Linstrum
09-28-2009, 08:54 AM
Keep an eye out and watch for drill sharpening tools like the two in the photos below. It isn't obvious what these tools are and they might be bought for a lot less than what they sell for new because nobody knows what they are or how they work.
Sharpening drills is a chore even a lot of really good machinists have a hard time with and these two machines take all the hassle out of that job, especially the small number series drills from the #41 on down to the little tiny #60 drill. A precision drill sharpening machine can cost as much as a pretty nice large lathe, but for the home machinist these two machines get the job done for just a fraction of that. My True Point sharpener was made during World War 2 and I don't know if anything like it is still made or what one would sell for nowadays. I got mine from a pawn shop back in about 1965, but I bought my Drill Doctor DD750X model new in 2005 through a promotional advertisement on late night TV for $99.95 back then, which was less than any online machine tool supply company I could find at that time. I just looked up the DD750X model like I have online and at Amazon it sells for $139.95 plus shipping. If you have a drawer full of dull drills because you can't sharpen them yourself get the Drill Doctor and stop buying new drills. I have a 1/4" cobalt high speed steel drill that I have been using for about 40 years and it is now about 2.5" long from being sharpened what I figure is about 300 times. Because that drill has been sharpened instead of buying a new one whenever it got dull, that one drill alone has saved more than what a new DD750X Drill Doctor costs. I didn't have the Drill Doctor for most of the life of that one drill, but for someone who can't sharpen a 1/4” drill by hand on a bench grinder it would save enough money from just that one drill alone over a few years to buy a Drill Doctor. Multiply that by the several dozen different sizes of drills most home machinists have and it would pay for itself pretty fast. On top of that, drilling most types of stainless steel requires a very sharp drill or it can't be drilled easily, so if you ever have to drill stainless steel, like for installing a scope base on a stainless steel gun, you will need a freshly sharpened drill before you even begin. For tapping stainless steel, having a sharp drill is of utmost importance to keep from work-hardening the material that the tap has to cut. Even if the hole is successfully drilled with a dull drill, a dull drill work-hardens stainless steel and there is a greater likelihood that even a new sharp tap will break or that it will prevent the tap from cutting the threads.
The True Point sharpening jig is for small drills from #41 to #60 plus all other sizes within that range (fractional, metric, etc), and the Drill Doctor DD750X works for larger drills from about #40 on up to 3/4". Sharpening a tiny #60 drill can be done free hand with an eye loupe and an Arkansas stone, but it might take half an hour of trial and error to get a point that will cut. The True point takes all the guess work out of it. The True Point is a jig that holds the drill at the correct 59° angle to make a 118° point plus guides the Arkansas or fine diamond hone in a curve to make a better relief profile and also indexes the drill exactly 180° to sharpen both cutting edges so that they both cut equally. Having both edges cut equally is very important for very small drills because it helps prevent breaking them by reducing the torque they require to cut plus balancing the torque distribution at the tip so one cutting edge doesn't take all the guff and break off. The drill is sharpened by hand with an Arkansas stone or fine diamond honing plate. The DD750X model Drill Doctor is a power tool that has an electric motor driven high speed diamond grinding wheel that will sharpen drills up to 3/4”. It holds the drill at a range of angles from about 67° to about 55° to make points from 134° to 110° so hard or soft materials can be drilled more efficiently. Hard steels cut better with a 135° drill point and soft steels cut better with a 110° point. The diamond wheels are replaceable and come in fine grit for small drills and coarse grit for large drills. I have been using my Drill Doctor several times a week for three years now and haven't needed to replace the diamond wheels yet. The Drill Doctor will also back-cut the drill edges so they come together at a lot smaller point than normal so hard metal will drill with lighter pressure.
rl635
Sharpening drills is a chore even a lot of really good machinists have a hard time with and these two machines take all the hassle out of that job, especially the small number series drills from the #41 on down to the little tiny #60 drill. A precision drill sharpening machine can cost as much as a pretty nice large lathe, but for the home machinist these two machines get the job done for just a fraction of that. My True Point sharpener was made during World War 2 and I don't know if anything like it is still made or what one would sell for nowadays. I got mine from a pawn shop back in about 1965, but I bought my Drill Doctor DD750X model new in 2005 through a promotional advertisement on late night TV for $99.95 back then, which was less than any online machine tool supply company I could find at that time. I just looked up the DD750X model like I have online and at Amazon it sells for $139.95 plus shipping. If you have a drawer full of dull drills because you can't sharpen them yourself get the Drill Doctor and stop buying new drills. I have a 1/4" cobalt high speed steel drill that I have been using for about 40 years and it is now about 2.5" long from being sharpened what I figure is about 300 times. Because that drill has been sharpened instead of buying a new one whenever it got dull, that one drill alone has saved more than what a new DD750X Drill Doctor costs. I didn't have the Drill Doctor for most of the life of that one drill, but for someone who can't sharpen a 1/4” drill by hand on a bench grinder it would save enough money from just that one drill alone over a few years to buy a Drill Doctor. Multiply that by the several dozen different sizes of drills most home machinists have and it would pay for itself pretty fast. On top of that, drilling most types of stainless steel requires a very sharp drill or it can't be drilled easily, so if you ever have to drill stainless steel, like for installing a scope base on a stainless steel gun, you will need a freshly sharpened drill before you even begin. For tapping stainless steel, having a sharp drill is of utmost importance to keep from work-hardening the material that the tap has to cut. Even if the hole is successfully drilled with a dull drill, a dull drill work-hardens stainless steel and there is a greater likelihood that even a new sharp tap will break or that it will prevent the tap from cutting the threads.
The True Point sharpening jig is for small drills from #41 to #60 plus all other sizes within that range (fractional, metric, etc), and the Drill Doctor DD750X works for larger drills from about #40 on up to 3/4". Sharpening a tiny #60 drill can be done free hand with an eye loupe and an Arkansas stone, but it might take half an hour of trial and error to get a point that will cut. The True point takes all the guess work out of it. The True Point is a jig that holds the drill at the correct 59° angle to make a 118° point plus guides the Arkansas or fine diamond hone in a curve to make a better relief profile and also indexes the drill exactly 180° to sharpen both cutting edges so that they both cut equally. Having both edges cut equally is very important for very small drills because it helps prevent breaking them by reducing the torque they require to cut plus balancing the torque distribution at the tip so one cutting edge doesn't take all the guff and break off. The drill is sharpened by hand with an Arkansas stone or fine diamond honing plate. The DD750X model Drill Doctor is a power tool that has an electric motor driven high speed diamond grinding wheel that will sharpen drills up to 3/4”. It holds the drill at a range of angles from about 67° to about 55° to make points from 134° to 110° so hard or soft materials can be drilled more efficiently. Hard steels cut better with a 135° drill point and soft steels cut better with a 110° point. The diamond wheels are replaceable and come in fine grit for small drills and coarse grit for large drills. I have been using my Drill Doctor several times a week for three years now and haven't needed to replace the diamond wheels yet. The Drill Doctor will also back-cut the drill edges so they come together at a lot smaller point than normal so hard metal will drill with lighter pressure.
rl635