The Rodding Roundtable
Motorhead Message Central => Rodder's Roundtable => Topic started by: enjenjo on April 16, 2020, 10:49:16 PM
When you have a choice what brand drill bits do you prefer? What alloy? HSS? TiN? Co?
HSS and spend money, the cheap ones have no cobalt. I have a hunch that most of the Ti coated bits are garbage with gold paint . A good check is to look at the factory sharpening job . If they are sharpened poorly that is probably only one of their problems . The problem with HSS drill bits is that there is no mention of the cobalt content ,square machining tool bits have the cobalt % printed on them . The more cobalt the better .
Interesting. I have bought a variety of drill bits over the last couple years from HB and the box stores. The sharpness is hit and miss and they all seem to catch in the hole just before going through - mostly on sheet metal. Some of that may be due to the age of my cordless Craftsman hand drills...don't know I try to do the bulk of my hole drilling in the drill press but can't bring chassis work to it. I used to use nut-serts a lot but am starting .to find wonky threads in them.
I do a lot of drilling and tapping for 10-32 and find that the drill bits for that size wear out quickly.
I used to buy all my drill bits from Reid Tool, a local supplier that had the best, and my wife worked there so I got a great discount. It was a family owned business that was sold off 6 or 7 years ago to British owners. They've screwed it up and made it difficult to buy from them.
I haven't done a study but my feeling is that China has flooded us with drill bits that drill good several times and then give up the ghost. They don't last long but they aren't cheap either....
A few years ago, my dad asked me to bring my Drill Doctor to his house and sharpen some of his bits. He had a Craftsman drill index with bits up to 1/2". While we were having a cold beverage and I was sharpening the bits he told me that it was the first time the bits had been sharpened and that he had bought them the year before I was born. I have that index and bits today. This last year I inherited another also identical set from my uncles estate. I will try to do a comparison of those bits and some of my recent purchases.
On You tube this fellow Project Farm has tested drill bit brands. He is purty thorough on his tests.
Project Farm (https://www.youtube.com/watch?v=xgQeSrsAXgE)
too slow of an rpm can wear out a small drill bit as the pressure you apply may produce a heavy chip load , dulling the bit prematurely . if you calculate 320/diameter of bit in decimal inches =RPM you should be good . a 1/4" drill bit HSS should be spun at 1280 rpm to drill properly ,use a little cutting oil. The chip coming off the bit should not change the color of the metal while going through the metal except towards the very end of the cut when it is already exiting the other side. I am not sure if cordless drills can spin fast enough to drill properly I have never checked the rpm . I am guilty of drilling too slow with small bits as it is sometimes a pain to change rpm on a drill press for one or two holes . When sharpening , always dip the bit in water after a short grind . If the bit starts to turn even a light straw color you have ground too long and have taken away its ability to maintain a sharp edge. If the bit goes brown or blue when sharpening you are best to slowly grind the bit to a flat end and start over .
My good bits are a set of hss that I bought from Snap On 40+ years ago. They still have them on the truck, the black ones. Great bits.
Now how about any opinions on the Drill Dr.
I tell my students if the bit came out of a plastic case its good for drilling wood and is probably just carbon steel.
Never used a drill doctor but have used a drill sharpener of a different brand . Consistent results . When you cant keep a bit sharp its not usually the edge that is the problem , its the amount of clearance .
Quote from: "chimp koose"Never used a drill doctor but have used a drill sharpener of a different brand . Consistent results . When you cant keep a bit sharp its not usually the edge that is the problem , its the amount of clearance .
I bought a Drill Doctor several years ago, and very happy with the results it gets
I have a Drill Doctor for several years. I am happy with it.
Likely it needs a new stone cutter gizmo in it by now. I would likely just buy the late design Drill Doc
The Project Farm guy on Youtube.. Liked the Drill Doctor unit. He had the late design Drill Doctor 750X model
I used to have to hand sharpen bits as large as 2" and larger. It was a relief when we got the sharpener we had . Used to always try to drill holes for welders rather than lend them a bit . It took less time to drill the hole than sharpen the bit when they were done :lol: