.

+1


$130 buys a lot of drill bits.

 

[Sal Lubrano]

If it is a piece of junk. Do you sharpen your bits or just replace? If you sharpen could you give me some pointers on how to do it?

 

[norbs]

The bit will sharpen good, but when you go to drill something it will walk all over the place. Ive tried all the settings, no help......

 

[chopped39]

I was told they work great so I bought the $139.99 one. After i had destroyed all the bits I tried to sharpen i put away in the cabinet and have not used it since. There is a guy at my work that loves his. Maybe i should have watched the video that was in the bottom of the box. My bad. Dont remember seeing that in there.I will try it again soon and post results.

 

[stevemon]

Not sure anyone can explain hand sharpening but I've done it long enough so will try to do so:
The main thing in hand sharpening is making sure the cutting edges are the highest part of each side. Most times when a bit you've sharpened won't cut the problem is the surface behind the edge is higher than the edge so the bit just rubs on the work.
Practice sharpening with a bit about 3/8" dia to make it easier to see what you're getting and have a factory sharpened bit there with you at the grinder to compare your results with.
I use a white aluminum oxide wheel on my grinder and keep it dressed so the surface is true. The white wheels have a softer bond so the grains break away as you sharpen leaving new, sharp grains and that takes away the heat with the grains which helps prevent burning the tool.
Start with the cutting edge of the bit over on the left side of the wheel and as you lightly touch the drill to the wheel move the bit towards the right and up and at the same time tilt the tail end of the bit downward. This movement automatically allows the entire side of the bit to be ground in one movement. Your aim is to get both cutting edges an equal length. When you think you've got it, try it out. Good luck.

 

[Sal Lubrano]

Why is it some twist bits have a relief cut in to the back end of the cutting side and some dont? Is thier a difference?

 

[Junior Samples]

Not sure anyone can explain hand sharpening but I've done it long enough so will try to do so:
The main thing in hand sharpening is making sure the cutting edges are the highest part of each side. Most times when a bit you've sharpened won't cut the problem is the surface behind the edge is higher than the edge so the bit just rubs on the work.
Practice sharpening with a bit about 3/8" dia to make it easier to see what you're getting and have a factory sharpened bit there with you at the grinder to compare your results with.
I use a white aluminum oxide wheel on my grinder and keep it dressed so the surface is true. The white wheels have a softer bond so the grains break away as you sharpen leaving new, sharp grains and that takes away the heat with the grains which helps prevent burning the tool.
Start with the cutting edge of the bit over on the left side of the wheel and as you lightly touch the drill to the wheel move the bit towards the right and up and at the same time tilt the tail end of the bit downward. This movement automatically allows the entire side of the bit to be ground in one movement. Your aim is to get both cutting edges an equal length. When you think you've got it, try it out. Good luck.

And after I got done beating on my TB i just sent it off to Steve Monroe to have it done right the first time:biggrin: :biggrin:

 

[stevemon]

Basically there are two types of common metal cutting bits.

The typical HSS bit which can be either black oxide treatment or natural finish (shiny steel). These bits are ground at a 118° included angle and are great for cutting non ferrous metals or softer ferrous metal. They're the only kind to drill aluminum with. (more on that later)

Then there are the cobalt drill bits. You can usually identify them by the golden tint to them but there'll also be a short reduced diameter at the base.
Or they may be marked "CO". These bits are sharpened at a 135° included angle and are made for hardened material. The cobalt alloy property is only there to help the bit withstand heat. Don't use cobalt bits on aluminum. The chips tend to stick in the flutes.
One more difference in the 135° bits is that they usualy are relieved behind the cutting edge. A flat is ground there to reduce drag.

 

[Sal Lubrano]

WOW. Stevemon !! You really know your stuff. Thank you for the info.