Forstner bits

I wanted to counterbore several 3/4" holes about an eighth of an inch deep in 3/4" plywood. I bought a set of Forstner bits at Lowe's, chucked the 3/4" one in a corded 1/2" drill, and made a practice swipe at a piece of pine. It was incredibly hard going. I really had to lean on it. I did manage to get down to about an eighth of an inch, both in the pine and eventually in the plywood, but I don't know what it would have taken to drill all the way through. I tried several diameters and they were all the same.

Did I get a crappy set of bits, or are they not meant to be used in a hand drill? I don't have a drill press to make a comparison.

Reply to
Richard Evans
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It's just about impossible to hold your hand drill at exactly straight up and down anda forstner has to be absolutely straight to cut. I've been able to do it by slightly altering the angle a little bit, all the way around the compass.

With a hand drill it's a royal pain. You can get better results with one of those hand drill guide jig things that essentially make your hand drill into a little mobile drill press but it's still a royal pain. Sometimes it's the only way, though.

And yes, those lowe's bits probably aren't all that sharp to begin with. My sister gave me a set one Christmas. It's nice having all those sizes but every time I have to drill a lot of holes I end up burning out the bit and buying one that costs about as much as the set.

Still, it really is nice to have all those sizes and they work if I don't push them too hard. :-)

Reply to
else24

Get a self feeding bit, they have a small screw thread to pull the bit through. I just bored some 2 1/2" holes through railroad ties, and it pulled through faster than I wanted. I used my Harbor Freight copy of the Milwaukee Hole Hog, one of the best HF tools I have bought. Terrific torque. I use self feeding augers for boring holes for electrical wiring, using the HF sideways in between studs, and you don't even have to press, just touch it to the wood and hold on.

Reply to
DT

I think you already know the answer since you typed the above. Even a cheap set at Woodcraft is sharp enough for a few holes.

Reply to
Edwin Pawlowski

Was it turning in the right direction? Are you sure?

John Martin

Reply to
John Martin

Reply to
mapdude

Yes, and yes.

Reply to
Richard Evans

I found myself having to make a 1.5" to 2" adapter ring tonight, and used a forstner bit and hole saw to do it, in a scrap piece of full 3/4" birch ply. Since I had the forstner bit out and I remembered your post, I chucked it up in my dewalt drill afterwards.

I clamped a scrap 2x4 stud cutoff to the bench, and in about 60 seconds (and much swearing/trying to keep the bit perpendicular) I managed to make just over a 1/8" impression.

By comparision, drilling completely through the ply took about 30 seconds at 580rpm on the drill press. (Probably could have done it faster, but I just kept even pressure and backed out occasionally for the waste.)

So.. my answer is "No, they ain't ment to be used in a drill."

(For reference, I was using a Rockler steel - not carbon - forstner bit.)

Jas> John Mart>

Reply to
Jason

Richard,

I don't wish to seem contrary to other posters here... but a forstner style bit can easily be used in a hand drill. And I said "forstner style" because there are a few configurations of bits on the market commonly referred to as "forstner". My guess is that your bits are not sharp. I purchased a set of Chiwanese made bits from Harbour Freight (24 bits in a wooden box for 20 bucks) that couldn't cut cheese. That is, until I sharpened every last one of 'em. You can sharpen them with a fine toothed round file and a fine grit stone (for the circumference). Diamond hones and India slip stones work well too. And lots of patience!!! (especially for the small ones). After sharpening, they cut like butter. Except not for long. The steel is low quality so they don't hold an edge very well. Also, use a slow speed to keep friction to a minimum (variable speed drill) and try to stay as perpendicular as possible.

To really appreciate how well a "forstner" bit can cut in a hand drill, invest in a Freud bit. They're sharp right out'a the box.

But there's no denying that a drill press works best.

Cheers.

Michael

Reply to
toolman946 via CraftKB.com

They're not meant to be used in a hand-held drill only because there is no central point to locate the bit. If you don't hold them perfectly straight - and sometimes even if you do - they can skate all over the workpiece.

It shouldn't take any great amount of force to get them to cut.

I presume you're referring to a steel bit as opposed to a "carbide" one.

John Martin

Reply to
John Martin

"Jason" wrote

Sharpen the one you have, or buy yourself a better bit.

I routinely use forstner bits in hand drills with no problem ... everything from drilling holes in kitchen cabinets for electrical/plumbing pathways during installation, to more delicate jobs like drilling depressions for figure 8 fasteners in the edge of table aprons.

Reply to
Swingman

"John Martin" wrote

Then your not talking about a "Forstner" bit ... proper Forstner bits indeed have a point, which is called the "gimlet point", as named by the man who invented the bit.

Reply to
Swingman

Yes, exactly right on both counts. I ment carbide, and yes, my problem was keeping the bit from skating around.

As I said originally, I stopped after a minute. However, once I got past the 1/8th inch mark I had enough of a "go" to where I could have continued on, since the bit was sharp enough. I didn't though, since I was already "job done" on the drill press.

Jason Buckler Marietta, GA

Reply to
Jason

I bought some High Speed Steel wood bits from an online vendor of some repute (the name of which escapes me) and was impressed when removing the plastic coating each tip had been dipped in as I sliced my finger on the bit as I removed the coating.

They worked wonders in the wood, too!

I bought HFT "Forstner" bits and another set from one of those mobile vendor "Tool Sales" and one from Bosch (at Lowes). The Bosch was more expensive (35mm?) than was the first set of six from HFT and the larger set (to 2.5") from the mobile vendor.

I use a drill press - mostly, But I have used them in "electric drills" from time to time with decent results - certainly nothing to complain about.

Having said that, I wonder if anyone has any experience with a HSS set from Hartville Tools, or another vendor as I would love to buy a set as sharp as the bits first referenced, above, in the Forstner style.

PS, the Irwin Auger Bits with Three (3) flutes are a joy to use. In my

14.4VDC Sears drill *shorter than my 19.2VDC model, with less torque/ power" I was easily able to "punch" holes through the floor joits to run my wiring "out of the way." They have that screw starter point and pull themselves through leaving a nice clean hole, If you hit a nail enroute, however, they suffer significantly!
Reply to
Hoosierpopi

Oh, I most definitely am. The Forstners I use are almost all by Connecticut Valley, BGI or PM - companies that have been making them for well over 100 years. Machine shanks and bit brace shanks. Some have small points that extend below the rim, some don't. On none of them does the center point extend more than about 1/16" below the rim. Of those that don't, some never did - it's not a re-sharpening mistake. The Forstner bits are meant to be guided by their rims, not their center points.

I even checked a couple of really big Forstners I have - 2-5/8" and

2-3/4", 3/4" shanks, about a foot long. Conn Valley, but they don't show them in their product list anymore. Original factory grinds. Each has a central point, but it's flat-topped and about 1/4" wide - it's certainly not intended to guide the bit.

With the brace bits, one trick is to turn them backward at first to get the rim to dig in slightly before you start to cut.

I've got no idea what was in Benjamin Forstner's original patents - all I know is that the companies that have been making them from the beginning have been making them without center points large enough to significantly guide them. They do help in getting them on the center mark, but that's about it. If you had a gimlet point, you wouldn't get a flat-bottomed hole, would you?

John Martin

Reply to
John Martin

Don't be so naive. Just because someone calls/sells a bit as a "forstner", does not make it so.

Once again, a true "Forstner" bit, BY DESIGN, has a point to guide the center of the initial drilling. This is an inarguable FACT, deal with it.

Reply to
Swingman

Not in the original patent, but others dated later do have the point. Ben sure liked drill bits!

(I hope the link works)

MikeB

Reply to
bq340

"Just because someone calls/sells a bit as a "forstner", does not make it so." I agree, but then I am so naive. If you bother re-reading my post, however, you'll see that the companies I mentioned were making Forstner bits well over 100 years ago, under license from Benjamin Forstner - the inventor. That's not a Forstner bit?

Someone else has already posted a link to Benjamin Forstner's patent - # 115148, dated August 15, 1874. Rather than make you search for it, though, here is a quote from it:

"The circular band serves to guide the bit accurately in its movement, and also give the hole that is bored a smooth and perfect finish. By its employment the gimlet-point may be dispensed with, and as the cutting lips do not project beyond its horizontal plane, it follows that the wood is not cut beyond the line operated upon by the circular cutting-edge of the band."

And that, Swingman, is an inarguable FACT, with which you must deal.

John Martin

Reply to
John Martin

"John Martin" wrote

I stand corrected ... mea culpa.

Reply to
Swingman

"bq340" Not in the original patent, but others dated later do have the point.

He called it a "gimlet point" and it was added specifically to aid in centering the bit for drilling.

Reply to
Swingman

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