What's a "Forstner" drill bit? - Chevelle Tech
Performance Our High Performance area

 11Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 17 (permalink) Old Jun 26th, 20, 11:34 AM Thread Starter
Lifetime Premium Member
 
Join Date: Oct 2005
Location: CT,USA
Posts: 13,430
What's a "Forstner" drill bit?

I've never seen these before, and they sure are inexpensive compared to other "high-carbon" steel drill bits. Are these for boring holes in wood only, or are they good for metals too?

70 Chevelle SS clone (632 CI powered).
BillyGman is offline  
Sponsored Links
Advertisement
 
post #2 of 17 (permalink) Old Jun 26th, 20, 11:59 AM
Senior Tech Team
 
Join Date: Feb 2005
Location: Michigan
Posts: 8,171
Re: What's a "Forstner" drill bit?

Not for metal. They are for drilling flat bottomed holes in wood.

Tighten it till it strips and back it off a quarter turn.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


67

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


70 (SOLD)

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Alwhite00 is online now  
post #3 of 17 (permalink) Old Jun 26th, 20, 12:13 PM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 62,897
Garage
Re: What's a "Forstner" drill bit?

https://www.wttool.com/index/page/pr...CABEgKGwPD_BwE

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
 
post #4 of 17 (permalink) Old Jun 26th, 20, 1:42 PM
Tech Team
Greg
 
Join Date: Jun 2017
Location: SF Bay Area, California
Posts: 76
Garage
Re: What's a "Forstner" drill bit?

Quote:
Originally Posted by Alwhite00 View Post
Not for metal. They are for drilling flat bottomed holes in wood.
I've also used them for acrylic plastic. But should not be used on metal, as you said.

Sent from my ONEPLUS A5010 using Tapatalk

Why do they call it rush hour when nothing moves?
howsad4me is offline  
post #5 of 17 (permalink) Old Jun 26th, 20, 2:07 PM Thread Starter
Lifetime Premium Member
 
Join Date: Oct 2005
Location: CT,USA
Posts: 13,430
Re: What's a "Forstner" drill bit?

ok thanks guys. The website I saw them on didn't specify what they were for. At those cheap prices I kinda suspected they weren't for metal.

70 Chevelle SS clone (632 CI powered).
BillyGman is offline  
post #6 of 17 (permalink) Old Jun 26th, 20, 3:53 PM
Tech Team
John
 
Join Date: Dec 2012
Location: 55.916, 10.733
Posts: 645
Re: What's a "Forstner" drill bit?

A good forstner bit will cut aluminum with no problem, slow speed is the key. Same goes for carbide saw blades. I cut aluminum with my table saw all the time.
68-13427 likes this.
SSJohn is offline  
post #7 of 17 (permalink) Old Jun 26th, 20, 8:28 PM
Tech Team
Mike
 
Join Date: Aug 2010
Location: Missouri
Posts: 332
Re: What's a "Forstner" drill bit?

Quote:
Originally Posted by SSJohn View Post
A good forstner bit will cut aluminum with no problem, slow speed is the key. Same goes for carbide saw blades. I cut aluminum with my table saw all the time.
I agree.

I've made a lot of counterbore holes in aluminum with those bits.
69ZL1 is offline  
post #8 of 17 (permalink) Old Jun 27th, 20, 2:08 AM Thread Starter
Lifetime Premium Member
 
Join Date: Oct 2005
Location: CT,USA
Posts: 13,430
Re: What's a "Forstner" drill bit?

Quote:
Originally Posted by SSJohn View Post
A good forstner bit will cut aluminum with no problem, slow speed is the key. Same goes for carbide saw blades. I cut aluminum with my table saw all the time.
Quote:
Originally Posted by 69ZL1 View Post
I agree.

I've made a lot of counterbore holes in aluminum with those bits.
Well guys, FWIW, these are the ones I saw. I don't know if they're all created equal, but I originally was considering using one of these on aluminum.....

https://www.rockler.com/rockler-high...gths-3-8-shank

70 Chevelle SS clone (632 CI powered).
BillyGman is offline  
post #9 of 17 (permalink) Old Jun 27th, 20, 8:19 AM
Lifetime Premium Member
rick
 
Join Date: Jul 2012
Location: st. pete. , fla
Posts: 6,685
Garage
Re: What's a "Forstner" drill bit?

Those would probably have no problem cutting into an aluminum intake, I'd use a slow speed and cutting oil like Tap Magic or something similar, maybe drill a pilot hole first with a regular steel bit
BillyGman likes this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
shovelrick is offline  
post #10 of 17 (permalink) Old Jun 27th, 20, 11:01 PM Thread Starter
Lifetime Premium Member
 
Join Date: Oct 2005
Location: CT,USA
Posts: 13,430
Re: What's a "Forstner" drill bit?

Quote:
Originally Posted by shovelrick View Post
Those would probably have no problem cutting into an aluminum intake, I'd use a slow speed and cutting oil like Tap Magic or something similar, maybe drill a pilot hole first with a regular steel bit
I hear ya Rick. Cutting oil, yes. I don't think they make Tap Magic anymore. I think it was banned by the EPA. We used to have it in the shop I work in, but that was a long time ago. That stuff would practically melt away aluminum.

I believe it was the same stuff that Dry cleaners used to use to clean clothes, (Trichorethane 1.1.1. ). If the Tap Magic brand name is still around, I bet it isn't the same stuff at all.
shovelrick likes this.

70 Chevelle SS clone (632 CI powered).
BillyGman is offline  
post #11 of 17 (permalink) Old Jun 28th, 20, 1:42 AM
Lifetime Premium Member
Kyle
 
Join Date: Apr 2005
Location: Tacoma,WA
Posts: 1,875
Re: What's a "Forstner" drill bit?

I use forstner bits all the time when I build stair systems. As others have stated, they are for drilling holes in wood and are 10x better than using a paddle pit when you are shooting for a certain depth. Plus, they are very accurate. I use 1 1/2” bits and put a 1 1/2” plug in and give it a light tap and it’s almost flush. Paddle bits suck for doing finish work.

They will work great on aluminum at a very slow speed and use oil to prevent galling.
steelcomp likes this.

Kyle

1987 corvette LeMons race car.
1968 Malibu, ZZ4, M-21 4 speed, 9" ford 3.73:1 Detroit truetrac posi



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


justkyle is offline  
post #12 of 17 (permalink) Old Jun 28th, 20, 1:44 AM
Lifetime Premium Member
Kyle
 
Join Date: Apr 2005
Location: Tacoma,WA
Posts: 1,875
Re: What's a "Forstner" drill bit?

Quote:
Originally Posted by shovelrick View Post
Those would probably have no problem cutting into an aluminum intake, I'd use a slow speed and cutting oil like Tap Magic or something similar, maybe drill a pilot hole first with a regular steel bit
Forstner bits will make their own pilot hole. All you need is a little tap with a fine punch to center it.
shovelrick and DragRac69 like this.

Kyle

1987 corvette LeMons race car.
1968 Malibu, ZZ4, M-21 4 speed, 9" ford 3.73:1 Detroit truetrac posi



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


justkyle is offline  
post #13 of 17 (permalink) Old Jul 7th, 20, 12:16 PM
Senior Tech Team
Scott Foxwell
 
Join Date: Dec 2008
Location: N/E Tennessee
Posts: 4,001
Re: What's a "Forstner" drill bit?

They were made for cutting holes in wood that were intended to be plugged. They leave a nice clean edge and a very round hole.

FOXWELL MOTORSPORTS

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
steelcomp is offline  
post #14 of 17 (permalink) Old Jul 7th, 20, 2:08 PM
Lifetime Premium Member
Mike
 
Join Date: May 2006
Location: Kapaa Kauai Hawaii
Posts: 9,491
Re: What's a "Forstner" drill bit?

Billy, aluminum cuts well with WD 40, or even kerosene. Amazon had a mis priced sale on Tap Magic once, and I got a case of the small squirt cans for the single can price.

YOU KNOW YOU HAVE THE POWER..... AND IF YOU USE THAT POWER BAD THINGS ARE GOING TO HAPPEN!!
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


Mike Lewis street 572

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Cale Aronson
Black Magic clutches

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Cam by UDHarold
Menscer Motorsports

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

TRZ

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

CEAutoelectric

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
aukai is offline  
post #15 of 17 (permalink) Old Jul 7th, 20, 2:10 PM
Senior Tech Team
 
Join Date: Feb 2005
Location: Michigan
Posts: 8,171
Re: What's a "Forstner" drill bit?

Tap Magic | Cutting Fluid | A Division of the Steco Corporation

Tighten it till it strips and back it off a quarter turn.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


67

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


70 (SOLD)

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Alwhite00 is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome