Drill bits

[tvrgeek]

As I may have mentioned, I have had miserable luck sharpening drill bits, be it by hand, old General jig, or Drill Dr. They just don't cut like a factory bit. Add to that, there is really no reason not to be using split-points, which are a little tricky to grind. ( and a Drill Dr. that does split points is expensive)

I recently saw a video on bit sharpening machines. Not a single one could match a factory fresh bit ( chisel point) So, what are the factories doing differently? Sure, small bits I buy by the pack and don't worry about it, but from about 1/4 up, they get darn right pricey. From what I see, the Drill Dr. is a bit rough and I never seem to get the relief sufficient. And yes, been through the instructions a dozen times, so I sold my machine. I have been getting rid of everything I don't use to declutter and be able to fine what I do use.

 

[bob vaughan]

A couple decades back I made the necessary sacrifices to get a Darex M-5 for metal working twist drills. It does a fantastic job for split point drills. When I put a new bit in service, the first thing I'll do is sharpen that bit. Compared to the edges the M-5 will do, new factory twist drills are dull. I even sprung for the accessory chuck to take up to 3/4" bits.
I see the M-5 rigs for sale from time to time but since they have been discontinued, the are in high demand.

 

[Bernhard]

...what Bob said. I have the same Darex M-5 (lucky buy from a shop going out of business). Even though the M-5 is discontinued, Darex still supports it, also a very good company wuth excellent customer service. Before I had the Darex, I tried all the usual suspects and none of them worked. There is one sharpener that seems to work quite well and is not nearly as expensive as a Darex: drill bit sharpening machine in End Mill Sharpener Online Shopping | VEVOR US , This machine is sold under a bunch of different brand names and has good reviews. Just based on the design (using ER collets to hold the bit), it should provide good results.

 

[coastiebob]

I bought a Drill Doctors 750x and it's good for what I do
I use 9/16 and ⅝ bits and it sharpens them

 

[chris_goris]

Are you drilling wood? Forstener bits are the way to go if you are. Using them in a drill press or hand drill? Ive had about 2 sets of twist drill bits in my shop for 30 years and havent sharpened any, ever, nor have I ever felt the need.

 

[Wilsoncb]

@tvrgeek great post, I have the same issue.

@Bernhard @bob vaughan do you think Darnex M-5 works good because of the setup or the grinding wheels used? What grinding wheel are you using.

 

[Bernhard]

@tvrgeek great post, I have the same issue.

@Bernhard @bob vaughan do you think Darnex M-5 works good because of the setup or the grinding wheels used? What grinding wheel are you using.

I think it is the design and built quality of the machine. It uses a regular white grinding wheel, not sure what it is off the to[p of my head. Once this grinding wheel is used up, I plan to replace with a CBN and a diamond wheel.

 

[tvrgeek]

Are you drilling wood? Forstener bits are the way to go if you are. Using them in a drill press or hand drill? Ive had about 2 sets of twist drill bits in my shop for 30 years and havent sharpened any, ever, nor have I ever felt the need.

I do a lot of metal. Yea, I have Forstner, spur, spade, adjustable hole, masonry, and twist in fractional, number, metric, HSS and cobalt. I found the DD won't even cut wood. It is only the HSS twist drills, chisel and split, that I have given up on.

I'll watch for an M5, but it looks like they go for a couple of grand, so I guess I keep buying bits.

 

[junquecol]

I use the old fashion General to sharpen bits over 1/2". Most of my bits in that size range were bought as trash and refurbished to like new. Takes some learning as to how to index bits. Would like to mount a grinder verical, so I'm not sharpening on side of the wheel. Anything smaller than 1/2" goes to the DD 750. Originally bought the 750 because it includes chuck for left handed bits, which our son the mechanic uses a lot of to remove broken bolts. When I first got the 750, went by a pawn shop and bought a coffee can full of bits for about five bucks. Spent the evenings for next couple weeks bringing them back to life

 

[coastiebob]

Are you drilling wood? Forstener bits are the way to go if you are. Using them in a drill press or hand drill? Ive had about 2 sets of twist drill bits in my shop for 30 years and havent sharpened any, ever, nor have I ever felt the need.

No I'm a sign fabricator (along with woodworking)...need them for the aluminum and steel

 

[bob vaughan]

@tvrgeek great post, I have the same issue.

@Bernhard @bob vaughan do you think Darnex M-5 works good because of the setup or the grinding wheels used? What grinding wheel are you using.

When I bought my M5. it came with either diamond or CBN wheels. I've used both and I can't tell the difference. I think the M4 came with regular grinding wheels.
The design is quite clever and incredibly versatile for the various tip configurations needed for industrial non-woodworking applications. Predictably, the build quality isn't all that great compared to the sharpeners costing five times as much.

I need to adjust my original post. I did indeed get the accessory pack that allows sharpening bits up to 1-1/4" diameter.

I called the Darex people inquiring about the sharpener. They were so confident that they said they would ship me the unit and only charge my card after I told them I was satisfied. Otherwise I could ship it back at no charge. After initialy fiddling with the M5 I realized that I didn't want to let that unit get out of my shop.

I keep things set for a 135º split point. You set the bit in the chuck and grind the initial angle on the left hand wheel then move the chuck to the right hand wheel to split the point.

 

[chris_goris]

No I'm a sign fabricator (along with woodworking)...need them for the aluminum and steel

Sorry, I thought this was a woodworking site. I cant imagine anyone using a 1/2" twist drill in wood unless youre just roughing (very) in for a jig or something to house a through bolt, maybe. Twist drills are the complete wrong application for wood. They are designed for metal to eject chips, there is no cutting edge on the diameter to shear wood grain to avoid tearout.

 

[bob vaughan]

Sorry, I thought this was a woodworking site. I cant imagine anyone using a 1/2" twist drill in wood unless youre just roughing (very) in for a jig or something to house a through bolt, maybe. Twist drills are the complete wrong application for wood. They are designed for metal to eject chips, there is no cutting edge on the diameter to shear wood grain to avoid tearout.

Well said.

Modifying a twist drill for woodworking takes a bit of work but can be done. In years back it could be done with a file but modern twist drills are mostly high speed steel so a file doesn't work all that well so a toolroom grinding wheel like the Norton A60 OBNA2 is an easy to do it.

From a 1939 Delta booklet:



And don't get me started on the horrible pocket hole drill bits.


My own modification on the left. Factory on the right.

 

[mdbuntyn]

Sorry, I thought this was a woodworking site.

Some of us do a bit of metal fabrication in service of our woodworking

 

[bob vaughan]

Good point. Conspicuously missing from Scott's original post was the type of material he was sharpening his drill bits for.

 

[tvrgeek]

Of course I use "wood" bits for wood. But I do a lot of fixturing, modification, and tool making along with all it takes to maintain my house and my other hobby, currently restoring a Triumph Stag. I use cheap twist drills for screw holes and use, when I stoop to a pocket hole, I their not so great stepped twist drill. Woodworkers need to be metal workers as we have to make and maintain our tools.

Actually, there are various angles to which a twist drill can be ground. Shallow to steep, some better for metal, some for wood, some for plastics. Then split vs chisel point. I gather chisel point are only best for very small drills and cheap larger ones. Notice how Bob ground the tip above into a steeper angle along with adding a spur.

Might I remind, most wood stepped/countersink drills have a twist drill as their core. And yea, it takes a lot to dull a wood bit*. A lot easier in cast iron, in hot rolled, cold rolled, and gasp, stainless and tempered for which I have a set of cobalt drills. Not coated, cobalt. I have my carbide and diamond drills for tile. Side note: The "Diablo lasts 10 times as long" drilling the tile I used in my bath project could manage about five holes before being done. Slow, wet. Really tough tile. 10 times longer than a wet noodle I guess.

It seems a Darex is upwards of a grand. I can buy a lot of bits for a grand.

Rant time: Something I noticed. I keep a set of the 1/4 inch snap in drills for houshold and crude work. Easy and cheap, but I did notice, many of the bits are not concentric with the 1/4 cast base, so they wobble. Cheap is cheap. So for anything that matters, a smooth, or machined shank is the way to go. The pathetic hand chucks in a lot of portable tools do not grip very well, so the flat-sided shanks are preferable. I have spun bits in my drills in just wood. Give me my keyed chucks back! I put a mid-price keyless on my DP. Gave up, when back to a mid priced keyed. Maybe a $1000 keyless would work, but out of my league.


*Well, the cheap Forsner bits from Horrible Freight did get dull drilling only wood, but I have a good set too. Kind of hard to sharpen. MDF and particle board are hard on drills.

 

[pop-pop]

One of the best small chucks ever was on B&D 1/4” drills from post WW2. It used an Allen wrench driving an eccentric for the final tightening . The drill bits just did not slip. That design never caught on.

 

[Wilsoncb]

@tvrgeek I can relate to much of what you’re saying. I have a rant as well. Colt Brad point bits from Taylor tools are absolute crap. They were cheap but I thought, all these come from China anyway so may as well not pay much. Well you get what you pay for. It’s the first time I’ve seen a drill bit so out of round I thought maybe my DP was broken. 5/16” drill bit can make a 3/8” hole.

 

[tvrgeek]

@tvrgeek I can relate to much of what you’re saying. I have a rant as well. Colt Brad point bits from Taylor tools are absolute crap. They were cheap but I thought, all these come from China anyway so may as well not pay much. Well you get what you pay for. It’s the first time I’ve seen a drill bit so out of round I thought maybe my DP was broken. 5/16” drill bit can make a 3/8” hole.

Yea, with Taylor you do have to watch. He goes for value, not necessarily top quality. Deals on PEC seconds are great, and with some work, his spokeshaves and rebate planes are fine. I snagged the deal on my 3M sander from him.