Production drilling large holes

[Cooler]

I am producing a product that calls for a 2-1/4" diameter hole be drilled through a 3/4" thick piece of red oak.

I am trying to pick up efficiency.

I started with a bi-metal hole saw. It cut reasonably fast but left a hole that required extensive sanding to make "furniture ready".

I got a carbide tipped forstner bit. It drilled slowly, generated huge amounts of chips, but did a nice job leaving the edges nearly "furniture ready".

There are carbide tipped hole saws out there. Will that give me a smooth finish?

Also is there a hole saw system out there that allows you to remove the slug quicker and easier than the Lenox system? Getting the slugs out is a chore and slows down the operation.

[Routerman]

Drilling a hole that big is not the fastest operation west of the Pecos.
If cosmetics are critical, I'd drill all the holes as fast as possible to ~2-2-/1/8.
Probably with a medium priced Forstner.
Then finish templet rout with a solid carbide straight bit.

[Cooler]

Routerman said:

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Drilling a hole that big is not the fastest operation west of the Pecos.
If cosmetics are critical, I'd drill all the holes as fast as possible to ~2-2-/1/8.
Probably with a medium priced Forstner.
Then finish templet rout with a solid carbide straight bit.

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I don't think that will enhance my productivity very much. I have the carbide tipped forstner bit that gives good results (but spits up huge amounts of big chips that have to be swept away after each hole. The hole saw creates much less (but it is dust).

I was really hoping that there was a carbide tipped hole saw out there that would give good clean cuts. Preferably with a system that allows easy removal of the slug.

I should also note that the slowest my current drill press will run is 600 rpm. I will probably burn that out pretty quickly as it is a hobby grade table top model. But it still works and I won't replace it until it craps out.

[blackhat]

If you want to speed up the slug removal, switch the pilot bit to a stubby 1" spade bit and make a hook to reach in and pull the slug. A couple holes in the flor of the saw cup will allow a rod to push the slug out instead of prying from the sides.

[Paul K. Murphy]

I apologize in advance for a slight hijack.
I can tell you how to improve the performance of your hole saw. I'm not really sure if a hole saw is the best way to go in this circumstance, but, here goes.
Drill at least one (possibly more) holes inside the footprint of the unwanted plug. Say, for example, at the 12 O'Clock position, there was a 1/2" hole. The hole should be drilled so that the circumference of each circle meets in one point.
The reason hole saws perform so poorly is that they do not extract sawdust from the cut. There isn't a place for the sawdust to go after you have buried the teeth. The 1/2" hole I described gives the dust a place to go. This allows the saw to actually cut wood, rather than swim around in a slurry of unwanted sawdust.

[Cooler]

Paul K. Murphy said:

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I apologize in advance for a slight hijack.
I can tell you how to improve the performance of your hole saw. I'm not really sure if a hole saw is the best way to go in this circumstance, but, here goes.
Drill at least one (possibly more) holes inside the footprint of the unwanted plug. Say, for example, at the 12 O'Clock position, there was a 1/2" hole. The hole should be drilled so that the circumference of each circle meets in one point.
The reason hole saws perform so poorly is that they do not extract sawdust from the cut. There isn't a place for the sawdust to go after you have buried the teeth. The 1/2" hole I described gives the dust a place to go. This allows the saw to actually cut wood, rather than swim around in a slurry of unwanted sawdust.

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I've done that in the past. I got sloppy with the second hole and it ended up slightly outside the cut and ruined the piece. And it is a two step method I was hoping to avoid.

The carbide tipped hole saws seem to have a wider cut than the steel cup and i thought that would resolve the saw dust issue. There are several systems out there, but I was hoping someone would know if it gives a good finish. All the reviews I've seen have to do with cutting through cinder block, plaster and drywall. All stuff that electricians and plumbers would do. So the ratings are not at all applicable to my situation.

But the second hole trick, and it need not be very large to work, makes for much faster hole saw work. Great when cutting through 2 x 8 joists where a little outside the hole does not matter, but I have to go really slow on the second hole to be sure I don't "color outside the lines" and that offsets much of the advantage.

So far the carbide tipped forstner bit is the better option. Sanding the inside is time consuming even with a flapper sander. And there are no slugs to remove. But it really strains my little drill press and the quantity of chips is beyond belief.

[JGrout]

I drill 2" holes a dozen in one sitting for a cabinet fixture I make

the 2" forstner bit is the cleanest and quickest hole I can get short of CNC machining or two step cutting. The chip collection is pretty rudimentary, I zip tie the hose of a shop vac to the drill post pointed toward the drill that grabs 80% of the chips as they exit.


Holes saws as stated are prone to loading issues and the solution is not easy to overcome and keep the progress in a reasonable amount of time.



Your drill speed is too fast also, that means an upgrade to fix.

Joe

[Routerman]

Not a problem to drill faster & better.
And without a secondary operation.
But you will not do it at 600rpm or for <$150.
A cutter known as a 3 wing carbide
can drill a clean walled through or blind 2.25" hole in one shot but not at 600.
You'll burn up the tool at that speed. 100 or less rpm is more reasonable.
Moreover, no matter what the drilling tool, you have to vacuum out the swarf as it's created,
not after you have a BF or 2 spread all over your press. Safe Drilling, no matter how you skin this.
upper left

[axlotal]

I don't know what "production" means in this context. It can't be much if it is one man and a hobby class single spindle drill press. But assuming you have hundreds of honkin' big holes in that oak:

stick with the carbide Forstner bit.
Consider it a disposable and replace it when it gets dull.
It is the only clean cutting hole device you can use in a DP and it is the fastest tool you can get if you are just using a DP
Make a fixture that you can get the work in and out of really fast
Maybe make it so you can stack the pieces and cut several holes in one setup


If it's thousands upon thousands of holes; you may be forced to consider building a purpose built CNC with hundreds of fixtures and multiple cutting heads


To deal with the shavings :
Move the DP out of doors or as near to a garage door as you can.

Use a leaf blower or rake to herd the shavings into a pile and compost them like leaves with a little bit of Urea for nitrogen.

I wouldn't bother trying to rig up a shop vac to deal with the shavings as you'll just be emptying the 30 gallon tank every half hour.

[Cooler]

axlotal said:

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I don't know what "production" means in this context. It can't be much if it is one man and a hobby class single spindle drill press. But assuming you have hundreds of honkin' big holes in that oak:

stick with the carbide Forstner bit.
Consider it a disposable and replace it when it gets dull.
It is the only clean cutting hole device you can use in a DP and it is the fastest tool you can get if you are just using a DP
Make a fixture that you can get the work in and out of really fast
Maybe make it so you can stack the pieces and cut several holes in one setup


If it's thousands upon thousands of holes; you may be forced to consider building a purpose built CNC with hundreds of fixtures and multiple cutting heads


To deal with the shavings :
Move the DP out of doors or as near to a garage door as you can.

Use a leaf blower or rake to herd the shavings into a pile and compost them like leaves with a little bit of Urea for nitrogen.

I wouldn't bother trying to rig up a shop vac to deal with the shavings as you'll just be emptying the 30 gallon tank every half hour.

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I'm doing lots of 25. I don't know if the product will take off. If it does I will get a bigger drill press. I am currently using a carbide forstner bit.

I did not know the recommended speed. I will see if I can fit a larger pulley on my drill press to slow things down. If the product takes off I will be buying some more substantial equipment. To date the drill press is one of my lesser used pieces of equipment. Not since I've had to drill these 2-1/4" holes has it gotten much use. If I get another it will be a free standing unit. Sears has some for $400.00 to $600.00 when on sale.

Thanks for the advice everyone. I have dust collection. I will run a hose to the drill press. I'm certain it will have enough pull to get rid of the chips.

Cooler