Brad point bits. What are the advantages? Especially for dowels?

[luvmytoolz]

The only time for me personally I've found brad points to be crucial is when drilling pen blanks, they definitely shine there.

 

[SilviaS7]

I have Montana bits, they're great, I use mine exclusively for woodworking and have cheaper DeWalt bits for anything that is a little abusive.

BTW, FOG, I am so disappointed... all the dads and granddads here, and nobody made the joke that this thread should have been titled, "Brad point bits.  What's the point?"  ;D

 

[rmhinden]

I have been buying these brad point bits:

Fuller Brad Points Drill Bits

also made in the USA.

Bob

 

[Packard]

I have been buying these brad point bits:

Fuller Brad Points Drill Bits

also made in the USA.

Bob

Something to consider if the Montana bits disappoint.  But about twice the price, so I will give the Montana bits a real workout before I would consider the Fullers.

 

[Cheese]

I have been buying these brad point bits:

Fuller Brad Points Drill Bits

also made in the USA.

Bob

I've also started to purchase the Fuller brad point bits to replace the Colt TwinLand bits I got on sale. I originally purchased the Colt bits because they were made in Germany, were made from chrome-vanadium steel and the TwinLand design helped guide the drill bit. 

What I didn't realize is that when drilling very hard wood such as hard maple or Jatoba, the TwinLand design creates extra friction and the drill bit becomes extremely hot and if you're not careful, the drill bit becomes so hot it will start to turn blue and burn the hole. That's not been an issue with the Fuller drill bits.

Here's the TwinLand design and then a 3/8" burned drill bit.

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[attachimg=2]

 

[Crazyraceguy]

[member=44099]Cheese[/member] I would assume that extra friction area of the Twin-Land bits would be a problem in a drill press especially. Since it is going straight by design, the extra contact is unnecessary. The best use-case for those has to be free-hand drilling, where the rub rib could help keep the bit straight, when your hand doesn't.

Kind of like hole saws. It always bugs me to see someone use a hole saw in a drill press. That perfect alignment makes the teeth all travel in exactly the same path. All that does is pack up the dust in the tiny gullets and cause heat and binding. The teeth cannot clear and even pulling out does not solve the problem, gravity keeps the debris in the kerf.
I see hole saws as the drilling equivalent of reciprocating saws. Rough/crude demo tools that can be wobbled around some to open the path and help clean out the dust.
If you need a nice (big) hole, use a Forstner bit.

I only own a couple of hole saws, mostly for grommet holes in countertops.
I don't really do that much drilling, other than screw/countersink holes, pocket screw holes, and those in access panels. Those are all regular twist drills.
I use the DeWalt bullet points for most other things, though I do have an import set of twist drills in all of the fractional sizes, for random stuff. The fractional Brad points are only by 1/8" increments and metric from 3mm up to 10mm. My Forstners are in 1/8" increments too, but I think there are 1/16" increments available?

 

[Cheese]

[member=44099]Cheese[/member] I would assume that extra friction area of the Twin-Land bits would be a problem in a drill press especially. Since it is going straight by design, the extra contact is unnecessary. The best use-case for those has to be free-hand drilling, where the rub rib could help keep the bit straight, when your hand doesn't.

Kind of like hole saws. It always bugs me to see someone use a hole saw in a drill press.

Ya, you're exactly right I was installing/pegging flooring & stair treads in hard maple/Jatoba and needed to drill the holes perfectly vertical so everything was done on a drill press.  [tongue]

As far as the hole saw goes...I always use a drill press.  [smile]  [popcorn]

[attachimg=1]

[attachimg=2]

[attachimg=3]

 

[Packard]

If it (the drill bit) gets hot enough the heat will start to anneal the steel and make it soft.  This will only occur at the very ends of the cutting edges.  They heat up faster because there is very little mass to absorb the heat.

I worry about that very issue on my Blum hinge drilling jig.  To reduce the likelihood of overheating the 35mm Forster bit, I pull back on the drill several times during the drilling process.  The bit remains spinning freely in the air, thus shedding some heat.

Of course I have no way to measure the effectiveness of this process (or the heat levels the bit endures) but it makes me feel like I am taking care.

The bit does get too hot to touch.  Constant exposure to 400 degrees F., will anneal the steel incrementally.

 

[Packard]

If it (the drill bit) gets hot enough the heat will start to anneal the steel and make it soft.  This will only occur at the very ends of the cutting edges.  They heat up faster because there is very little mass to absorb the heat.

I worry about that very issue on my Blum hinge drilling jig.  To reduce the likelihood of overheating the 35mm Forster bit, I pull back on the drill several times during the drilling process.  The bit remains spinning freely in the air, thus shedding some heat.

Of course I have no way to measure the effectiveness of this process (or the heat levels the bit endures) but it makes me feel like I am taking care.

The bit does get too hot to touch.  Constant exposure to 400 degrees F., will anneal the steel incrementally.

Note: “Soft” is a relative term.  It might draw down the hardness from file-hard to knife blade-hard.  Still very hard, but relatively softer and more susceptible to wear.  If you let a drill bit to get excessively hot, it can bur away some of the carbon content and the steel will break down.  Gettin a bit that how will almost certainly make it glow orange or even yellow as it grows in heat.

 

[Michael Kellough]

In my experience the main cause of overheating when drilling is too slow a feed rate. When drilling with a Forstner bit I start the hole slowly to get the best entrance then feed aggressively and quickly withdraw the bit to clear the chips. Forstner bits are more susceptible to softening from heat than bits made of high speed steel.

The second cause is letting the flutes get packed with chips. The bit will also stop advancing when full so when the feed rate slows I extract and clear.

 

[Packard]

In my experience the main cause of overheating when drilling is too slow a feed rate. When drilling with a Forstner bit I start the hole slowly to get the best entrance then feed aggressively and quickly withdraw the bit to clear the chips. Forstner bits are more susceptible to softening from heat than bits made of high speed steel.

The second cause is letting the flutes get packed with chips. The bit will also stop advancing when full so when the feed rate slows I extract and clear.

That all makes sense to me.  The one issue I have with the Blum jig is that there is no provision for the wood shavings to escape.  I have to use a screw driver to prize the shavings out and a vacuum to clean them up. 

Other than that, an excellent (but crazy-expensive) jig.  (About $350.00 now.)

This image shows the void that gets filled with shavings.

 

[Crazyraceguy]

At least Forstner bits provide a means to extract the chips from the hole. Hole saws are generally terrible at that. The older "Professional" line of Craftsman hole saws has 2 very large gaps in the teeth, which help some, but not nearly as good as Forstner bits. I think those openings were really there to help with plug removal, but accidental benefits are still nice.

Most everyone I see runs them both way too fast, which overheats them.

[member=44099]Cheese[/member] I'm certainly not going to pick at you over it, if it works for you, so be it. The job looks great.

 

[Michael Kellough]

When I release that Blum drilling jig, before I move it I position a vac hose just behind it off the edge of the door then slowly slide the jig over the edge. Gets most of the debris.

 

[Packard]

When I release that Blum drilling jig, before I move it I position a vac hose just behind it off the edge of the door then slowly slide the jig over the edge. Gets most of the debris.

I do that as well, using a vacuum hose attached to my shop dust collection.  Dust collection moves a great deal more air than a vacuum, but under less suction.  It removes the loose shavings, but not the ones pressed against the flat edge.  I will try it with a shop vac next time.  I am building three cabinet doors tomorrow, as soon as the glue dries, I’ll give it a try.

Do you find that th 35mm bit gets hot?  The two smaller ones are not an issue, they cut fast (I use the knock-in hinges, so I use those smaller bits each time).

 

[Mini Me]

[member=44099]Cheese[/member] I would assume that extra friction area of the Twin-Land bits would be a problem in a drill press especially. Since it is going straight by design, the extra contact is unnecessary. The best use-case for those has to be free-hand drilling, where the rub rib could help keep the bit straight, when your hand doesn't.

Kind of like hole saws. It always bugs me to see someone use a hole saw in a drill press. That perfect alignment makes the teeth all travel in exactly the same path. All that does is pack up the dust in the tiny gullets and cause heat and binding. The teeth cannot clear and even pulling out does not solve the problem, gravity keeps the debris in the kerf.
I see hole saws as the drilling equivalent of reciprocating saws. Rough/crude demo tools that can be wobbled around some to open the path and help clean out the dust.
If you need a nice (big) hole, use a Forstner bit.

I only own a couple of hole saws, mostly for grommet holes in countertops.
I don't really do that much drilling, other than screw/countersink holes, pocket screw holes, and those in access panels. Those are all regular twist drills.
I use the DeWalt bullet points for most other things, though I do have an import set of twist drills in all of the fractional sizes, for random stuff. The fractional Brad points are only by 1/8" increments and metric from 3mm up to 10mm. My Forstners are in 1/8" increments too, but I think there are 1/16" increments available?

I have twin land Colt bits (RIP) and have not experienced any visible overheating problems but I do generally run it at lower speeds. When using hole saws in a drill press or even hand held drill two holes with a drill bit on the inside perimeter of the hole saw size and the debris will be cleared as the hole saw is used.

 

[Packard]

I’ve used a hole saw and put the drop off to use.  If you drill a hoe off center in the circular disc, you can use it as a cam to lock stock in position on the MFT top.  The location of the off center hole is crucial, but luckily you can try several on the same disc. 

You can’t do that with a forstner bit.

 

[Packard]

Note:  Using my memory to cite “facts” may not be the best way to present them.  I was able to fish the original packaging from my shop trash and I am posting that now.  I don’t think it affects the many valuable posts here, but I feel it is best that I come clean.  [eek]

 

[ChuckM]

Technically correct and no longer misleading:

[attachimg=1]

 

[Michael Kellough]

Also note that a “spur bit” isn’t exactly the same as a brad point drill.
The spur bit center point is more robust (more like the bullet point) and is less susceptible to following misleading end grain.

 

[Crazyraceguy]

When using hole saws in a drill press or even hand held drill two holes with a drill bit on the inside perimeter of the hole saw size and the debris will be cleared as the hole saw is used.

That does indeed help to clear the swarf out of the path of the saw, but it's an extra step. For a hole or two, not so bad, more than that it gets old.
The other limitation to holesaws is that they only work for through-holes.